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Easter crafts, any besides eggs? Are there any home crafts regarding Easter besides eggs? Easter will be coming fairly soon calendar-wise after all. <Q> Making an Easter bonnet is a fairly common activity for young children round here (encouraged by schools, nurseries). <S> Decorated planters for spring bulbs (e.g. daffodils) are quite popular gifts, requiring both craft and gardening. <S> Closely related to eggs is baskets to put them in. <A> There are many motifs besides eggs that are closely related to Easter: <S> the Easter bunny and carrots the lamb, sometimes in combination with other christian symbols the chick or chicken spring flowers like daffodils or forsythia (depending on your location) <S> You could stitch these motifs on an embroidery project like a table cloth, a bag or sachet that is used to wrap gifts or as a picture framed by an embroidery hoop. <S> You could just as well stamp these motives instead of stitching them, if you prefer paint rather than yarn. <S> Crafting and sending personal greeting cards is a nice tradition, too. <A> Blogs will be the best place to find an extensive lists of Easter crafts, but I have enumerated a small list of options that I find to be unique and aesthetic. <S> FOR ADULTS & OLDER KIDS 1.) <S> Resurrection Garden . <S> This project can be highly customized and created with real or fake plants or plants grown from seeds as parts of a longer project meant to be enjoyed and cared for over the Easter season. <S> (Think moss, succulents, quick seeding grass or flowers). <S> 2.) <S> Needle Felted Creatures . <S> For a more artistic adult, needle felting allows for crafting in 3 dimensions and is well-suited for creating small animals associated with Easter like bunnies or chicks. <S> 3.) <S> Hand Embroidery . <S> These can be left in the hoop and displayed as-is or used in as a decorative embellishment in other fabric based crafts. <S> FOR KIDS <S> 1.) <S> Easter Egg Bath Bombs . <S> With adult supervision, even younger kids can enjoy mixing up their favorite colors and packing them into molds to create vibrant stripes or other patterns to watch dissolve in their next bath. <S> 2.) <S> Felt Finger Puppets . <S> Finger puppets can be simple or highly intricate. <S> For kids, stick with basic shapes. <S> This craft works well as a teaching tool for introducing the basics of sewing as needles for sewing felt are not very sharp and are larger, making them easier for young ones to hold. <S> For very young kids, drawing details with marker will be easier than stitching them in. <S> 3.) <S> Edible Easter Nests . <S> Kids can have fun getting a little messy shaping these cereal bars into edible nests and placing tiny candy eggs inside.
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For the detail-oriented, hand embroidery can be used to create an endless variety of Easter or Spring designs.
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Can I make handmade invitation cards on a tight budget? I'm planning on making DIY cards for invitations to my sister's 8th birthday party. I want it to be special so I decided to do everything myself. But I'm really on a tight budget right now, and so I need advice on what materials I can use which will not exceed my allowance. <Q> If you have plain white paper that is thick enough to make invitations cards, you can do the rest with free materials. <S> Cut and fold the paper into cards, then neatly write the invitation. <S> Cut decorative forms like hearts, lollipops, bonbons or Hello Kitty heads and glue them onto the cards. <S> You can cut these forms out of colorfull sheets of ads or catalogs or anything colorfull you have lying around. <S> Catalogs for clothes or furniture often have single items printed very big (like a carpet, windows drapes or a t-shirt). <S> The only disadvantage is that the pages are often so thin you can see the backside through. <S> An alternative is wrapping paper. <S> If it's the birthday of your little sister, you probably have a gift to wrap for her. <S> Use some scraps of that paper to decorate the cards. <S> Pieces of gift wrap ribbons add a special flair. <S> Depending on what you have lying around at home, you can also repurpose things like confetti, glitter, small beads or golden makeup powder do decorate the cards. <S> Take care not to add too much to the card. <S> 1 - 3 decorations are enough to make the card look special. <A> To save on the budget you could cut patterns into potato halves and use an ink or paint soaked sponge as the ink pad. <S> Either way they would let you decorate a number of matching cards quickly and easily. <A> My hint is how I made my wedding invitations: I used pressed flowers. <S> As Elmy explained above, fold cardstock or construction paper into invitation cards and write the invitations carefully. <S> Pick the nicest blooms from some local flowers (with permission from the gardener, of course!) <S> and immediately press for a few days by placing them carefully between layers of newspaper, and weighting the paper with books. <S> When they are dry, use school glue to decorate the cards. <S> To protect the flowers, you can either place them in the envelopes with a piece of waxed paper held over the flowers, or alternatively, put the flowers on the inside of the card rather than the outside. <S> Each invitation will be a one of a kind work of art!
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You could use an ink pad and decorative rubber stamps to make your cards as well, they are available in most art or craft stores.
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Sewing machine: how to sew a straight line left ⇆ right (instead of front ⇆ back)? Instead of reinventing the wheel, I'm looking for advice to use a (basic) sewing machine to sew a line from right to left (or the other way). The feed dog of my sewing machine (and most machines) is made to stitch a line front to back I know that I will need to cover the feed dog (using a cover plate), then I will need to slide the fabric manually from right to left with the steadiest speed (for aesthetic: to keep a regular space between the stitches). If you tried it with a normal sewing machine, I'll be glad to collect your advice! (Does anyone knows what this is called? It's difficult to Google it without knowing the term.) (That would be useful for many things like drawing a long line following a long tube such as a pant leg) I don't see how to cover or deactivate the feeding dog so it won't interfere.(@Elmy). You just need a feed dog cover plate : <Q> You are describing the technique used for "free motion quilting. <S> Your machine may come with a "darning foot" or a "free motion quilting" foot which should be used when doing this type of stitching to hold the fabric down while the needle is in the fabric, then lifts when the needle comes up so you can move the fabric. <A> You need to change your perspective to solve this problem. <S> Short of breaking your sewing machine, I don't see how to cover or deactivate the feeding dog so it won't interfere. <S> Usually, you can remove a cover or compartment right under the bobbin case to expose the "sleeve arm" or "free arm". <S> Then you align your fabric in a way that the seam lies on top of the arm and the opposite end below the arm. <S> You should pin the seam very well for this. <S> Simply start sewing the normal way. <S> The left side of the tube can move forward freely, but the fabric will bunch up on the right side ( <S> In a certain way, the fabric will actually move left to right, but you still sew from the back to the front). <S> Keep sewing and bunching the fabric up, until you've sewn at least half of the entire length. <S> As a general advice, ignore the bunched up fabric as much as possible. <S> Just push it out of your way as best as you can. <S> the only important thing is to keep the seam aligned with the feeding dog. <S> If the tube you're trying to sew is still to long for this method, I'm afraid you'll need to use a professional sewing machine like this one. <A> it's actually much easier than I thought (if you don't mind about spacing). <S> But I guess there are some tricks I don't know. <S> What I did is put the "feed dog cover plate" <S> (it disable the feed dog) <S> so you could saw in any direction) <S> pass the "tube" through the machine <S> It's pretty easy a low speed <S> (what I find difficult is to keep a low and constant speed, using the "foot speed controller". <S> It would have been easier with a preset speed). <S> Basically the more you pull the fabric, and the slower the needle goes, the bigger are the spaces between stitches. <S> if you are not sure, run the machine manually (by turning the wheel) for a few stitches. <S> It's slow but still much quicker than sewing by hand, and you can set spacing exactly where you want. <S> It more difficult with the motor on, but not impossible if you manage to have a constant slow speed. <S> I also tried on the tricky part to saw without the presser foot (I put it up) which worked well. <S> (I tried nearly 2x1meter <S> a kind of jeans fabric, I did not break the needle without really caring about it) <S> Here is a video : <S> Edit : <S> A precious info from @Linda's answer: <S> a "darning foot" or a "free motion quilting" foot which should be used when doing this type of stitching to hold the fabric down while the needle is in the fabric, then lifts when the needle comes up <S> so you can move the fabric <A> For perfect topstitching on the side seams of pants specifically, one answer could be to sew and topstitch the side seams earlier in the order of construction, before a tube is created. <S> This is not the usual order of sewing pants, but can help in making beautifully perfect sideseam topstitching... <S> Here is an Angela Kane video demonstrating this idea.
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just pull back slowly the fabric to sew a straight line " On some sewing machines, you can lower the feed dogs instead of covering them. Then you can repeat the same process from the other side if the bunched up fabric hinders you too much.
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Is there a method for setting up my palette on axes by Hue, Value, and Intensity? I'm a very technical person, even with painting.I wanted to set up my palette like a graph so that it does not become messy, no matter what color I want to mix. This is not an issue if I was only concerned with hue and value (e.g. hue is the X axis and value the Y). However, intensity would seem to require a third axis. Are there any established methods for laying out the three "axes" of color on a 2D palette? <Q> Alternately just use a different area of the pallet for tints or saturations depending on your preference. <S> Other than starting with a cool and warm version of the primary colors I have never heard of a standardized pallet or one that seeks to capture the entire available spectrum. <S> Each artist I know has their own layout and each painting calls for different colors. <S> I think you would be wasting paint and time trying to create a pallet like the color picker from Photoshop, and even in digital painting applications there are multiple areas for choosing by hue, tone or saturation. <S> You just need to find what works for your style through experimentation. <A> What you want to achieve is impossible on a 2D surface and probably wouldn't help you much. <S> What you describe is pretty much the YUV color sheme. <S> It's usually represented as a 3D cone or cylinder, with the purest colors ( H ue) spread around the perimeter, medium grey (the least S aturated color) at the center and black & white (the colors of most and least L uminance) at the highest and lowest point, respectively. <S> The 2 problems that make it impossible to recreate something similar on a palette are: <S> The number of variables. <S> If you insist on having 3 variables (hue, saturation, luminance) you can only represent them on 3 axes. <S> Real paint doesn't mix like that. <S> The color cone suggests that mixing opposite colors yields grey, which is wrong. <S> You could argue that mixing opposite colors yields the one right between them on the perimeter, but that's wrong, too. <S> I dare you to try mixing any 2 colors and create such a vibrant violet or green. <S> It's impossible. <S> Have a look at these rows of mixed colors (and the corresponding blog post ): <S> On a computer screen, mixing yellow and blue yields green. <S> In reality, you get a muddy, ugly brown. <S> Instead of trying to recreate a digital palette in real paint, you should invest in a color wheel that displays color mixes as well, like this one: <S> Then lay your colors on the palette according to the hues you want to mix and the effects you want to create in your painting. <A> The simplest answer I can think of is two use two palletes, or divide your pallette into two sections, and use them for seperate things. <S> For example, you could have one pallete that is for the hue and saturation and then have white and black on the separate pallete. <S> When you get the desired hue and saturation you move it to the white pallet and mix the value. <S> You could organize these in circles or lines, it doesn't matter, what matters is organizing it in a way that makes sense and works for you. <S> A very helpful tool for this is a numbered grey scale, in addition to the color wheel. <S> Many illustrators begin each piece in greyscale, to make sure the image reads properly, and then match the value of the colors they mix to the value of the greyscale drawing accordingly. <S> It's a great way to break down your coloring process and achieve consistency. <S> Which is why I would recommend using your second pallets just for value.
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You could mix your fully saturated base hues on one axis, run the desaturated mixes at a right angle to those and if there is room go off on a diagonal with tints of the colors you are using.
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Advice on weaving/looming machine I am looking to create woven patches as a hobby. I was playing a bit with embroidery patches, but I want to see the difference between the two. My question is: what would be a starting weaving/looming machine for home use that does not require an entire room to store it? <Q> You can make a very basic small loom out of a single piece of thick cardboard. <S> This is ideal for small weaving, around 10cm - 20cm size. <S> You can use it to make small patches (or even small pouches/bags). <S> I learned to do this at primary/elementary school, so it is very accessible. <S> This gives you a loom that you can use for tapestry weaving. <S> I will explain the basics of how you would start weaving with such a loom, but details of how to weave are outside the scope of the question. <S> To make a simple patch: Take a piece of cardboard a little bigger (1 cm in each dimension) than the size of the patch you want to make. <S> Cut notches 0.5 cm long, 0.5 cm apart on two opposite edges. <S> Now you have a loom! <S> To set up the loom, you need to add the "warp" threads, which form the basis of the fabric. <S> I would recommend something like knitting yarn for this. <S> Arrange the loom so that the notches are top and bottom. <S> Take some yarn and wind it a couple of times around the top-left notch, ending with the long end of the thread at the back. <S> (This is just to keep the thread secure while you weave. <S> At the end you will remove it from the cardboard <S> and you can weave in the end of this thread.) <S> Bring the thread from back to front through the top-left notch. <S> Then take it down to the bottom left notch and thread it through to the back. <S> Bring the yarn to the front through the second notch on the bottom. <S> Bring it to the next notch at the top, round the back and so on... <S> Keep going until you have filled all the notches. <S> Wind a couple of times around the right. <S> Now you can take your "weft" thread and weave it through under and over starting on the lower right and going through to the lower left. <S> You can use something like a pencil to press the threads firmly down to the bottom. <S> Then weave back from left to right, alternating the over and under threads. <S> Press the thread firmly down again. <S> Keep going until you have filled the card. <S> Then you can remove it from the loom, weave in the ends, and you have a piece of woven fabric. <A> There are small portable looms in a couple of different styles. <S> One that my knitting group really likes is the Schacht Cricket Loom . <S> It's what's called a rigid heddle loom - <S> it weaves much like the big room-sized looms you're thinking of. <S> They have 2 sizes, a 10" width and a 15" width. <S> Very easy to use & put away too. <S> Sold on Amazon, Etsy, and most yarn shops have or can get them for you easily. <S> You might find a used one on Ravelry, but they go fast, if you can find one. <S> People tend to keep them :) <S> If you have a local yarn shop, try there first.. <S> they will often have beginner loom classes available. <A> Look for an Inkle Loom : Lots of hits on YouTube. <S> It was designed for weaving straps, but is usable for work up to <S> about 4" wide. <A> for thousands or millions of years, earth-kind have woven fibers. <S> by hand, with a hand-held tool, or a tool typically used in the shade of a tree. <S> Not everyone has had a dedicated "loom room". <S> Videos are limitless online about weaving. <S> A loom can be made with 4 boards, a box of nails, and fiber of some kind. <S> Commercial yarn, handspun yarn either animal or vegetable, even forageable fiber. <S> Again use a search engine. <S> I'm a working fiber artist. <S> I am NOT LACKING IN TOOLS. <S> My collection dates from the 1700s to the 2000s. <S> Stash is an addiction. <S> I am happy to clarify, just ask. <S> I'm not trying to be vague, but adhering to non-commercial reference rules of the forum.
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Used Frame/tapestry, tabletop, folding floor looms are readily available for sale.
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Advice for making wired jewelry charm I need to make the following symbol from crafting metal wire (5 mm) for a pendant. (It is a combination of zodiac symbols, for anyone who's curious.) How can I join the wire in between the places where the lines are overlapping ( the blue encircled part ), as well as where the two horns of the Aries symbol are emerging from the branch ( the green encircled part )? Could you suggest a successful method other than soldering ? Any other advice would be appreciated too, as I'm new to this. Thanks! <Q> so maybe something like that? <S> I just used 2 pieces of bent and shaped 18 gauged wire, hammered out to make the pieces sit more flat, and then used 2 thin pieces of beading wire to anchor the 2 pieces together <A> Other than using wire, you could create the design using precious metal clay such as silver metal clay and setting it in a kiln <S> or you can use a blow torch and fire-proof mat. <S> Fine silver metal clay results in objects containing 99.9% pure silver, which is suitable for enameling. <A> I'm sorry, but I have my doubts you could ever create this design with metal wires. <S> I would have suggested using either epoxy resin or a similar glue or a slightly flexible power adhesive, but there are several problems: <S> The overlap in the blue circle is very thin (fragile), but has to withstand high leverage forces because of the long structure attached to it. <S> You need to join both symbols in the bottom margin of the design as well to make it more stable. <S> You need to roughen the surface of the metal to give the adhesive something to grab onto. <S> This can be done with a nail file or a knife, but it might bend the wires too much. <S> Epoxy is a strong adhesive, but it's inflexible and no more solid than plastic, <S> so it breaks easily if it's too thin. <S> A flexible power adhesive doesn't break, but in general it needs a bigger surface area to be able to hold objects together. <S> Many power adhesives have to be "activated" by applying a force, which would bend your pendant. <S> The adhesive will show. <S> There's not a chance you can apply so little adhesive that it won't be squeezed out but still hold both pieces together. <S> In fact, the safest solution would probably be to completely coat the juncture in resin. <S> Then everything is connected from the beginning and you don't have to solder / glue pieces together. <S> Or you could encase the whole design in resin (like a mosquito in amber). <S> A google search for "resin jewelry" yields many different approaches (with and without molds) and products (resins and accessories).
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Instead of trying to glue wires together, I think you could try sawing the pattern out of a solid metal plate.
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How do I clean dried brushes? I have a bunch of brushes with dried paint and glue. I've tried to clean them up but they're still hard. What medium is best to restore my brushes? <Q> You need a Brush Cleaner and Restorer formulated for this task. <S> There are a few of these available, only in art supply stores; you'll want to check with the ones around you to see what you can purchase. <S> If you are in the United States, Winsor & Newton makes a widely available product I have used with great results; it's formulated for dried acrylic and oil paints, but I have also used it to dissolve away dried latex (house) paint, as well as years-long set dry varnishes. <S> With this product, you'll let the brush soak up the solution, checking periodically to monitor the progress. <S> In a low quality brush, it may end up damaging it by damaging any glues holding the bristles in place in the ferrule, but at the point you're using a restorer on a brush, it's typically ruined anyway, so there's no risk in trying. <S> In my experience, I've only had one or two brushes lost this way out of dozens. <S> Unfortunately, this particular product is not available outside of the United States, but other companies do make similar products that you'll be able to find by asking your friendly local art supply shop. <S> The employees there should be able to recommend a product to you with which they're familiar. <S> Ultimately, the best option is to avoid needing a restorer in the first place; take proper care of your brushes, cleaning them right away instead of letting paints dry in them. <S> Avoid getting paint up into the ferrule, and dry them bristles down so paint and water don't soak down into the ferrule and cause damage. <A> I used paint thinner to wash and clean the brush first. <S> And after a while, rinsed with kerosene. <S> That worked and saved my brushes. <A> As an alternative, I have used a low-fume paint stripper to smother the brushes in, and then wrap in clingwrap, and let soak for several hours. <S> (I have not tried paint thinnners: this probably works better with oil paint than others. <S> Correct me if I am wrong.) <S> These may be off topic? <S> Happy to delete. <S> Restoring big brushes For the really stubborn bits, I've used a heat gun on a low setting (but only on bristle brushes, not plastic filament, as I found it melts <S> /deforms a plastic brush) will soften paint, especially plastic paint. <S> Then use a painter's comb or even a not-too-hard wire brush to remove paint. <S> You may need to go through the process more than once. <S> Cleaning artists oil bushes I use mineral turps, and then pure soap all the way down to the ferrule (push the brush into your soapy palm with warm water). <S> Lay on an old towel. <S> Then to help the brush keep its shape, coat it lightly in petroleum jelly. <S> I was using SARD wonder soap, but this leaves a residue. <A> If the brushes where used with acrylics then a soak in methylated spirits could help.
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I have also boiled brushes in water to soften the paint, and then scraped the paint out while soft.
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Any White Pens/Markers To Write Over Black Pens? I'm just getting into drawing, and I've made a sketch that I would like to fill in with black, red, and white pens (or markers). Since pen is permanent, though, I'm concerned that I might accidentally go a bit into the white parts with the black pen, ruining my drawing. Are there any white pens opaque enough that they could cover up mistakes I might make with the black pen? Thanks! <Q> I'd try a correction pen, there are now quite a lot to choose from. <S> This web page shows over a dozen kinds, and how opaque they are over black ink. <A> With a gel pen you will have more control over the lines you are creating, and can layer the markings as needed. <S> You might also enjoy using toned sketch paper in the future to play around with color values. <S> Here is an example of a quick, light pressure pass-over I did over black marker: <A> As I often write white text on top of black, I've been looking for a good white pen myself. <S> A correction pen doesn't do it for me, as the correction liquid doesn't stick very well. <S> The above-mentioned list of the best white ink pens seems like a good one. <S> However, the pen I ended up using is not on that list. <S> I've found that the " Edding 780 paint marker " fills (no pun intended) my needs. <S> It's a bit tricky to use, though, as it's easy to get too much liquid on the paper. <S> However, you'll get the hang of it. <S> Example of white on black, using the Edding 780:
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The best white ink pens Matching the paper colour and white pen might be tricky. Personally, for purposes such as you have listed, I use the uni-ball Signa white gel pen UM-153.
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How to dye or tint epoxy resin to produce translucent colors? A while ago I started crafting with epoxy resin. At first I just coated objects with clear resin, but recently I experimented with adding colors to it. I got nice results with powders (like glittery eye shadow) and a tiny bit of acrylic paint, but the result always loses the crystal clarity of the resin and gets somewhat cloudy or opaque. Next I bought transparent liquid glass paints in the hopes of mixing a more transparent but colorful resin. But to my surprise the color didn't mix with the resin at all and instead formed tiny flakes of (still liquid) color in the otherwise absolutely untinted resin. The effect is not bad, but not at all what I wanted. The glass color was water soluble, but probably not acrylic paint. It didn't say exactly what was in there on the packaging. My goal is to find something that will tint the resin but keep it translucent . If I go shopping in my craft store, how do I know which colors will mix with epoxy resin without having to buy a bunch of material for experimentation and ending up not using most of them? I'd appreciate general answers like "acrylic paints mix well but oil paints don't" instead of naming specific brands of paints that might not be available where I live. Since I got the best results with powders so far, I thought about buying high quality aquarelle paints (the solid blocks) and grinding them into powder, but I'm afraid the resin will get cloudy / opaque again and the money will be wasted. <Q> I've done this myself successfully with alcohol inks. <S> I use the ones from Ranger; Piñata's inks are likely to work as well. <S> Avoid Sharpies as they tend to fade and change color over to time. <S> I know this the hard way from having used them with polymer clay. :-( <A> You need something that's soluble in the liquid epoxy, or possibly a liquid that's miscible with it. <S> Water isn't miscible with epoxy, and if you try too hard to mix it you'll produce cloudiness. <S> I suspect that rules out acrylic paints as well. <S> Typical solvents don't dissolve epoxy; some may be miscible. <S> I'm not sure what the liquid phase is to investigate solubility. <S> Powders in general - unless you want a glitter or speckle effect - are unlikely to work however fine <S> you grind them. <S> There are specific dyes for epoxy ( Amazon example ), and this article also recommends alcohol inks - you can try making your own from old marker pens if you just want a test batch, though I'd use solvent-based markers to start with (such as Sharpies or cheap equivalents). <S> It would appear that alcohols mix with the solvents used in the epoxy components and in fact can apparently be used to thin epoxy . <S> You may have a little more trouble getting bubbles out than normal - a vacuum system is one way to help with this, but thinning should also help. <A> I found food coloring and acryllic paint to be the cheapest solutions, but certainly not the best. <S> The results remain inconsistent, even with 2 colors of the same package. <S> Following Chris' answer <S> and I usually cannot get alcohol based food colors where I live. <S> Then I tried sugar based (glucose syrup) food color gels and some of them work, some don't. <S> They have a low water content (less risk of cloudyness) and are easier to dispense. <S> I bought a package of 4 colors: one didn't mix evenly and caused speckles, one mixed very well but turned the resin into goop <S> (it still cured very hard). <S> I haven't tried the other 2 colors yet. <S> Another downside is that food colors are not meant to last long, so I suspect they will fade rather quickly if exposed to sunlight. <S> In my tests acryllic colors always mixed evenly with resin, but depending on the formular of the color, the result won't be translucent. <S> Expecially cheap paints contain chalk-like powders as fillers, which will be wisible in the resin. <S> Some paints changed colors quite drastically. <S> Here's a recent example of my castings and the same colors I used in the resin applied to paper: From left to right: <S> Blue food coloring. <S> Turned the resin into goop, but cured correctly. <S> The cloudyness is partially intended because I mixed a lot of tiny air bubbles into the goop. <S> Red food coloring (of the same package as 1) didn't mix evenly and caused speckles instead. <S> The color also changed in the resin. <S> Dark red acryllic paint. <S> As soon as I mixed it with resin, it turned into strawberry color. <S> When the resin was cured, it looked more like sunflower yellow. <S> Purple acryllic paint. <S> Mixed perfectly and didn't change color at all.
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I used alcohol based food colorings at first, but they are hard to dispense (too liquid, the resin turned cloudy because there was too much liquid compared to the amount of resin)
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Removing stitching from jacket I have a sports jacket from a team I used to play for. It's a very high quality jacket and I would like to continue wearing it, but the team name is written in large text across the upper-back of the jacket. I would like to remove this writing but I don't know how. It appears to be some kind of stitching but it's quite heavily coupled with the jacket material. Is it possible to remove this? See attached photos: Outside: Inside: I've tried cutting just a small section of one of the letters but I'm not sure if it's working properly. The stitching is so fine that there's still a thin white outline: Edit : Thanks everyone for the feedback! This strategy is working. It will take a very long time, but I will get there: <Q> If the jacket's fabric is synthetic do this more carefully than if it is cotton. <S> You might need to as a last step, go over it with a green kitchen scourer. <S> This will help remove fibres caught in the actual jacket fabric. <S> Again if synthetic, go gently. <A> This article lists several methods: https://www.wikihow.com/Remove-Embroidery Based on your pictures alone, I can’t tell quite what you mean about the outline. <S> The first step I would try is to use clear packing tape or masking tape to try to lift the bits of thread out. <A> A great technique for removing embroidery stitches popped up in a post on steemit https://steemit.com/needleworkmonday/@sheilamenher/fabrics-embroidery-and-designs-how-to-undo-embroidered-cap-without-detail <S> Fabrics, Embroidery and Designs - how to undo embroidered cap without detail @sheilamenher suggests using a shaver, brush and snippers. <S> Check it out, she provides instructions. <S> If you’ve already finished, please let us see the results. <S> Thanks!I also resteemed it on my blog @oceanmoon
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I’d be using tweezers to remove the final remaining thread with a magnifying glass if needed.
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How do you make a large grafitti stencil? When it comes to making large complex grafitti stencils (say, 2x2 meters or larger), how is it actually done? With small stencils with fine details I assume you can just get stiffer card to keep the small cut parts into place, but how do you keep a large stencil in place, so that all its cut details don't bend over and you don't get spray paint underneath them? Getting that size of a stiff cardboard would be expensive, heavy and difficult manage, so I doubt this is the best way to go about it. <Q> I have never done one, but for a large stencil, I would probably use a program like the free Paint software which comes with windows. <S> Start by changing your image size to enormous proportions calculated by multiplying your desired stencil size in inches by the dot-per-inch resolution of your printer. <S> In the software, zoom out until you can see the whole image space and then draw some light colored lines both across the page from edge to edge and from top to bottom. <S> The resulting grid is going to help you align the printed pages with each other later in the process. <S> Now paste in your desired image and stretch it to fit the image size. <S> ...then choose the print menu option. <S> On the option screen, turn off the "stretch to fit page" checkbox, then click the print button. <S> The program is going to do is subdivide your "too-big-for-a-page" graphic into a matrix of pages, each containing a portion of your image. <S> Cut off the unprinted borders and then line up the light colored lines until every page is in its' place. <S> Then tape them all together. <S> Next it is time to grab an exacto knife and remove the stencil parts where you want the paint to get through. <S> This is where the fine cut details are going get troublesome. <S> When your stencil is completed, turn it over and spray the back with a repositionable spray glue. <S> Make sure that all the details get enough glue on them to hold them onto the target surface without curling. <S> Once the glue is sticky, you can apply the stencil to the target surface, rub down all the edges and get to painting. <S> The spray glue will make up for the flimsiness of your stencil material and as long as you apply your paint lightly, the printer paper should suffice to keep the shielded areas paint free. <S> You may need to trace your applied stencil with your xacto knife after the paint dies, just to assure clean edges and unwanted peeling. <A> Use acetate or another form of plastic. <S> It is available in sheets or rolls for larger work. <S> Acetate is used as frisket, ie. <S> masks of various sizes, in airbrushing: it is clear (or sometimes translucent) so easy to trace over designs, cuts easily and thicker gauges are quite durable. <A> There is also corrugated plastic that could be stiffened by pushing wire through multiple pieces. <S> It's the same plastic used to make political signs. <S> In fact, post election time is a great time to collect used signs, so if you volunteer to collect them for a campaign, it could be a free source of material. <S> Then tape them on both sides at the seems, and that should provide additional stiffness.
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You might be able to glue (or tape) toothpicks (or thin wire) to the front of such details to strengthen them up a little.
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What Is "liquid white" that Bob Ross uses? I am doing some acrylic painting and watched some Bob Ross and he wets his canvas with "liquid white" and then paints on it while it's wet. Is this just acrylic white paint or is it gesso? I have tubes of white paint but it is so thick, definitely is not liquidy. <Q> It's a proprietary product from the Bob Ross company. <S> There's 3 such basecoats that the company makes: Liquid White, Liquid Black, Liquid clear. <S> The official description reads: <S> These basecoats (Liquid White/Black/Clear) allow us to actually blend and mix colors right on the canvas rather than working ourselves to death on the palette. <S> The Liquid White/Black/Clear can also be used to thin other colors for application over thicker paints. <S> The idea that a thin paint will stick to a thick paint is the basis for this entire technique. <S> Bob Ross's mentor, Bill Alexander, used a similar wet-on-wet technique using "magic white" as a base, or sometimes called "fluid white". <S> It seems entirely possible to make your own . <S> All you need to do is dilute titanium white with linseed oil. <S> Mix these together until you get a creamy consistency. <S> Some artists choose to mix equal parts of linseed oil and Turpenoid (or turpentine) to create this homemade medium. <S> So, linseed oil and titanium white (paint). <S> I would presume that the quality of the titanium white paint you use will affect the quality of the fluid white you make. <S> Since oil paint itself is generally made from linseed oil, pigment, and a binder/emulsifier to get the oil and pigment to "stick", it's likely feasible to make liquid white using pure pigment (titanium dioxide), linseed oil and something like white beeswax. <A> If you are using acrylics and not oils you could make something similar by thinning the base white with some gloss or semi-gloss medium and adding retarder. <S> You can adjust the liquidity with water. <S> The retarder would be key since the idea is to keep the ground wet while painting to be able to do the special Bob Ross techniques. <S> It will probably be needed to be mixed in with all the paints. <S> But I think Bob's method really calls for using oils. <S> You will have a much harder time with acrylics since they dry so much faster. <A> To make your own liquid white mix 1to 1 linseed oil and titanium white. <S> It's essential for the bob ross style of wet on wet painting which must be oil not acrylic just make sure you gesso the canvas before applying liquid white. <S> Hope this helps happy painting
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Liquid White is one of three Bob Ross Liquid Basecoats essential to the Bob Ross Wet-on-Wet Technique®.
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How to tell which way a colour is leaning? I'm only just now learning how to best estimate less or more vibrant colours and a large part of this seems to be to see what colours make up the secondary colours being used to mix. I'm finding it very difficult to tell which colours are made by which primaries. I would like to learn to tell how certain colours were mixed. I'm only using acrylic paint. Mostly these paints are for miniature painting, though I am sure the colour theories are the same as canvas painting ;) <Q> If you are looking to identify how a color is mixed first and foremost you need a color wheel which will show you where the color you want lands relative to the primaries. <S> Second, read up on color theory which will help you understand what is going on with that color wheel and how colors behave in general. <S> Once you have that down, here are some tips for keeping your mixed colors vibrant (or not): First... for any two colors you are mixing, be sure their value/lightness/tone are similar. <S> Use white to bring up the darker color to match the lightness of the lighter color. <S> Second... there are cool and warm versions of the primaries (Red, Yellow, Blue). <S> Cool colors tend towards blue, warm toward red. <S> If you mix a cool color with a warm color it will lose intensity, so mix cool with cool and warm with warm. <S> If you keep that in mind your mixtures will be cleaner. <S> As far as which colors produce which, look for a color wheel. <S> But you probably know the basic idea: Primaries lead to secondaries: <S> Red+Yellow = Orange <S> , Red+Blue = Purple/Violet, Yellow+Blue <S> = Green. <S> A secondary color mixed with its "opposite" (the primary -not- used to form it) will desaturate the color, eventually leading to a chromatic grey. <S> You should be able to get most any color you want using warm and cold primaries and white. <S> However if you know the secondary color you want to use start with that as a base pigment and "customize it" using small amounts of other colors. <S> That is where experimentation and experience come it. <S> Finally the concept of relative color comes in. <S> That is how one color is affected by the colors adjacent to it. <S> A color next to its complement will appear more intense as the contrast is greater. <S> Look up Joseph Albers who did extensive research into this. <S> The paint binder (acrylic, oil, ...) and scale of the work do not effect the color theory, however cheaper paints will have less pure pigments and therefore will have less intensity and will not handle mixing as well as professional grade paints. <A> The best way to learn how to mix complex colours is trial-and-error (in my opinion) - you see how colours turn out when you mix them while painting. <S> Keep in mind that acrylic does not support mixing as well as oil, tempera, watercolours and the like. <S> You could also analyse colours digitally - most graphic applications show what is the value of each primary colour a particular colour consists of. <S> It sounds like what you are looking for <S> but I don't think it will actually be very useful in practice. <A> The mixing is the first. <S> But a detailed color wheel would be very helpful in your process. <S> Ends by the means. <S> Color indexing is a science in itself. <S> One for paints, one for monitors, one for printing, inkjet, laser, 8+ color lithographic press. <S> Press Operations Markup departments have very sophisticated tools. <S> They must intermittently index their monitors to the pallets of the colors used by the print department (I've worked in this world). <S> You will have something you can use as a reference.
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Search for a color wheel, more details are better.
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What are good ways to spray paint a QR code on a footpath? The QR would be of a URL. The QR should be big enough like 4 A4 size papers. I though of cutting out the white boxes from a printed paper and spray on it but what about white dot islands. The precision needs to be good enough for a cell phone camera to detect it on the floor from standing distance. <Q> As mentioned by @Aloisdg : It is a Processing project and it is hosted on GitHub . <S> I tested it successfully on the pavement last year. <S> The pavement should be as slick as possible, though. <A> One approach to avoid the "island" problem could be to split the pattern into two stencils. <S> In each stencil only the holes of every other row are cut out. <S> First colour is applied to one of the stencils. <S> Then the stencil is exchanged and the colour is applied to the other stencil. <S> The weak point of this approach is that both stencil need to be placed at the same position. <A> What about a custom 3D printed embossing roller? <A> Instead of spraypaint - consider a "pavement sticker" or "footpath decal" that looks something like these. <S> And you can peel, stick, stomp and go, whereas paint takes at least a minute to be touch dry, risking people standing in your tag. <S> Paper won't last very long, which might be suitable for your needs. <S> A solid vinyl sticker could last up to years. <A> How about buying some grid-shaped welded wire metal mesh (commonly used for rabbit or chicken hutches), and using sticky tape to cover the squares you want to mask? <S> The wires would be thin enough that they wouldn't affect the scan, but strong enough to support isolated islands (much stronger than relying on tiny thin pieces of paper or card, which might break once they've been soaked in paint). <S> More importantly, it would be quicker to make than a hand-cut stencil <S> and you wouldn't need any expensive machines like a CNC router or 3D printer. <S> I recommend buying a flat sheet, the stuff that comes on a roll is usually twisted and won't lie flat. <A> Your islands can become insignificant by creating stencil like bridges to the more solidly founded segments. <S> A bridge of a few millimeters will bleed paint underneath but also will be small enough to be ignored by the QR software from a distance appropriate to the size of the code print. <S> If the few millimeters is excessive, hot glue applied to ordinary sewing thread in more locations (spider web?) will provide the support and almost assure bleed under.
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Here's a QR Code Stencil Generator which automatically generates thin bridges between islands. A brighter background colour will help it stand out much more than paint on a dingy pavement/sidewalk.
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Are there cases where we do not reverse stitch when sewing? I purchased a Singer Start 1304 Sewing Machine and am watching tutorials. In one of them, the lady demonstrates how to make a simple stitch. She goes a few stitches forward, a few stitches back, and continues stitching forward to the end. Then she goes a few stitches back, a few stitches forwards, and then cuts the fabric: https://youtu.be/ZC0Rhc_stfI?t=799 Later in the video, she demonstrates making a zig-zag stitch. However, she does not demonstrate going back a few stitches in the beginning, and going back few stitches in end: https://youtu.be/ZC0Rhc_stfI?t=900 Is this correct? If I decide to make a zig-zag stitch, should I only go forwards (and not backwards)? If so, then how do I ensure my zig-zag stitch does not come apart? <Q> To understand when to use backstitching, you need to understand the purpose of it in the first place. <S> It's not just "a thing that is done," it is a technique to "lock" the stitches in place on a seam. <S> To illustrate this for yourself, get some scrap fabric and stitch two pieces of it together along a straight edge. <S> Backstitch at one end, and just stitch off the edge on the other, trim the threads, then attempt to pull the fabric apart at the seam on both ends. <S> You'll see that the end you didn't backstitch will pull apart much more easily, while the end that is backstitched will hold more securely. <S> Cases where one would expect to backstitch the seams are primarily in structural areas; finishing <S> (top) stitching is also frequently backstitched to prevent the stitches from pulling out. <S> Similarly, you'll need to understand the purpose of the zigzag stitch. <S> In most cases for home sewing, the zigzag is used to help prevent fraying in woven fabrics; because it's not structural, there's minimal benefit to backstitching at either end, though you may find it easier on some fabrics that are more prone to fraying to start on the fabric and backstitch to the edge before going forward in order to help prevent the fabric from being pulled down through the throat plate. <S> For further information, I would highly recommend taking a beginning sewing course that can be tailored to your knowledge level. <S> Online tutorials and videos are only marginally useful when you don't have the basic experience expected from them. <A> You can back stitch a zigzag, but usually it’s not your stress stitch. <S> Also, you probably don’t want to back stitch when making gathers or basting. <S> Good habit to start with <S> but i have found many times that it’s unnecessary. <S> Like darts! <S> Have fun! <A> If fabrics are very delicate leaving long tails and tying the threads may be preferable to backstitching. <S> I also rarely backstitch if I am piecing quilt blocks or doing aplique work, but instead make sure that all stitches get sewn through or rows will be crossed with other stithcingto hold in place. <S> Never back stitch if you do not want to show extra bulk or more thread density in your stichline.
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Back stitching helps secure your stitch and is very useful.
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Prevent black colored pencil from blending into adjacent colors I'm new to drawing with colored pencils. I've drawn a bear that has a nose and mouth in black, but I can't quite figure out how or when to draw these black parts without accidentally grabbing some of the black color when filling in adjacent colors. I've tried doing the black at the end after the rest of the colors, but it doesn't seem to be as crisp compared to when I put the black down first. It might be hard to tell in the attached drawing, but the black from the nose and the line down to the mouth, as well as the dots on the chest, sort of got blended into the light tan/brown color, even though I tried to be super careful to avoid the black. My pencils are very sharp so I don't think that's the issue. I'm wondering if this is something that just comes with practice? Or can someone recommend a method or technique to applying crisp black lines to colored pencil drawings that prevents them from accidentally blending into the colors next to it. Btw, in case it makes a difference, I'm just using cheap Crayola pencils. <Q> Lots of good advice here, but you may also want to consider using a fixative to preserve the drawing as you work it. <S> It is nearly a requirement when working in pastels and I regularly use it to protect my graphite pencil drawings. <S> Look for workable spray fix in this case. <S> So you would draw the dark details <S> , spray fix them, then work the light areas and there will be no smudges. <S> The reverse is possible as well but sometimes the fix will darken light colors. <S> Fix is toxic so spray outside or have good ventilation. <A> I think the problem you're facing has more to do with the type of paper you use - especially its texture, or the 'tooth' of its surface. <S> If you want crisper lines, and hence less smudging, try drawing on smoother paper. <S> You can check the smoothness of paper simply by looking at it, and feeling it. <S> Make sure the paper is of good quality, or you might scratch the surface and get similar problems all the same. <S> For the quality you can look both at the price (which is a very decent indicator), and the weight (usually in g/m 2 ). <A> The layering could be causing the blending issue. <S> Instead of coloring in between the black dots with the brown on the chest, you can try coloring the lighter brown as the first layer, and then going over it with black. <S> Almost like an outline. <S> Short source with imagery: https://www.artistsnetwork.com/art-techniques/burnishing-with-colored-pencil-gary-greene/ <A> I’d suggest you buy one black Faber-Castell pencil. <S> They are beautiful to draw with. <S> And they have more pigment than the Crayolas <S> so the blacks will be blacker when you need them to be. <S> You will be surprised by the difference. <S> If you want to cheat, you could use a black fine liner, but you would need to experiment with this approach first on a separate drawing. <S> Alternatively you could use a black watercolour pencil, also by Faber-Castell (my favourites). <S> Good luck and keep going.
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Also consider that when the tips of the lighter colors aren't clean (having black on the tip from previous blending) they can give darker smudges on former layers, which might be causing the blending issue. Try out some different smoothnesses, but don't go for very smooth paper at first (like the ones that say they're "extra smooth" or "ultra smooth"), as it can have an unpleasant effect (it does for me, at least). Judging by the look of your work, I’d say you’re quite accomplished in drawing, so buying a quality pencil is an essential next step. Fixative, found in convenient to use spray cans although you can get it in liquid form, chemically bonds and protects the pigments applied to the paper.
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My Mod Podge coat is still sticky. What do I do? I painted some Jenga blocks and gave them a clear coat in Mod Podge to seal the paint. The Mod Podge coat is still sticky after a few days, which is definitely not good for Jenga blocks. How can I make the blocks not sticky? UPDATE Unfortunately after more than a month of curing, my blocks still stick together! What are my options? <Q> Mod Podge takes a very long time to cure; around four weeks, depending on humidity and coat thickness. <S> To properly use Mod Podge, you need to apply multiple thin layers (not thick ones), allowing them to dry completely between each coat. <S> According to Meaningful Mama , If you don’t let [the Mod Podge] dry completely between coats, your project can end up more sticky and may bubble a bit. <S> "Dry" is not "cured," however; while it will only take an hour or so (again, depending on humidity) for each coat to dry, you need to leave the pieces alone for roughly a month to become fully cured and hardened. <S> Once fully cured, the Mod Podge will be a durable coating resistant to damage, but during the cure time, it will remain soft and susceptible to damage, including shifting and peeling. <A> Just to supplement the good answer by Allison C, there is a wide variety of Mod Podges with different characteristics (see descriptions on this blog ). <S> Certain ones are more prone to be sticky than others, especially if there is high humidity. <S> If thin coats and long curing still don't solve the problem, one solution is to try a different Mod Podge product that may be less prone to stickiness (see linked blog). <A> This might seem or sound a little silly, but I always do this, and have done it for bigger projects as well (like when I made a speaker out of cardboard). <S> I wanted a nice coating <S> so I used a little bit too much mod podge (and too little water), <S> so well... <S> The solution basically is: get dust, sand, or any other very smooth and light powder (you can also try any dry color powders, as they could even give texture to your blocks). <S> Get it to the finest stage (blend it if it is coarse or has granules and such). <S> Use a sieve to filter out crude leftovers, collect it in a paper, or something similar, and just plainly blow it across the blocks (do so with every single one). <A> Sandpaper helps a lot actually! <S> As long as you don’t mind a few scuff marks, the sandpaper gets rid of almost all of the stickiness. <S> I painted my Switch controllers the other day and hated the stick, but I used some sandpaper, and with a few scuff marks on the back, they're good and smooth now!
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Another solution is to give the item time for the Mod Podge to dry and cure, then spray it with several light coats of a clear acrylic sealer.
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Is coconut shell good to produce charcoal for drawing? Is coconut shell good to produce charcoal for drawing? Does the material that we use to make the charcoal decide its tonal character? <Q> Is coconut shell good to produce charcoal for drawing? <S> I am sure that will work just fine. <S> It does depend on the type of shape you want, as the structure of coconut shell is not optimal: it is naturally curved, making it hard - if not impossible - to get nice straight styluses out of it, and it might splinter more easily when exposed to high temperatures, because of the inherent tension. <S> Does the material that we use to make the charcoal decide its tonal character? <S> It does, but not a lot. <S> Different source materials have slight differences in pigmentation, texture, and strength. <S> Generally, types of wood are used, of which willow and grapevine are the most popular types for drawing. <S> You will notice larger differences between charcoal and charcoal pencils , than between types of wood. <A> Drawing charcoal is made in two general ways. <S> One is to start with wood that is naturally in stick form and turn it into charcoal by burning it in a kiln without air. <S> Grape vines and willow sticks are commonly used for that, but DIYers use almost any kind of available sticks, or even lumber cut into sticks. <S> The drawing characteristics of the result are whatever the source wood gives you. <S> The other method is similar to how graphite pencils are made, only using charcoal instead of graphite. <S> The charcoal is ground into a fine powder and mixed with a binder, typically a gum or wax. <S> The manufacturing process controls the hardness of the result, mainly by the amount of binder used. <S> Compressed charcoal can produce darker lines than stick charcoal. <S> If you're thinking about making your own, you aren't likely to be able to replicate the compressed powder, but you can easily replicate the stick method. <S> You would need to cut the coconut into strips of the desired size, get all of the coconut meat off, and give it plenty of time to thoroughly dry out before trying to turn it into charcoal. <S> They'll be curved, but that wouldn't necessarily affect their usability (straight wood sometimes curves in the kiln). <S> A bigger problem may be the nature of the coconut shell. <S> It's relatively thin, and is a mat of fibers rather than solid wood. <S> It might not have the strength to draw with (the fibers may also not hold together after it's turned to charcoal). <S> If that's the case, you could try reinforcing it by wrapping a strip of paper around it for strength. <S> Here's a good article on doing it in a paint can: https://www.sightsize.com/making-charcoal/ . <S> The author's experience was that the hardness of the wood made a difference. <S> This video, https://www.youtube.com/watch?v=UpwlnaUwnoQ , covers more detail on the preparation when starting with sticks (the other author started with lumber cut into "sticks"). <S> I couldn't find anything online where people had used coconuts. <S> You will need to experiment, then post your results and any lessons learned. :-) <A> I tried my hands on making charcoal with coconut shells. <S> I used the technique shared by most of the youtubers where they use a perforated can to cook the raw material(in this case broken pieces of coconut shell). <S> The result was not that appealing in the sense that the charcoal I ended up with was not making dark marks as expected in the paper. <S> Instead, there was grooves on paper. <S> In effect, the charcoal was not soft enough to get disintegrated and absorbed to the paper. <S> Later I tried with a stick of Gliricidia sepium a locally available soft wood. <S> It has excellent blending ability.
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Various kinds of wood can be used to make the charcoal, but that isn't the major factor that controls the drawing characteristics. Like graphite leads, the hardness is the major factor driving the drawing characteristics.
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How can I make a faux gold finish less garish? I just purchased a cheap gold lamp. As expected, the gold is typically super shiny and yellow (see below). How can I make it look more like weathered/antique gold? <Q> I assume the look you're hoping for is a little like this, a dirty gold: <S> source , actually a 3d render If you're not planning on rebending the stand a lot, I'd suggest taking some acrylic paint (maybe some raw umber and black or similar dark and muddy colour), mix it with a little chalk or plaster (gypsum) to make it more dirty and matte (but make sure it doesn't dry out too quickly - you can add a little water while you mix), take a piece of cloth, dip it into the mixture, and rub it unto the lamp. <S> This way, all crevices will take the paint, and all larger smooth surfaces will be wiped clean again by the cloth. <S> As a side note: I don't really see the 'gold' in the lamp, only a very subtle, almost green hue. <S> Is it the lighting, the colour profile, or is it really that faint? <S> Depending on how clear the 'gold' is on the lamp, you can first coat it with some acrylic gold paint, using either spray paint, or acrylic, after you've sanded it with very fine sandpaper. <S> Regular acrylic gold paint is usually too cool or too warm, and too shiny (or, rather, glittery). <S> There are more professional paints available, but you can of course also create your own mixture (white, yellow, and if you're so inclined, maybe warm it up with a very little bit of red). <S> In both cases, parts of the coating might come off afterwards (especially with acrylics), but this could actually increase the faux antique look. <A> It depends on what you want to achieve in the end. <S> Just a few ideas: <S> Use something abrasive, very fine grain, and destroy the shine. <S> Spray <S> some non-glossy paint over the shine. <S> Choose the color of the paint according to your wishes. <S> Go back to the shop and exchange the shiny lamp for a non-shiny one. <S> Well, gold and antique-looking don't really go hand in hand :( <S> However, I saw lamps which might look like you want, and this is how you might get there. <S> Apply some layer of paint - which will give the "antique" look. <S> Before it dries / cures, use a brush, even some soft paper, to comb the paint over the surface of the lamp. <S> In a way it would look scratched, but it will also look like it has "deposits" due to time passing by. <S> You may even uses different colors and / or different shades of paint. <S> Maybe gray for dust, brown for rust, blue / green for some copper oxides... <S> Imagination, baby :) <S> Just decide the details about how you want it to look like. <A> The gold-coloured coating is probably very thin so abrading it could easily scratch right through. <S> Besides, it would look more like scratched-up shiny stuff than old weathered stuff. <S> Depending on the look you're going for and the thickness of the base material, beating it (try a wooden or rubber mallet before anything metal) could be used to make it less mirror-like. <S> I've found water-based varnish sticks <S> well to real brass, at least when I don't want it to. <A> This product is perfect for just that job. <S> It's not as cumbersome as gold flake leafing which is what is traditionally used for antiquing. <S> ✌
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A coat or two of satin varnish will also make the shine less garish, but test how will it sticks.
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How Do I Save This Shirt This is the shirt I purchased when I was heavier: I was able to slim the sides. Unfortunately, fixing the shoulders was a train-wreck (now I've learned the hard way: I need to take-in the shoulders) When I tried to sew along the thread seams, it was crooked and I couldn't put on the shirt. However, when I tried removing the threads, it made a nice hole in the shoulder area. How to darn this hole so that it is not noticeable? <Q> It's unlikely that you'll be able to disguise the holes in any way that's not noticeable; instead, I would recommend looking into the Japanese process " sashiko ," a mending process made deliberately visible. <S> Based on your other questions, you are quite new to sewing and embroidery, so you may wish to start with a more simple pattern like the one shown on the bottom; with practice, a wide range of more complex patterns exist that you can use in the future. <S> A wide range of online tutorials exist to get you started, frequently focusing on a diamond or square pattern similar to the bottom example; the repair will be solid and should help prevent further damage to the area, and will make your shirt uniquely your own. <A> You're asking a lot to repair that so it isn't noticeable (although if time or cost is no object it could probably be done; I've seen damaged art canvases invisibly repaired with a microscope, surgical tools, and days of work). <S> A more practical strategy might be to hide it in plain sight. <S> Incorporate the repair into something like embroidery. <S> Maybe do something matching on both sides so it looks like it was the original design. <S> Another idea would be to intentionally fray both sides the same way jeans are done. <A> A less noticable way to repair such a tear is to patch it from behind. <S> Cut a patch of matching fabric that covers the whole gap plus one inch in every dimension. <S> Position the patch behind the tear and hand-sew a few stitches to keep it in place and keep the edges of the tear closed. <S> You should use a contrasting thread color because you need to remove the stitches later. <S> Then choose which stitch and yarn color you want to decorate your shirt with on your sewing machine. <S> At the end, cut and remove the contrasting basting thread. <S> The advantages of this method are: <S> The patch isn't visible from the front. <S> The criss-cross stabilizes the fabric in the whole area and reduces the risk of further tearing. <S> You can make it look as if intended. <A> You're slightly lucky it's torn in a fashionable way, so what I would do (and did with one of my jackets) is to use small strips (scraps, if you have them) of something like leather, faux leather, corduroy, velvet, basically any high fashion fabric. <S> If you're female, laces would also work. <S> If you're using fabric instead of laces, cut a straight rectangular strip (something similar to what is often sewn on the back of jeans near the loops in the belt line, but a little less wide) and then just sew it over the torn area (yes, it's a patch, but that's a style nowadays); like above, if you want you can do it on both sides. <S> Have a fabric of that exact length of that portion of the jacket (from collar to shoulder to collar bone) and just sew it all over the whole piece. <S> (I'm always thinking leather or leather-y texture like faux leather, but it's also fine if it is any other fabric.) <S> If you don't want extreme but advanced and complicated, you could get some extra denim from a pair of jeans or old clothes you no longer wear, make some mini pockets out of it, and sew it on both sides to hide the torn side and the patch. <S> I'll be honest, there's many ways of fixing it. <S> You just have to think a bit creatively and out of the box. <A> And then apply on top of it a bright smiley. <S> Or a skeleton. <S> Or a climbing Santa.
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Sew a wild criss-cross pattern all over the tear and make sure the edges of the stitches overlap the edge of the patch below (to keep it from fraying). Just lace the gap from the shoulder seam all the way through the side seam only on that particular side (if your mind is able to allow asymmetry, which a matter of fact looks awesome); if not, just repeat it on the other side. I suggest going for a chaotic pattern, because it's very hard to sew a perfectly geometrical criss-cross with a sewing machine and any slight deviation will look odd. If you want, you can also go a bit extreme! Make a basic repair of the area.
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Something against hand pain due to writing? I sometimes write for hours per day (calligraphy), and my hand starts hurting because of holding the pen for so long. Is there a solution to this problem, e.g. some kind of glove or pen-strap that reduces pressure on the fingers? <Q> If your hands start hurting or feeling sore, take a break. <S> Listen to your body - if something hurts, it needs to rest. <S> Otherwise, you can risk permanently injuring/disabling yourself. <S> One artist whom I follow, Yuumei, has shared her experience with this: https://www.deviantart.com/yuumei/journal/PSA-for-Artists-Don-t-make-the-same-mistake-I-did-577426340 . <S> If they're still hurting after a break, then it means I'm done for the day. <S> It's not worth risking permanent disability by pushing yourself to draw/write for a few more hours. <S> Check your hand/wrist alignment when you're writing. <S> I've found it helpful to rest my wrist on a rubber/foam coaster <S> - it adjusts the angle of my wrist just enough to relieve some of the pressure. <S> Explore other methods of calligraphy. <S> I used to draw extensively in pencil (graphic and colored pencil), but over time I found that the pressure created a lot of pain in my joints, especially where I held the pencil or rested my hand/fingers against the table. <S> I started painting instead, which doesn't require much pressure to create a visible mark (and requires much less energy to fill a space with color). <S> Perhaps try using a brush instead of a pen from time to time, and see if that provides an outlet for you to continue doing calligraphy without wearing your hands out as much. <A> If you are "very concerned", talk to your General Practitioner MD. <S> He may refer you for physical therapy. <S> Therapists have access to many writing assistive technologies. <S> I have used (and still do sometimes) different rubber tubes, slipped over pens, pencils, etc. <S> They relieve my hand pain, which is due to a neurological injury. <S> Be sure your PC environment is ergonomically correct. <S> Easy workstation guides are easily found (online). <A> People with arthritis and various other ailments and injuries that affect their hands increase the size of what they hold. <S> This lets you use more of your hand to hold the pen and apply less pressure. <S> I have no idea how compatible this would be with the motions and control needed for calligraphy, but it's an inexpensive thing to try. <S> Perhaps the most important thing is to listen to your body. <S> Take regular breaks, and do other motions with your hands to relax your muscles. <S> If you're feeling pain, you've been doing it for too long without a break. <S> I'm not familiar with calligraphy techniques, but there may be things like hand positions that are less stressful on your body <S> , that would allow you to work longer before needing a break. <A> Something I have done is soaking my hands in warm water (not lukewarm, not boiling hot, just as much heat as you can handle) before, after, and in between the periods of writing (say, taking a break for half an hour or so). <S> I did that for many of my long writing projects in school. <S> Another, slightly foolish trick would be trying to hold the pen with all your fingers at once; one of my classmates did that. <S> She was one of those students who wrote nine pages for a one line question, so maybe that habit helped (or at least didn't cause any harm. <A> You may want to consider using a wrist brace while writing. <S> It'll constrict your writing, so you'll need to practice with it before doing something that needs to look perfect. <S> You can also search for "writing brace" to find something that's a little less obtrusive. <S> There's always the neoprene half-glove that makes moving your hand easier, too. <S> Beyond that <S> , and I think the root of the problem, is that you are holding the pen too tightly. <S> Maybe a different sized pen would help with that. <S> Getting a thicker grip would likely let you relax your hand some. <S> Again, this might take some time to practice with the new stylus, but it should help. <S> Also, I've heard that cramps happen due to dehydration. <S> Try drinking more water. <S> Actual water, not tea, coffee, pop, alcohol, sports drinks, or anything else but straight water. <S> Almost everything else has something in it to diminish the effect of straight water. <A> There are triangular pen grips that can enable you to hold the pen more gently and with your hand in a more relaxed position. <S> Many are aimed at kids but there are bigger ones with rounded corners <S> I don't have to write for long periods these days but used them as a substitute for my Lamy Safari pens when I had to write a lot of lecture notes and take written exams. <S> These have a much nicer grip than many pens, but may not be suitable for what you're doing, despite being available with a range of fountain pen nibs.
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I personally will take breaks to stretch my hands and massage the sore parts of my fingers. The common technique is to stick the pen into some form of foam or rubber grip, or even a rubber ball. I've seen something that you can rest your hand on while you write that allows you to move more freely, like a mechanics creeper, but I can't find what I'm looking for.
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What papers are suitable for markers? I am planning on using markers for a drawing. As I have never used markers, I lack knowledge about them. Is it okay to use them on normal drawing paper, or should I use sketch paper? <Q> I'm not sure what you're defining as "normal drawing paper" or "sketch paper," but you can ultimately use markers on any surface, however you will experience different results depending on the qualities of the paper. <S> Tooth <S> You'll generally get a smoother result with a smoother surface, though depending on the result you're looking for, you may like the look of using a paper with more tooth to it. <S> Experiment here to see what you prefer. <S> Coatings <S> Some papers (marker pads, for instance) will be coated to prevent bleed-through on a thinner sheet; this can allow for better workability in blending, but may also result in less saturated colors as the ink cannot soak into the surface. <S> This can also create issues with layering multiple colors or extensive blending; again, this may come to personal preference and style. <S> Absorption <S> If you're planning on extremely heavy blending, particularly using water and water-based markers, you may wish to consider a paper that is better suited to heavy water applications such as a smooth watercolor paper over a lighter paper that may warp or disintegrate when saturated with water. <S> Bleed <S> You may also wish to experiment with the amount of bleeding your chosen markers will exhibit on different papers. <S> All markers will bleed to some degree (except, possibly, on coated papers), but some papers will wick the ink away from where you deposited it more than others. <S> You'll want to find an amount of bleed that works for you, and learn to work with it as you're drawing. <A> When you say "is it okay", that implies that there's a rule about what you can use with what, or that everybody who uses markers, uses a particular kind of paper for a reason. <S> Any medium will have different characteristics on different kinds of paper. <S> You probably want to avoid something that's incompatible. <S> For example: a medium that's thick and brittle on tissue paper; it's likely to flake off a medium that won't adhere to the surface, so it will tend to aggregate in spots rather than stay where you put it a chemical incompatibility like acidity/alkalinity, where the medium and paper can interact and change color or other characteristics a medium that requires a different kind of surface texture to work as intended, like a rough surface to abrade a material like chalk or charcoal, or an extremely smooth surface to use a metal-tipped technical pen. <S> Once you get beyond those kinds of problems, it's more a case that different kinds of paper will give you different kinds of appearance. <S> It may also require the right techniques and some practice to "bend the combination to your will". <S> Part of art is experimenting with those variations to see what combinations give you results you find pleasing or achieve what you're trying to accomplish. <A> I know this isn't the official answer, but I wanted to give an easy one for people as I've been drawing with markers for years now. <S> Marker paper . <S> Yes it's that simple. <S> It's pure white, and doesn't bleed or spread when you apply the tip. <S> It also instantly absorbs the marker only where you apply the tip. <S> Comic book art, illustrations, graphic drawing, cartoons, anime, etc. <S> all look perfect on this. <S> Cardstock . <S> You have options of different colors and textures. <S> But I like the benefit because it bleeds and spreads a little, which can help out when shading more because you can blend and fade the markers over really well. <S> This helps when making a more realistic drawing. <S> Again <S> I know this isn't the official answer but for newbies who don't want to learn everything there is about paper and just want a straight answer here you go. <A> "Bond" paper is usually best for markers, it has a smooth flat surface and is usually thick enough to prevent too much bleed through. <S> If fact there are specifically made papers for magic markers called "Marker Bond", "Marker Layout" or just "Marker Paper". <S> With markers the main issue you will face is bleed, where the ink soaks in and expands in the paper. <S> Bonds and Marker papers are made in a way that minimizes this. <S> Also markers do not gain any benefit from roughness or tooth in a paper, so avoid papers with a lot of texture, like charcoal paper, watercolor paper, or even a lot of sketch papers (where bleed will be an issue anyway.) <A> You'll need a thick type of paper. <S> Ordinary bond paper is a bad idea as the markers will bleed through to the surface below. <S> Some art stores sell paper billed as "marker paper". <S> I haven't used them myself but can vouch for bristol paper; I use this to draw my comics and they can absorb markers well. <S> Illustration board is another good choice though it can be pricey. <S> Smoother watercolor papers are another option. <S> As an example, this is one of my color comic strips; I used markers on watercolor paper - http://www.poisonivygulch.com/comic/poison-ivy-gulch-7-12-2020/
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Weight Markers will generally soak into the paper and bleed to some degree (with some brands tending to bleed more than others); working with a thicker paper like bristol or watercolor paper will tend to resist bleed-through better than thinner papers like newsprint.
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How can I make paper look old without wetting it? I want to make paper look aged and then print on it a picture, I tried with coffee but the results were bad, the picture quality is poor on the coffee paper compared with the white paper, the colors are really dull and it is less saturated. I tired to fix this with photoshop but nothing worked out, We don't have ivory/yellow/brown papers available in my country and I can't get it online too. I was thinking to buy maybe a fixative spray, I contacted all stores here, they don't sell it but they do sell a acrylic varnish mat spray, will that helps ? or I shouldn't be using an acrylic spray on an inkjet photo ? it'd be much appreciated if you guys can help me with an aging technique (it doesn't need to appear really old or something) just a yellowish/brownish color. I don't want to wet the paper with coffee or tea or anything because I lose quality <Q> If you're printing, why not print the aged effect as well? <S> Print it as close to the margins as possible - <S> your printer may even do borderless, but if not you need to crop (physically) to the aged bit. <S> This doesn't have to be perfect; in fact it may be better done rather roughly, depending on just how old and weathered you're looking for. <S> If you do tea- or coffee-stain your paper, you need to dry it really well before printing. <S> This may make that an option after all. <A> You will need to go slow to ensure that you do not light it on fire, scorch, or get too many crinkles. <S> I have done this <S> this make scrolls for a project, it works fairly well. <S> If you end up getting some waves or crinkles in the paper you can try to lightly mist it with water and then put it under something heavy. <S> It might be worth it to print the picture first and then try to weather the paper as well! <A> May be you should try smoking it with a candle. <S> It might help i am not sure. <S> It can be done in many ways , smoking means as simple as showing the paper on top of the flame. <S> Its better to fix it to a wooden frame or cardboard and then showing it upon a flame so as to prevent burning . <S> After smoking the paper we can smudge it with finger or cotton. <S> I am uploading a picture here of a paper piece i smoked right now using a candle without smudging.(only a small portion is smoked). <A> stick the paper in your dryer with something heavy, like poker chips, the kind they have in vegas, not the little thin ones for home use. <S> Or you can use racket balls or tennis balls. <S> Use low heat or none at all if your dryer has an air dry setting, that would be best. <S> Run it for about 5 minutes and see how its coming along, might want to go about 15. <S> That outta add some years to it. <S> Add some wadded up news paper to the dryer as well, for a little color transfer.
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Showing the paper alone might work but may burn the paper and also takes time since we should take care not to burn it. If you have a candle or heat source you can try to hold the paper over it carefully and "bake" the paper to get it to a different color.
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How can I keep my paint brushes long lasting? I am not a trained artist.My paint brushes are getting damage easily after finishing one or two creations.Below I have added the images of the brush that I am using now.I do not know what are best types of paint brushes that I can use corresponding to acrylic color that I am using or the colors that are suitable to the paint brush that I am using. Currently I am using these brushes.Also I am mainly using Camel Fabric acrylic colors.This one. <Q> How can I keep my paint brushes long lasting? <S> Awaiting more specific information, I can already tell it's best to rinse your brushes directly after every use . <S> Whether it's oil or acrylic <S> you're working with, the brushes can easily be cleaned with a little soap and water. <S> I use general hand soap bars for this - nothing fancy: don't be persuaded by the overpriced "artist soap" (but more on that later on). <S> I fixed a spring on top of the jar to hold the brushes, so that the bristles don't get squished as they dry, preventing deformation. <S> You can adapt the spring from a spring holder like the one here: Using a jar instead of a tin allows for more soapwater, slower evaporation, and fewer refills. <S> When the paint has dried up already, I usually either soften it up again in that same jar - but you have to wait for days if not weeks ( <S> depending on the size of your brush) - or use a small hammer to hammer the paint out (this I only really do with acrylic paint). <S> This is bad practice for high-quality brushes, but with those you wouldn't let it come this far in the first place :) <S> And, nevertheless, a usable bad-quality brush is still better than an unusable high-quality one. <S> What are best types of paint brushes? <S> That is a different question altogether, but, in the light of your main question, the brushes with the greatest longevity are usually those with plastic (nylon, polyester) bristles , as they are less easily damaged. <S> If you're starting out with painting, I'd suggest using hog hair bristles for oils and synthetic brushes for acrylic paint. <S> They are both cheap and relatively resilient, and abusing or losing them while getting used to the painting process won't be the proverbial end of the world. <A> If you clean them before the paint or substance (varnish, oil paint, etc.) <S> dries on the bristles, they will last a really long time. <S> I've kept both cheap and expensive brushes for over 30 years or more. <S> I use this kind of brush soap . <S> If I've used an oil-based substance, I'll clean it first with mineral spirits, then use the soap. <S> The soap will condition the bristles and clean the particles out from between the hairs. <S> Also, don't use laquer thinner to clean your brushes! <S> That stuff will eat the finish off the handles and damage the brush hairs themselves. <S> That being said, I've done this before and still kept the brushes (with missing finishes) for use anyway. <S> Old brushes that have distorted brush ends can be used for effects and for other projects where you don't need to do fine work. <S> I use my old, not-so-nice brushes for applying glue and varnish. <S> And I clean them anyway, just like I would my good brushes. <S> This policy keeps my good brushes good because I don't have to use them for not-so-fine applications. <A> Keep them moist, clean them. <S> If wooden be careful of leaving submerged as the coating will peel or warp them. <S> Personally I keep hold of my dilapidated brushes too as a distressed brush can give some interesting effects when combined with different media.... <A> Aside from cleaning them in a timely fashion. <S> You might be using them the wrong way. <S> If your "pushing" your brush, its going to wear out very fast. <S> You want to drag your brush. <S> Sometimes you may want to push, for the effect, but when you do, it has a negative effect on the brushes longevity. <S> Also, after you clean your brush and you've gotten all of the paint out, drag it across a bar of soap, then reshape it, and let it dry that way. <S> Brushes that hold their shape longer, also last longer.
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Natural hairs usually paint better (depending on the paint you work with, your style, the size, etc., and high-quality acrylic bristles are improving), but they are more susceptible to degradation, as organic fibers tend to be, so you have to make sure you take good care of them. I leave my brushes in a jar with soapy water at all times.
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How can I secure stiff fabric to wood without risking ripping and without adhesives? I am planning a project using simple 1" x 2" pieces of wood and attaching a length of textile between the planks. The wood will be about 12 inches long, and the fabric will go from long-edge to long edge and up to 3-4 feet wide. So, 12 inch by 36-46 inch pieces of fabric. The ends of the fabric will be flush with the outer edges of the wood, and each end will be sandwiched between two of the pieces of wood. Once everything is assembled, the fabric will be taut, but still flexible, and need to support up to 40 pounds without the fabric tearing from screws I use to attach the top and bottom wood strips to one another. I want to be able to attach the fabric to the wood, without having to use glue. I want to be able to swap out the fabric with different lengths as desired, or attach multiple pieces that branch out in different directions. Some type of eyelet protector comes to mind, but I'm not sure how to attach one to a pre-made hole. Here's a 2-minute diagram of what I'm trying to achieve: This is the view you would see from the side, once this hammock/shelf is attached to a wall. The brown pieces are the woods sandwiching the blue fabric, and the grey parts are the screws/bolts I will be putting through the wood and fabric. For those curious, I have been inspired by some cat shelf/highway products, but am not satisfied with the appearance of them. I want to make something myself that is functional and pretty. But, since living creatures will be playing and sleeping on these modular pieces, safety is of the utmost import. <Q> Instead of securing the fabric with the scews, I'd let the fabric secure itself on the outer edge of the wood. <S> The less holes you poke into a fabric, the stronger it is to withstand tearing or wearing out. <S> Instead of a simple hem, you could roll and secure the fabric (light blue) around a cord or other thick material (dark blue) to create a bulge that is held by the wood (brown). <S> If the material is somewhat thick and the wood closes well without big gaps, a "simple" hem might even be enough. <S> Advantages : <S> Preserves the fabric's strength by avoiding holes <S> If a weight pulls the fabric down, the force is distributed between all points on the edge instead of single holes. <S> You can easily replace one piece of fabric with another one. <S> No need to sew button holes or inser grommets into the new fabric <S> Disadvantages : <S> You need to sew a thick or corded hem on the fabric <S> The hem is always visible on the "outside" of the wood pieces <A> I can think of a couple possibilities. <S> A "fabric only" method would be to sew buttonholes . <S> These are reinforced with thread all around a slit in the fabric, which prevents fraying and tearing at a frequently-stressed point. <S> While they're most often used in clothing, I have also used buttonholes on a shower curtain -- I haven't tried on an application that would hold up to 40 pounds. <S> * Many sewing machines have a buttonhole foot and stitch available. <S> Using grommets would be the eyelet protectors that you mention as a possibility. <S> These are stronger reinforcement (basically metal buttonhole edging!) <S> but do require tools to install. <S> In either case, I'd recommend... <S> Run a nice sturdy seam along the outermost edge of each shelf piece to have a "safety" barrier in the event that a tear does start at one of the mounting holes. <S> Fabric can often rip fairly easily, but trying to rip through a seam is much more difficult -- think of a pair of jeans, for example, you won't get through the side seams without cutting! <S> Keep the wood sandwich pieces cinched down tightly when assembled, so the fabric isn't able to move at the hole locations. <S> The less it rubs against the bolts in general, the less wear and therefore the less chance of tearing. <S> * Remember, the more holes you have, the less weight each one has to hold. <S> 4 holes would each only need to stand up to 10 pounds of pulling, for example. <A> That way, there is no localized stress on the fabric, and you can position the fabric wherever you want (including small length/tension adjustments). <S> The catch is that you will have to either: Make the clamps longer than the fabric is wide, so that there can be one screw at each end, not going through the fabric, or Design them so that the clamping screws are past the end of the fabric (which requires more complex woodworking). <S> In order to ensure the wood gets a good grip on the fabric: (For the first option) Shape a slight convex curve on each of the two pieces of wood so that they meet in the middle first, and when the screws tighten down they try to straighten the curve. <S> This will counteract the wood's tendency to bend and exert less clamping pressure in the center. <S> The curves do need to be very smooth to avoid gripping in only some spots, but we can compensate for that: <S> Add some type of rubber sheet material (e.g. shelf liner, the kind that is a rubber mesh) to increase friction. <S> This would also allow compensation for irregularity in the wood (whether original or in your work) since the rubber is compressible. <S> For the second design, the necessary curve is exaggerated in the diagram, but if you provide enough room in the middle area you could combine it with sewing rods into the ends of the fabric as Elmy's answer proposes.
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Instead of adding any holes or other fittings to the fabric, you could design the brackets to clamp the fabric, along its entire width .
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Where can I find/make paintable opaque green domes? I've been looking for an item I need which is a hollow hemisphere with outer diameter of ~25 mm. Ideally, I'd like them in green, but I can only find them in clear. Do these sorts of domes exist in opaque color? Would I be able to just stain the clear ones? Is there another material for this type of object that can serve the same function? I need to be able to paint onto it. This object will be decorated with a custom image and used to cover pieces in a board game I'm designing for my family. <Q> If you're going to paint them anyway, especially opaque, <S> I suggest spray-painting the semi-spheres . <S> That way, you can get the exact green hue <S> you want them to have, you can control whether you like it glossy or matte, and - dependent on your skills <S> - can have them look really smooth. <S> I suggest sanding <S> these transparent domes a little first, with very fine sandpaper (≥ ~300); applying a layer (or two) of the spray-paint . <S> To prevent the light plastic domes from flying away when paint-brushing, tape them on something heavy (like a wooden plank) with double-sided tape; gluing the custom images onto the surface (depending on the paper by letting them soak in the glue, so they will follow the curved shape of the domes closely); and finishing it off by applying a layer of transparent (glossy or matte) varnish . <A> Simply mache over the ball and cut it along the middle when it dries. <S> Voila! <S> two small paintable domes. <S> (fyi - paper mache is strips of paper soaked in wheat paste. ) <S> edit: <S> Use the inside of the ball to get the dome smooth on the outside. <A> You might be able to find cheap green plastic Xmas ornaments that you could cut in half. <S> Hmmm, maybe those catnip balls that unscrew so you can refresh the catnip.
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If you are feeling crafty you could make paper mache (papier-mâché) domes using a ping-pong ball or similar as a form.
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How can one leave internal void cavity in fused glass piece I am trying to make a solid fused piece that would have a shape in the center. I suppose you could make the shape in the glass with a fuse step and then tact fuse a top and bottom on to it. I am worried about losing some features and having the glass collapse. Is there any way to do something like this in a single step? tube running through it <Q> I've never tried this, so this answer will be largely speculation based on the physical properties. <S> You can leave a void, but I don't think you would be able to make the void a complex or delicate shape. <S> There are a few ways to start with a well-defined void: engrave it into one or both mating faces of two pieces; start with three pieces and cut the shape out of the middle piece like a stencil; make the shape using a glass tube and seal the ends to trap the air, then embed the tube in a bed of glass dust and fuse the bed (this wouldn't be applicable for a 2 mm final thickness). <S> With all of these approaches, glass fuses by becoming a liquid and flowing. <S> The molten glass will flow in a way to minimize the surface area of the void. <S> It will fill thin areas first, forcing any trapped air into bubbles, so you will lose the shape. <S> However, that wouldn't be a void. <S> The only way I can think of to have a void of a specific, desired shape is to not fuse the glass. <S> Use one of the methods, like mentioned above (e.g., engraving or stencil), to create the void, then bond the pieces together with clear adhesive that bonds glass. <S> If the goal is the appearance of fused glass, another approach would be to fuse the glass. <S> Then engrave the shape in the back side. <S> Another idea that might come close to your objective. <S> Create the void as in the gluing approach. <S> Fill the void with fine dust of colored glass. <S> Then fuse the glass. <S> Colored glass dust would melt, and it might hold the shape, and at least be a contrasting, embedded shape. <A> A fully encapsulated void in thin glass is difficult to impossible to do hot in a kiln. <S> A carved out indentation open on one side is trivial. <S> You could the encapsulate it by cold-fusing (i.e. gluing) <S> another sheet of glass to the back. <S> For a design such as you show <S> I’d <S> kiln carve it by cutting the design out of ceramic fiber paper, placing a double sheet of glass over the fiber paper in the kiln, and firing to a full fuse. <S> Trying to tack fuse a cover into this will have problems because the tack fuse temp is high enough that the glass will move and distort the carved pattern, and because trapping air in the pattern is likely to cause bubbles. <S> You can avoid these problems by filling the pattern with enamel or powdered glass to form a sold block. <S> Either way will end up thicker than the your 2mm final size by default, but you could create a blank for pressing this way. <S> The pressing will likely distort the image some. <S> Bullseye has a TipSheet on kiln carving at https://www.bullseyeglass.com/methods-ideas/tipsheet-1-kilncarving.html <S> Another option (similar to previous suggestions of engraving or acid etchjng) would be to sand-blast the pattern. <S> It really depends on the effect you’re looking for and the tools you have available. <S> You could get your single layer look by sandblasting, filling the sandblasted cavity with a low fire enamel and then firing to a temp that’s high enough for the enamel to mature but low enough that the glass doesn’t deform. <A> I would just use a Dremel rotary tool with grinding bits and simply carve out the design. <S> I've carved glass before with a Dremel <S> - it's slow going, but it works. <S> You'll need different grade bits, starting with coarse and then with finer grits, finishing with rubber polishing tips to get it super smooth. <S> But with the dremel, you can use whatever kind of glass square or shape you want.
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You could embed a specific shape in fused glass by making the shape out of a material that melts at a higher temperature. If I understand you correctly, you just want to cut out the hollow of that shape in your glass square.
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Determine kind of jewelry I have found my grandmother's brooch. She is dead now, so I can’t ask her about it. Can anybody determine what kind of jewelry this is? I'm also curious about whether this type of jewelry had or has value of significance, if someone happens to know (yes, maybe it’s cheap, it doesn’t matter). I have already tried to find it in Google pictures search, got 0 common results. My grandmom lived in USSR, Italy and France; maybe this information can help somehow. <Q> Some more observations that didn't fit into a comment: The stones are certainly no precious stones. <S> The color indicates glass stones. <S> If you're willing, you could try scratching the surface in an unobtrusive place like the edge where they're connected to the metal. <S> If you can chip or scratch them with a nail or other sharp object, they are glass stones. <S> You can clearly see the color in the areas of the leftmost cross. <S> All silver (or gold) objects should have a " Hallmark " at the backside, which is a special punch denoting the content of precious metals. <S> If there is no hallmark anywhere on the piece, it is not silver or any precious metal. <S> If this were a high value artisan work, these hallmarks would be on each of the pendants as well. <S> There would also be special hallmarks indicating the artist. <S> Example of english silver hallmarks: <S> All things considered it doesn't give the impression of having any material value. <S> Far more interesting would be the symbolic value, but unfortunately I cannot help you with that. <S> It could be that each of the pendants has a certain meaning that, combined with the other symbols and the place where it was made, could tell a story, commemorate an event, show the association with a certain society or symbolize wishes for the bearer's life. <A> I have very little expertise in jewelry, but can offer some observations and guesses. <S> The colored cabochons appear glued on; stones of any value would typically be mounted in a secure setting. <S> The metal looks like it may be silver. <S> "High end" jewelry tends to have a symmetry and/or regularity, and very fine "fit and finish". <S> It usually has a certain design "delicacy". <S> This piece is the opposite in all of those respects. <S> It's the kind of item created by an artisan with some technical skill, but probably little training in, or appreciation of, "art". <S> They make individual pieces that are not what anyone would call "gorgeous", but are more kind of interesting because they break the traditional rules and are unusual, and a little "unrefined". <S> So it looks like it was made by a crafter rather than a jeweler. <S> Also, it wouldn't need to be made from scratch; it is made from components that a crafter could purchase and assemble with basic, inexpensive tools. <S> I've encountered jewelry of this general nature in places like craft fairs and small shops that sell handcrafted items. <S> My guess would be that your grandmother came across this in such a place and thought it was cool. <S> It might even be the brooch equivalent of a charm bracelet, where your grandmother picked the component charms that represented something personal. <S> Or perhaps she knew somebody who crafted these kinds of items who made it for her, so it had special meaning or sentimental value to her. <A> Cherry amber and chrysoprase. <S> Common in those areas for use of in costume jewelry
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The brooch appears to be handmade costume jewelry (i.e., decorative but not containing elements of significant value like gem stones or a lot of precious metals). The shade of the metal could indicate silver, but the dark and consistent shadows in all the recesses could mean it's a non-precious metal that was dipped into a color wash to make it look like silver.
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Why and how do some people use circular knitting needles when working flat / not in the round? Some people use circular knitting needles when they are working flat, aka not working in the round. Why is that and how does it work? <Q> I personally only use circular knitting needles. <S> To work flat on circular needles, you do not need to do anything special. <S> Just turn them around when you reach the end of your row, as you would normally, never join. <S> If you think of it as two separate needles with a string holding them together, it may be easier to imagine how it works. <S> I believe there are quite a few advantages to using just circular needles: <S> You only need a set of circular needles rather than a set of straight needles and a set of circular needles. <S> You can't lose the "other needle". <S> Once your work starts getting bigger and heavier, it will rest on your lap instead of on the end of your long needle with seemingly increased weight due to the lever effect. <S> You don't poke the person next to you. <S> You can get long cables that support big items like blankets. <S> Various brand of circular knitting needles have removable cables. <S> This allows you to move the knitting to the cables and remove or change the needles. <S> This is especially helpful in a few small ways, for example picking up dropped stitches with a smaller needle becomes easier, but you can also store your knitting away on the cable white reusing the needles. <A> When knitting straight, the beginning of a new row is a stitch on which the working yarn is connected. <S> When knitting straight with circular needles, one knits till one exhausts all the stitches in the working row, flips the needles (such that working needle is now in the opposite hand), and starts a new row by first working the last worked stitch, with the opposite side of the knitting facing us. <S> In comparison, while knitting in the round, once the knitting is joined, one never encounters the last worked stitch. <S> Also: Many airlines have arbitrary restrictions on straight needles. <S> Circular needles are great for getting through security. <A> You can get needles longer than straight needles (which max out at about 16 inches) for working wide pieces like a blanket or a sweater for fat Uncle Ed. <S> As your work grows on straight needles the weight can take a toll on your wrists and hands. <S> Seamless sweaters can't be done on straight needles. <S> If you're into making socks <S> there's the magic loop method of working two at a time (TAAT) that can't be done on straight needles. <S> If you're making a tube (sleeve, sock, pullover) you can use a circular needle instead of double points. <S> Then you only have the one needle to keep track of instead of 4 or 5 double points. <S> If you drop one or both they don't go anywhere.
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With circular needles most of the weight is in your lap.
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Trying to turn a vintage wash basin into a vessel sink. How can I get rid of this standing water? First off I screwed up where I drilled the hole for the drain. The middle of the bowl is actually raised so the water pools in a circle around the drain: I'm curious what my options are now... Is there any way I can salvage this? There's about 3-4mm of standing water in a ring around the bowl. Could I put another smaller drain in back of the bowl? I'm wondering if I could even plug the hole I drilled and not have it look awful. <Q> If you don't object to a transparent substance in the bottom of the basin, you can use acrylic casting resin, aiming for a product which specifically advertises itself as clear, as some of the available casting resins are not. <S> Mixing the product per directions and pouring it into the basin with a bowl under the drain will allow you to place the exact amount, while the excess runs into the bowl. <S> Ensure that the basin is perfectly level prior to the pour for what I hope is an obvious reason. <S> It's typical to subject casting resin to a pressure pot to remove bubbles, but that's not necessarily practical in this situation. <S> A heat gun (preferred) or hair dryer will help to clear bubbles. <S> As a possible bonus, you can mix a small amount of glitter or similar decoration if you wish to add a different touch, although that's not consistent with the flower motif currently in place. <S> This may not be suited if you intend to use abrasive cleansers on the surface, but they can be polished out with appropriate abrasives and plenty of labor. <A> There is nothing you can do, except to put in another drain. <S> You cannot tilt that bowl in any direction that will but the hole you have at the bottom, so there is no way to avoid the standing water without having an additional outlet. <S> If you want it to be unobtrusive, the best place to put an addition hole is toward the front of the vessel (the side farthest from the tap), since a user will generally spend to most time looking toward the back side of the bowl, underneath the tap. <S> Unfortunately, if you want to be able to fill up the sink, you will need to have plugs for both holes. <A> You could make another little flat hole on just one side of the round plate and have a little plumb to converge from there in the main central plumbing, so as the main hole will got the direct water and the new small one just the remaining. <S> Obviously you'll need a little of inclination to get the water stream to the right direction. <S> Just an idea.
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Plugging the center hole will probably (as you suggest) result in something that does not look very good (unless you can perfectly match the color on the ceramic), so I think your best option is to introduce a smaller additional drain hole somewhere along the bottom of the trough.
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Is there a tool that will make a rounded cut in flat metal wire? Is there a tool that can cut flat 5mm-wide aluminum jewelry wire to leave a rounded end? (An as-yet nonexistent extremely heavy duty nail clipper comes to mind). In the image below, the wire on the left is an example of what we started with. We've used a grinder to round the end of the wire on the right. If we could just cut it in a round shape and then polish the end, it would save a lot of metal dust about a minute of grinding per end (and we may have hundreds to do). An answer to this other question mentioned the use of a deburring tool, which may be useful after making a round cut. This metal piece helps snug a medical mask to a person's nose. We wanted it to be rounded to prevent it from breaking through the material. My wife is making medical masks for friends that are health care providers who are worried about the current mask shortage. Hers is a five layered design that I'll encourage her to post soon. Without this metal piece, air leaks around the nose. <Q> It will need sharpening fairly often (a diamond file is probably easiest) to go through easily but should do a good job. <S> Use scrapwood clamped down securely as your anvil. <S> I don't have a gouge, but I've tested a straight chisel successfully. <S> My scrap aluminium is 3mm thick and a cut of about 8mm long took a couple of blows with a carpenter's mallet on the back of my roughest (not very sharp, as well as chipped) chisel. <S> This is bigger than your cut, so you should be able to do it in a single blow. <S> An offcut of oak worktop was a much better anvil than softwood: the cut was easier and the burr on the back much less. <S> If doing a lot you may wish to make a jig, or at least attach a fence/length guide. <S> There are also curved tin snips, but ones as curved as this old pair are rare nowadays. <A> I think the best option are sheet metal cutting shears, either manually handled ones (like heavy duty scissors), or electrical ones (power tools), although the latter one seems a little overkill for these small strips. <S> Here is a demonstration video of both. <S> You can get quite clean cuts with the 'scissors' variant. <S> A variant of these, referred to as 'tin snips' or ' aviation snips ', seem to be a perfect match for your intended use. <A> Pure Aluminum melts at 660°C <S> so a soldering iron won't be enough, I suggest you to use a Blow Torch that can reach a temperature of 1300 <S> °C, if you keep the wire vertical and melt it the end of the cable would result in a perfect round. <S> Be careful, droplets are very hot, it's much worse than a classic soldering burn! <A> I popped out a 'net search using "scalloped edge shears" and found a variety of sewing related cutters that may work, if your material is thin enough. <S> The first link I selected, from Amazon , has a user question regarding the size of the scallop. <S> It's 5 millimeters, although there are others with 3 and 7 mm sizes according to my search results. <S> It's important to note that the edge on the downstroke will probably have a bit of a burr, but one can remove the burr with a few strokes of abrasive material such as sandpaper. <S> The shears will not last long cutting aluminum, but may provide for a few hundred cuts before needing replacement. <S> It's important to note that you'll have to carefully align a 5 mm wide strip with a 5 mm wide cut to ensure you get a smooth profile. <S> It might be more practical (easier) to use a 7 mm scallop to provide a bit of leeway. <S> A jig of sorts holding one handle of the shears braced against a surface, along with a guide channel to place the material consistently will facilitate production. <A> aluminium is very soft, maybe you can use some kind of press to get it into shape? <A> Ok all you need to do is either get a bag of glue sticks put them in something like a tuna fish <S> can use a sterno can for heat or however you choose to heat <S> the can of glue sticks cut your strips <S> dip <S> the ends in the hot glue <S> im sure the more you keep the hot glue as liquid as possible the thinner the material left after dipping let cool or rapidly put in cool water to instantly set the glue if you have any streamers use a heat gun to quickly clean up the excess streamer/ problem solved think of a bobby pin and how the ends are on one to prevent it cutting skin when put in hair in fact get one and pull the end off <S> and you will see why bobby pins look the way they do there is many other ways to do what your asking you can take a pair of plyers and a dremil with a cut off wheel and grind one face of the plyers jaws smooth the other jaws <S> do the same except you leave a raised section that looks like this U a little profileing to <S> give the shape of the U when viewed from The side it looks like this V hope this helps
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The heavy-duty nail clippers you were thinking of do exist , but I suspect that they'd push the strip out when you squeeze them. As you're only working in thin aluminium, I suggest a gouge chisel .
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What kind of paint should I choose to start painting? To start painting what paint should I choose? Oil, acrylic, or another? I use pencils now, and would like to upgrade to colors. <Q> A lot is based on opinion where to start. <S> As a child, I started with watercolor. <S> For some artists, they say that watercolor is more difficult because of how fluid it is, and how it spreads compared to other paints. <S> Making it more difficult to control for a first-timer. <S> Acrylic could be a good start, because it is easy to dry, and you can get more done with acrylic paint, over a short amount of time. <S> Compared to oil paint, that will take a longer time to dry. <S> Oil paint can be very messy for a beginner paint. <S> It really depends on what you would enjoy. <S> I found enjoyment in all three paints, but each one is kind of their own kind of technique and ability. <S> From personal preference only have found mine to be from easiest. <S> 1)Watercolor. <S> Pros: fluid colors, dries fast. <S> Cons: Could spread to other colors and ripping paper from getting damp. <S> 2)Acrylic. <S> Pros: <S> Fast drying, can make layers fast. <S> Cons: Not as well blended colors. <S> 3)Oil paint. <S> Pros <S> : Blends well, combines colors well. <S> Cons: Takes forever to dry, messy, and if you aren't careful could get on clothing and stain. <A> I would start with acrylic paint. <S> It’s not too expensive and also doesn’t take months to dry/, versus oil paints.. which are pricey, messy and takes a long time to dry. <A> I'd recommend watercolor. <S> I started on them and the paper can be used on both sides if you get good quality. <S> Blending is easy to do and you can easily control the color's intensity.
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I have found with oil paint, it is beautiful ability to blend colors, compared to acrylic or watercolor. It depends on what you would like/enjoy to get involved in.
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How do I replicate this misty spray paint texture/pattern? I am restoring some old Microscopes and the existing coatings are in poor shape. I would like to strip the castings and refinish them to look as original as possible. Unfortunately, I am unable to determine what coating or process was used to achieve the fine water mist texture as shown: Is there a paint or process available to achieve something at least close to it? <Q> It's not quite exactly the same texture, but wrinkle finish powdercoat may qualify in that it's random and irregular. <S> Using search terms "texture powder coat" provides a number of similar finishes, including hammertone and silver vein, the latter shown below: <S> If there is a powder coating service in your area, they can advise of the available finishes. <S> You can also purchase a home powder coating system which can be used with an inexpensive (yard sale) toaster oven for small parts. <A> The best way i could think of getting this would be to hold the spray paint far back from the object. <S> This will usually result in some sort of bumpy texture like the one pictured. <S> The only real way to do this would be a special powder coat, but <S> im <S> assuming you dont want to pay for that. <S> You could also try stippling with a brush and thick paint. <S> My last idea would be getting a grip spray paint/anti slip paint. <S> These are the only ways using spray paint I can think of to get that texture. <A> The true way to do it is as fred_dot_u (upvoted your answer!) <S> suggested - a powder coat. <S> However if you did want to hack it, you could spread a very thin layer of elmer's glue or a spray adhesive and roll the surface in a light layer of sand and let dry for a couple of hours. <S> Once fully dry, spray paint it over. <S> That should give you a similar sort of texture. <S> My husband uses this method when he paints mini figurines and mini landscapes, and it works well.
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If the material is metal, one can use a wrinkle finish powdercoat to accomplish this result.
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What is the best method of hanging canvas on a wall to work on? I've seen several videos and images of artists having their canvas stuck on the walls - paintings that they are currently working on. I was wondering how they stick/place it on there? These canvases are still unstretched and aren't framed, like those in the background of this picture: I've tried using sticky putty but it isn't so effective when stuck on canvas. Also duck tape isn't so effective. Would appreciate any help, thanks! <Q> Staple gun or hammering finishing nails to the wall. <S> How will it be presented after completion? <A> Because the canvas will have to endure a lot of tension and movement, especially when you work with large and rough gestures, and because canvas consists of fibres and has a lot of texture, using tape or putty won't work. <S> You need hardware. <S> Make sure to stretch the canvas as much as you can while attaching it to the wall, so it is as flat as possible, and you can work on it cleanly. <S> Also consider grounding the canvas after pinning it to the wall, so it will become even tighter. <S> In case you take this approach, staples or nails are more appropriate, as they have a stronger grip (depending, of course, on the length of the nails, staples, and thumb tacks, the method used to put them in the wall, and the material of the wall itself). <A> If you're working with a concrete wall, the best bet with minimal damage all around would be RebusB's suggestion on attaching it to a wood board. <S> Stretch it prior to attaching <S> so it's taught and staple down onto plywood <S> - this will give you the flexibility of moving it from one place to another as you need and minimal damage to the concrete wall. <A> I use thumbtacks too, sometimes even just tape for small canvases. <S> and once you are done painting, you can stretch it very tight (though it is much harder to stretch a finished painting) as the paint is still flexible (I do it with oil paintings, it maybe different for other mediums or very thick paint) it will "adapt" and it won't crack on you or something. <S> Do not apply varnishes before stretching.
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It is easiest to use prestreched, factory gessoed canvas, but you can also stretch the canvas on a temporary frame, gesso it and then unmount it and, relatively, paint on it loose, the gesso drying pretty much stiffens it In addition to Not The Face 's answer, I suggest using thumbtacks .
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Where can I find good crocheting patterns? I'm pretty new to crocheting and am trying to find interesting patterns online. I'm especially interested in crocheting rugs. Sadly, I haven't had too much luck finding patterns for them. Can somebody recommend a good site or a person to get crocheting patterns from? <Q> The best resource for all crochet and knitting needs by far is Ravelry . <S> Ravelry requires you to create an account and provides an astounding library of patterns, yarns (so it's easy to find a substitute), a community platform and your own project notebook. <S> Some paterns are paid-for, but many are available free. <S> As of me writing this reply there are over 1600 crochet <S> rug patterns listed on Ravelry <S> , some 600 of which are free <S> Youtube is full of crochet tutorials if you look around a little. <S> For example Elena Rugal has a great library of crochet technique videos <S> If you want to dig into public domain resources, Antique Pattern Library has a section with hundreds of old magazines with patterns, though they may be hard to read for a modern, inexperienced crocheter because of the differences in writing style and extensive use of abbreviations <S> Yarn brands publish their own patterns, for crochet I particularly recommend Scheepjes . <S> Similarly, many magazines exist and can be bought both online and in paper, check out titles such as 'Inside Crochet', 'Molly Makes' or 'Love Crochet'. <S> Note that most of these will be included in Ravelry's library <S> Finally, there are countless crafty blogs, <S> e.g. Moogly's , with tutorials and patterns <A> Woolpatterns.com lists a lot of very nice patterns. <S> I signed up for notifications from them and haven't been disappointed once. <A> While there are a ton of sources, such as Ravelry , that offer a lot of patterns, you have specifically asked for "good patterns. <S> " <S> Ravelry allows user submissions, which means that many patterns may have typos, defects, or other issues that make them considerably less than "good." <S> In general, when looking for new patterns, you'll want to focus more on those that have been tested, not just written out. <S> If a given pattern has a comment or review section attached to its page, read through it to identify any errors that others may have already found; if there are no reviews, check other patterns by the same author to see if they have a record of issues with their other patterns. <S> As a beginner, you may wish to lean more on sites designed specifically for teaching. <S> There are a few rug patterns available there, and the additional resources in the form of explanations and videos can help you gain the skills to start identifying good patterns from other sources and take them on as well.
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I've had very good luck with The Crochet Crowd ; many if not most of the patterns are linked (with permission) from the designs available through yarn companies directly, but with extensive notes and video tutorials that address both actual errors and design elements that may feel like errors but are correct.
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Can you use Poster Paint for fantasy miniatures? I recently came across an old version of HeroQuest whilst having a sort-out, and remembered back to when I used to paint these (as well as some other similar) miniatures. I also remember how much they cost. So I was looking at some videos on YouTube and found a few people using general hardware store acrylics, and figured this would be a great idea, as they're inexpensive, and actually come in a great range of colours. The only thing I don't like is the fact that they are in tubes, and you have to mix them together on a pallet. I thought, "what if you could get some pots like the ones old Citadel Miniatures had back in the day?". I did a search at a local (UK) shop and couldn't find any empty pots, but found these: So they're 'poster paint', not 'acrylic', but the pots are exactly what I'm looking for. But I wondered if painting miniatures with this is possible at all? It seems a shame to waste them. I would be using a general spray primer for the undercoat, and probably a clear spray for gloss, but will these affect the paint? <Q> I strongly advise against using poster paints for miniature painting. <S> Poster paints <S> are described as (emphasis mine): a distemper paint that usually uses a type of gum-water or glue size as its binder. <S> It either comes in large bottles or jars or in a powdered form. <S> It is normally a "cheap" paint used in school art classes . <S> With the correct primer the paints should be able to stick to the miniatures, but in contrast to acryllic paints they stay water soluble after drying. <S> They are vulnerable to moisture and abrasion and rub off while handling the miniatures. <S> A protective sealing coat could help, but any sealing (either spay or brush-on) is a liquid, which starts dissolving the paints again. <S> You'd need to very carefully spray several thin coats of sealing or you risk your paints bleeding and loosing details. <S> The biggest problem, though, is the quality of the paints, more precisely the pigment density. <S> Poster paints are usually cheep and intended for kids to paint on paper. <S> You can have a whole lot of fillers and just a tiny amount of (expensive) pigments in those paints, because all they have to do is cover a white piece of paper with a colored paste. <S> In miniature painting, you want to apply coats of paint as thinly as possible to preserve all the details in the miniature. <S> You may want to layer different colors or highlight a detail on a dark background. <S> You need paints with a high pigment density for this job, or you'll be forced to literally cover the miniature with a colored paste, just to paint a white dot on a black background. <S> That's usually the reason why dedicated paints for miniatures are as expensive as they are. <S> They contain much more pigments than your average hobby paints. <A> It has relatively large colour particles . <S> This makes it harder to use for detailed painting, as well making it more opaque, allowing for less blending options. <S> Poster paint is usually dissolvable by water , making your miniatures more susceptible to discolouration. <S> It is cheap for a reason: the pigments are cheap and coarse , and not very lightfast . <S> It easily gets muddy , since many hues actually consist of several colours. <S> As always, there are more expensive poster paints, that have far less of these defects, but buying those would defeat the purpose of your question. <A> You can, but its a pretty bad idea. <S> Acrylic paint is permanent, and has many good qualities. <S> Its highly pigmented, fade resistant, and has various other properties. <S> Poster paint is made for paper, and thats it. <S> Its most likely going to fade and fall off. <S> Maybe youre looking for something like these: https://bit.ly/2LXKinH
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The poster paint is also designed to be used on large areas, and using it on a small paintbrush isnt going to be easy. I don't recommend using poster paint:
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A kind of paper where you can pull away the top layer? I’m trying to make a Mother’s Day art project with my toddler. My idea is to trace their hand on some special paper, use a craft knife to cut the hand outline out, and then pull off the hand. My toddler would then paint the paper, and once done, I would pull off the entire top layer of paper so only the hand print persisted. Does paper like this exist? What’s it called? Any recommendations on where I can obtain it? Bonus if a kind of paper exists that reacts to heat and causes it to dissolve, letting me use a laser printer to cut out the hand print instead of a knife for better accuracy. Thanks! <Q> While Elmy has the right idea with masking tape, I have found that, in practice, even the gentlest painter's tape tends to tear up paper. <S> What you want here is temporary repositionable adhesive (glue). <S> It's available under a variety of brand names (Aleene's Repositionable Tacky Spray, Aleene's Tack-It Over and Over, Elmer's Craftbond Repositionable Glue, 3M Spray Mount Repositionable Adhesive, etc). <S> These glues come in a variety of forms (spray, stick, and liquid) and function much like the line of glue on the back of a Post-It note--they hold in place, and peel away easily. <S> Because of how gentle the glue is, it's very unlikely to damage paper when pulled away. <S> Cut the paper, run the glue around the cut edge, and follow the instructions on how long to let it dry before adhering it to your heavier ground, pressing along the cut edge to ensure it's as sealed as possible before giving it to the child to paint. <A> I hope I understood your plan... <S> You want to create an outline of the hand, let your toddler draw all over the place, then remove any paint from outside of the outline? <S> That's exactly what masking tape <S> / painters tape is there for. <S> You should probably use a somewhat thicker paper or white cardstock as your base. <S> Cover the whole project with a layer of masking tape and outline the hand of your toddler. <S> Then carefully cut through the masking tape along the outline and remove the masking tape inside the outline. <S> Let your toddler have some fun with paints and when they are finished and everything is dried, you peel off the remaining masking tape. <S> If your child is supposed to color the hand with pencils, the masking tape could be dislodged in places. <S> I think crayons would work very well for this project and create a nice, sharp outline. <A> While not a single piece of paper with removable top it allows you to create essentially the same set up. <S> Frisket is a thin film sheet with low tack adhesive on one side. <S> You attach it to your paper, cut out your shape, lift off the sections you want to paint, then let your child go to town on it. <S> When done just lift off the frisk. <S> Some are even reusable so you can make multiple versions. <S> It is basically a stencil that sticks to the paper. <S> I have used it often when doing air brush work and it is very versatile and easy to use. <S> You could even cut it before attaching to the paper, so the laser cutter option is there too.
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In a project like yours, you may wish to use a stick or stick and spray combination, to ensure you get enough adhesive around the edges of the cut-out to prevent glue from bleeding underneath. What you are looking for is called frisk or frisket film .
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How much fabric is needed in this instructional? My wife comes and asks me whether or not she has enough fabric to complete a project. She gives me a square footage of what we have on hand and then a yardage — not square yardage — called for by the instructions : I double check just in case, but nowhere does it state a width on the page. So then I think to myself, "there must be some standard width then, that's common or universal to textiles?", except a Google search later my conjecture is unceremoniously debunked. Is the author going senile or is there some secret trick to converting one-dimensional units into two that only the textile industry is privy to? <Q> The instructions you've posted call for "two 43" x 65" pieces of fabric. <S> " While there are a wide variation of fabric widths available, the standard US widths are (approximately) 45" and 60". <S> As this piece easily fits into a length of 45" fabric (which is often actually closer to 43"), it stands to reason that the pattern is calling for the more common 45" width. <S> Therefore, you need the called-for 7 1/4 yards of 45" fabric, in an appropriate material (heavy for outdoor use, any for an indoor play tent). <S> Note that you could also purchase 60" fabric for this project, but you'll have more left over than if you used 45" fabric; patterns that can use either size typically won't call out the width specifically, or will give different yardages for both. <S> Patterns calling for 60" fabric specifically will be explicit about the width, as these patterns generally include pieces that won't fit easily or at all on a 45" wide piece of fabric. <A> I just returned from the JOANN Fabrics and Crafts web site. <S> A search of "fabric" resulted in hundreds of returns, no surprise there. <S> I found material as narrow as 19" and as wide as 72". <S> This reference is USA only, as I don't know if standards in the countries using the metric system will be different. <S> What you'd have to do in the case of this project is determine the narrowest bolt that will fit the widest part of your cuts. <S> Obviously if you have a part that is only 40" in one dimension and much longer in the other, you'd be able to cut it from a 48" bolt. <S> If a part is unusually large, say 75 x 70, you'd have to have something at least 70 inches wide. <S> A tent implies rugged use, unless it's an inside play type tent. <S> You should be able to identify "common" but not standard widths for bolts of your choice of material and do a bit of math to determine the necessary quantity. <S> I agree that it would have been useful to have a width reference in the instructions. <A> The width varies by the type of fabric. <S> Quilting cotton is almost always 44/45” wide, apparel fabric is most often between 44” and 60” and home decor fabric is usually 54”. <S> source Note the last bit. <S> 54" is 43"+10"+1" for seams. <S> Fits the instructions perfectly: <S> (2x 43"x65", 2x 10"x65") <S> There is nothing wrong with the directions... you just need to get 2 x 65 <S> " (the longer dimension) = 130" = <S> 3.6 yards of home decor (54" wide) fabric. <S> This is an indoor play tent, so it is likely that is what they are assuming you would use. <S> That gives you exactly the material needed to make the 4 panels.
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The width of fabric is usually measured in inches (in US) and most common widths are 44/45 inches and 60 inches. What was a surprise was a "standard" width is not standard.
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How can I force metal sheet to rust rapidly? Basically my metal sheets are new and I need them to be with that rust effect rapidly. Thanks <Q> The corrugated certainly looks like galvanized steel where some galvanized has corroded. <S> You need to remove the remaining zinc . <S> Dissolving it with hydrochloridic / muriatic acid would be fast , 10% should be strong enough. <S> Salt water, vinegar, citric acid etc, would do it but slower. <S> Once the zinc is gone it should rust pretty fast , a little dilute salt or acidic water spray will speed it up. <A> The least expensive method to rust a sheet of metal would be a light spray of salt water. <S> Even ordinary water will rust steel if it's not particularly rust resistant. <S> I've used 4130 chromoly steel which rusts overnight if left with moisture on the surface. <S> Diluted chlorine bleach will cause rapid corrosion in aluminum, nearly instantaneous, but I'm not sure if the same effect will happen with steel. <S> Chlorine is corrosive to steel, it's the time involved that I'm unsure. <A> Usually within minutes. <S> I've put to mixture into spray bottles and it has given rusty results. <S> 16oz Hydrogen Peroxide2oz White Vinegar1/2 tbsp of salt
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A mixture of hydrogen peroxide, vinegar, and salt will cause steel to rust at a fast pace.
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What tool or technique is best for cutting circles in matte board? I am laying out a frame where I will have to cut approximately 200 aligned 35mm circles in a matte board or foam core board. I will be putting plastic coins into the holes and backing with another board (exposed foam board or something with a little give to mould to the piece) to secure the coins from sliding or rotating. I purchased a Fiskars Circle Cutter but have discovered through testing that while the device can make the circles, it lacks the depth to cut through the whole board. I checked to see if they sell a replacement blade with more exposed length but they do not appear to. This then resulted in me fiddling about with an Exacto knife trying to make a clean completion cut. If I had to do a few holes I would accept this method, but I am somewhat nervous at the thought of repeating the process 200 times without scoring or marring the matte. Is anyone aware of a simpler technique? I believe a punch is probably the correct tool, however I am reluctant to invest too much for a one-off project. I also considered using a bore saw and my hand drill but am concerned that it would just make a horrid mess of things. <Q> A hole saw should work fine if you can find a fine tooth model. <S> They are not as easy to find as the common coarse teeth models meant for wood. <S> One with a thin kerf would be best. <S> I have also used the sharpened steel tubing trick mentioned by @fred_dot_u. <S> An alternative to punching is pressing the sharpened tube against the board and spinning it. <S> The spinning action makes it work like a circular knife, cutting the fibers cleanly. <S> If you can't find a 35 mm steel tube, you can get almost as good a result by wrapping thin aluminum from a soda can around a 35 mm thick piece of plastic or wood. <S> To align the holes perfectly, it will help to make a template. <S> Cut three holes in a smaller piece of board, align two of them to existing holes on your workpiece and then put your cutting / drilling tool in the third hole to keep it in correct position. <A> Using a file or grinding wheel, work away at the outside edge of the tubing to create a sharp edge. <S> Further refine the edge with sandpaper of gradually increasing grits. <S> You can stop periodically and test your work by placing a piece of the board atop the pipe, sandwich it between the pipe and a piece of solid lumber. <S> Hardwood end grain is best, also more difficult to source, but for a 35 mm hole, not as bad as a 200 mm hole. <S> Rap the wood with a mallet until the hole is created. <S> This process will eventually dull the edge, but you can touch it up with a file (or grinding wheel) as needed to keep a clean cut. <S> You can also place the lumber under the foam board and wallop the pipe. <S> Laser cutting is an option if there is a suitably equipped maker space, but that will leave burned edges unless the power is quite high. <S> My 60w laser will create discolored edges and also under-cut (melt) the foam in foam core. <S> Hobby cutters may work but require more than one pass. <S> CNC routers will definitely work (maker space possibly) and if one equips a CNC router with a drag knife, you're good to go. <A> Have you tried using the circle cutter from the front and back? <S> On mine the centre pin is long enough to mark the back of the foam board I've used, but you may need to push a stiff pin through in your case. <S> You do need to be very careful to hold it exactly vertical if you're doing this, or the holes won't align, but that's always true in thick material. <A> You're gonna need a bigger boat! <S> .. <S> I mean knife .. <S> The simplest would be to have a blade manufactured (or 3d printed if that gets sharp enough edges?) <S> that meets your criteria, e.g length. <S> if you order a bigger batch, they might get cheaper. <S> Also you could try finding a blade from another manufacturer and then build an adapter to fit it to yours. <S> If you post some photos, people could come up with solutions. <A> A "circle clicker die" in a "clicker press" will do the job cleanly and efficiently at just a few seconds per hole. <S> Circle clicker dies are available online in many sizes, and a clicker press can be found in any shop that makes leather goods. <S> The shop might even have the exact size clicker die that you need. <S> If you lay out the matte board with appropriate pencil marks where the holes need to be, it should all go smoothly. <A> Several years ago I had my own "mount these coins" project. <S> My solution was to use a forstner drill bit mounted in a drill press. <S> In my case I was mounting dimes in matte board and they squeezed into the holes very nicely. <S> It sounds like you are mounting US fifty cent pieces which are slightly larger than the 30mm that you mentioned, but should be able to nicely squeeze-mounted in 30 mm holes. <S> If you Google "50 mm forstner bit" you will find several choices ranging in price from $9 to $25. <S> If you are going to drill only 200 holes in matte board, a less expensive bit will certainly be adequate. <S> You will need to carefully mark the locations of the centers of the holes <S> and I would push an awl through the matte board to help make certain that the tip of bit goes to the exact center of the hole. <S> As with any first time project, it would be wise to make several practice holes so that you certain that you can get each hole started exactly where you want it to be. <S> You will want to set the speed on the drill press to approximately the middle speed on the drill press. <S> Of course if you do not have access to drill press (any woodworking pals?) <S> all bets are off. <S> I would not try this method with a hand held power drill because the quality and consistency of the holes is quite likely to suffer.
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You may be able to create your own punch by finding a piece of steel tubing of the correct inside diameter for your holes.
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How to retroactively remove the shiny effect of graphite pencils? I made a sketch using graphite and charcoal pencils in low-light. When I looked at the sketch under normal lighting, it was very shiny. How can I retroactively make a graphite sketch less shiny? <Q> If you use graphite, then you have the properties of graphite: it conducts electricity and it shines. <S> You can try some of the following: special plastic sheet, used instead of glass, to protect the front of the paintings; it was especially designed for the purpose to minimize reflections; apply a layer of fluid, which will cure into a non-glossy solid; e.g. hair spray, special fixating spray for graphite / charcoal / crayon drawings; linseed oil (or any other oils for painting)... <S> Note: before you apply anything on the original drawing, make a test on a separate piece of paper, on which you draw some shape. <S> In that way you do not destroy the important art, trying to improve it (see below a sample of what I mean). <S> Be warned: I am not an artist and I did not try any of this myself (yet). <A> Vertruvian Fine Art Studio, an online drawing and painting school has a very good answer to your question, provided by instructor David Jamieson. <S> The shininess is "burnishing" which happens when an area is worked too much or you press too hard. <S> He says: <S> " In my experience, there are only 3 ways to prevent your pencil drawings from becoming burnished: <S> Limit the amount of graphite on the page. <S> Limit how many times you rework an area. " <S> More detail on these is provided in the article . <A> Actually I doubt that there's a way to do that. <S> Every drawing medium has its own traits and one of graphite is to be shiny. <S> (To be honest, I like that a lot about graphite, so <S> it's not a bad thing). <S> Because of the different shininess I simply wouldn't use charcoal and graphite together in one picture. <S> You can try adding a layer of matt varnish (a spray one). <S> It will make the overall picture matt, though I'm not sure if it works with graphite's shininess. <S> Also your paper shouldn't be too thin or it will become wavy. <S> For the future you could try switching completely to charcoal. <S> You are able to create similar drawings as the one you drew but charcoal is not shiny.
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Using 7B instead of charcoal will give the drawing an even shiny effect. To make it less shiny after using it, you most likely need to apply a layer of something which washes away (partially) the shine, but still leaves the drawing visible. Limit how hard you press with the pencil.
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How can I use a fountain pen while onboard an airplane? When a fountain pen is onboard an aircraft, it can leak ink due to the strong pressure difference inside the pen vs. outside the pen. This can result in messes to clean up on the flight even if the pen is not used, and at best ink blots when it is used. Most of the advice I've been seeing about bringing fountain pens onto airplanes is that one should either completely fill them, or leave them completely empty before boarding the plane. However, this only works for storing the pen while in flight, and not for actually using the pen while in flight. How can I effectively use a fountain pen while on an airplane? Is the only way to leave it empty and to fill it while onboard? I can think of a design for a pen that would allow it to be used on a plane effectively (store the ink in a bladder that changes size), but are there any pens that work like that? <Q> There are things you can do to reduce the risks, as described in the other answers, but I would be wary of using any kind of pen containing liquid ink on a plane (although a "felt or fiber tipped" pen may be OK; never investigated that). <S> I've had a Pilot Precise technical-style pen that uses disposable refills (the entire guts of the pen), leak while sealed in the tip-up position. <S> If you need to write on a plane, pens with gel ink (which also includes most ballpoint pens), are much less likely to leak. <S> The best type would be a Fisher "Space Pen" (various other pens can also use those refills). <S> These are manufactured pressurized and are designed to use that pressure to feed a very thick ink without leaking (they can write in the vacuum of space without leaking). <S> If writing with a fountain pen is important, I would just wait until you land to do it. <A> That means you should be able to use it without a problem. <A> There are flexible ink receptacles for fountain pens known as ink sacs or bladders, like these: source <S> However, they apparently don't give any advantage over rigid cartridges when it comes to air travel <S> ( here : " sacked pens also have trouble with rapid pressure changes ", which is understandable as the material is quite rigid). <S> What you can do, is to always point the nib upward , as any air in the cartridge or sac will expand during cabin pressure adjustments and will force the (negligibly influenced) ink out of the nib. <S> Having the nib topside will minimize potential flow. <S> This is also why having the cartridge completely full (that is, without any air inside) causes the least leakage problems.
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If boarding with it completely full prevents leaks in storage, that's because there's no bubble of air at ground pressure in the ink. After having used it (and before descending) you can always take out the cartridge and place it in a sealable container or bag.
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Remove scratches from a (resin or plastic) stuffed animal eye I recently visited my childhood home and brought back some of my old favorite stuffed animals. One of them, Snip the Beanie Baby, has noticeable scratches/dents/nicks/chips on her eyes. What is the best way to repair scratches like these without resorting to a full replacement of the eye? Do I need to know if it is resin vs plastic? If so how can I find this out? EDIT: In my case specifically, this toy will remain in a child-free home so I do not have to worry about choking hazards/mouth hazards. I will care a bit about toxicity because she will continued to be snuggled (and thus have human skin contact). <Q> The eyes are almost certainly molded thermoplastic of some kind rather than a cast resin (casting resins are too expensive and time-consuming for a high-volume, mass market item like these eyes, and are generally risky for items that may end up in a toddler's mouth). <S> The specific plastic probably depends on how old the stuffed animal is, and where the eyes were manufactured. <S> Without knowing the plastic, it will be hard to fill the deep pockmarks. <S> The fill material may not bond to the eyes, and may have a different refractive index so repairs could end up as very noticeable dots. <S> However, there are a couple of things that might make the damage a little less apparent. <S> You would probably want to remove the eyes for repair and then sew them back in to avoid damaging or staining the fabric (if it's synthetic fabric, the heat suggestion will likely melt it; if it's natural material, polishing the eyes will soil it). <S> Heat: Thermoplastic can be remelted. <S> You don't want to apply so much heat that the eyes melt into a blob; be careful to use just enough heat to soften the surface. <S> If the heat is too high, you can scorch the surface, so use a heat gun at the low setting. <S> Hit the surface for a few seconds until you see signs of the plastic getting shiny. <S> Then stop and let the eyes cool back to room temperature. <S> You can repeat this a few times. <S> This may make some of the damage less noticeable, but don't expect to be able to have deep scratches or pockmarks level out. <S> Polishing: <S> Fine scratches and damage with a "frosted" look that makes the damage very visible can be improved to make it less noticeable by polishing. <S> There are plastic polishes, but you can use ordinary toothpaste, which is mildly abrasive. <S> Polish the surface with an old toothbrush and some toothpaste. <S> Clean off the toothpaste residue, then buff the surface with a cloth (a soft, natural material like cotton; synthetic materials may scratch the plastic). <S> It will help, but this won't work miracles. <S> Or, don't "fix" it at all. <S> This is a sentimental item. <S> The scars tell a story. <S> Love it for what it is and its history. <S> Don't try to turn it into something new. <A> Additional to the polishing recommended by @fixer1234 <S> Note: depending on the exact damage, the nail polish might work even without the polishing. <S> In case you make errors, you can easily remove it with a bit of cotton dipped in acetone. <S> And start all over. <S> Warning: this solution might be unsuitable, if children still chew those beautiful eyes. <A> You can try to smoothen it out with a solvent. <S> This will not remove the scars but will smoothen them out and reduce the "white" spots caused by fragmented plastic. <S> This will require you to re-polish the eye, after applying the solvent it may become a bit dull. <S> You must remove the eye for this process if the bear is made of synthetic materials. <S> It probably is, so you cannot do this with the eye in the socket. <S> Any solvent you try should first be applied somewhere not-visible on the eye to see if it doesn't change the colour of the plastic. <S> The hard problem is finding the solvent. <S> You can start with acetone, try it out on the edge of the eye. <S> Another good one is tetrahydrofuran , I use it to smoothen and glue 3D printed objects. <S> The process will require you to dip the eye in the solvent for about 2 seconds, then use brush natural material to "paint" the top layer of diluted plastic over the eye. <S> Then dip it again, shake the solvent away and blow on it. <S> Do not touch the affected surface, it will leave fingerprints. <S> When you are satisfied, leave it to dry for a day. <S> Only after that you can start polishing the plastic.
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, you can try to apply a thin layer of transparent nail polish - preferably extra-diluted (with acetone) for a shinier / smoother final look.
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Gold nibs vs steel nibs in fountain pens - Does it really matter? I recently purchased a steel nib fountain pen of Parker. I saw that the gold nib one was more expensive and I thought that gold nib might be for style hence I didn't purchase it. What are gold nibs made of? Are they worth the price? Do they serve any other benefit other than style? <Q> Gold nib fountain pens - invented around 1850 - were originally the standard <S> as early (fountain pen) inks had corrosive properties. <S> Pens of all kinds of metal (alloys) are often tipped with 'iridium' * , as the tip will have to endure the most. <S> Apart from thickness and shape, the material qualities of the rest of the nib are decisive for the writing experience, as they determine ink flow and comfort of writing (that is, when compared to similar nibs of other materials on pens of equal size, shape, weight, balance, &c.). <S> Gold is the most malleable of the metals, so pure gold tips will relatively easily deform under the pressure of writing. <S> This is why standard gold fountain pen nibs are made of 14, 18, or 21 karat gold (out of 24k), meaning (+/-) <S> 42%, 25%, or 12,5% respectively consists of other metal(s) to strengthen the nib. <S> Nevertheless, when compared to other nibs, gold nibs are known for their suppleness, springiness, and a softer writing experience that adapts to the writer's hand . <S> Golden nibs are also praised for their durability. <S> Gold (alloy) will last longer as it is less prone to corrosion than other metals, but modern steel alloys in combination with most modern inks will wear relatively slowly as well. <S> Whether golden nib fountain pens are worth the investment is impossible to answer objectively : it depends on how often and much one writes, personal preference with regards to the writing experience compared to the (wealth and often comparable qualities of) alternatives and the aesthetics of the precious metal over that of other materials, the cost-quality and cost-durability ratios, and whether or not and to what extent one regards such a pen as a statement and symbol of prestige. <S> One author makes the compelling case that gold nibs are only really worth it when you want the additional flexibility for line variation. <S> * <S> More a synonym for 'fountain pen tip' than the actual metal, see https://www.nibs.com/blog/nibster-writes/wheres-iridium Sources: <S> https://www.penheaven.co.uk/ <S> https://www.writeherekitenow.co.uk/news/the-gold-standard-is-a-gold-nib-worth-the-money/ <S> https://www.nibs.com/content/what-fountain-pen-nib <S> Further reading: <S> https://www.reddit.com/r/fountainpens/comments/4cfflr/gold_nibs_vs_steel_nibs_and_why/ <S> https://edisonpen.com/in-praise-of-steel-nibs-2/ <A> I am not an expert in this matter, but here is my understanding. <S> The tip of the nib slowly "erodes", according to the writing style of the owner (that is why some people do not lend their fountain pens). <S> Gold erodes faster <S> , so you will get the optimum writing quality sooner. <S> On the other hand, if the entire fountain pen is steel / silvery, then a yellow gold nib would look unesthetic. <A> When it comes to gold, it is aesthetically pleasing to the eye. <S> It seems as though the manufacture comes into play when it comes to quality control of nibs and pens. <S> More so than what type of material is better to use. <S> Source: <S> Haas Berkeley http://faculty.haas.berkeley.edu/rjmorgan/openions/does_the_gold_content_in_nibs_matter.htm <A> What are gold nibs made of? <S> Gold. <S> Pretty much truth in advertising, but in terms of usability, 14k is actually better than the higher karat counts, and stainless steel is just fine. <S> 18k is often too soft to have the tensile "spring" required for flexible nibs, while stainless steel is what makes springs, and does just fine. <S> Nibs are usually tipped with a harder substance (iridium was common on vintage pens), to make them harder wearing, and polished to make them write smoothly. <S> Gold, on its own, is typically too soft for a good writing tip, and would wear out relatively quickly. <S> Are they worth the price? <S> Depends on the nib. <S> On a modern pen, though, I'd say no. <S> On a vintage Waterman fountain pen where the nib is actually flexible? <S> Absolutely. <S> On a vintage Sheaffer Touchdown or Snorkel, where the gold nib is platinum plated? <S> You bet. <S> Do they serve any other benefit other than style? <S> The main reason for the usage of gold and platinum in nibs used to be corrosion-resistance, but is pretty much as you suspected, for the "office jewellery" factor on modern pens.
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Although corrosion of nibs is no longer a problem, gold nibs have other advantages.
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Using microcontrollers in an Introductory course Are there any advantages to using small microcontrollers (such as an Arduino, etc.) with tactile, physical I/O (such as buttons, LEDs, robotic actuators, etc.)? For instance, does it help create more interest in learning computer programming, or widen the potential audience among kids and undergrads for going further in their CS education? <Q> Microcontrollers can address two important aspects. <S> The first is bridging the gap between the code, and the real world. <S> Particularly if you have sensors (accelerometer, buttons) and outputs (an LED array, sound, motors). <S> Not just to address the robotics aspect (which can rapidly get complex), but some simple game concepts (patterns, reactions). <S> Nothing which is any harder than doing the same on a Raspberry Pi with a GPIO extension, but potentially cheaper hardware (which is important if it is likely to get fried). <S> Also, if you want a battery powered device, or a small data-logger, a microbit is more suitable than a Raspberry-Pi. <S> For introductory use, I think creating a simple tilt-sensitive animation is a very effective way of making 'coding' seem more real. <S> Yes, the coding gets more complicated if you want to do more - but starting in a block editor or python avoids this. <S> The more tactile, less 'black box' approach to coding seems (according to research by the BBC ) seems to provide more up-front interest to less technical students. <S> The second aspect is working in a resource-constrained environment. <S> Admittedly this is more a advanced concept to teach, but the microcontroller is 'clearly' a different beast to a laptop or a phone. <S> Having some restrictions sometimes help people to solve problems more easily than giving them the blank sheet of 'plus anything you can find a python library for'. <S> A computer small enough to wear on a lanyard will shift the way students think about what is possible. <A> If the goal is to create more interest in learning programming (as you state above), then Arduinos are not the strongest vehicles for reaching that end. <S> The logic of void setup() and void loop() are not immediately accessible nor intuitive to a student brand new to programming. <S> That being said, I have seen firsthand how a Raspberry Pi can indeed be that inspiring device for wanting to learn more. <S> It's a full computer. <S> The simple fact that you can spend $35 on a computer (not including peripherals) is mind-blowing to start. <S> The sheer size/cost is initially surprising and piques curiosity. <S> Plus, this makes for a great conversation about operating systems and open source. <S> Students can level up. <S> A student can begin with Scratch, make music with Sonic Pi, make art with Processing, hack Minecraft with Python, learn the basics of the Linux command line, and potentially move on to Java with BlueJ. To me, it is the essence of "low-floor, high-ceiling" when it comes to learning programming. <S> GPIO pins unite programming and physical computing. <S> A student who becomes adept at Scratch can move on to interacting with lights, buttons, and sensors even from just within Scratch. <S> Using a variety of accessories, such as the Pi Camera or the Sense Hat, students can go from software to hardware seamlessly. <S> I could go on and on, but I think in terms of creating excitement and interest, the Pi is incredibly successful. <A> Advantages compared to what? <S> I will assume compared to programming abstract applications on a desktop. <S> Programming abstract applications on a microcontroller does not provide any obvious advantages, beyond teaching students what a microcontroller is. <S> You get advantages when it comes to what I call " Applied Programming ". <S> On a desktop, it's difficult (but not impossible) to come up with something that's within students' capabilities to program, is useful or fun, and of which you can't download a better version from the internet. <S> If your application involves hardware, you can't download it from the internet. <S> Something they can see and touch. <S> For some - but not all - students this offers far greater motivation, especially in a context that is more akin to a workshop than a classroom. <S> Microcontrollers are not the only way to produce something tangible, but given their low price point they are a competitive option.
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Microcontrollers + hardware allow students to build something "tangible". For one who is experienced and/or is inclined toward mechanical/electrical engineering, then Arduinos are fantastic. If you're not producing something tangible, I don't see much benefit to using microcontrollers.
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on-What are pre-requisites for teaching version control to a high school CS class? I'm interested in introducing version control to a HS CS class, and was considering starting with Github since it's a fairly standard tool used by developers. What are pre-requisites for understanding version control that I should make sure students master first? Any suggestions on other ways to introduce this topic to students are definitely welcome! <Q> The biggest one for me would be a reason to use version control. <S> When you're writing small lab assignments, version control probably isn't worth all that much. <S> It's when they get to a point where projects become larger than a handful of methods, or when you're working on separate pieces of a larger project with partners that it becomes useful. <S> Version control, specifically Git and GitHub, is definitely on my list of new topics to add to my 2nd year course next year. <S> My students are doing collaborative projects right now <S> and it's painful to watch them email code back and forth. <A> Version control and the associated tool addresses the following (at least) Backups (for when you lost or deleted something) History of changes (for when you made a mistake and need to go back) Collaborative working (sharing and merging) <S> Reviewing <S> Bug fixing and development on different branches <S> As I've written these, I think they're roughly in order of being less obvious or harder to grasp. <S> Everyone is familiar with the need to keep a backup of an essay (we hope) but the idea of going back to look at how something was written at the start of last week's lesson is rather more unique to writing code. <S> This is roughly the same point where you start to care about loosing something (to start with, code gets better if you write it, throw away and start from scratch again). <S> Although it's slightly tangential, I would also say it is better to talk about review and collaboration before introducing version control. <S> I don't think it's as important to be in a position (from the start) to need to explain about switching between different branches, cherry picking, etc. <S> A lot of the really useful ideas come from the head, logs and diffs. <A> The pre-requisits <S> Use of a computer to, create some artefact (e.g. document), and to then improve on this artefact (create multiple revisions). <S> However It may be possible to teach a non-computerised revision control system. <S> What to revision control <S> The artefacts do not need to be source code. <S> We often mix up revision-control with source-control. <S> However revision control can be used for so much more. <S> You can use revision control for every file in your home directory (I also revision control /etc ). <S> However to get the best value from it, you will need a good diff tool for each file type. <S> Thus making Microsoft's Office documents not a good choice. <S> Therefore it may be better to start with some other artefacts, that are not programs. <S> Which tool. <S> There are many revision control tools. <S> Three of the most powerful/popular are git, mercurial, and subversion. <S> The tool that you start with, will make a large difference to the learning. <S> git ( git ): very powerful, distributed repositories, very hard to use/learn, flavour of the month, free repo hosting service available. <S> mercurial ( hg ): <S> very powerful, distributed repositories, easy to use/learn, similar to git, free repo hosting service available. <S> tourtoisehg: a graphical tool that integrated mercurial with the file explores, and other graphical tools, for Gnu/Linux and Microsoft's Windows. <S> subversion ( svn ): a slightly older tool, very powerful, centralised repository, supports locking where needed, makes it better for non-mergable documents, easy to use/learn. <S> tourtoisesvn: a graphical tool that integrated subversion with the file explores, and other graphical tools, for Gnu/Linux and Microsoft's Windows.
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The only pre-requisites to using a computerised revision control system are: Use of a computer. The most obvious prerequisite would be to get to the stage where rather than starting to write a program from scratch, it's better to take something old and re-purpose it.
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How to raise students' security awareness in programming? My first website with a login form had the password hardcoded in the JavaScript code, and if the entered password matched it would redirect to a private URL that was just not linked anywhere, but still public if anyone knew the URL, and yes, that URL was also hardcoded in the JavaScript code. So in terms of security this was basically a "Do not read" banner, with the "private" content just written below it. Now, this is just a specific example of me not knowing any better in the early days of web development. There are many other domains in programming where you might introduce vulnerabilities if you don't think about what you're doing. Is there a generic technique to teach students to keep an eye on their code's security, maybe trying to get them into figuratively hacking their own programs and exploit vulnerabilities? <Q> Make it into an assignment/game. <S> Each student creates a project that is passed to another, randomly chosen student, to hack. <S> Give points for both the project and the "hacking" results. <S> The hacking assignment should also be graded. <S> Security has to be taught and the value learned, usually painfully. <S> I have lived through many "no one will do that!" <S> only to have a product, or network, broken because someone did. <A> As mentioned in other answer making education like a game is good idea. <S> You can use SQL Injection as one of the examples, other like password to be word from the web page itself, other can be default username/passwords like root/root, admin/admin and so on. <S> During the class you mention this keyword (SQL for example) and give them as home work URL to dig. <S> Also those teams can create some site, program, etc and give to other team as challenge to hack. <A> I would just try to make resources available to them and make sure to give examples of what not to do (e.g. Your example). <S> Specifically I'd provide the OWASP top 10. <A> Security vulnerabilities are just bugs. <S> In your example the code does not do what it is supposed to do (keep the bad people out). <S> So treat them this way. <S> “We have a bug. <S> The program does not meet its security requirement of …”. <S> The worse thing we can do <S> (and I have seen this in classes), is to demonstrate bad code, unless it is part of a “What is wrong with this?”. <S> I have seen a teacher present this as an example of how to do things (a lesson on selection). <S> if entered_password == <S> "fred1234": print ("welcome") <S> I have heard the argument that doing this properly would be do difficult for a beginner class. <S> I agree. <S> I would not try to fix this program. <S> I would just present a different program. <S> I have seen a lot of bad practice taught, that then needs to be untaught latter on. <S> When I was a software engineer, it was often me un-teaching new recruits. <S> This was not easy when they were not good at critical thinking, and saw what they were taught as truth . <A> Emphasize the 'stupidity' of security holes - they aren't weaknesses that only geniuses with a bone to pick can root out, they're the same mistakes repeated ad nauseam between different companies, therefore every application is liable to run into them. <S> Using the CWSS (common weakness scoring system) <S> the highest priority vulnerabilities are SQL Injection, OS Command Injection and classic buffer overflow. <S> (full list) <S> Example <A> I would have a "guest lecturer" who was a cybersecurity professional teach one class. <S> (Maybe I would give a test on the lecture the following day.) <S> Most CS instructors are aware of security problems connected with software, but not all of them understand the hardware issues. <S> Unless you happen to have a professional cybersecurity background, you may be better off "farming out" that one session to someone that does. <S> In such matters, you want to present an integrated view, or at least one that is as fully integrated as you can make it.
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As other answers have said, a game is the best approach; preferably a readymade "Please hack me" style website for them to attack. Further you can create teams which can try to work together on specific challenge. In terms of resources, I'd provide info about attack vectors, threat models, etc.
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Should I teach modern web development in an introductory programming course? How? I'm currently teaching a introductory programming class in a technological university course (FYI, this is a type of university course that is not a BS). The recommended language to use for this class is C and I'm following this guideline, but I know that most of the students will work as web developers at the end of the course (some of them already works as client support in IT companies), so I want to introduce them to some modern web concepts, but I don't know how. They will have other classes during the course on other important subjects for web development (like computer networks and software engineering), but won't have any class that teaches modern programming languages for web, like Javascript. Is this introductory programming class a good point to introduce some modern web development concepts (maybe with some Javascript snippets together with the C examples for comparison), or would this approach confuse them more than help them? <Q> You could also have HTML/CSS/JS as an extra credit assignment or something the class can do if they're ahead of schedule. <S> This will keep the class motivated to learn HTML/CSS/JS, which you probably shouldn't grade as it's an extra addition to the curriculum. <S> This will teach the class the necessary topics along with them not being bored out of their mind, studying for programming AND web development. <A> I think it depends on what the goals for the course are. <S> You are teaching an intro programming course, so what are the students expected to know when they finish? <S> Data types and structures, loops, functions, syntax, etc? <S> If so you don't need to teach web development skills as part of this since arguably HTML, CSS, etc. <S> are not really "programming" in the computer science sense. <S> Also the technologies and languages available in web development are lightweight and limited compared to back end technologies and so using them to teach programming concepts is like teaching someone to cook using prepared food. <S> It has been said that "Java is to JavaScript as ham is to hamster" . <S> However, basic text-only coding can be boring and may not be very accessible to many people. <S> The advantage of front-end technologies is that they are literally visible and people can see the results of their programming efforts as something besides text in an editor. <S> Also if the goal is to provide people with the shortest path to a possible job, it is probably far easier to teach them the basics of web development than it is to teach them true software engineering and computer science concepts. <S> Which isn't to say that these concepts are always needed on a job. <A> Teaching web programming would be self defeating to the topic. <S> On the other had using examples of parsing “CSS” files or “HTML” files would aid them in learning web development, while maintaining the intended goal of the course. <S> Personally I hate web development as a matter of personal taste. <S> I wish my school offered a “C” programming class. <S> It is truly nice to see that there are teachers trying to find ways to tailor their courses to what the students are interested in. <S> Keep up the good work. <A> I believe that the learning of WEB programming must start with understanding the concepts: XML, HTML, DOM, HTTP, REST / RPC and javascript bases. <S> Javascript is easier to understand if students have ideas about functional and objective paradigms.
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If you want to teach students programming concepts along with web-development (HTML/CSS/JS) you should consider lacing programming examples or lessons with examples of HTML/CSS/JS or similar concepts in both.
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How to encourage participation in the national olympiad in informatics? Currently, relatively few participate in the national olympiad in informatics (high school) of my country. This is partially because the first round takes a bit of time (up to 40 hours if one wants to reach a perfect score, but 10 hours should be sufficient for a passing score). I'd like to encourage participation in the national olympiad in informatics, because I think that several students are good enough to do well in the olympiad and I think they would like it. How can I encourage participation? <Q> Personally, assembling a team (or club etc.) of those students and teach them the relevant material would encourage most (if not all) of them to participate. <S> Also, finding a guide\mentor who can teach them would give the sense of, for lack of a better word, prestige. <S> Here, where I live, there's a national competition and it's very popular, due to the use of the aforementioned method. <A> You can either 'force' participation by including it in the lesson program or make it extra-curricular, where you can give additional incentive by handing out 'bonus points' to grades for all participating students. <S> For the students that are good enough and enjoy your contest, the contest can strongly encourage them to participate in the olympiad. <S> An advantage of this approach is that you not only encourage the students you think are 'suitable' for the olympiad, but simultaneously have an activity that can motivate the other students into programming and algorithmic thinking and, ultimately, your course. <S> The main disadvantage is that this will take time and some skill to pull it off successfully. <S> This may be less daunting than it seems <S> : you can get questions from various sources and relatively small contests need no complicated submission software. <S> However, I'll refrain from discussing further how to host such a competition; that would be worth a question on its own. <S> Then again, I agree with @Itamar Green that you likely need someone to deliberately invest time to encourage the students, so it is likely the time has to be spent anyway. <A> Set students tasks inside your lessons that are similar to the Olympiad(or as extension/home tasks for your most able). <S> A good selection come from http://projecteuler.net/index.php?section=problems and http://codingbat.com/python
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One approach is to host a contest for your students yourself.
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How can I maintain interest in front end? When I teach front end web development, it always happens that I start the year with a bunch of students who are ready to redesign Facebook on day 1. With expectations like that, it's always a letdown when I start talking about what a tag is, what a markup language is, CSS priorities, code quality, and generally the details of how good design is implemented. How can I stop students from dropping off and losing interest? This is especially pertinent to me because my class is extracurricular and is something interested kids can take if they want to, but if they get bored they can just stop coming. The kids are in high school. Specifically, I'd think that my activities could be changed to be more exciting and let the students do more from the get go, I'm just not sure how I could do that. <Q> As Choirbean noted, this is fundamentally a question of motivation. <S> I don't think it's about making something more "exciting. <S> " That is, the secret is not in something extrinsic, which is what makes this such a challenging issue whether it be front-end development or really any topic. <S> I draw on Daniel Pink's TED <S> Talk <S> whenever I think about getting students to do something. <S> The gist is that there are "three elements of true motivation -- autonomy, mastery, and purpose. <S> " The key to start is autonomy; students need that freedom of choice to get personally invested and be motivated by more than a grade. <S> I can speak to autonomy with front-end development based on a project I did this year. <S> I assign two HTML/CSS assignments. <S> For each, they can make anything they want the subject of their pages: a travel destination, a TV show, a sports team, anything . <S> That was the key. <S> They were so excited about describing something they loved that they were invested enough in the topic to work on the HTML/CSS. <S> The requirements of the first assignment were the following: DOCTYPE <S> html tags head tags body tags <S> title element header element paragraph element proper filename bonus: comment with HTML definition As you can see, it was elementary. <S> That way they had mastery of HTML basics (i.e. the DOM) and could then grow to build something more sophisticated and aesthetically pleasing. <S> With the second, they had to include the following: table link to external website <S> button <S> two divs (with div IDs) <S> list heading paragraph three images text not left <S> -aligned two fonts three colors additional HTML feature additional CSS feature <S> Nowhere did I grade the subject matter of their sites. <S> Rather, I focused on the skills they needed to demonstrate competency in and let them prove to me -- in whatever form they liked -- that they were indeed competent in them. <S> That freedom, to me, made the difference in motivating students to want to complete this work. <A> I teach game programming, and I have a very similar issue. <S> Day 1 <S> : They want to make Overwatch, and on Day 2-End of the year, they want to play overwatch. <S> I usually start the year with an explanation of the parts that go into professional development and then explain that we are only scratching the surface of what is required to develop an AAA game, you might try the same. <S> Giving them this perspective can help them understand better how they can plan an important role in the development of websites by learning the material that you are about to teach them. <S> You might dissect YouTube. <S> Talk about the native applications, the FE web applications (the player, the profile, my channel); the back end, the streaming service, the storage service, etc. <S> Discuss how they need servers in every region of the world! <A> So, if you're teaching CSS, you might show the kind of final product that you expect them to be able to make by the end of the course on day 1 . <S> You can also explain the limits. <S> Something like, <S> "CSS doesn't let you make the websites interactive on it's own, but it's how we design the pages themselves, and it's a pre-requisite skill if you EVER want to be able to make those more involved, interactive web sites." <A> Another element to add to the solution is to slightly delay the HTML tags. <S> You can start with a WYSIWYG web page tool. <S> In that they create the web page that meets your listed objectives. <S> Then you can switch from the visual results into the raw HTML. <S> Using the generated HTML you can demonstrate simple changes to the code that are then visible in the rendered page. <S> Add in simple CSS next, and they can witness the explosion of possibilities. <S> If you can do that yourself on a large-screen, or projector, in a short demonstration first, then have them do it themselves, while making it all fit into one class session, that would be good. <S> An additional tool would be a server for the room that each has a directory on that they can "publish" their page, and you can display it on the projector. <S> Any simple server would work, even IIS on Windows XP could handle the task. <S> That provides them with the chance to have their work on display as well, giving a nice ego boost, and likely increasing their investment in learning more to make it better. <A> In my client-side dev classes, I start by introducing the HTTP protocol so that the students can understand what really happens when they click one link or type one URL. <S> Then, I start with the flow: Structure (HTML5) - Look (CSS) - <S> Behaviour (JS) <S> They have three assignments which are in fact 3 iterations of the same: the first is the site with only the structure, then they add the look, and finally add some features like a store or something where they have to use JS / localstorage / JSON ... <S> This has worked for me. <S> But if your students are eager for more, you can build a REST API, provide them the basic HTML/CSS/JS concepts, and ask the students to develop a front-end for that App. <S> The number of hours that you have available will influence what you can do.
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Assuming that you have reasonably motivate students in the first place, the first rule of motivation is to explain the goal, and where that fits into a larger framework. Tell them a bit about how the web works, that there are engineers who work on the various parts, and that is their full-time job, and that they work in teams to create the functionality that you see on popular websites. A little bit of contextualization goes a long way in keeping people interested, because we naturally lose interest when it feels like something is meandering and purposeless.
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Encourage students to be independent As is often the case, there is usually more than one way to approach a problem or task. Currently, my students use what they were taught in the lessons (which is expected). When they stumble upon a problem (e.g. a project that has parts that they are unsure how to approach) they very often get stuck. This is because they haven't been taught some specific thing that is related. I want the students to be more independent in their learning, and to look for that other approach on their own. How can I structure a lesson that would foster independence and give the students the ability to look for a new approach when needed? The students' level is somewhat advanced high school level. <Q> I think there's a few different skills students need for independence, and they require quite different teaching approaches. <S> Independence is the end result <S> but you can't teach it directly. <S> Confidence. <S> They need to think it's possible to try out a new toolset and make something. <S> Guiding them prescriptively through a variety of different new tools is a good way to do this, as with @BrDaHa's answer. <S> i.e. Don't teach independence as such but show through example that different and new approaches are possible and not too difficult. <S> Once they've achieved several different projects, even tiny ones, with different technologies they'll be more confident to explore different options rather than use the same thing every time. <S> Abstract understanding. <S> The hard bit of programming is thinking about problems and solutions in the right way. <S> Once you know conceptually what you want to do <S> it's much less scary to go find a tool to implement that well, and that conceptual understanding will help guide you through using a new tool. <S> Teaching CS generally addresses this, plus a specific focus on systems design. <S> Ability to learn something they don't already know. <S> Reading documentation, using stack overflow, reading blog posts and books. <S> Students need to learn each of these, they're different skills, and they're often not taught well or at all in CS courses. <S> When you can do these things then approaching a new tech is fun rather than daunting. <S> Appreciate <S> there's different tools for different jobs. <S> You need to demonstrate, or better have them experience, that some technologies are great for some things and not others. <S> So they know there's worthwhile in exploring different tech. <S> On the one hand, when you have a hammer everything looks like a nail. <S> Conversely though, it's often a lot faster to use a tool you know than learn a whole new one for a small job, even if that tool is 'better'. <S> Negotiating that trade off is an important part of general software development. <S> Part of the fun of being a developer. <A> The best "win" I've had with this is drawing on tables. <S> I gave challenges to my Y12s (about a dozen students). <S> While talking through the problems I was annotating ideas, flowcharting, tracing etc on the tables beside them with a board marker. <S> Now when I give them a problem they grab a table from the centre of the room and start drawing out ideas. <S> And because they're 'winning' with what they're doing they start going above and beyond. <A> I think it's hugely beneficial to create projects that require use of a certain language or technology , or in other words, don't leave students to their own devices to solve a problem. <S> As a student, I found that learning Java and then moving to "weird" languages like Ocaml really expands how you think of how to solve a problem. <S> Knowing JavaScript is pretty much a requirement in web development. <S> Learning Python can expose students to beautiful, concise ways of solving problems, and opens the door to a lot of machine learning libraries. <S> I can't count how many times I've read about some technology, dismissed it, then was forced to use it somewhere, and came out thinking, " <S> Huh, that's pretty cool" <A> There is an argument for facilitated and directed learning to encourage independence. <S> Students should be allowed to discuss problems and options with their peers in order to make judgements; evidence shows that adults tend to interfere with that process. <S> Ensure activities are hands on and try pairing students. <S> This may be of interested to help structure a critical thinking approach - Search Kivunjas article Using Dear Bono's Six Thinking Hats Model to Teach Critical Thinking and Problem Solving Essential for Success in the 21st Century Economy. <A> I don't think there are shortcuts here—the students just need more foundational knowledge before they can be independent. <S> It takes significant expertise to be able to transfer knowledge to new contexts [ ref ]. <S> Novices have shallow knowledge that is closely tied to shallow features. <S> As an expert, you have insight into meaningful patterns in your area of expertise. <S> You have also seen many, many different problems and cases that you can relate to current problem-solving. <S> Your knowledge is organized in terms of its applicability to new problems [ ref ]. <S> It seems so straightforward from your perspective! <S> But think about the challenges facing novices. <S> To them, the problem looks different than anything they've seen because they don't recognize the generalities. <S> Do they even know what words to Google? <S> I agree with other posters that confidence is necessary. <S> Knowing good resources to use (e.g. user-friendly documentation) also helps. <S> But most important is foundational knowledge. <A> Once the students begin to gain this skill, they can explore APIs and libraries that interest them.
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Teach your students well, with many examples, and as they learn more they will begin to seek out knowledge on their own. Early in the process, you should emphasize using and applying documentation.
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How to avoid getting emotionally attached to my students' projects? I run a workshop with a few students. They often do large projects alone that they inevitably run into trouble with. That's completely normal, it's why they need some help in the workshop. As the instructor, I usually spot the issue and solution pretty quickly. I try and nudge the student in the correct direction, but they don't always get it. After a while, I become personally invested in the project, and I may end up just implementing the fixes I suggest myself (while they watch), and because they aren't responsible for the implementation, they gain less that than if I had let them do it. This happens especially when I help them with the initial design and architecture of the program, as I end up feeling a little like it's mine too. How can I make myself pull back a little and not do the work for them? <Q> I think this an essential and main part of teaching programming and cs (and teaching in general). <S> The ability to hold the answer and guide the student to it. <S> When working with them to help them find the problem, I ask various questions (usually "what do you thing is causing this?" etc.) <S> and by their answers it's possible to see what sentences would guide them to the solution. <S> This method works great (that sound out of the sky <S> but it's based on student feedback) as it allows the student to feel that they found it on their own. <S> I find that they also learn to spot issues on their own afterwards. <S> Additionally, it's worthwhile remembering that you are the instructor, and not the student. <S> And that the project is a student's project, so keeping that in mind often helps with holding back from doing the work yourself. <S> However when all else fails, showing the students how you might do it could be a last ( last ) resort. <S> Just be sure to explain every step you're doing, so that the student understands. <S> I cannot express enough how bad this last resort is. <S> But if it gets to that, make sure you're not doing their work, but rather show them something similar <A> While sometimes it may be hard to step back from a particularly interesting student project, you just have to remember that your role on the project is just as vital as theirs: <S> A teacher. <S> As a teacher, your job is to explain and teach so that they can actually create an implementation. <S> Even though you don't touch the code, the project couldn't be completed without you. <S> It may also be helpful to step back during the design phase, because if you haven't been responsible for the design, you feel less like the project is your baby. <S> Also, maybe start your own projects. <S> It is OK it <S> guide the student to a solution, and even guide very closely. <S> It's good to get the student to understand how their code could be better by simply asking questions about them. <S> Questions are good, because they help the students understand what is going on and the help you as a tool to guide them. <S> If you simply confine yourself to asking questions, even very specific ones, like "Why wouldn't you put the code between lines 23 and 27 into it's own method?", because that's better than telling them how to do it or doing it yourself. <S> It may also be helpful to you to remember that the maintainer of the project will be the student, and so they have to know how it works. <S> If they don't, although the project may look good when it leaves your workshop, it will fall apart because the projects owner won't be able to maintain the code when inevitably it has to be changed. <A> Perhaps you can remind yourself by thinking of times that someone helped by not helping? <S> For example, when I was in college (30 years ago), I was struggling with a bug in the Lab (we had computer labs back then) and the TA could clearly see the bug <S> but she did not offer any guidance. <S> Because I knew <S> she saw the problem immediately, I knew it was solvable. <S> Because she didn't say anything, I knew she believed I could find it. <S> It took a while, but I eventually tracked down a simple memory overrun error in C (wrote one past the end of an array on to the next declared variable). <S> Silence is one 'guardrail' that I could go to. <S> The other extreme would be explaining everything to someone every time they ask. <S> We call that "spoon feeding" and it is awful. <S> The student learns... to be dependent, and I can't think by the end of the day and the other students are about ready to kill because they can't think during class either. <S> This is more like "the third rail" <S> so we won't go there. <S> I once TAed <S> an introductory programming college class for non-majors. <S> I very quickly learned to spot every kind of error they made. <S> My goal was to stay between the rails: help, but let them learn. <S> It is a difficult dance, and depends heavily on circumstances. <S> Sometimes I give a generous prompt knowing that they are bound to come across the same thing again. <S> I am not so arrogant as to think that I will determine the outcome of their experience.
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If you are getting engaged in everything that your students do, then maybe you should become invested in some new project of your own to serve as a distraction from what your students are doing. What I do is try to follow the thought process of the student.
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Workflow for Code Submission Next year will be my first year teaching AP CS A. While I've spent a lot of time preparing by choosing textbooks, picking an IDE, and writing the syllabus, I'm not yet settled on my workflow for how to push out assignment instructions/starter code and how to collect work back. I registered for GitHub Classroom with an education account, but I haven't yet had a chance to explore its resources and would like to hear from those who have used it. I can easily collect files via our LMS or Google Classroom. I just have doubts that that method is the most efficient for either me or my students. Also, this past year, CS50 took care of the distribution code, so I didn't have to worry about that. Now I do need to consider how I can get files to students efficiently if needed. What workflow do you follow for the submission of student work, particularly in the context of Java files? Do you provide students with starter code? If so, how? <Q> Here is my system. <S> I give it top marks for ease of sharing , but one downside is that it does not do any kind of autograding without some scripting on my part. <S> I purchased a paid subscription to Dropbox. <S> This allows me to set up read-only folders. <S> I then create a series of folders using <S> a .bat <S> file <S> (I am a Windows user), generated with a function like ="mkdir ""APCS 1 - "&A2&", "&B2&"""" . <S> This creates lines like mkdir "APCS 1 - Johnson, Cathy" <S> I copy and paste this group into a .txt <S> file, rename it to .bat , and - voilà! <S> - I can double-click to create a directory for every student in my class section. <S> I run the batch file in some subdirectory of the Dropbox folder so that they will ultimately be sharable. <S> I then go through and share each of these folders with the respective student with write privileges. <S> Finally, I create one last folder, something like AP Computer Science Section 1 . <S> I then copy and paste the email <S> addresses themselves into the share box for this folder, but only allow read priveleges . <S> Now, I can drop my assignments into to class folder (which is basically instantaneous), and I receive my submissions through their private folders. <S> I get everything timestamped, and don't have to log into any websites to get the assignments. <S> One more side-benefit of this arrangement is that when I need to send a file to some student, we already have a shared folder that I can drop it into. <S> No need for emailed attachments. <A> I wrote a series of posts on how I use raw GitHub with my classes: <S> Part 1 - Introducing your students to GitHub by using it as a method for distributing code to your class. <S> Part 2 - Having students submit homework and small assignments using GitHub - this has them adding content to GitHub and sets the stage to teach them about "playing well with others." <S> Part 3 - Taking the kids from working on solo projects to collaborating with classmates and leveraging things like version history <S> Part 4 - Talks about some of the pedagogical benefits I've discovered while working with Git and GitHub with my classes. <A> On CodeHS we have a very streamlined system for submitting and managing student work. <S> You can use our courses, or if you want, create your own assignments and starter code. <S> The students can run the Java code all in the web browser (or if you'd like in your own IDE), and then when they click submit it goes into your grading queue. <S> No need for folders, emails, printing, scp, dropbox, it all just works. <S> You can easily run it and test it, you can also create your own graders if you'd like. <S> There's also an easy to use grading queue for doing code review on each problem which can be customized how you like. <S> I think in a lot of cases it is helpful to provide students with some basic starter code, but that can vary depending on what type of assignment you are doing.
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At the beginning of the term, I copy/paste all of the names from the course into an Excel spreadsheet and collect an email address from every student for a Dropbox.
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Effectiveness of Parsons Problems I first heard of Parsons Problems thanks to CS Teaching Tips . They define these problems as follows: "Parsons problems are problems where students build programs from ordering small chunks of provided code." An example can be found here . When I research these, I see very little in terms of classroom resources. I find a handful of articles discussing them but not many examples of them in practice. On the surface, these problems -- emphasizing logic and structure separate from syntax -- could be a great activity at varying levels of experience and ability. What skills or concepts have you used (or would you use) Parsons Problems to teach/reinforce? <Q> I used a Parsons problem to teach functions. <S> I used Google Slides to put different colored text boxes on one slide and gave the students instructions to arrange the text boxes in the proper order. <S> A screenshot of what the activity looked like is below: <S> I wanted students to have experience with the ordering of function calls in <S> C. There are technically two correct ways to approach this, but because I specify the requirement to use each block, there's only solution here: <S> Seeing how information gets passed from function to function and how to lay out the structure was helpful for students. <S> Focusing on those skills outside of/separate from the syntax helped because students only had to worry about one thing at a time. <S> As I look ahead to next year, I want to do more of these problems, especially when teaching loops and sorting algorithms. <S> They are quick and simple to make and differentiate instruction effectively. <S> In the context of AP CSP, they provide great practice for the AP Exam which includes a number of code samples to read and understand. <A> I think they are especially good when students start learning a certain code pattern, and would be overwhelmed by too many details. <S> Ebooks written on the Runestone platform can have Parsons problems embedded in them. <S> Teachers can choose to use and potentially adapt one of many existing ebooks , or write their own from scratch . <S> Multiple ebooks contain Parsons problems you could use directly or adapt: <S> The AP CS A ebook , using Java ( Example ) The AP CSP ebook , using Python ( Example (scroll down a bit)) How to Think Like a Computer Scientist , using Python ( Example (scroll down a bit)) <S> Here's an example of the look and feel of these problems: (Note that this problem provides indentation information, but others on Runestone do not, allowing students to choose their own indentation -- <S> this is known as a 2D Parsons problem ) <S> Recent development is in the process of adding cool new features to these Parsons problems within Runesone [reference] , like paired distractors - a tile that works is paired with a similar tile that doesn't work, and students must choose between them dynamic adaptation - the difficulty of the problem changes based on the user's performance accessibility <S> - Parsons problems can be completed with the keyboard only, helping those who can't use a mouse <A> We use Parsons puzzles when teaching robotics: The student has to select which of the three event blocks on the right causes the behavior specified in the question. <S> This example is for the Thymio robot with the VPL programming environment but similar puzzles could be developed in any block environments. <A> I would use it to introduce them to working on large projects, that incorporate many parts. <S> Parsons Problems force the students to think how separate code segments bond and interact. <S> They would have to think about getting those parts to work together. <S> This teaches them the mindset of working on large projects. <S> It can be used to teach them proper structure of projects: Every part of the project is stored in a separate package, and Parsons Problems are convenient to teach them that. <S> You could give them a repository of code segments, that can only be changed a bit, and they need to use some or all of those segments in order to create a program of your choosing (e.g. a simple chat with gui, hangman with gui or other programs that have more than one part). <S> Additionally, making it into a group-project would teach them how to work together and divide the work on the different parts between the group members. <A> I just started playing with these. <S> What I have been doing is writing some code and testing it and then moving things around before giving the projects to my students to rearrange. <S> So far I have just played with loops and decision structures. <S> I'm using Visual Basic and C# with different classes.
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I think Parsons problems offer a low-cognitive load way to offer practice for just about any code-writing topic.
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What should be the difference between a university course and developer training? I teach university students and would like to start teaching prospective developers. As such, I have been thinking about the core differences between these two audiences. I find that students are sometimes less motivated and less prepared, while developers are more experienced and sometimes really enthusiastic. Is this correct? And if so, how should this difference impact my methods of instruction? <Q> I teach and develop curriculum at a training-oriented nonprofit, and have taught in an academic setting as well. <S> Here are some of the ways that I try to approach trainings for professional developers: <S> Remembering that trainings are for practitioners, and as such, the lessons should be oriented toward objectives that will be immediately useful in their work. <S> So, for example, with entry-level developers we de-emphasize (and sometimes leave out completely) topics such as concurrency and algorithm analysis. <S> In general, relate the presentation of topics as much as possible to how they will be used on the job. <S> With assignments, this can be essentially a linguistic slight-of-hand: state assignment tasks as user stories, provide a narrative for the assignment that aligns with workplace practices ("The client has asked for feature X, and your team lead has tasked you with this feature"), etc. <S> Using current, professional-grade tools: Git+GitHub, widely-used IDEs, professional-grade databases (e.g. not DBs like SQLite). <S> Using as supplemental (and sometimes primary) resources that professional developers use. <S> In particular, we emphasize use of official documentation and references. <S> These approaches often are employed in an academic setting, but they are essential (in my view) in a training setting, where developers will highly optimize their own learning toward direct, practical application. <S> As the instructor, it's my job to make clear the connection between the material and their day-to-day work. <A> Colleges and universities in the United States are required by our accreditors to have explicit learning goals and assess our effectiveness at meeting them. <S> (I assume there are similar rules in other countries.) <S> For example, here's how my upper-division Programming Languages course satisfies goals: College-wide goals <S> Students will learn to think critically , which they will demonstrate byanalyzing the behavior of programs in diverse languages without executing them. <S> Students will learn to develop and realize their own creative visions across the arts and sciences , which they will demonstrate by choosing the appropriate programming language or abstractions for a task <S> Students will learn to communicate responsibility and effectively , which they will demonstrate by justifying choices among and within programming languages. <S> Computer science department goals Design and write a correct computer program , which they will demonstrate by writing programs both in and implementing new programming languages Understand how computer systems (including architecture, operatingsystems, networks, and compilers) work , which they will demonstrate byadding languages features to an interpreter. <S> General education goals for quantitative and computational reasoning <S> Translate problems into the language of mathematics and computer science,and solve them by using mathematical and computational methods andtools , which they will demonstrate by writing and reasoning about programs in novel programming languages. <S> Understand the structure and development of logical arguments , which they will demonstrate by analyzing the behavior of programs in diverselanguages without executing them. <S> If I were to teach a course in industry, I would be under no obligation to meet any goals other than those advertised for the course. <A> Rather crudely you might see the differences as being: A university - students engaged in study, where study is an end in itself . <S> What does this mean in practice? <S> Developer training might be more inclined towards studying using the latest technologies (Javascript, Rust etc). <S> Whilst University might tend more towards studying conceptual understanding (Matrices, Functional programming) and place less importance on the programming language (some unis teach with Fortran, Delphi etc.). <S> You might also get courses at universities that don't appear so immediately applicable to job roles (courses on provability of programs, compiler creation), whilst developer training might be shorn of any course that isn't in high demand by the industry. <S> However. <S> Working in the UK, the job readiness of a university degree is seen as a major indicator of the 'success' of a university course. <S> We have the British Computer Society accrediting courses and universities are ranked on the employment rate of their students. <S> So in reality, there might be no difference at all.
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Developer training - students engaged in study, where being job ready is the end goal.
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What are good projects for metaprogramming? When I teach metaprogramming like dynamically defining methods and method delegation, students usually understand what it is fairly quickly because it's simply a dynamic way of doing something they've already done. I now want to assign them a project that utilizes the metaprogamming I've taught. I'm having trouble thinking of a project to assign them which would be made significantly easier by using metaprogramming. The only use I know of is in a DSL. Creating a DSL is a rather large project to assign a group of high school students, so I'd prefer something smaller. Specifically this project is for fairly advanced students working with ruby, but more general answers are better. So, what projects could you assign to illustrate the utility of metaprogramming? <Q> During lecture, my students and I recreate Javascript objects in Ruby. <S> In Javascript, these two lines are synonymous: config['indent'] <S> = <S> 2;config.indent = 2; Ruby doesn't support this duality natively, but metaprogramming makes it possible. <S> We create a class AutoObject that internally stores a dictionary to hold all of the object's properties. <S> Its method_missing consults this dictionary when something like config.indent is executed. <S> If the method name suggests an assignment, it updates the dictionary. <S> If it's a read of an existing property, it returns the value. <S> Otherwise we raise an exception. <S> Once the automatic properties are in place, it's not much more work to add serialization and file <S> I/ <S> O. <S> By the end, we are reading and writing configuration files that are useful for any application. <S> ActiveRecord does something similar when it automatically creates an object and its interface based only on the database schema. <A> The obvious introductory example would be re-implementing <S> Module#attr_reader <S> attrs.each do |attr| define_method(attr) <S> do p instance_variable_get(:"@#{attr}") end <S> end <S> end <S> def attr_writer(*attrs) <S> attrs.each do |attr| define_method(:"#{attr}=" <S> ) do |val| p instance_variable_set(:"@#{attr} <S> ", val) end <S> end <S> end <S> def attr_accessor(*attrs) <S> attrs.each do |attr| p attr attr_reader attr attr_writer attr end <S> end <S> Module.prepend selfend <S> Then, you could add validation, for example, which dynamically looks for validator methods named after the attribute, i.e. validated_attr_writer : <S> foo would create a method <S> foo= <S> which sets an instance variable @foo , but only if it passes validation, which is defined as a set of methods named <S> foo_must_be_* . <S> The result could look something like this: class Module def validated_attr_writer(*attrs) <S> attrs.each do |attr| define_method(:"#{attr}=") <S> do |val| raise ArgumentError unless methods.grep(/^#{attr}_must_be/).all? <S> {|meth| send(meth, val) } instance_variable_set(:"@#{attr}", val) end <S> end <S> endend <A> A documentation system similar to Python's, where documentation isn't stored in the source text, but as dynamic data inside of instance variables of the documented objects themselves. <S> This also allows you to talk about Ruby's object model, <S> e.g. the fact that methods aren't objects and thus you can't store the documentation of a method inside the method, you have to store it somewhere else (e.g. in the module the method is defined in). <S> The API looks a bit like this: class <S> Foo doc ' <S> This method does something totally interesting.' <S> def bar( <S> *) endendFoo.show_doc(:bar)#=> ' <S> This method does something totally interesting.' <S> The implementation looks something like this: module MethodAddedHook private def method_added(meth) <S> (@__doc__ ||= {}) <S> [meth] = <S> @__last_doc__ <S> if @__last_doc__ <S> @__last_doc__ = nil <S> super endendclass <S> Module <S> prepend MethodAddedHook def show_doc(meth) <S> instance_variable_get(:@__doc__)[meth] <S> end <S> private def doc(str) <S> @__last_doc__ = <S> str <S> endend
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/ Module#attr_writer / Module#attr_accessor , which after all are typically the first example of metaprogramming a Ruby programmer comes in contact with: module MyAttrAccessor def attr_reader(*attrs)
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Suggestions for encouraging good Coding Practices? From an instructor perspective (Middle School or High School), Is there a method, or a set of guidelines, for grading early coders' projects that could enhance good coding practices as the students advance further into computer science? Are any "online practice sites" or "auto-graders" worthy enough to look at for daily or lab project/practice? <Q> We use the Eclipse plugin Checkstyle. <S> The plugin is configured with a set of rules (defaults styles are available with the plugin), and then generates a set of warnings for any violations of these rules. <S> Toward the end of our CS1, we introduce students to the tool (the students have been taught our expectations throughout the semester). <S> After they are introduced to the plugin, all of their remaining projects will lose points if they have Checkstyle warnings in their project submission (e.g., one points off per warning to a max of 10 points). <S> This practice is continued in CS2 from the start of the semester. <S> This experience is at University level, but should be applicable to anyone using Eclipse in an AP CS A or similar course. <A> Before that I would run unit tests on the submitted code and then leave comments. <S> But I've found that the immediate feedback, especially on smaller assignments, helps them learn to solve the problems on their own. <S> Plus, it saves me from having to look at 10 or 15 versions of their code. <S> I typically only look at the one that works. <S> For style, I'll leave comments on completed assignments when it's bad. <S> What I've found really helps though is to not help them with questions if the code is a mess. <S> Especially early in the year "clean up your code, and I'll come back <S> " is my stock answer if it's messy. <S> After a couple times they'll clean it up on their own, and usually they'll figure out the problem on their own. <S> I don't have specific rules other than it's easy to follow. <S> Coding styles tend to be pretty subjective - braces on the same line, or the next line; should the brace be indented; should an else be on the same line as the brace closing the if. <S> I tell them it's like handwriting. <S> If it's neat, it's easier to read. <S> I will show examples, both good and bad, anonymously on the board. <S> Some kids don't understand what a good snippet of code looks like. <S> But almost everyone can agree on messy code. <A> In my high school class, decades ago, all programs had to be submitted to a fellow student of choice for a "peer review" and critique before being submitted to the teacher. <S> People took these reviewing tasks seriously, because the score for the review was the same as the score for the underlying program itself. <S> That tended to improve the coding practices of both parties by aligning their interests. <S> In the first semester, the highest grade was earned by the person with most reviews. <S> That was true even though he submitted relatively few programs himself. <S> Instead, he had become the "go to" person for reviewing others' work, and his "best practices" permeated the rest of the class.
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Checkstyle gives them immediate feedback as they are writing code (in the same way compiler warnings/errors are presented in Eclipse) with the loss of points as incentive to not just ignore the warnings. I use an online auto grader for probably 95% of the assignments my students - high school, AP-A - do in class.
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Teaching Other Markup Languages I've been spending a lot of time lately using both $\LaTeX$ and Markdown and have found them incredibly useful. Some colleagues were blown away by some work I'm doing with $\LaTeX$. The more I think about my own use of them, the more I think about teaching/learning markup languages on a general level. What are the merits of teaching languages like $\LaTeX$ and Markdown in a computer science class? Are they appropriate there? I have seen the personal and professional value of these languages, but I'm wavering on if and how they fit into a formal CS course. (HTML is obviously relevant for its intrinsic connection to web development, so my question is really focused on other languages like the two aforementioned ones.) <Q> Next year I'm planning on having some of my second and third year students build an API that can then be used by students in our mobile development classes, and possibly web development classes. <S> Hadn't thought of this before reading your post, but I think I may have part of the requirements <S> be that they write documentation for the API so that the other classes can use it without having direct interaction with the authors. <S> Since git, and specifically GitHub, is part of the task it makes sense that the documentation should be written in markdown. <S> Seems like a good excuse to go over it in class. <S> A couple years ago I had a student that started teaching themselves Latex as part of an independent project. <S> His goal was to create a calculus equation solver. <S> He did fairly well learning Latex, but I'm not sure how I would go about bridging that in to a full class project. <A> To elaborate on why @RyanNutt said, a CS student should learn markdown and/or latex because they should be using those industry-standard tools to document their code. <S> To teach them, you could integrate teaching markdown with teaching git and teaching documentation. <S> If you assigned a project, you could assigned students to write documentation as extra credit or as a part of the project. <S> As a part of this, you could ask that the documentation be in markdown because that is the industry standard. <S> The students can then push their finished work to a git provider (like GitHub ) and see their full project as it would be in the "real world." <A> As others have said, another good idea is to write documentation in markdown or $\LaTeX$. Also, depending on the class, using $\LaTeX$ might be nice so you can read the math equations more easily (this being for more advanced, theoretical classes) <S> when grading. <S> I started using $\LaTeX$ because on Physics. <S> SE <S> when I edit, I needed to figure out the commands for various symbols (there can be some quite math heavy posts, and sometimes newer users don't use any MathJax at all, or post a picture), at which point I found out about Detexify, and then from there TeX.SE, and <S> - well - I figured out I really enjoy it. <S> From there I started teaching myself and now I can do some passably nice documents. <S> So that's another thing to consider - some people in the class may start using it due to your classes and find that they really enjoy it <S> so they learn more on their own. <S> One resource that may be useful if you do start using $\LaTeX$ more regularly is ShareLaTeX <S> which is an online editor, which also has documentation for basic tasks in $\LaTeX$, and - more importantly for a teacher - sharing and history abilities, though I believe the more advanced ones require some sort of premium account. <S> You can also put documents in a Github repository or pull them out of a repository, I believe.
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Well, depending on how many papers you have your class write, you can give them a quick crash course in $\LaTeX$ and have them write the papers (or whatever other written material) in it.
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How to teach which loop should be used In most languages, there are many different types of loops. The most common ones seem to be for loop, while loops, and do while loops. What is the best way to illustrate the differences between the loops, not in terms of syntax, but in terms of recommended usage. For example, a while loop with an iterator variables can usually be replaced by a for loop. A while true loop with a break statement at the end could be better expressed as a do while loop. How can I get my students to use the correct loops in each situation? How can I show them when a loop can be better expressed in another form? <Q> Use while or do .. <S> while if you don't. <S> The choice between while and do .. while is if you need to do the loop one time before the test use do ... while otherwise use while . <S> A full explanation can be found on Stack Overflow in this accepted answer. <A> What I've found is that while loops tend to make the most sense for students. <S> The idea of while I'm hungry, eat pizza is something they understand. <S> But, forgetting to change the condition is really common <S> so we wind up with a lot of infinite loops. <S> I sell for loops as a loop where is harder to forget to change the counter. <S> I tell them for each loops are a less codey way of iterating, but generally only work if you want to start at the beginning at look at every element. <S> As long as the code works, the only time I care what kind of loop they use is when we first introduce that type. <S> During the while loop labs they have to use while loops. <S> Once we've covered loops, it's their call. <S> I don't explicitly cover do while loops as a topic, but they do show up in a couple of project shells. <S> Most students settle on for loops when it's their choice. <A> I find that a useful way of teaching the different types of loops is simply giving examples and asking student to express them more concisely. <S> For example, I'd give my students a loops of the format: i = <S> 0while <S> (i < 100) { <S> # Some code here i++} <S> Then I'd ask them to simplify it to something more like: for (i=0; <S> i < 100; i++) { # Some code here} <S> For while loops, you can also teach the difference between while and do while with examples <S> , for example you can show your students an example of the format: while (true) { <S> # Some code here break if some_boolean} And try to get them to correct it to <S> do <S> # Some code herewhile (! <S> some_boolean) <S> As a bonus, this also teaches how to clean up code, which is another valuable skill. <A> I introduce loops by showing them loops in the physical world. <S> For example I have a student take 7 steps - counting loop. <S> An other student walks to a specified point - while/until loop. <S> We talk about how these loops work in our minds before we talk about how they work in code. <S> Many daily activities can be discussed in terms of loops and we discuss several. <S> Eating is a good "loop" with several possible indicators of when to stop. <S> When you are full or when you are out of food or when you don't have more time to eat (end of lunch bell rang.) <S> Steps can be counted or one can tell that they are at the top. <S> Even better what happens if you "stop" early or late. <S> Concepts first and syntax later.
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I teach them while loops, for loops, and for each loops; in that order. Use the for when you know how many times to execute it, such as counting, or iterating over an array.
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How can I set up Eclipse/eGit/GitHub in a way that is easy for students? My students struggle terribly with Eclipse, and with any form of version control. I want them to use Eclipse with Git, but I am struggling myself to find a way to set it up that would make sense to a student. What I want to do is have them put entire Eclipse projects (without the binaries) on GitHub. I want them to use the eGit plugin because if I ask them to use the command line, they will never do it. Researching this, the stock advice seems to be to set up the repository outside of the Eclipse project. That, however, has the effect of putting all the source code outside of the Eclipse workspace, which is confusing. Worse yet, I can't then import the project correctly into another Eclipse environment. The other method would be to put the repository (and .git) under the Eclipse project. This, I think, would be less confusing to students, but when I try that, I get all kinds of nasty warning messages. So does anyone have a setup for Eclipse and eGit that successfully puts the entire project into version control, and is not confusing for students? And that allows the project to correctly import into Eclipse? <Q> To me it sounds like your students lack an understanding of the fundamentals of IDEs and Git. <S> if I ask them to use the command line, they will never do it. <S> If they don't know git init and git clone (origin) <S> then I'm sorry <S> , they do not know Git, they should learn this first (along with push, pull, commit, status, fetch). <S> That, however, has the effect of putting all the source code outside of the Eclipse workspace, which is confusing. <S> Worse yet, I can't then import the project correctly into another Eclipse environment. <S> This is another problem in itself. <S> The high level explanation is you only need package level codebase with only the src, the bin is generated by Eclipse. <S> You still need to create a project in Eclipse and then import the package. <S> Any further problems should be asked on StackOverflow. <S> The other method would be to put the repository (and .git) under the Eclipse project. <S> NO! <S> The .git is generated by git init . <S> Do not copy any configuration, especially hidden files from project to project. <S> I think you are jumping the gun here. <S> Eclipse and Git should be separate lessons. <S> If they are confused by both then that just means they need to learn what each of them are, before combining them. <S> I suggest: Teach Eclipse, how to create projects, what packages mean, how to import, etc. <S> Teach Git, init, clone, pull, commit, push, status, fetch using Terminal or CommandLine for Git. <S> Depending on the age group you might want to teach them how to resolve conflicts, what decentralized means, branching, pull requests, etc. <S> Now teach them Eclipse Marketplace, download plugin and integrate Git with Eclipse. <S> So does anyone have a setup for Eclipse and eGit that successfully puts the entire project into version control, and is not confusing for students? <S> And that allows the project to correctly import into Eclipse? <S> As all my professors do it, you need to create the repository with the project for each student and have each student clone and import into Eclipse. <S> I'm not an educator <S> so I don't know if there is an existing setup available online. <S> However, I do think this is actually a very trivial task if they understand Eclipse and Git. <A> I ran into a similar challenge of simplifying the use of source control with my students. <S> I ended up switching over to the JetBrains suite -- IntelliJ in the case of Java. <S> The software is free for students/teachers and integrates very, very easily with Github. <S> No command line required. <S> Also, you will need to install git.exe on your machine. <S> Rather than using the GitHub desktop install, I have found the git-scm.com to be less troublesome. <S> Github desktop installs in a user/version based directory and makes configuration inside JetBrains a challenge. <S> Git-scm installs in a standard Program Files directory. <A> I teach Java to high school students as well using Eclipse. <S> You don't have to teach command line (much to the dismay of professionals here). <S> Egit works fine. <S> GitHub offers an education teacher account where you can control all of the git accounts for the students. <S> I'm going to make up a step by step instructions for using Egit/Eclipse. <S> It's not too bad; I was able to easily clone the repo at home to work on assignments that were started in the classroom. <S> You have to understand that unlike old source control (SVN), github is designed to setup a local repo that is different than your workspace; and that repo is pushed to the cloud one; and pulled when you want it back. <S> So when students save to the cloud, it's this: workspace <S> ====commit====> localrepo ==== <S> push====> github cloud repo <S> and when they want to continue working at home they have to clone the repo and import into their workspace. <S> To the people here complaining that ignoring the command line is blasphemy... COME ON... <S> we teach tons of 14 year olds and want to encourage them. <S> GUI is the way to go for most of them.
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Researching this, the stock advice seems to be to set up the repository outside of the Eclipse project.
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Looking for a block-based programming language for AP CS P This question is specific for teachers of the United States College Board's AP Computer Science Principles class. I'm looking for a block based programming language that allows for: Procedures that return values For each that will iterate through lists In addition, we are to teach basic 2D robot programming with commands such as TURN_AROUND(), MOVE(), TURN_RIGHT() etc. My research has come up with MIT's Scratch IDE ; but I was wondering if there is a better choice for high school students. <Q> You will probably want to look into Snap! . <S> It was built upon Scratch and would probably meet your needs. <S> This is from its About page: <S> Snap! <S> (formerly BYOB) is a visual, drag-and-drop programming language. <S> It is an extended reimplementation of Scratch (a project of the Lifelong Kindergarten Group at the MIT Media Lab) that allows you to Build Your Own Blocks. <S> It also features first class lists, first class procedures, and continuations. <S> These added capabilities make it suitable for a serious introduction to computer science for high school or college students. <S> Additionally, I asked a question a few weeks ago about the differences between Scratch and Snap!. <S> You might find this discussion helpful: <S> "What can Snap! <S> do that Scratch <S> cannot?" <S> Edit : In the context of AP CS Principles, it may also be helpful to know there is a full curriculum available from Berkeley that utilizes Snap!. <S> It is called The Beauty and Joy of Computing . <A> It has a DnD interface but the blocks you drop become Python code. <A> Code.org has a CS Principles curriculum available for free, and I think this would meet your needs. <S> https://studio.code.org/courses/csp <S> I've never used it with a class, but it starts with an implementation of blockly ( https://developers.google.com/blockly/ ) and transitions to Javascript in Units 3 and 5. <S> It also allows students to create apps, using AppLab. <S> It starts with a turtle and moves through to user interfaces and beyond. <A> While I definitely recommend Snap!, for completeness sake you might take a look at: Scratch -- though w/o custom functions this may be limiting PencilCode -- a blocks+text environment around CoffeeScript GP (gpblocks.org) -- <S> a desktop environment that looks similar to Scratch/Snap! <S> But has dozens more blocks as well as a very interesting model for exploring classes and inheritance. <S> AppInventor -- using blocks to build Android apps. <S> For me, Snap! <S> strikes a good middle ground between freedom and complexity. <A> On CodeHS we have a block-to-text based programming environment and a full curriculum for <S> AP CS Principles that you can use for JavaScript. <S> It has a unit to teach JavaScript, including functions and lists among other topics, and also starts with a unit on Karel the Dog. <S> Karel the Dog is a JavaScript implementation of the Karel programming language , which is very similar to the style of problems on the AP CSP exam. <S> Karel knows the commands move(); putBall(); takeBall() ; turnLeft() ; and later turnAround(); Essentially it is the same as 2D robot programming but with a dog instead of a robot, which is a bit friendlier. <S> You can use this with blocks or text - it's just in JavaScript, and you or students can also easily build their own worlds. <S> Hope that helps! <A> StarLogo Nova is another MIT project. <S> It's block based like scratch, but I personally find it much nicer to use, and it allows (I think) for more complex programs. <S> It is more simulation oriented than scratch, but you can still make just about anything with it. <S> Also, it has a flying turtle for a logo: <S> It's got a nice setup for classes - each user has a profile with a public and a private gallery. <S> You can add collaborators to projects, set up some form of "class" on the system, though I don't know quite what that entails, etc. <S> Here's a screenshot of the coding environment with some code for a project I did in it: <S> On the left, you have a menu with the different coding blocks, the drop down has categories very similar to those in scratch. <S> The tabs on top of the coding section are basically for the different "agents" and for the "world". <S> This program, if you're wondering why there's a "Killers" tab, is to simulate an epidemic. <S> There's support for all sorts of things - procedures that return values, movement of "turtles" which are basically robots on the screen, etc. <S> Here's a screenshot of the section of the screen that shows the result of your program: <S> This shows the level of complexity you can get too - you can have output graphs and number boxes, input sliders, etc. <S> You can also keep it very simple - the two things that are pretty much always there are the "setup" and "forever" buttons. <S> This screenshot was taken right after "setup" was pressed - it initialized the turtles, widgets, breeds in the right proportions, etc. <S> I'd definitely recommend this language. <A> Python has a turtle graphics module that is quite a bit of fun to play around with. <S> It is simple to use and you can have your students write functions to drive it and to draw custom graphical elements such as stars. <S> Turtle graphics can be used to make looping visual. <S> You can also add an event-driven element by making your drawing panels mouse-sensitive. <S> The Python site has complete documentation. <S> Tough exercise: Draw an American flag. <S> Easier: <S> Draw a Texas flag; making a five-sided star is a fun puzzle. <S> You can incorporate this into your class and experiment with it a variety of levels.
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Not strictly block based, but I like Codesters as a nice midway point.
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Thoughts on copying and pasting code? I'm curious to hear people's experiences with allowing (or disallowing) students to use copy and paste in code when learning as beginners. I feel like there are two kinds of copy/pasting. Copying code you found somewhere in docs or on the internet and pasting it into your code Utilizing copy paste with your own code to write similar code more quickly I see some upsides and downsides to both, so I'm wondering what other instructors have learned. e.g. Upside to allowing it. It's a useful tool for moving quickly and everyone who writes code professionally would use it. Downside: students who are beginners could really use the practice typing everything out Downside: it makes it much easier to copy code you find somewhere without needing to understand it. What are other instructors' experiences and insights? Do you allow your students to use copy and paste? <Q> I let the kids cut and paste code but with the following caveats: They must cite the source (be it a classmate, another student or a site like StackOverflow) <S> There has to be enough of their project that is their own code to show mastery of whatever the assignment's all about <S> At times, I encourage them to use others code (and libraries) to enhance their projects, that is, add features that they otherwise wouldn't have had <A> In my class, the only rules I set are that kids may not give code to each other, either directly or indirectly. <S> I also set a "rule of thumb" that if student A needs help from student B on a portion of a lab, student B must have finished that portion, and may look at student A's (relevant) work, but that A may not look at B's work. <S> Part of the logic here is that I already consider labs to be "suspect" with regards to plagiarism, so the giant brunt of their grades come from tests and quizzes. <S> The labs, then, are primarily a tool that the kids should use to prepare for the assessment. <S> I explain this to them often, and point out that not fully understanding their own lab is a great way to shoot themselves in the foot. <A> I think it is fine, as long as it isn't an essential part. <S> It saves time, and the students can learn from professionals, and can learn new ways of doing something that they never would have thought of. <S> Also, it helps you become a more efficient coder, and if you borrow someone else's functions that is more efficient it makes the rest of your program faster, and it saves a lot of time that could be spent on the main goal, not just some function that was already created before. <S> Don't reinvent the wheel! <A> I don't think that student learn that much from just running someone else's code without going through it. <S> That way they get the speed advantages of copy / paste <S> but they also have to engage their brains whilst getting experience debugging. <S> Alternatively, you can give students code to copy that they then have to comment / adapt / extend. <A> Item #2, a form of code re-use, especially if it is tested known working lines of code, is usually considered to be a good software engineering practice. <S> Copying a line or two from the official documentation might in some cases be considered the proper way to learn or to code. <S> Some professional IDEs do this automagically in the auto-complete hints. <S> Copying from a web search or stackoverflow requires supervision or auditing. <S> The instructor needs to confirm that the student understands (what it does, the algorithm, etc.) and has checked what they are copying against more official (for the language, library, etc.) documentation. <A> I'm late to the discussion, but here are two reasons against copying and pasting code: <S> I believe something is lost when you simply copy and paste code. <S> They say that to learn a definition of a word, you read it, say it, and write it. <S> So I think typing code definitely adds value, especially when IDEs like Eclipse have autocomplete and syntax checking. <S> Typing is a learning experience. <S> Unless you are copying from a raw format, copy and paste could bring in invalid characters. <S> For example, try copy and pasting "hello world" from Microsoft Word to your favorite code editor. <S> You'll see invalid double-quote characters pasted.
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Copy & pasting can be really useful for sharing code that has been deliberately 'broken': you can demonstrate / explain code that is working and then introduce deliberate mistakes for students to find and fix when they copy / paste.
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What would be a good first choice to teach game programming to beginners? In my institution we are close to starting a new graduate level program for game development. However, this program will accept non-digital game designers or other non-experts (real architects who are into interactive design), too. Therefore, the programming course must cover inexperienced programmers (an introductory course for adults who have bachelor's). At the same time, it is preferable if it also includes tools for expert programmers who may also have bachelor's in computer science (this part is optional). The program is designed to be generic. So, some people may prefer to come up with 3D games using an engine, while others prefer to instantiate board games for children. As you may see, programming is not the aim as in CS courses, but just another tool, here. What language might be a good choice to teach inexperienced programming in the game domain? <Q> For those interested in 3D (though, it can be used in 2D) game making with an engine, I would suggest teaching Unity . <S> It's an engine and a platform for creating games. <S> Unity can be used with C# and Javascript, which means that those who choose to use it will also have some experience with some very popular high-level programming languages. <S> Additionally, Unity is, in part, a graphical engine. <S> This means that the game is made in a graphical way, and the student can decide how much coding would be involved (Unity has an asset store, in which some scripts can be used. <S> Some are free and others are not). <S> This allows students to be comfortable with the game they are making, and they decide how much programming they do. <S> This degree of freedom is often very beneficial for students. <S> A portion of making a game in unity involves designing, and artistic work. <S> This can be a very convenient environment for the students who are into interactive design. <S> Overall, Unity fits the bill by being flexible and answering each students needs and areas of interests and expertise. <S> So I think that it is a very good choice to start with. <S> From my experience, it's quite enjoyable to make games with it just for the sake of playing around with the software. <S> This isn't too relevant to the question, but students who enjoy working on projects are more likely to make great projects. <A> There are commercial flavours of the BASIC language that specialise in creating games; I remember briefly playing with Blitz Basic many many years ago and found it easy to work with, but there are numerous competing products you might want to also consider. <S> Despite dramatically reducing the complexity of creating games, absolute beginners are still going to have to do a lot of coding before they get to the point where they can create more than ultra-trivial games. <S> Python is a fairly modern and friendly language, often used in schools as a first language, and Pygame is a fairly popular (and therefore well supported/documented) extension. <S> Again, absolute novices will need to do a lot of work with Python before they reach the Pygame level. <S> As a way of making the grunt work of learning to code more interesting/rewarding for novices, you might want to investigate games that feature editors for building new levels. <S> These editors often use scripting for game events (Lua I believe is a popular language in such cases), meaning novices can learn to code by augmenting an existing game rather than building their own game from scratch. <S> The issue here is that transitioning away from writing event scripts to writing full game code may be traumatic, particularly as it will almost certainly require learning a new language. <S> Of course Scratch (and its various siblings/clones) offers a way of covering the theory behind coding in a rewarding and friendly way, without actually 'writing' any code. <S> Given its popularity, no doubt there are plenty of resources to help transition students from Scratch to 'real' languages such as Python. <A> Python (probably Python 3) would be a great option. <S> That being said, Python has many fantastic tools for experienced programmers, and is a very flexible language. <S> It also has the already mentioned Pygame extension. <S> Python is also widely used outside of the classroom, meaning it might be more useful to have experience with it than, say, BASIC or Scratch or game-specific platforms. <A> We used processing in our summer program. <S> It's a 4 week full day Mon-Fri program for rising 9 - 12 graders with no experience. <S> In that time frame, they're able to learn some good CS fundamentals and write a nice project and games are the most common projects. <S> Processing isn't a game development platform per se so that is both an advantage (teaching core cs using essentially Java) and a disadvantage (no built in game support although Processing is made for graphical applications that are dynamic with respect to time). <A> I would probably say Python or Ruby, being that they are fairly easy languages to read and learn for beginners while still being worth their salt for CS pros. <S> Another suggestion if you prefer a graphics-oriented course is using Javascript in the Unity engine is the best way to go. <S> There is a graphical element (creator's choice of 2D or 3D) to the course then for the architects/engineers while still implementing a very heavily used and recruited programming language at the student's discretion.
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Python is a very user-friendly language, perfect for beginner programmers (it also enforces good practices like indentation, etc). A non-commercial option would be to use Python and Pygame.
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Explaining pointers to highschoolers How would you explain pointers and their use to high school students with some prior knowledge in programming, mainly in Python, but very limited knowledge of C? Note that this isn't a duplicate of Simple Pointer Examples in C , because here I'm asking for an explanation of how they work, not an example of them working. <Q> A prerequisite to understanding pointers is a basic understanding of memory. <S> At least on the broadest level, students need to know that when they declare a variable in their programs, that variable is stored somewhere, so they can use it, access it, update it, etc. <S> Where that variable is stored also has some address, so it can be located (specific addressing techniques need not be introduced yet). <S> The specifics of heap v. stack, memory size (int v. long long), and other such concepts are not necessary to understand what a pointer is (but they certainly would help). <S> All this background established, here is the easy way to think of pointers: <S> A pointer is a variable that contains an address of a variable. <S> Simple enough on the surface. <S> That sentence comes from Chapter 5 of K&R ( The C Programming Language by Kernighan and Ritchie). <S> This chapter has a great explanation of pointers and arrays, and I would highly recommend it for an understanding of pointers, <S> at least in the context of C. One key point for C is the following: <S> Since C passes arguments to functions by value, there is no direct way for the called function to alter a variable in the calling function. <S> ... <S> Pointer arguments enable a function to access and change objects in the function that called it. <S> Now, to get into the details of pointer arithmetic, passing by reference, syntactic sugar <S> vis-a-vis arrays, pointers do become more complicated. <S> However, always keep in mind the simple definition that gets at their essence: pointers store addresses for other locations in memory. <A> I set the stage from the beginning. <S> When we first do variables, I draw a big box and call it the computers memory and then draw a small box of memory and say "it's at some address" (having already explained that memory is set up so you can identify each piece with a number) <S> so when we say: x = 20 (or int <S> x = 20 or whatever) <S> I draw something like: x100____| <S> || <S> |----- <S> explaining that we have a block of memory at location 100 large enough to store an int (in this case) and we can get to it using the identifier x. <S> then x=10 takes the 10 and stores it in the memory and a = <S> x + 5 looks to see that x is an identifier to memory 100 <S> , we get the 10 then add 5 and then store it in the box referred to by a (which is at memory location 108. <S> x <S> a100 <S> 108 ____ ____| | <S> | <S> ||10 <S> | | 20|----- <S> ----- <S> This sets the stage for pointers later on. <S> When we get to pointers, we merely have to explain that the box holds a number that refers to another memory address or location: *p i100 108------- ------| 108 <S> | | 49 || <S> | ----- <S> > <S> | |------- <S> ------- <S> all the while using lots of drawings and arrows. <S> Also, when we talk about functions, I don't formally describe the stack but talk about it and then the memory for parameters and locals is in a subsection of memory allocated for that function call. <A> for example suppose we have a integer variable int a = <S> 10;then <S> the value 10 i.e. is stored at a memory cell which can be accessed with the help of a pointer. <S> With the help of pointer we can directly access the value the variable to which the pointer is pointing.
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Pointers are simply variables which are used to store memeory addresses of another variables.
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Benefits of explaining low-level architecture in a programming class When teaching an intermediate or advanced highschool programming class that also touches on general CS concepts (algorithms, etc), what are the benefits of explaining low-level computer architecture? How much added understanding of programming/computer science does a student get when learning about logic gates, for example? My question isn't a duplicate of Is it more effective to teach low level languages before high level ones or vice versa? as it's asking about logic gates, registers, instruction set architectures, etc, and the benefits of teaching those in a programming class, not about low level programming languages in particular. <Q> Students should understand the importance of the memory hierarchy, including how caches use temporal and spatial locality to tremendously speed up memory accesses. <S> Otherwise, a student would not know there is any difference between: for (int i = 0; i < 1000000; i++) { for (int j = 0; j < 1000000; j++) { arr[i] += <S> j; }} and the logically equivalent reordered code: for (int j = 0; j < 1000000; j++) { for (int i = 0; i < 1000000; i++) { arr[i] <S> += j; }} <S> The difference is that, in the first piece of code, each array element is retrieved from memory once and placed in either a register or the cache, from which it is operated on a million times. <S> Ignoring spatial locality (which would apply equally to both versions), the total number of reads from memory would be 1,000,000, and the total number of writes would be 1,000,000. <S> With the second version of code, each array element is fetched from memory once for each value of j . <S> The total number of reads from memory would be 1,000,000 x 1,000,000 (10^12); the total number of writes would be the same. <S> Per <S> Latency Numbers <S> Every Programmer Should Know , a main memory access takes about 100 ns; an L1-cache reference takes .5 ns. <S> Accessing a register adds no time to instruction execution. <S> Ignoring the times for the writes (which may not be in the critical path) and spatial locality (which applies the same to both versions) and assuming that a[i] is stored in a register, the data memory access time for the first is 10^6 <S> * 100 ns = <S> .1 <S> s. <S> The data memory access time for the second is 10^12 <S> * 100 <S> ns = 10 <S> ^5 s. <A> TL;DR Understanding the levels of abstraction in a computer <S> My AP <S> Computer Science Principles course teaches three languages: Scratch, C, and Python. <S> One of the 7 Big Ideas for the course is abstraction . <S> At the end of the course, I emphasize how Scratch exists at the highest level of abstraction relative to the other two as a block-based language and how the Python interpreter we use is written in C. Connecting this to lower levels of a computer, we form a chain that looks like this (from high to low): ScratchPythonCAssembly <S> LanguageMachine CodeLogic Gates <S> Obviously for the purposes of the class, it is a bit of a simplification as we don't cover instruction sets or adders and ALUs or assembly language specifically. <S> However, as an introduction, students can begin to form a conception as to how a computer operates at each level. <S> This lays the foundation for further study as students look ahead to pursuing computer science in college. <S> Despite any potential future benefit, I take this more philosophical approach to this topic: there is an intrinsic benefit and reward to looking "under the hood" at how things actually work; in that sense learning lower levels of computer architecture is an end in and of itself. <S> To contextualize my class as a whole, I use the following quote at the top of my syllabus: <S> "Any sufficiently advanced technology is indistinguishable from magic." <S> -Arthur <S> C. Clarke <S> Learning how charges of electricity on transistors can be constructed to form logic gates, which in turn form the building blocks for computer architecture -- that is magical. <A> One doesn't need to teach actually using assembly language to explain how a basic fetch execute cycle works. <S> Etc. <A> Describing the low level architecture at the level of what the machine is able to do can greatly help some students to identify with the task of coding. <S> If you do this, I think you also need to consider how to describe the link between this internal machine architecture, and the external (analogue) world. <S> I don't think it's necessary to go into great detail, just describe the basic load/store/add as a very simple process which is powerful because it can be performed extremely rapidly. <S> I'm dubious about the value of going down to the level of logic gates or transistors. <S> These are not the elements that processors are designed with (not for maybe 20 years), and seem like a little bit too much detail to present until you are at a point where manipulating and minimising logical equations makes sense. <S> A simple assembly code expresses the right sort of low level unit, and there are plenty of examples of mechanical programmable machines that you can draw on (via you-tube) to demonstrate that the magic is realisable. <A> Regarding architecture specifically, I don't see a tremendous benefit in high-school level programming classes. <S> However, at just one level or so of higher abstraction, discussing the principles of memory management as it applies to programs they write (such as stack and heap operation, how function calls are handled, etc) can make a big difference. <S> It is very hard to describe why tail recursion is important, or the operational output of (mystring <S> == mystring2) in Java, or <S> even what the code below accomplishes without discussing some lower level operation of the computer: public static void main(String[] args) { int[] v = new int[1] <S> ; v[0] = 5; mystery(v); System.out.println(v[0]);}public static void mystery(int[] a){ a[0] = 7; a = new int[10]; a[0] = 10;}
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A touch of some minimal explanation of logic gates, binary numbers, state machines and the processor-memory divide helps make computing seem less like magic, and more like technology (something of which they could become designers in the future).
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Introducing image processing - Should I teach the math During the summer I am teaching a programming workshop for students in a high school computer science major. The purpose of the workshop is to introduce them to image processing, and to have them experience using it. Naturally, an image processing library is necessary (teaching in java, so probably JavaCV, though I might go for python and then just do openCV, but the question isn't about library choice). These libraries do calculations with relatively advanced mathematics. Things that are aren't taught in the school, nor anything close to the level of math they know (It requires knowledge of matrix multiplication and many other things). The students are at an advanced level in mathematics (calculus, algebra, vectors and a few other things). Should I teach the mathematics behind those computations, before teaching the image processing material? I think they can understand the math, if it is taught. Is that knowledge necessary to understanding how those libraries work? The image processing in question is feature extraction, edge detection etc. Examples of a mathematical background is how to write an algorithm to compute the determinant of a matrix, or one for matrix multiplication etc. <Q> I would tread lightly here for a few reasons: <S> The math is not strictly necessary. <S> The students signed up for an image processing workshop in the context of programming. <S> The core skill that they expect to come out with is the ability to program graphics manipulations. <S> Spending a substantial portion of this time learning about the underlying math, certainly important in a full semester's undergraduate or graduate coursework, only moves very slowly towards what they (presumably think) they signed up for. <S> Some kids get turned off by math. <S> One of the unstated goals of every course is to both show the value of the field, and hope that the student wants to go on with the material and learn further. <S> That means that we want them to like it. <S> Using a voluntary summer workshop to emphasize the more abstract parts of the material may turn many of them away from graphical processing entirely. <S> So, don't do any math then? <S> Actually, I would not say that. <A> I've never taught image processing with a library, only with direct array manipulation so take my thoughts in that context. <S> Ben's correct in that some kids are turned off by math <S> and it's true that the math isn't strictly necessary but the other side is that some kids will find a basic understanding empowering and, as a friend of mine always says " never use a tool you couldn't write yourself" - there's a benefit to understanding what's going on under the hood. <S> Of course, being a summer program, you don't have the luxury of temporarily losing them, you've got one shot <S> so Ben's points are really important to consider. <S> On the other side, depending on your audience, and only you can judge that you can teach some of the math or at least the intuition behind the math. <S> For example, we reading about edge detection, you'll see things like: <S> Take the derivative of the color gradient using a 3x3 kernel.... <S> or something similar. <S> But at the core, what every description is really saying is: If the color changes a lot from one pixel to another then it's probably part of an edge. <S> Kids can easily see this (particularly if you first convert the image to gray scale. <S> They can easily get the concepts and even write a simple edge detector with none of the hard math or terminology. <S> The matrix stuff can be shown mechanically for computational efficiency if you want to show it. <S> I wouldn't teach the math first but depending on the audience <S> I'd probably try to get some in. <A> I find that classes are usually divided into a few groups: the kids who are really interested and want the math, the kids who just want to make the thing do the other thing, and the kids who don't really have any interested. <S> Based on this distinction, you'll see that some kids want the math, and others don't. <S> The best way to deal with this in my experience is to give the interested kids a quick (5-10 minute) tangent into the math, and make sure to provide a list of "further reading" and resources so that kids can look into it on their own, if they want to take that initiative. <S> Optionally, you could reward that with extra credit to encourage even the less math interested kids to learn about it.
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I would touch on a some of the underlying mathematics, but briefly, and (because it is a summer workshop) with the simple goal of illustrating that there is important material that isn't too difficult to tackle if they eventually want to go further into the topic.
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What statistics should be in a computer science degree? My university has decided that it should give a core (that is compulsory) statistics class to its computer science undergraduates. This opens the interesting question of what should be in such a class that everyone has to take. As far as I know most CS degrees don't currently contain statistics classes so it's hard to compare to what already exists. Does anyone have any experience of this and what would people recommend for a new statistics class for computer science students? <Q> My first thought to provide a bit of something for you to go on was CS2013: <S> The ACM/IEEE Joint Curriculum Guidelines for Undergraduate Degree Programs in Computer Science. <S> This is available at https://www.acm.org/education/CS2013-final-report.pdf . <S> I've copied out two relevant passages from that here: "Computer science curricula should be designed to provide students with the flexibility to work across many disciplines. <S> Computing is a broad field that connects to and draws from many disciplines, including mathematics, electrical engineering, psychology, statistics, fine arts, linguistics, and physical and life sciences. <S> Computer Science students should develop the flexibility to work across disciplines." <S> (p.20) <S> "Similarly, while we do note a growing trend in the use of probability and statistics in computing (reflected by the increased number of core hours on these topics in the Body of Knowledge) and believe that this trend is likely to continue in the future, we still believe it is not necessary for all CS programs to require a full course in probability theory for all majors. <S> (p.50)". <S> It is worth searching that document for 'statistics'. <S> It is mentioned in many other areas, but <S> mostly as something learned in other areas such as Networks, HCI, Cryptography, etc. <S> The December 2013 issue of ACM Inroads had a good article ( http://dl.acm.org/citation.cfm?id=2537777 ) on the role of mathematics in CS. <S> This included a section on "The Current State of Mathematics in Computer Science Curricula". <S> The article states that "The most-connected mathematical topic [to CS] by far is probability and statistics" and has some references to such. <S> They also present the mathematics requirements of 25 'high quality' CS programs. <S> Stats and Prob was required for 15, Calculus for 21 and Discrete Mathematics for 22. <S> http://dl.acm.org/citation.cfm?id=1240202 discusses statistics in liberal arts CS curricula. <S> Searching the CITIDEL syllabus collection (citidel.villanova.edu/ then look for syllabus collection) for 'statistics' might be worth a try, although the website has been varying between unresponsive to slow to responsive lately. <S> Also, some of the material in there is a bit dated, but then again, statistics dates fairly well! <S> Given that in 2013 60% of sampled 'high quality' CS programmes had statistics, maybe it is more prevalent than you think. <S> Perhaps the best way to obtain the most up to date information is to check the websites of several good CS programmes and hope that if they include statistics, the syllabi are available online. <A> I recently completed the MITx MOOC 6.00.2x , which is modeled after an introductory programming class in Python at MIT. <S> The course addressed the following topics from statistics that integrate nicely with computer science (especially data science and machine learning): <S> Confidence Intervals Variation Distributions Probability Sample Sizes Standard Error Central Limit <S> Theorem <S> Goodness of Fit Model Predictions and Overfitting Cross-Validation <S> Depending on the level of students and their familiarity with some basic concepts from statistics, I would also recommend looking at HackerRank's 10 Day of Statistics challenge. <S> While the pedagogy isn't the greatest, it does scaffold nicely from mean, median, and mode through standard deviation and distributions to end up at linear regression and correlation coefficients. <S> There is also some discussion of probability along the way. <S> Taken together, these two examples provide some big picture concepts to address that are fundamental to stats and that have relevance for computer science and programming. <A> While statistics can be useful for professional developers that knowledge is not as critical as it is for researchers. <S> The CS2013: The ACM/IEEE Joint Curriculum Guidelines for Undergraduate Degree Programs in Computer Science breaks knowledge units into three broad categories. <S> Things <S> every CS department should offer Things that every CS Department should offer 85-90% of Electives Statistics falls into the third category. <S> I would not make statistics a required course <S> but if you are going to do so I would suggest you look at the sort of topics you most want researchers to know. <S> Ideally you are providing your students with the knowledge to properly evaluate research so that they can make informed decisions based on it. <S> You'd probably want a deeper level for people actually doing research. <S> FWIW <S> I was on the CS2013 task force but opinions here <S> are my own and I am not speaking for the task force. <A> I got my CS degree in the 1990's and at the time (and perhaps still today) there was a lot of crossover between math and CS. <S> By just taking the minimum math requirements to meet my CS degree I was one math class away from a math minor. <S> Subsequently in 25+ years as a software engineer I have never used most of that math, the only math I've actually used is geometry, trig, and probability/statistics. <S> Especially these days with "big data" being a popular topic in computer science, and map/reduce being a primary technique, the concepts of frequency, concentration, correlation, regression, distribution, expected values, etc. are very applicable to problems that you see every day. <S> Also the type of thinking and reasoning you need for stats and probability is much more applicable to real-world problems since it has more to do with estimation, approximation and trends. <S> One of the faults in my opinion with math is that you are often expected to arrive at a single clear and concise answer, when in fact few real world problems are solved that way. <S> Conversely I've never once used all of that calculus (which is a shame because I liked it) and related math. <S> It was fun to take and probably a good (extended) mental exercise and weed-out for students <S> but I think the stats and probability should have been emphasized a lot more than it was.
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I think that statistics courses are most useful for computer scientists who are anticipating a career in research.
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Overcoming a friend's self-discouragement Before I turned 19 I just kind of... fell into coding. I used to think programming was something incredibly hard that only child prodigies and people with a 160+ IQ could do. (A view often reinforced by Hollywood stereotypes.) And I thought that I just wasn't smart enough. Since getting into programming,${}^1$ I have learned that even a monkey could take up coding. (Seeing some code, it seems in fact, they do.) This is not evident to many outsiders, however. I currently have a friend that is about to finish school and she has no idea what to do with her life. I am trying to encourage her to give coding a shot. I know she would be great at it as she's one of the smartest people I know, even if she won't believe it. Just like younger me, however, she thinks she's too dumb to have a chance at coding. How do I convince her to give it a shot?${}^2$ What tools are there to show her it is much easier than it looks at a glance? ${}^1$I just kind of happened to get into coding via databases, but that is a rather unusual path to take and not one I would recommend to start out with. ${}^2$I don't want to pressure her into a career in programming; if she decides it's not for her, that's fine, but basic coding knowledge is surely not a bad skill to have. <Q> I am not sure if I agree with the "monkey" part! <S> Maybe everyone is capable of writing some code. <S> Building serious apps is another thing... <S> Anyway, show her the code.org website, and let her play around for a while. <S> If she does not like, then probably she is not fitted for this "monkey thing" :) <A> What do you like about programming? <S> Think of something you saw/did when you were starting out that inspired you. <S> I remember during my undergrad when one of my professors all of a sudden one day wrote a program that output itself. <S> I was blown away! <S> Why didn't I think of that? <S> What could I do with that? <S> That was it for me! <S> If your friend is like you, she might be inspired by similar things to you, and the personal approach coming from you, not from a website/book/whatever , is something that no website/book/whatever can do. <A> First, try setting up some sort of "coding hangout time" - you and her can practice coding together. <S> You can help her when she gets stuck, and encourage her. <S> It's always good to have a buddy in what you're doing <S> =) Second, start with the right things. <S> Try a little visual programming first, using hour of code programs, or a language like Python, which will teach good practice (indentation, etc) and remove worries like memory control, which make it harder for new learners. <S> Third, start small. <S> The classic hello world program in Python is literally print("Hello world!") . <S> From there, maybe go to things like adding, or using variables. <S> I particularly enjoy Codecademy's course - problems with instructions. <S> And remind her that you'll be willing to help when you have time, and so will people on sites like stack exchange (Codecademy also has a forum, though I haven't really used it). <S> To conclude - show, don't tell. <A> I want to focus on this part of your question: <S> What tools are there to show her it is much easier than it looks at a glance? <S> It reminded me of this blog post from Scott Hanselman: <S> "Stop saying learning to code is easy." <S> The entire post is relevant for this topic, but I'll just excerpt this paragraph: <S> When we tell folks - kids or otherwise - that programming is easy , what will they think when it gets difficult? <S> And it will get difficult. <S> That's where people find themselves saying " <S> well, I guess I'm not wired for coding. <S> It's just not for me." <S> I tell my students often that programming is difficult, frustrating, annoying, and challenging. <S> However, I also explain that there is a reward to programming that is unlike that of any other discipline I've experienced. <S> When you rock an essay in English, say, you feel good, but the chances of you coming back to your excellent analysis of Hester Prynne in The Scarlet Letter over and over again are quite slim. <S> (I say that with all the affection of a former English teacher.) <S> Yet, if you write a cool program, especially one that it is an original idea, chances are you will revisit it, expand it, and/or play with it often. <S> There's great satisfaction that comes with the staying power of a working computer program. <S> You can actually use the fruit of your labor when learning programming. <S> Just keep in mind what Heather said above in her first point <S> : don't let your friend make this a solo effort. <S> Be a mentor, a Virgil to her Dante. <S> Guide her along this journey (should she choose to make it). <S> And when in doubt about where to start, choose this: CS50 Week 0 <S> Lecture - Fall 2016 . <A> Well, I know that starting out it is encouraging to do something simple that still has use. <S> I would recommend trying to set your friend up with an easy to read language like vb.net and helping them through some simple programs that can show them the uses of programming (a personal favorite is an interest calculator with textboxes to put in the principal amount and interest rate). <S> Please give her warning though that while there are easy things in programming, there is also a difficult side. <S> And if she shows interest but seems discouraged by the prospect of the challenging side, point out that there are sites like Stack Overflow where there are others who've probably dealt with the problem who are willing to help. <A> What are your friend's major worries about coding? <S> If it's just the difficulty, I would maybe show her something drag-and-drop such as App Inventor . <S> While an actual career in the field would most likely involve programming using code instead of blocks, I think showing her what she can build using a block-based language could help her realize how approachable the field can be. <A> I agree with your first part. <S> A trained monkey can code Show this to her and say If a monkey can write code, then why can't you. <S> Some encouraging things you should tell <S> World's first programmer was a lady, Ada Lovelace <S> The previous CEO of Yahoo was a lady, Marissa Mayer <S> So, A Girl can be a good programmer. <S> Regarding to Smartness <S> There is a great article in this site about college dropped out programmers. <S> Tech's 10 most famous college dropouts Ask her to read it. <S> Programming is really an another world. <S> The Logic and the choosing of correct language and method matters. <S> Smartness is a plus but not necessary. <S> image courtsey : http://cdn2.hubspot.net/hubfs/174241/code_monkey.jpg <S> Affiliation disclosure : I am in no way affiliated to the blog mentioned above nor to wikipedia
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Don't tell her she can code, show her she can code.
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Is it worth it for high school teachers to join SIGCSE? I just saw this question about SIGCSE for college professors, and it made me curious about whether it is a good organization for high school teachers. I am currently a member of my local CSTA, which I find to be of some value. Are there additional benefits from SIGCSE that could help me in my classroom practice? (Note: I would love to hear from current or past members of the organization, but please avoid ad copy and the like. This is not intended as a promotional question.) <Q> Yes! <S> (with some qualifications.) <S> Benefits (most apply to conference attendance): <S> connections with other teachers to share ideas and experience research results on <S> CS teaching practices/methods <S> TIME away from class to reflect and plan broader perspective on new/existing computing curricula (especially honest feedback on others' experience with CS material/curricula) <S> perspective on what is out there for your students in computing careers and in college information-dense listserv <S> (you hear about sites like this one) <S> However, most of the sessions/listserv posts are still geared toward research on college classes, so you have to be picky about sessions at the conference. <S> There is a K-12 track for sessions, which makes things easier. <S> There are more K-12 sessions every year, and more K-12 educators attending as well. <S> This year my district (Chicago Public Schools) had 20 people attend, and there were a good number of other (mostly high school) teachers from other districts. <S> Two of this year's keynotes (Gail Chapman and Mitch Resnick) were people whose main impact has been in the K-12 space, and next year's theme is CS for All, so they really recognize the importance of what is happening in high school and earlier grades. <A> I've known many HS teachers who have joined and become valued members. <S> I think it is most useful for those contemplating further graduate study and seeking contacts and research ideas and such. <S> Some have gone on to earn doctorates. <S> However, for your stated goal, you will find that the members there, while not focused on secondary education, will have a lot to contribute to your programming and general CS classes. <S> SIGCSE folk are especially interested in APCS. <S> The curriculum gets developed by many of these people, as do supporting materials (case studies), and many, many of them are AP graders. <S> CSTA, of course, is more directly focused on your needs. <S> You can even participate in the development. <S> For example, Greenfoot, an interesting Java environment for beginners, as well as BlueJ (more advanced), were developed by a team led by members (Michael Kölling and his team). <S> He does tutorials, etc. <S> at the SIGCSE and ITICSE conferences. <A> I started teaching CS in higher ed and knew of ACM. <S> CSTA was not really around when I joined SIGCSE. <S> I think that both are great for K-12 CS teachers. <S> I am not directly in the classroom today, but I am more involved in policy <S> I consider both organizations critical for that work. <S> For example, many states are now implementing CS standards. <S> The amazing continuity between K-12 CS educators and the collegiate level is apparent in discussions is both groups. <S> The SIGCSE listserve, gives me daily information. <S> The CSTA newsletter gives me less frequent and newsworthy articles. <S> It is very easy to use both resources to show that the effort to support CS education in K-12 is of use, as the standards are in line with the content and pedagogy in higher ed.
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But SIGCSE can help you learn early of educational trends before they become embodied in curricula.
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How to adapt pair programming to a shared terminal environment like Cloud9? Pair programming rather than solo programming is best practice in the CS classroom. Online IDEs like Cloud9 allow both members in the pair to work in a shared environment like google docs: working with independent keyboards and mice. What are effective practices for students working side-by-side to collaborate in such an environment? I've experimented in my classroom and have arrived at my own solution, but I think the question deserves crowd creativity and crowd evaluation. Note: I've experimented with Cloud9 in both online and onsite instruction, with different results. This question is about students working onsite, side-by-side. Background: Extensive use of pair programming in the K-12 environment is best practice over solo programming. Pair programming increases persistence and engagement, and reduces frustration and boredom. See for example Hanks et al. (2011) Pair programming in education: A literature review. Computer Science Education 21 :2. Schools are increasingly using Chromebooks, which preclude a locally installed IDE. Computer science is being taught in an increasing number of sections on a school's master schedule, precluding instruction exclusively in a desktop computer lab environment. Effectively teaching programming using Chromebooks is important. <Q> doesn't understand what's happening. <S> Either that or students tend to get distracted by what the other is writing. <S> Having said that, you could try: One person writes code whilst the other writes comments. <S> This forces the two to discuss both what they're doing and what they're planning to do next. <S> Other paired programming techniques that don't involve simultaneous access: <S> Allocating a 'driver' and a 'navigator' to each pair of students: the navigator isn't allowed to touch the mouse of keyboard. <S> The driver has to follow the navigator's instructions. <S> Students swap after a set time. <S> Sabotage and share: get students to make deliberate syntax / runtime / logical errors in their code then share a link to their code in a shared document / forum. <S> Get students to record each error they find and fix. <S> Award points per bug fixed. <A> If you are using Cloud9 <S> and you want them to be working on the same code at the same time (Google Docs-style), you can have one user share their workspace with the other (with read/write permission). <S> There is a "share" button in the upper-right hand corner. <S> We have successfully used this for group projects on Cloud9. <A> Paired programming is very effective at work too. <S> We use Skype for Business to share screens (i.e., editor/output windows) and communicate in real time. <S> Add <S> GitHub or Bitbucket to quickly share code, and you have a very collaborative environment.
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I tend to avoid multiple students working on the same code simultaneously (Google Docs style) because it's really difficult to assess what has been done by each student or to stop one student dominating whilst the other If you don't have Skype, you can use Slack .
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Classroom use of a limited port scan in the wild? Under what circumstances is it ethical for teachers to teach the existence of a tool such as MXtoolbox ? Under what circumstances is it legal and ethical to use a superficial scan with protocol-adhering requests to scan a target that is not your own? Portscanning a school district's web or mail server is likely to be regarded as hostile under any circumstances without working with the school's IT department. Students are likely to do so if they know about such a tool, even if warned about the consequences. Background: The Computer Fraud and Abuse Act (CFAA) makes it a felony to access computer resources that are not your own without written permission from the owner if such access causes $5000 damage or more. The CFAA identifies as damages the cost to investigate any potentially unauthorized use and harden the resource against such future access. No one has ever been found guilty under the CFAA for portscanning, but only one judge has ever ruled on the matter and it is considered ambiguous under the law if it involves thousands of ports across thousands of computers, especially if the scan uses requests that do not conform to the expectations of the protocol at each corresponding port. Ports and protocols are important concepts early in a student's learning. Tools like MXtoolbox perform non-damaging scans and send a dozen or so requests, one of which is identical to directing a web browser to the target. <Q> I taught a Cisco networking class for a couple of years and we had to stay off of the district network any time we were doing networking stuff. <S> What I did was build a separate network in the middle of my room with old computers. <S> Ran network drops from there to the racks in the back of the room so we could hook into switches, routers, and stuff. <S> Once we got to the point where they knew how to program routers over IP instead of wiring directly in <S> I started messing with them. <S> For one of the labs I closed the ports they needed on the router. <S> One student figured it out and started scanning ports on the router to see if I had changed it. <S> I had. <S> We spent a lot of time going over the reasons you would want to do certain things like port scanning. <S> When it's the right thing to do and when it's not. <S> I also posted links to several articles about people getting arrested for computer crimes each week. <S> Since our network was segregated, we could do pretty much anything we wanted to on it though. <S> A couple of times I setup a web server and had them try and break in. <S> My personal favorite though was having a student put their iPhone on our network and had about 20 computers constantly pinging it. <S> You could watch the battery meter dropping and by the end the phone was seriously hot. <A> It's certainly ethical to teach the existence of such tools. <S> It's rare that a tool is not ethical, it's more common that a use of the tool is not ethical. <S> It's ethical because the students could also find it on their own and get in legal trouble, or they could here it from you and <S> at least know the risks in advance. <A> In general is is unethical to teach people skills that they intend to employ to harm others. <S> That said, it is hard to know the intent of your students. <S> Do you have Beavis and Butthead in your class? <S> Pretty problematic then. <S> But many people the age of secondary school students make a lot of judgment mistakes. <S> (The human race probably wouldn't exist if most people that age didn't take risks.) <S> So you need to be cautious. <S> Some of my undergraduate classmates were pretty off-the-wall. <S> (We had a mad-bomber who mostly blew up harmless things.) <S> Teaching how to make high explosives in his Chem class would be irresponsible. <S> So, if you want to teach dangerous tools, you need to provide a safe environment ( <S> likely not the wild) and give legal and ethical guidance with strong warnings about consequences. <S> I'll second @thesecretmaster's answer. <S> But even if you aren't responsible for the actions of others, your life could be ruined if someone goes off the rails with things you teach. <S> There is controversy in the industry about the place of white-hat hackers, for example. <S> They may mean good and may do good, but bad things happen and some are in jail. <S> Tread carefully. <S> Teachers in martial arts are cautioned not to take on a student who displays traits of a bully. <S> It is clearer to see there, of course. <S> That tradition is at least a thousand years old. <A> Teaching about the existence of such tools is totally ethical. <S> We need people who understand computer security, period. <S> Mentioning the law is also almost self-apparently necessary. <S> In my district, I am lucky, because I can get folks from the district IT staff to run the port scanner in front of my hacking class and discuss the results themselves. <S> No one in my prior district would have allowed such an activity (or, for that matter, a hacking class in the first place). <S> In situations where IT would not be as understanding, I would recommend discussing the tool, discussing the ramifications, and going to YouTube to find an example of someone using your tool of choice.
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It's only unethical if the teacher neglects to teach the legality of these tools along with their existence, or if the teacher advises students to use the tool in an unethical way.
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How to communicate expectations around "rabbit holes"? Without guidance, students will sometimes spend a large amount of time on a computer science assignment in a portion of the assignment that does not engage CS skills and knowledge. An example is a student who spends a lot of time creating costumes using the drawing tools in Scratch. The problem can include code, however, such as a student who has established expertise in simple conditionals but continues to build out an adventure game using repeated application of the same pattern without gaining any conceptual ground. What practices do teachers use to successfully retain the student engagement driving a student to exert ongoing effort but redirect their effort to realize greater gains in learning skills and knowledge intended by the teacher? <Q> There is another sort of rabbit hole, one that your best students can fall in to. <S> I once had a situation in which students were programming with a certain library that provided a simulation - a virtual world. <S> They had certain exercises designed to teach specific thought processes; think recursion, or design patterns, but it could be lots of things. <S> Some of the best students figured out that they could get the right answer, not by programming within the simulation, but by re-programming the library itself to make the exercise trivial. <S> They got the right answer by rewiring the foundation. <S> But the intent was to help them rewire their brains. <S> It is hard to condemn such students, of course. <S> They were very clever. <S> They learned something . <S> But the worry is that what they learned helped them avoid learning something else that may be more important in the long run. <S> In this case the solution was that I tightened up the simulator (which made it better/more secure), but I also needed to assure that they did in fact learn the lesson of the day. <S> It isn't that they did anything wrong, or learned the wrong thing, just that they may have failed to learn something important. <S> The same situation would apply if a student, asked to write a program with some hard bits, modified the compiler to make those bits easy. <S> Good that they teach themselves something about compilers, but bad if the hard bits held some important insights that programming around them left them in the dark about. <S> I sometimes have to tell a few (usually good) students that the purpose of programming exercises isn't to produce a program, but to produce learning. <S> Usually, if I needed the program I could write a pretty good one myself. <A> Wish I had a good answer, but I can sympathize with your Scratch example. <S> What I started doing was just giving up on the first day we did Scratch. <S> I would show them the drawing tools before we did any coding. <S> Spent about 5 minutes showing how to make sprites and backgrounds and then gave them the rest of the period to play, with the understanding that was the only day that they had to just play around and doodle. <S> Day two, we start coding. <S> Worked fairly well. <S> It was at least better after I started doing this than before. <S> I think the novelty of it wore off when they were allowed to goof off for a day. <S> Haven't taught Scratch in a few years, but I noticed the same thing happening with Jeroo. <S> Kids love painting the island with flowers and water. <S> The last lab in the set is one where they get to build their own lab, and make their own island. <S> I think having that to look forward to helps. <A> Well, in terms of your second example - inefficient code, because it's "easier" - try doing a code golf style game. <S> Whoever gets the shortest code on an assignment, project, lab, or whatever goes on a leaderboard, for extra points. <S> This may help improve coding knowledge. <S> As for the other problem - well, if it's on the student's time they are doing this, then it's theirs to spend. <S> Make sure you also have clear expectations - it needs to be neat, but not a work of art. <S> Also, if they are "going down a rabbit hole" by adding extra features to a project in the code, I would encourage that, again perhaps on a leaderboard of some sort (for "most well-done" project, or something like that). <S> So, in summary - it depends on the rabbit hole. <S> Make sure there are clear expectations and challenge them to push themselves with leaderboards/competition/extra credit. <S> Edit: As Buffy points out in the comments, there is too much of a good thing. <S> In industry, there is no need for "extra features" - <S> you do what the client wants, no more, no less. <S> And code golfing taken too far can lead to terrible pieces of code - of course as the teacher, one would have to accept only "golfed" solutions with good variable names, etc.
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Perhaps show them how they can iterate - starting by creating a quick stick figure for a character and then improving it once the key stuff - the code - is done.
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What are the benefits/uses of a SMART Board in CS education (or are there none)? A few years back I taught in a lab equipped with a SMART Board. I typically only used it as a regular whiteboard and the only benefit I could identify was that I didn't finish every lesson with ink on my fingers from absentmindedly erasing the odd illegible letter here and there. On the downside, it was something of an attractive nuisance for the kids with shorter attention spans, and writing on it was less precise and natural than writing with an ink marker. On balance I would probably have gotten rid of it, given the choice. Now I am being offered the chance to have a SMART Board installed in my lab. I can't think of how it could really be useful in teaching CS but then I am a bit of a Luddite when it comes to ed tech in general. My curriculum focuses on web design (HTML/CSS/JS) and I am looking at bringing in Scratch and/or Python. So am I wrong about it just being a fancy, overpriced wall hanging? Are there actual uses or benefits of a SMART Board in teaching CS that I'm just not seeing? How have you used SMART Boards in your classes? <Q> I've been in rooms with smartboards that aren't dry erase marker safe which means if the smartboard goes down the board space is lost. <S> I've never used a smartboard but think I get the most bang for the buck with a projector onto a whiteboard. <A> I had a smart board at previous school. <S> I used it when we did scratch, and it worked fairly well for that. <S> Not as useful when teaching typed languages. <S> But the screen was pretty small relative to the size of my room <S> so it was tough to see from the back of the room. <S> My room now doesn't have a smart board, but has a very large projector screen <S> and it's way better because it's way bigger. <S> Although, I do sort of miss the smart board when kids present projects. <S> It was great for demoing game projects. <A> I just love it, and show it to my students every year!
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We can project sites, code, etc and also annotate by writing on the board directly (although the annotations can't easily be saved other than by taking a picture). Although you may think mine is a less than serious answer, the best example I have seen for the use of a smart-board in computer science is in a video from De Pauw University , when they implement a time machine to explain program code debugging.
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How to document the developed work using an agile methodology? In the final report of their internship, the students of our school must have one chapter where they "document" the developed work. When using the “waterfall” methodology, they usually have one sub-section for each stage: requirements detailed design implementation tests ... What if an agile methodology like XP or SCRUM is used? Every year we have the same problem, as some teachers say it should be done one way, while others say the exact opposite. Any ideas? <Q> In SCRUM, during the end of each sprint, there is a Sprint Retrospective and Spring Review . <S> Important artifacts from the two should be extracted into this report, as it reflects the "developed work". <S> I'm not sure <S> the scope of what you require from your students for documenting the work, is it for the whole internship, or just one cycle? <S> In any case, because Agile is done incrementally, they can just write one template per sprint they've completed. <S> Sprint Number Sprint velocity <S> List of stories completed <S> Did it meet success criteria (definition of done and agile manifesto) <S> Notes from sprint review Notes from sprint retrospective Implementation strategies (if it is required by you) ... <A> Agile doesn't mean "don't plan", so there should be plenty to talk about. <S> Have your students developed user stories ? <S> Can they talk about these? <S> For example, let's take this example user story: <S> As a teacher, I want to automatically mark assignments <S> so I'm not spending time checking code that could be done automatically. <S> It might be worthwhile to encourage your students to consider how and why they wrote their user stories as they did. <S> You can check that they're not developing user stories that are too broad ( too many epics rather than stories) as they go along if you want to provide some support and prevent them from being too unrealistic. <S> As you should probably be estimating the amount of work for each user story, ask them to document that so you can check it. <S> Unrealistic timings—or no timings at all—should be caught early so that you can make sure they finish the project on time. <S> If you follow the ' planning game ' of XP, then you can also look at how the requirements were sorted by risk and value. <S> Yet another point to document and mark if needed. <S> As mentioned by Kaneki , sprint retrospectives provide time for your students to reflect on their progress. <S> Encourage them to use this wisely in place of a huge specification detailing implementations, tests, etc. <S> In short, there's loads to document about Agile, but you might not need to write everything on paper. <S> If it's easier for you, consider just being a part of the retrospective meetings and looking at how these go instead of meticulously writing down every detail. <A> Eclipse has a plugin called ObjectAid <S> that generates these diagrams from the source code (no additional work required). <S> Students can generate professional documentation from their source code. <S> There is jsdoc for JavaScript and <S> javadoc for Java. <S> These require specific comments and tags, but it's well worth it. <S> For all types of diagrams, there's draw.io , Balsamiq , PowerPoint, Visio, and many more. <S> A picture is worth a thousand words.
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If the system is object-oriented, you can use UML class diagrams to document the design. Source code documentation is important for future development.
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Uses of selection in programming (if, switch etc) I am an experienced programmer that has just started teaching. I am struggling to see how to introduce selection to my programming classes. None of the examples that I have seen so far are good. I am struggling to find examples other than the ones below. (These are more advanced than I need.) Termination condition for recursion (We don't do recursion until upper years of school, exams do not need it). Input validation (Again the exams say don't worry about checking input (I think this is a mistake, as it leads to cowboy programmers)). Both of these are only in the syllabus from UK year 12. I am teaching from UK year 7. Can you help with good examples, and exercises that my younger pupils can use? year 7 is age 11-12year 12 is age 16-17 <Q> There are endless examples that illustrate selection. <S> As you know, most useful programs have at least one selection statement. <S> I've found that some students struggle with the concept, so I start small and pick examples that resonate with students, for example: <S> if (hungry) System.out.println("Eat <S> a sandwich."); if (age > 17) System.out.println("You can vote."); else System.out.println("You cannot vote."); For a switch statement, I like to show some type of menu: switch(choice) { case 0: System.out.println("Balance Inquiry."); break; case 1: System.out.println("Transfer"); break; case 2: System.out.println("Withdrawal"); break; case 3: System.out.println("Deposit"); break; default: System.out.println("Quit"); break; } <A> If you want something very elementary: Write a program that determines the age of a person, where the person's date of birth and the current date are given. <S> For simplicity assume that both dates have already been split into three integer variables. <S> (The age is the difference of the years minus 1, <S> if the current date comes before the birthday in the calendar, otherwise it's the difference of the years.). <A> I suppose that a traffic light is a very good example and easy to understand by your target audience. <S> if (light is green) goelse if (light is yellow) <S> stop and goelse [if (light is red)] stop <A> I think of a factory where you decide upon requirements which type of object to build: LuquidsContainer produceByRequirement(String requirement1,String requirement2){ if("can be closed".equals(requirement1) <S> { if("keeps temperature".equals(requirement2){ <S> return new ThermosCan <S> (); } else { return new Bottle(); } } else { if("individual use".equals(requirement2){ return new Glass(); } else { return new Flagon(); } }} <A> Since many languages don't like that old square root of a negative number thing <S> it's a nice place for a conditional.
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One of the early examples I usually use is a quadratic equation solver using the quadratic formula.
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What would be reasonable to include in an Introduction to AI class for a 7th-8th grade after school program? The class meets just 8 times for 2.5 hours weekly, aimed at 7-8th graders with very basic programming skills. Possibilities off the top of my head: computer learning (neural nets and/or genetic algorithms), constraint/logic based programming (well, it came out of AI, right?), a Brief History of AI, and/or basic game states and alpha-beta pruning. I probably can't fit it all in, and I don't want to make it so difficult as to be discouraging. <Q> I don't have a lot of insight into your overall problem, but there is a resource you might consider. <S> There is a simple game, The French Military Game, in which a person plays against the computer. <S> The totality of game information is small enough that the computer can remember every position in every game played, so it doesn't make the same mistakes in subsequent games. <S> While it is a known win for the human player, after 6 or so plays it is very difficult to beat the computer. <S> The game is available (Java) in a couple of forms at the Greenroom , a place for educators using Greenfoot . <S> Membership is open to any interested teacher. <S> The FMG once appeared in Creative Computing, now defunct, as an Apple II BASIC game. <S> It uses a bit of math, but ok at the level you are interested in. <S> It is, at best, a simple, even naive, introduction to machine learning. <S> Disclaimer: I'm not associated with Greenfoot or the Greenroom. <S> The game is also discussed with code in Beyond <S> Karel J Robot though that book probably isn't a good resource for your class. <S> Another user here (@Ben_I.) points to an applet version with a brief explanation of the game. <A> I'll share a few things that I have done in the past to expose students to interesting AI topics without having them write working programs. <S> 1.) <S> To discuss expert systems and rules-based systems, have the students write out a list of rules (their best strategy) for playing tic-tac-toe (or another simple game that they should all be able to play well). <S> After finishing their own set of rules, have them swap with a partner and attempt to lose, but still following the rules that were handed to them. <S> This exercise has shown the difficulty in creating expert systems and exposes that we have so many assumptions that we don't realize. <S> 2.) <S> I really like Reinforcement Learning and created an activity where students are given a simple two-player game in which one student plays against the learning agent. <S> The learning agent starts off choosing between actions with equal probability of selection. <S> After a game is won or lost, the probabilities for actions taken that game or increased or decreased respectively. <S> I implement this by using sets of colored tokens that can be removed or added to. <S> For this activity to work, the game was be brief; the one I created never has more than 3 moves for the RL agent, it can only visit 14 possible states. <S> I print out each of these states and tape the pictures to 14 different cups. <S> The legal actions are color-coded with the colored tokens in the cups. <S> 3.) <S> Ant Colony Optimization is interesting and accessible. <S> I'll show pictures from Marco Dorigo's experiments with actual ants and bridges. <S> We'll discuss the concept of minimal spanning trees and some real world applications for them. <S> The I'll end up using an online ant colony simulator. <S> If you want more detail about any of these, I'd be glad to share my experiences and more details. <S> If you're looking specifically for something they can program that exhibits intelligent behavior, you'll be extremely limited. <A> I built a light but fun AI project using the Twitter developer API and a simple Python program to bring my dog Maggie to Twitter. <S> If you send a direct message to @maggielistens , you'll see what I mean. <S> This program uses a version of an old program from the 60s called Eliza . <S> It acts like a therapist by responding to your commments and questions. <S> It uses regular expressions and text replacement to appear like a real person. <S> It won't pass the Turing Test, but it's a fun way to get students interested in AI and programming. <A> I would recommend at least teaching genetic algorithm techniques. <S> The basic principles of heredity, mutation, and selection is fairly easy to grasp, and the ability to watch the intermediate steps between the first iteration and the last can be fascinating to watch. <S> Building the DNA portion of the code requires some intuition though, so problems have to be picked carefully. <S> The later chapters of Daniel Shiffman's The Nature of Code , especially Chapter 9.
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One option might be an accessible robot kit (Mindstorms, etc) and have students work on obstacle avoidance, color detection, etc. The Evolution of Code , is a great resource for basic AI principles based in biological principles.
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Working on practical projects as a team - good or bad? We are trying to implement a course where students develop web apps using PHP+AgileUI (no HTML, JavaScript or CSS) with a strong emphasis on "object oriented" approach, designing business logic and reuse of UI components. When it comes to the practical tasks, we are undecided. Should we encourage students to work in teams to achieve project together, or should we make them submit their unique work? Since most of the work is in PHP, there are no design/frontend/backend separation, we have a feeling that some students may "miss out" on some skills if another team-mate implements it. On another hand - teamwork is crucial in software design. What would you recommend - should we design material for teams or individual? <Q> Ultimately it comes down to if the work can be done alone ? <S> The purpose of group work should not be so that everyone has less work to do, but rather if the original work could not be done within the given span by a single person. <S> In the workforce, you're most likely to be working in a team and contribute to iterative releasts (Agile Methodologies). <S> If your expectation is that because you're in a group, you don't have to work as hard compared to working alone, then you are set to fail. <S> My suggestion would be to design a project such that bi-weekly or monthly iterations are presented, building up towards the final product. <S> Incorporate Agile Methodologies into this as it is very useful in the workforce and teaches team management / tracking. <S> Groups should be no bigger than 3-4, otherwise it is too big to be efficient. <S> The number of hours required for the project should be big enough that everyone is kept busy. <S> If this is too heavy for your course, then I'd suggest stick with single person projects as there is no merit to group work. <A> In my experience, group projects are valuable, but in any group of more than 2 people it is almost guaranteed that some students will put in more effort than others. <S> So my recommendation is simply to make 2 person groups. <A> I think it depends on the goals of the course. <S> Does your course have specific objectives for working in a team? <S> Is the primary goal to learn some aspect of programming? <S> I teach a software practicum course where students must collaborate like a real software engineering team using an Agile Development Methodology. <S> All the work they do is shared. <S> But if the primary goal of the course is to teach programming fundamentals, web development, game programming, etc., then I would lean toward individual assignments. <S> It's so crucial to practice programming. <S> You can maximize this with individual assignments.
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Of course some will do more than others, however one person should not be able to do the entire project. There are many things to be learned about coding as a team even with a single teammate, but the work won't be so diluted that students would completely miss out on the key aspects of the course. Learning to work in a team is an important skill.
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Is SICP appropriate for an advanced high school CS course? One of the most influential texts in computer science is Structure and Interpretation of Computer Programs . Before changing to a Python-based approach, MIT used this book for their introductory programming course. It is freely available with a number of resources thanks to the textbook site . When perusing the list of schools using SICP , I see that all of them are universities/colleges, which leads me to my question. Is SICP appropriate for an advanced high school computer science course? In particular, I'm thinking of students who have taken two years of AP Computer Science, so they would have completed a year of CS50 AP and a year of Java. I see that UC Berkeley has a self-paced CS class that works through it. I understand that some things are at the university level for a reason, but I am trying to bridge the gap between post-AP CS classes in high school and intro CS classes in college. <Q> First, I love SICP. <S> I took and later TA'd 6.001. <S> Like many MIT grads, I tried to teach it where I became a professor, and, like most who attempted it, decided not to do so again. <S> The main reason it is rarely successful outside of MIT isn't the difference in student quality but the difference in the support the school can offer. <S> If I remember correctly, at MIT, there were three lectures a week, two recitation sections, one tutorial section (approximately 4 students meeting for an hour with a graduate TA), and many staffed lab hours. <S> A high school or small college cannot generally provide that level of support. <S> Also, when taught outside MIT, it is usually as a junior-level course, and students still usually find it overwhelming. <S> (An exception is UC Berkeley, which taught it successfully for many years at the freshman level.) <S> I am not saying a high school class could not succeed, just that it would be very difficult, and the amount of work required would be exceptional. <S> It might also be hard to motivate students to work so hard on something so abstract, when they could be learning app development, computer games, or another more immediately rewarding topic with less effort. <A> Absolutely, the book is a gem. <S> It's filled with great insightful stuff right from the foreword. <S> One such gem: <S> computer language is not just a way of getting a computer to perform operations but rather that it is a novel formal medium for expressing ideas about methodology. <S> Thus, programs must be written for people to read, and only incidentally for machines to execute <S> Now, as to why I consider this book appropriate for High-School CS is this: essential material to be addressed by a subject at this level is not the syntax of particular programming-language constructs, nor clever algorithms for computing particular functions efficiently, nor even the mathematical analysis of algorithms and the foundations of computing, but rather the techniques used to control the intellectual complexity of large software systems <S> The book doesn't focus on learning the language but instead on solving some problem. <S> It builds from a explaining basic primitive type to using those to create abstractions and complex stuff. <S> The language used, Scheme (a dialect of lisp), is great for this purpose. <S> The authors explain various concepts clearly. <S> here's a good example explaining compound procedures. <S> Now, as pointed out by fellow community folks here, managing the material is a bit hard <S> and I believe that one don't have to cover the entirety of the book but cover enough so that people can infer as how to solve a particular problem given to them. <A> The book is quite deep. <S> I'd only consider it in secondary school if the students typically go off to top universities, MIT, Cambridge, Berkeley, or similar. <S> Otherwise, I's strongly suggest that they get a deeper knowledge of whatever language they already know. <S> Java version 8 has extensions that permit learning much about functional programming, for example. <S> Learning lots of languages shallowly isn't really a path to success. <S> Of course Scheme and Java are sufficiently unlike that studying both opens new thought processes to the student that learning both Java and Ruby would not. <S> But learning how to become a true expert in one language gives you a powerful tool for whatever you want to do. <S> It is often a shock when a top student at a top secondary school winds up at, say MIT and finds themselves just average.
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In summary, I would advise against using SICP for a class at the high school level, although I do think it is possible to supervise an independent study with a sufficiently motivated and sophisticated individual or small group of students.
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Jargon/Vocab about variables--- yes or no? In my experience (working with college freshmen mostly), I've tried to emphasize precise vocabulary about the concepts and syntax related to creating and changing variables. This is wording like: identifier declare initialize assignment token execute compiler My reasoning is that these words are immediately necessary to understand error messages, intermediately necessary to Google things, and necessary in the long term to communicate to other programmers. However, some teachers I've talked to try to avoid this type of language because they feel it introduces another barrier to their students' understanding. I guess they'd say I'm trying to introduce compiler concepts too early. What's your view? How do you know when there's too much jargon? <Q> Some of these words are entirely necessary, some (such as tokenize) you might want to avoid early on. <S> However, I would suggest this as a guiding principle: use vocabulary as is necessary to get at the core goals you hold for your students, but do not emphasize vocabulary for its own sake. <S> A great visualization or metaphor at the very start (after all, freshmen!) will take your students much further along than a series of fine distinctions. <S> Here is a fun little article about <S> 10 <S> Extremely Precise Words for Emotions <S> You Didn’t Even Know <S> You Had . <S> The title is correct; when you read through the article, you will find emotions that you have experienced, but never described. <S> Nevertheless, you were able to experience the emotions perfectly fully. <S> Similarly, with the help of a great diagram or metaphor, students will be able to utilize concepts that are more advanced than they can fully describe. <S> That's okay - great even! <S> - and later coursework can help them nail down finer distinctions as they advance. <A> Certainly mention the vocabulary, but I wouldn't make it mandatory to learn the words or use them correctly in class. <S> What matters is that the students understand the concepts that go with the words, not that the know the dictionary definitions. <S> Introduce all the vocabulary when it comes up in class, but don't be a stickler, especially early on. <S> Let the students get a feel for the different types, so that they have concepts to associate the words with, rather than associating the words with (possibly incorrect) ideas. <S> I'd also make sure to draw the distinctions when talking about the different types, so that the students mentally understand the different types conceptually before actually assigning vocab to the concepts. <A> Commonly, the jargon I see in class (former student, new to being a teacher assistant) is meant to serve one single purpose: increasing student understanding. <S> This seems relatively straightforward, but it is not as simple. <S> If one explains the jargon ahead of time (each subject has its related jargon explained before delving deep into the material) then one can use the jargon while teaching, which is a powerful aid. <S> If you explain what you mean by "declare" and "identifier", then whenever you use those words, it's as if you used the "new" keyword in java. <S> Java knows exactly how to deal with that keyword. <S> Your students will know precisely what to do when you say "create a declaration for so <S> and so with an assignment to such and such...". <S> This worked wonders with students I have worked with. <S> The key point is to explain your jargon . <A> It's a balance, as with all things. <S> Concepts are of course more important than vocabulary, but it's awfully hard to convey your questions and ideas without vocabulary. <S> Just look at some old math papers (like, really old, before the invention of the plus sign old) to see what I mean. <S> A couple of checks to make sure concepts are coming first: <S> Make sure they know what the vocab means. <S> I've read books where jargon and words were used in a confusing and improper manner. <S> Make sure they can generally explain without the vocab to another person, maybe not in your class. <S> That's often the true test of understanding. <S> There's a great story about Richard Feynman that he was trying to prepare a lecture on an advanced topic for an undergraduate audience, but he later told a faculty member that he couldn't break it down to that level, meaning that he didn't understand it well enough. <S> A couple of checks to make sure they know enough vocab: <S> Can they figure out most compiler/interpreter errors? <S> (Most) Python errors, for example, are fairly clear, so if they know some vocab, they should be able to figure most out. <S> Can they find the answer to their problem using google? <S> A student who is having a problem with a for loop but does not know that it is called a for loop will have a hard time finding a solution. <S> Can they follow the discussion in a simpler scientific paper, or later chapters in their textbook, or are do they have to keep a dictionary by at all times? <A> Use the vocabulary for the things that are directly relevant to what the students are learning, so they can intelligently talk about what they are doing. <S> This means that students should definitely know the verbs associated with programming. <S> Variables need to be declared, objects need to be instantiated, and programs need to be compiled/interpreted. <S> You can't really talk about code without these. <S> What about the nouns? <S> I usually don't focus much presenting on these. <S> Unless the they aren't native English speakers, students will (eventually) understand what an identifier or token is without much input from the lecturer. <S> There are nouns you should obviously go over, however, such as variables, objects, and data type. <A> I think it's actually really important to use the jargon and stress understanding. <S> A lot of the common mistakes students make have a root cause of misunderstanding the difference between, say, declaring and calling a function. <S> If students have the vocab list and the jargon at their fingertips, it makes it actually possible to have debugging discussions that will help students learn.
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The jargon is meant to make expressions and keywords easier to explain.
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Lesson plan for teaching java graphics Background: This lesson should give a firm foundation for graphics in Swing in java to students in high school who know OOP in java ( extends , implements and abstract , as well as composition). They are in the school's CS major. This year they need to create a project which is a part of their final grade in the CS major, and part of the requirements are a visible GUI. As of such, a lesson plan was created to teach them one of the ways of making GUI in java. However, this lesson doesn't teach what goes on in the background of java GUI. (unintended pun) What I have: Currently the lesson plan is as follows: Purpose: To teach the basics of creating GUI in java, for the students' final project. Needed knowledge: Object Oriented Programming, as taught in previous grade (In the previous grade they were taught the concepts listed in the Background section) Needed materials: Computers, preferably one per student (Students can bring their laptops), Internet connection. Procedure: Explain the basic objects inside the Swing library: JFrame , JPanel etc. Explain the Container object in AWT , and elaborate on how Swing is heavily dependent on AWT . All* objects in Swing are children of objects in AWT . Also explain the Component class object. Show that Container essentially contains (hence the fancy name) other Component s and that creates a GUI. Show the students a simple GUI for a chat application ( no server-client, just the gui! ) which composes of a JButton , JTextField (for entering messages), JTextPane (chat history) and JLabel . This step includes showing them the code. let them work for the remaining time (45 mins plus 45-time_it_took_to_get_to_this_step ) on creating a gui of their own, of their choosing, which can have any Swing object they find. The GUI must have JLabel , JButton and JTextField . Other than that, go wild. My problem: This lesson shows absolutely nothing about what Java does in the background for the GUI. I am talking about the intensive OOP the goes on in the JFrame class, and the incredible flexibility with everything extending JContainer (allows JButton , JLabel and many others to be treated almost identically). How could I extends one (or more) of the above steps, or possibly add a new one, that will teach these parts of java GUI? I find that these parts are important for anyone who wants to make Java GUI. Would simply saying what I have written in the previous paragraph be enough? *Haven't checked, but never seen one that isn't. <Q> You could extend (heh) <S> your lesson to include custom painting . <S> Basically, you do this by extending JComponent or JPanel and overriding the paintComponent() function. <S> This is how "real" Swing components draw themselves, and it gives students a window into how everything works behind the scenes. <S> You could have them draw basic scenes, animations, or even games. <S> Or you could have them create custom components like circular buttons <S> (disclaimer <S> : I wrote this example). <S> If you have enough time, you might want to split this into multiple lessons: start with basic Swing, then do a lesson on input listeners, then do a lesson on custom painting. <S> At the end of those lessons they'll have enough knowledge to create some pretty fun programs. <S> I'd also urge you to stick with functional GUIs instead of using a non-functional chat application. <S> Make a fun calculator that does something like convert dog years, or create a basic game that plays rock-paper-scissors. <S> Encourage students to make these as interesting as possible. <S> IMHO <S> this is much more engaging than a non-functional example gui. <A> The lesson looks pretty good to me. <S> First, the last part, extending the lesson to show how the power of JFrame class is harnessed in the backend. <S> Don't. <S> 1) <S> The students are presumed to already understand the OOP involved, and how the extends concept works. <S> 2) Give them the remaining time, as you've indicated, to work on the project assigned. <S> 3) <S> Allowing them to explore what they learned, and maybe get a second sense about the power hiding under the hood will make them more receptive, and more curious, about that power, and its source. <S> So, make that a separate lesson for the next class period. <S> The only thing I can think of to make it possibly better, is to add some structure, or expectations, to the assignment. <S> Possibly add some constraints, such as that it must include 2 previously undiscussed objects from the library <A> There are two things you can do (surely more, of course) that will enhance the overall education of your students. <S> First is to discuss the general situation of nested structures and the relationship to trees and to recursion. <S> The frame contains Panels which contain Panels, which contain... down to some non-recursive things like Buttons. <S> This lesson, when generalized from the specific GUI layout case, is important for understanding modern languages and how they are compiled and processed. <S> It also gives them the background to understand web page layouts, etc. <S> The second big topic you can introduce here, assuming you haven't already, is Design Patterns, both programming and architecture patterns. <S> Understanding the Observer pattern is essential to Java GUI programming for example. <S> Once they have seen one pattern in some detail (perhaps a truncated version) you have the power to discuss others. <S> The Java libraries are completely full of design patterns since Java and Design Patterns sort of grew up together. <S> The Java i/o libraries depend fundamentally on the decorator pattern, for example and the students likely already know about Iterator, but perhaps not the full structure of it and why it works and other solutions to the problem are sub-optimal. <S> Moreover, if you discuss Observer in some detail you have an entry into the Model-View-Controller architectural pattern (MVC). <S> So it is quite rich. <S> MVC is also used in the Web architecture as well, of course. <S> Once you introduce Patterns to your students you have a way to talk about reusable software at a much higher level than just "reusing classes", which has a lot of issues and often leads to ugly and unusable software. <S> Reusing proven designs, however, is a much more important idea.
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Possibly present a limited set of GUI templates to reproduce, allowing the students to pick the one they like to implement.
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Framework choice for AP CS A students: Swing or JavaFX? I attended an AP workshop this week to prepare for teaching AP CS A this coming school year. It gave me my first glimpse of Swing, which has now piqued my interest about including some GUI components in my course (something I had heretofore not anticipated). There are a couple other excellent questions/comments here about frameworks for GUIs in Java: Introducing the MVC pattern along with JavaFX and Lesson plan for teaching java graphics . All this got me thinking... Which framework is more appropriate for students learning Java as a part of the AP CS A curriculum? I'm looking for something that allows students to get up and running relatively quickly and easily with something small yet meaningful. It won't be able to become a huge component of the class, so I'm hoping one or the other is more suited for somewhat fast learning appropriate for high school AP students. Note: I hope I'm not unknowingly wading into a religious war akin to emacs/vim or tabs/spaces... <Q> Disclaimer: some do consider this a war like emacs/vim. <S> I don't. <S> I'll quote you on this: "I'm looking for something that allows students to get up and running relatively quickly and easily with something small yet meaningful". <S> From this: JavaFX. <S> Along with IntelliJ, and Scene Builder , students can build a GUI very, very quickly. <S> The FXML file which "creates" the GUI also gives an introduction to XML file structure. <S> It also teaches many Java 8 things. <S> This is vague, but here are some examples: <S> A lot of lambda expressions. <S> Work with Collection . <S> The students would need to use the collections in java 8, if they learn JavaFX. <S> This is handy, because those classes are obviously useful outside of <S> AP CS A <S> The Stream API (which gets buffed in Java 9, coming out soon) has a lot of usage as well in JavaFX. <S> I could continue this rant forever, but the main point is that JavaFX is self-dependent, which means that it only requires itself and java, unlike Swing, which requires AWT. <S> I hope this give you some idea about putting a GUI library in your curriculum. <S> I say this because Oracle said so : 6. <S> Is JavaFX replacing Swing as the new client UI library for Java SE? <S> Yes. <S> The link contains more details, but the core of that part of the faq is that it is a replacement. <S> (Which is in no way saying that Swing will not be included in future Java releases, because of backwards compatibility). <A> Like everything else in programming, it's a mix of tradeoffs: <S> Benefits of Swing: <S> There are a metric ton of tutorials and examples on the web. <S> It still has a very active community here on Stack Overflow. <S> Downsides of Swing: <S> It's old, and it looks old. <S> It's not being actively developed anymore. <S> (But it's not deprecated either.) <S> Benefits of JavaFX: <S> It's new(er), <S> and it's being actively developed. <S> Downsides of JavaFX: <S> There are fewer tutorials and examples on the web, and many of them are outdated because JavaFX is under active development. <S> I also find it more complicated than Swing, but maybe that's just me. <S> Which framework is more appropriate for students learning Java as a part of the AP CS A curriculum? <S> I don't think either one is very obviously better or worse than the other. <S> They're very similar in a lot of ways, especially if you haven't used either one at all yet. <S> Honestly the best thing you can do is try out a few hello world programs in both and see which one you like better. <S> I will also say that neither one of these is used extensively in the real world. <S> Everything is either a web app or a mobile app. <S> I can only think of a couple of Java-based desktop applications. <S> I'll also add a shout-out to Processing , which is a Java-based language (which can be used as a Java library) that makes it easy to create visual, animated programs without all of the boilerplate that Swing or JavaFX require. <S> Might not be right for your class, but definitely worth checking out. <A> I'm going to suggest that you don't use either Swing or JavaFX for an AP CS course. <S> Instead, I'm going to suggest that you use Princeton's Standard Draw library . <S> It does a great job of abstracting all of the ugly canvas and window setup that traditionally comes along with Swing or JavaFX. <S> I have leveraged their library for multiple projects throughout the year and my students never complained about not understanding the graphics side of the projects. <S> Full disclosure <S> : StdDraw isn't as powerful as Swing of JavaFX, but why bring a nail gun to a job when a simple little hammer will do the trick? <S> We use StdDraw within the first couple of weeks in the course <S> and it simplifies the process for both teacher and student, while still allowing you to focus on the important learning outcomes. <S> Plus their API is easy to read and serves as a great introduction to students about how to read documentation. <S> tl;dr: <S> The easiest library to add graphics to your project and for your students' use is Princeton's Standard Draw library .
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As was pointed out in a comment, JavaFX has an added bonus: It's more likely to become the library your students would use, if their careers lead them to doing GUI in Java.
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Book recommendations for rigorous CS books I am a mathematician but I would like to learn basics of computer science. I have seen many books that are fine but has some mistakes. For example, Introduction to algorithms even says that one should use $f(n)\in O(g(n))$ but still uses the notation $f(n)= O(g(n))$. Is there university level computer science books that are suitable for person who wants to study computer science on very rigorous books, or that are aimed to mathematician? <Q> The Art of Computer Programming in four volumes by Knuth is an obvious choice. <S> The first chapter of the first volume is a pretty solid course in discrete mathematics all by itself. <S> If you can do all of the problems in that chapter you can earn a PhD in CS. <S> (Some of the problems remain unsolved, I think - at least they were when the book was first published.) <S> Knuth is a Mathematician turned Computer Scientist and gives the mathematician's view of the field about as well as anyone can. <S> You can depend on the accuracy of the book as the author has induced the community to drive out all inaccuracies using bounties. <A> It covers such topics as: Writing simple programs that do powerful things, Blurring the lines between data and code, including functions as first-class objects, Creating little languages to solve problems, Writing an interpreter, and much more. <S> It is one of the most loved and respected CS books. <S> See also: <S> Why Structure and Interpretation of Computer Programs matters , by Brian Harvey Is "Structure and Interpretation of Computer Programs" (SICP) <S> worth reading? <S> (Quora) <S> Note that the text, in various formats ( original HTML , HTML5 , PDF ), is available for free online, as are video lectures by the authors . <A> The Semantics of Programming Languages is an important and very mathematical subject. <S> Great strides have been made in the past 20 or so years. <S> One book that stands out is A Theory of Objects by Luca Cardelli and Martín Abadi Luca, especially, is an expert in operational semantics. <S> He presents a generalized operational calculus for analyzing all aspects of object-oriented languages. <S> The book is deep, but essential for those wanting a deep understanding of the underlying principles of OO languages and, perhaps, wanting to design future languages. <S> Language is more than syntax. <S> It is the semantics that lets the student form proper hypotheses about programs and programming. <S> Most compilers are still "syntax directed" but Peter Lee , in his doctoral dissertation (U of Michigan). <S> shows how a compiler can be built from the semantics instead. <A> Another classic is Computers and Intractability: <S> A Guide to the Theory of NP-Completeness by Garey and Johnson. <S> As you may know, NP (which stands for "nondeterministic polynomial time") refers to a set of problems that are computationally very difficult but whose answers can be checked in polynomial time relative to the size of their input. <S> Whether all such problems can be solved in polynomial time ( P=NP ?) is one of the greatest unsolved questions in computer science. <S> Garey and Johnson (as the book is referred to) is about NP-Complete problems, members of NP to which all other members of NP could be reduced. <S> The book catalogs problems known to be NP-complete, including proofs that they are members, usually reductions from other NP-complete problems. <S> Published in 1979, the book is somewhat outdated but is still regarded as a classic [3] . <S> ( Google Scholar lists about 60,000 citations.) <S> The introduction (available online ), in which an employee explains to their boss why they can't provide a simple solution to a problem, is also classic. <S> Disclaimer: I am not a theoretical computer scientist. <S> I welcome comments from any.
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In addition to Knuth, I would recommend the classic Structure and Interpretation of Computer Programming by Abelson and Sussman.
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How do I teach about inequity in computing resources? What activities, and with what resources, are effective for students to learn about the status and consequences of inequities in computing resources? Activities could address inequities within a community or across the globe. Background: The Advanced Placement™ CS Principles course has two "essential knowledge" (EK) statements related to this topic: EK 7.4.1C The global distribution of computing resources raises issues of equity, access, and power. EK 7.4.1D Groups and individuals are affected by the "digital divide" - differing access to computing and the Internet based on socioeconomic or geographic characteristics. The AP framework indicates these objectives should be associated in the classroom with the computational thinking practice of "connecting computing" by finding ties among computing concepts, impacts of computing, and connections between people and computing. My question is not necessarily constrained that way, though it seems inherent in achieving the objective. (I came across a resource on this topic that I wanted to share. A related question here did not exist, so I intend to share the resource in an answer but not to imply that the resource or lesson format I share is the best one. Please share other resources and lesson formats!) <Q> This seems to me to be the sort of topic that is best covered with an assignment such as Write a paper, citing resources, on the topic of XYZ. <S> There are a number of other things that can be addressed this way. <S> One advantage of such an assignment is that students have to write using natural language, which often gets too little attention in technical fields. <S> Another advantage is that you can have the work done in pairs or teams. <S> Another advantage is that you can follow up with class discussion, seeking consensus on the problem. <S> You can, of course, provide them with an initial set of resources so that they are forced to look beyond Wikipedia and other easily found resources. <S> You can also ask for critique of the resources that they find, not just reporting. <S> You can even have a debate. <S> Lots of possibilities since the topic is both serious and open ended. <A> Have students analyze data about the inequity of access to computing resources, and facilitate the discussion of an assigned reading . <S> Here's one procedure for doing that: Students could be asked to read an article (ideally containing tables or figures with large amounts of data with analysis in the text of the article) and write a few sentences about an article as homework. <S> Facilitate a whole-class discussion. <S> The discussion could be structured around a sequence of questions such as "How could this issue be addressed with policy, and what might be the beneficial and adverse consequences of such a policy?" <S> Assign a follow-up writing assignment. <S> The assignment could give students practice writing about a particular line of argument. <S> For example, to practice writing about the beneficial and harmful effects of a computing innovation with respect to data flows (one of the two AP CS Principles open-ended assessment tasks), the writing prompt could posit an innovation that makes it easy and cheap to provide Internet access to remote locations and asking students to write about the impacts including analysis of data flows. <S> Here is one article, covering many countries and focused on data about adolescents, that could be used for this purpose: <S> https://www.weforum.org/agenda/2016/07/rich-and-poor-teenagers-spend-a-similar-amount-of-time-online-so-why-aren-t-we-closing-the-digital-divide/ <S> The graphics in this article are rich with both data and data concepts. <S> The article summarizes a more exhaustive primary source. <A> By constructing and using simple examples. <S> Divide the class into two groups. <S> One half gets to use calculators, the other half uses pencil and paper. <S> Give the whole class the same test. <S> Compare the average scores of the "calculator" and "non-calculator" groups. <A> Focus on inequities in environmental consequences from mining, manufacturing, and disposal. <S> This was suggested by richard . <S> He also recommended The Story of Stuff: Electronics 8-minute video. <S> I think environmental injustice of computing is worth learning about and considering alongside inequities in access to computing resources. <S> Understanding the issue helps students digest domestic news and is presumably within the scope of the CS Principles writers' intentions and easily within the scope of the Explore PT. <S> Wisconsin's governor, for example, is pushing for \$3 billion subsidies and relaxed environmental requirements in exchange for Taiwanese Foxconn to make a \$10 billion investment in a manufacturing plant rippling to create 13,000 jobs to make flat screen TVs here instead of China.
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In class, students could discuss in groups of 2 or 3, each presenting one figure or section of the assigned article to their group. News articles on the issue would be easy to find for the 2018 Explore task.
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Incorporating algorithmic complexity in grading What are some advantages of incorporating algorithmic complexity in grading tests and assignments given to students? Currently, students in 11th grade at my school are required in tests to write functions that should preform some operation (usually operations on data structures like LinkedList , Stack and Queue ). This works fairly well in terms of checking whether a student knows how to use those data structures. However, it's not uncommon to see an answer that does, eventually, preform the required operation; and yet its complexity is $O(n^3)$ (no kidding. The specific case I'm thinking of is one where the student worked with the unsorted linked list of stacks 1 in 3 nested for loops). The students are required, after they write their functions, to also write the complexity of their solutions. In a quest to improve the students' thinking skills, I thought that maybe we should give bonus points if the solutions are inventive and less complex than a head on approach. This means that if a student's function is $O(n)$ for a task that a direct assault would be of $O(n^2)$, they should get more points. This can also apply to various assignments we can give them, in addition to the tests we already have (or maybe make the tests slightly easier and then add assignments). The students are in a CS major, and they have experience with java, OOP, Data structures and basic calculations of complexity for various, simple, algorithms) 1 We gave them some arbitrary way of comparing stacks (of Integers): The sum of elements. <Q> I wouldn't want to penalize kids who are really relatively inexperienced for not coming up with the fastest solutions on a test. <S> Even if they're in 11th grade and have a couple of years under their belts, they likely haven't been in real situations where run time is important. <S> If I were to want a specific run time on a test I'd say something like "for full credit make sure your solution runs in $O(blah)$ time." <S> If I give an open ended solutions and I don't specify any restrictions on run time, storage limitations, or data set size <S> I tell the kids that I won't penalize them for efficiency unless it's so grossly horrible. <S> For example, if they were to write a sort in their code (and I wouldn't really ask this but it makes for an easy example), I wouldn't penalize a kid for coding an $N^2$ sort even if we covered $n log(n)$ unless I talk about a large data set size. <S> On the other hand if they sorted by say an $N^3$ solution or worse, they would lose some points. <S> In any event, if you're requiring certain run times you have to be careful that you're not just getting kids to memorize and spit back what the teacher expects. <S> Also remember that there are plenty of times where a simpler, slower algorithm is both clearer and more than sufficient and that complex fast code that doesn't work isn't nearly as good as simple code that does. <S> To encourage creativity, give multi level assignments. <S> Create lessons where you can have them develop a solution, see that it's too slow, and then refine it. <S> I do that with finding the mode of a data set ( https://cestlaz.github.io/posts/2014-11-17-hidden-complexity.html ). <S> You can also create assignments that encourage this and make test data sets and situations that force kids to work on time efficiency issues. <A> I recognize that this isn't exactly an answer to your question, but is a different way to think of the issue. <S> I applaud the answer of Mike Zamansky given here already, but suggest an orthogonal approach. <S> One way to get students to focus on efficiency is to ask them to name (or select from a list, perhaps) <S> the efficiency of the solution they present and also possibly to reply whether it is the most efficient algorithm that they have studied. <S> You can go further in an assignment and ask them to say why they think their solution is a good one even if not the most efficient. <S> And if you teach sorting for this sort of thing, you, and likely your students, should be aware of this paper (pdf) by Owen Astrachan which says, among other things that Bubble Sort is never the best solution - either for simplicity or efficiency. <S> If you ask for a discussion, in other words, you have more information on which to grade them than just looking at the algorithm itself. <S> It also forces them to think deeper; generally a good thing. <A> You may want to consider a minimum efficiency requirement as an explicit requirement for the assignment (e.g. "must be more efficient than brute force", "must be $O(n^2)$ or less", etc.), especially since brute force solutions may reduce the educational value of the assignment in the first place because brute force solutions are often much easier to come up with than efficient solutions. <S> Consider by way of example the Project Euler problems , many of which are relatively easy to brute-force. <S> The entire point of these questions is to come up with something <S> better than brute force - there's little to no learning value in brute force. <S> Of course, some questions are simply not feasible to solve with brute force in the first place. <S> For example, the description of problem 67 says that "It is not possible to try every route to solve this problem, as there are $2^{99}$ altogether! <S> If you could check one trillion (1012) routes every second it would take over twenty billion years to check them all. <S> There is an efficient algorithm to solve it. <S> " It turns out that you'll often encounter problems like this in actual programming: consider what would happen if Google's search engine relied on brute force, for example. <S> So really, specific performance, efficiency, or scalability requirements are often intrinsic to the problem itself, both in educational settings and in actual engineering - if you didn't solve the problem in a way that meets those requirements, it's quite possible that you didn't really solve the problem at all. <S> Beyond that, you may want to offer extra points to students who have better solutions <S> (e.g. "solutions must be $O(n^2)$ or better to be considered complete, but you get extra points if you can make your solution $O(n log n)$). <S> TL;DR <S> All assignments have requirements, so why not just make minimum efficiency requirements one of the requirements and then give extra points to people who exceed the minimum?
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The first step is to mention what the computational complexity of the best solution is so that students will know to look for an algorithm with that efficiency.
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What hardware can I use when teaching Compiler Language and Assembly Code This year course includes creating a compiler of course using Syntax Analyzer and Lexical Analyzer, Semantics and of course through all this generate Assembly Code But also the teaching program includes using at least a little piece of hardware to pass assembly code to it. Does anyone know a programmable hardware that we can use just for education purposes? We will pass assembly code to the hardware. <Q> The 32-bit subsets of ARM assembly language are fairly clean, orthogonal and RISC-like, as well as being a reasonably nice target for a simple compiler. <S> Inexpensive Raspberry Pi's run 32-bit ARM code, as well as natively supporting a complete compiler development tool set (lex, yak, bison, et.al.) <S> Almost every student is likely to possess a mobile phone that will also run ARM machine code, and both Apple and Google provide free development tools that allow coding portions of a mobile app (iOS or Android) in ARM assembly language. <S> The 6502 and 8051 ISAs were not designed for modern compiler output, even though otherwise suitable for teaching hand-coded assembly language and running it on inexpensive (vintage or microcontroller) hardware. <A> My first piece of advice would be to avoid any modern hardware (and possibly to avoid hardware itself, as the simulators out there are pretty good). <S> In a prior discussion , I talked about the experience I've had teaching with 6502 Assembly, and I would recommend this course as well. <S> This plucky little processor (and, therefore, its assembly language as well) is about as clean, simple, and streamlined as a processor can be. <S> Additionally, there is a lovely simulator for the 6502, a complete assembly specification , <S> a community devoted to it, and <S> And if you do want to continue on to use actual hardware, the following computers used the 6502, many of which are readily available on eBay and the like: Apple IIe. <S> Commodore PET. <S> BBC Micro. <S> Atari 2600. <S> Atari 800. <S> Commodore VIC-20. <S> Commodore 64. <A> Dr Michelle Strout (now at University of Arizona) used this approach when she was at Colorado State University. <S> For hardware, the students used Meggy JR . <S> Students were expected to write simple programs/games using a Java interface to the hardware. <S> Initially, the hardware was purchased as kits and there was a pizza party to assemble it. <S> The students then wrote compilers for a subset of Java (MeggyJava), using Java. <S> See class web page . <S> The code their compiler created could be executed on the hardware, or in a simulator. <S> In another year, the students did the same project, See class web page , but the implementation language was in Haskell. <S> The students enjoyed creating simple games and displays and then using their compiler to realize the result on the physical hardware. <S> For grading, the course used our autograder to compare the "output" of the instructors compiler (i.e. what did the code do to the state of the Meggy JR when the code was executed on the simulator), to that of the code produced by their compiler. <S> I hope this helps. <A> If you want to look at hardware which might also be suitable for programming in C/C++, the BBC micro:bit might be a good alternative to an arduino. <S> It has a more self-contained set of peripherals, and is programmed in ARM assembler. <S> It uses drag-drop style programming (you need an ASCII format hex file) over USB. <S> Of course, you need to set up a tool chain to compile the code, unless you want to write raw hex by hand (or analyse compiled code from the online tool chains). <S> Halting debug (single step and modifying registers) is supported, so it's a capable platform to work on if you want hardware. <S> In terms of a compiler for Cortex-M0 (as in the micro:bit), the educational toolchains support an in-browser compiler which demonstrates that it's not actually too complicated. <S> Of course, there is a fair amount of initialisation required if you want to actually turn the LEDs on or look at the push buttons (let alone the SPI accelerometer on board). <S> You might include some assembler within an online compiler C++ project - that ought to work (if you use the ARM mbed toolchain rather than the school specific toolchains). <S> An alternative is to look at something more low-level , using a verilog simulator (but there is non-trivial cost involved in the simulator which might put this out of reach to schools - it's more targeted at universities who are teaching embedded hardware, and start-ups). <S> The whole Cortex-M3 processor and a supporting system can be downloaded from ARM for free. <S> This runs code (and has a model which prints out disassembly as it runs). <S> - disclaimer - I developed this product.
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As far as I can tell, all of the very cheap processors out there right now (such as come with Arduino) use languages like asm, and do not lend themselves to the kind of conceptually clear assembly programming that would presumably be most helpful for your students.
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What professional development events or conferences are out there for CS educators? I'm trying to find a professional development event for myself as a relatively new CS educator. I'm interested in something that showcases innovative ways to teach and engage students in the subject -- any recommendations? In particular, conferences for high school educators, and those that showcase new technology/tools for CS educators would be brilliant. I am based in the USA and am happy to travel to events. <Q> In UK England, there are CAS Computing <S> At Schools events. <S> They are regional events. <S> They are focused on primary and secondary schools. <S> They are usually inspiring, but can be a bit simplistic if you have done programming for a job. <S> The events I have been to I have ether chosen the groups that are teaching focused (as opposed to technical focused). <S> Or in smaller events steered it towards teaching techniques. <S> Each event has been multi-threaded (choose your thread), or small and adaptable. <S> You can sign-up to their e-mail mailing list, to be informed of events in your area. <A> You don't specify Secondary School, but your AP tag seems to imply that as your main interest. <S> I'll start with that, but give a more general answer. <S> There are some organizations that hold regular conferences and to which you should belong in any case. <S> The conferences normally have workshops in which experienced educators teach some tools-of-the-trade. <S> The first, focused on Secondary School, is Computer Science Teachers Association . <S> They have both a newsletter and a national conference. <S> The next, focused on AP itself is AP Teacher Community which has a useful set of discussion boards. <S> They have events (and tutorials) in conjunction with the SIGCSE national conference. <S> The SIGCSE organization within ACM is somewhat more dedicated to post secondary education. <S> It has several conferences every year, including some outside the US, usually Europe. <S> Many secondary teachers belong and there is support here for such teachers. <S> The Consortium for Computing in Small Colleges , while focused on college teaching has many annual conferences spread around the US. <S> Like the others here, the conferences often have workshops given by educators. <S> Many topics are covered. <S> Welcome to CS Teaching. <S> Explore the above organizations for their offerings and subscribe, if appropriate, to their newsletters. <S> You will get a lot of information, and a forum for asking for help. <A> CSTA membership is free. <S> The annual conference is \$175 - \$275 USD. <S> Chapter membership is typically free. <S> Some local professional development may be free as well. <S> Code.org also offers professional development for computer science teachers. <S> Some Code.org professional development is free and sometimes sponsors even cover travel expenses. <S> Also, visit PD for Computer Science Principles and third party PD resources . <S> ISTE <S> (Internationl Society of Technology Educators) hosts Computer Science Network special interest group. <S> ISTE Members have access to a number of webinars you may be interested in. <S> Membership is \$125 USD per year. <S> Their annual conference is in Chicago — June 24–27, 2018. <S> Conference is \$300 - \$400 USD for members or \$450 - \$550 for nonmembers which includes membership. <S> FETC <S> (Future of Education Technology Conference) has more of a digital literacy focus but may have some sessions of interest to you. <S> Conference price varies depending on number of days you attend (\$300 - \$450 USD). <S> Regular sessions are included but certain workshops have an additional fee. <S> Degreed is a platform for micro-credentialling (badging). <S> It provides access to courses, articles, videos, etc. <S> Degreed has partnered with Computer Science Teachers Association ( CSTA ) mentioned above, so there are a number of curated computer science assets. <S> Degreed is free. <S> Apple, <S> Inc. offers professional development on its language (Swift) through iTunes which is free. <A> Most events for CPD will be specific to a region, so why not consider using MOOCs as a CPD? <S> Many award certificates, and can be used as part of a more substantial award. <S> I am teaching CS for about 5 years now, and learned Python by completing a number of MOOCs. <S> The absolute BEST one I've found is from Dr. Chuck . <S> You can review all the videos on Coursera. <S> All of the code is available <S> The book is available (free) in many languages <S> There are ideas for assessment in the course <S> All the lecture notes are made available <S> I really like the lecturers presentation style <S> There are many more courses out there and <S> each one that you complete gives ideas for teaching materials and assessments that you can use. <S> For example, the Rice University Wk2 assessment is Rock Paper Scissors. <S> My first term assignment is Rock Paper Scissors Lizard Spock. <S> Hope that helps... <S> somewhat :)
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There are also local chapters of CSTA which may have professional development. I agree that Computer Science Teachers Association ( CSTA ) membership and conference are the best place to start if you are in the US.
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Teaching a blind high school student I am teaching a blind high school student in my APCSA class. All students are using a combination of CodeHS and Project Lead the Way curriculum. Neither of these are very friendly to my blind student because there are so many visual that his screen reader can't interpret. Does anyone have experience in this? I'm looking for something that can be done pretty independently as he will be in the class with others working on a different curriculum. I want to support him in his endeavors to become a computer scientist but I don't know where to start as an inexperienced CS teacher myself! Any help would be greatly appreciated. <Q> A quick online search led me to this. <S> A Beginner's Guide to Access Technology for Blind Students <S> It covers all the essentials Screen Access Software Braille Embosser <S> Notetaker Scanner and Optical Character Recognition <S> I am essentially listing things from that article <S> It seems like something that was written years ago, but I assume, it should be a good starting point for you. <S> Further, the city I live in does have a national institute on speech and hearing, which includes folks who are sight challenged. <S> If this is something serious, I can drive up there and talk to someone and hook you up with a professor or something. <A> I think it is bad practice to have the computer draw pictures, and then try to describe them, when in would be much easier (and better for the blind person) to interpret a text interface (command line). <S> Wasting power on a screen, that you can not see is wrong (though having something the teacher can see is useful). <S> Therefore use a system that is optimised for a blind person, or at least one that is very similar. <S> This leaves tactile, audio, or linier speech (that can be converted to audio). <S> Here I will only discuss the speech part. <S> I would recommend Gnu/Linux, it is a Unix system. <S> Unix was designed from the beginning to be text based. <S> The GUI saw added latter. <S> This has made it a very strong operating system, that a variety of interfaces can be added to. <S> Most of the programming languages that we teach were first written for Unix: Java, python, C. <S> The only exception that I can think of would be C#, however that now runs on Unix. <S> I have run it on a raspberry pi model 1b. <S> UNIX( a type of Unix ) is the system that we could not afford in the 1980s, so instead we bought Microsoft Dos, and then Microsoft Windows. <S> Gnu/Linux is a newer Unix, as well as being Free Software is also very cheap. <A> I have never had this situation, but can offer some general advice that is also applicable to other students whose needs require specialized techniques. <S> As suggested in other answers here, talk to the student, of course. <S> But ask the student for permission to do at least some of the following. <S> You probably have a school counselor who can offer some general advice. <S> You can talk to the parents about what they suggest and what has been useful to the student in the past. <S> You may be able, with permission, to talk to the student's former teachers, even in grammar school, to see what might work. <S> You can also seek, perhaps online, advice from specialists in the student's need-area. <S> The student might, in fact, already be working with a professional. <S> You might see if you can have a conference with them. <S> As I suggested in a comment, get connected to the APCS community and ask for advice in their fora. <S> Do the same for the ACM SIGCSE group. <S> It is probably too late to modify your curriculum, though others in your school should do some anticipatory planning for helping this student in the future. <S> It may require some curricular changes generally. <S> I would suggest, however, that curricular updates consider changes that benefit all the students, not just the one. <S> Every student learns differently, not just the blind student. <S> Every student can contribute to a team, though different students contribute differently. <S> Presumably the student has skills that compensate for lack of sight. <S> Try to bring them to bear in the class so that the student is a part of things, not an outlier. <S> For example, he might have an exceptional memory or an exceptional organizational ability. <S> All of these are needed by professionals and can be capitalized on in the classroom. <S> In taking APCS the student is obviously not looking for an easy way out. <S> But do what you can to make the classroom a supportive community that benefits all students. <A> A language called Quorum is a lot like Python but optimized across a few more syntactic details, and the corresponding development environment is designed with the blind in mind. <S> https://quorumlanguage.com/ <S> This might fit especially well with the use case where most students are using Python. <S> A 2016 blog about CSed (actually a response to a blog post) points to program-l discussion board for blind programmers at https://www.freelists.org/list/program-l <S> The EPIQ conference for blind and other programmers interested in Quorum https://quorumlanguage.com/epiq.html <A> I think it is very important to start by discovering what the student wants. <S> What do they think computer science is. <S> It is usually not the same as what we think it is, and sometime a long way off, that they should be doing a different course, or an adapted course. <S> Therefore find out what your student is planning to use there computer science for. <S> What job they may want to do, and why. <S> What their interests are. <S> Focus on them as a person, not on their disability. <S> Then look to see what problem caused by their lack of sight, need solving.
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You can have a meeting with other teachers who have, or had, this student in class to see what they suggest. Having a blind person try to use a system that is optimised to sight, is wrong. My go-to suggestion for many things is to incorporate teamwork into the curriculum as much as possible.
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Minecraft to teach programming? Minecraft is very popular, and I know that it can be programmed/scripted. I looked into it myself but was put off by the learning curve for the Java based version (it looked like it needed Minecraft, NetBeans, a library for my Java code to talk to Minecraft, and possibly setting up a server). I later found https://www.learntomod.com/ , which appears to have a Block-based programming UI (I haven't tried it personally). My Question(s): Has anyone used Minecraft to teach an 'introduction to programming' type course (CS0 moreso than CS1)? How did you make the tech work (did you use something like LearnToMod.com, or the whole Minecraft+NetBeans+Java+etc route)? What sort of lessons did you learn? (I'm particularly interested in "Gee, I wish I had known about X, back when I started") <Q> I am not so certain about teaching people to program by starting out with something like modding Minecraft. <S> There are a lot of technical details that someone just learning to program shouldn't be required to understand or worry about. <S> However, Minecraft can still be excellent playground to learn to program by using pre-made mods like ComputerCraft that add programmable blocks to the game. <S> In ComputerCraft users are given a couple programmable blocks: computers, which are stationary and have the ability to send serial signals; robots, which you can program to move, pick up elements from the environment, and perform actions; and both elements can communicate over a network. <S> The computers and all the pre-packaged applications are programmed entirely in Lua (including the OS). <S> This means there exists a large existing source code base for students to study. <S> Lua is a very simple and elegant language and I have had no problem teaching it besides the fact there isn't really an introduction to programming book using it <S> ( Programming in Lua is written by the language author and is very good, but much like Programming in C in that it isn't meant for beginners). <S> Using ComputerCraft with blocks from other common mods would allow the students to build machines as well as programs; something more than the sum of its parts. <S> This would allow them to see programs as a part of a greater design, which I believe most students don't get enough experience with in school. <S> Personally, one of my favorite projects I've done in Minecraft using ComputerCraft was implementing a mail delivery system using several computers, ender chests, and pipes. <A> I am currently using Minecraft (especially Minecraft realms) to teach my developers (not starters but folks who have already covered some distance) how to work in team and also to improve their spatial and logical thinking. <S> Also math, to some extent. <S> So, first up, I am using Minecraft to teach, but not the basics of programming. <S> If you wish to introduce someone to programming though, I would say Minecraft is useful but not with the whole MineCraft + NetBeans <S> + <S> all that jazz route. <S> If you are going to all that trouble of configuring that for a freshers batch, you might as well just setup the real developer environment which would be simpler. <S> For instance, a lot of girls where I live are afraid and/or hesitant to get into programming. <S> Many would find the concept of using their computers for anything other than watching a movie or checking email, extremely alien. <S> In such scenarios, Minecraft would help. <S> If you were to check the Minecraft Education site, that is also what Microsoft is doing with the program. <A> First, a caveat: I usually teach software design, and have only taught basic programming to maybe 150 to 200 students. <S> That said, I'm not a huge fan of visual devices in teaching basic program structures (like selection, loops, and variable manipulation) because the art of programming involves writing at its core. <S> Doing that feels like I'm teaching somepony to write short stories by having them rearrange photographs of sentences. <S> I want to show students how to write, and if the algorithms are very simple, the results are something all students can be taught to visualize and follow (provided they're around the sixth grade level or higher). <S> I have tried using the Alice visual programming language to teach young girls once or twice. <S> I suppose the theme for the language (which is aimed at girls) is based upon a theory that girls will be more interested in programming if it looks less sterile, or some other nonsensical shot in the dark about why we fled the science decades ago when computers first became boy toys. <S> I'd honestly rather have a lesson on syntax followed by very simple programs with output that students can play around with directly. <S> Let them change things in an IDE that will catch syntax errors and see what happens that way. <S> They need to think in terms of written descriptions eventually, why not start them out like that? <S> Diagrams and pictures are important, but I prefer to save them for the lesson itself, or as a tool on paper to guide composition. <S> (For the record, I also have no idea how to get more of us interested in programming, but pandering to gender stereotypes ain't gonna be it.)
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When in comes to newcomers, I have found that Minecraft is more useful in bringing people into the world of computer based thinking.
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Scheme - Which implementation to use for teaching A few days ago, I asked a question if I should use F sharp to learn functional programming and the discussion eventually suggested that I take up Scheme. So, I visited the scheme site (which did not say much) and then I ended up at the MIT site . and I also read on the wikipedia that there are several implementations of scheme. So, the question is which implementation ( I have given a reference of MIT implementation above) should I use for my beginner class on Scheme. <Q> The DrRacket system is probably all you need. <S> DrRacket is widely used and there is quite a bit of information about it online. <S> It provides a very simple interface. <S> There are also Scheme plugins for NetBeans and Eclipse if you want a more complete IDE. <A> I would add to Buffy's answer that DrRacket also contains several built-in learning languages that allow you to dip into Scheme slowly. <S> These languages are designed to be used with the free online textbook How to Design Programs by Felleisen, Findler, Flatt, and Krishnamurthi (the last of whom is a user on this very site ). <S> Please see my answer here <S> ( Scheme - Which book To Use ) for further details. <A> I won't tell you which one, as I don't know, and would just be my opinion. <S> But here are some criteria. <S> First look at what other learning materials you have, and use the same language. <S> Some versions of scheme are not pure (that is they have mutation). <S> Do not use one of these. <S> Half way through structure and interpretation of computer programs, we learn how to implement mutation. <S> But not until we have learnt that we never need it, and 99% of the time it is evil and best avoided. <S> And then how to abstract it away, that is encapsulate it. <S> Consider GNU/MIT Scheme <S> it is Free Software and from MIT. <S> I don't know if it meets the other criteria, but I would expect so (as it is from MIT). <S> An opinion from https://wingolog.org/archives/2013/01/07/an-opinionated-guide-to-scheme-implementations (some random website, where the author seems to know what they are on about.) <S> The Scheme for SICP <S> Many people come by #scheme asking which Scheme they should use for following along with Structure and Interpretation of Computer Programs. <S> SICP was originally written for MIT Scheme, but these days it's easier to use Neil Van Dyke's SICP mode for Racket. <S> It has nice support for SICP's "picture langauge". <S> So do that! <S> Racket is also Free Software , so I would go with that. <S> (Sorry I said that I would not recommend one.)
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Racket is a variant of Scheme that is both very good and very popular.
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Could you recommend books on concurrent programming? I am self-learning concurrent programming. I have some experience with concurrent programming. Have self learned OS and programming. There are both programming languages and libraries that provide concurrent programming facilities. I would like to learn about concurrent programming at OS and library levels (e.g. multithreading, multiprocessing, spin locks, semaphore, ...) and language level (e.g. monitor, future, promise, channels, conditional critical regions, Coroutine, ...). For the specific topics, I am referring to sections "Models", "Prevalence" and "Languages supporting concurrent programming" in https://en.wikipedia.org/wiki/Concurrent_computing and also concurrency patterns . I would like to learn at conceptual as well as specific language levels. Could you recommend some books which explain the different approaches at a concept level? It is good for such books to have specific languages and libraries as examples, but not necessarily especially if the books you recommend are classic but not contemporary. Could you also recommend which specific languages and libraries and books on specific languages and libraries? For specific languages, I am currently interested in functional languages (such as Scala, Haskell, OCaml ...), Python, C#, Java, C/C++ and Go. Academic books (text books, survey) and professional/practical books are both welcome. <Q> Concurrent programming is easy, synchronisation is hard. <S> Have a look at this video for an alternative to synchronisation: <S> https://www.youtube.com/watch?v=2yXtZ8x7TXw <S> When you have to synchronize Use easy (High level) synchronization. <S> see: <S> Scoop from Eiffel. <S> Transactions <S> Pipelines / message passing coroutines (for when you don't need parallelisation) <S> See also no lock / zero lock structures: <S> Most pipes that are thread safe use locking. <S> Or are not thread safe, and expect the user to do the locking. <S> However it is possible to get thread safe zero lock queues. <S> There rely on a few atomic instructions. <S> (I prefer the name minimal lock, because the atomic instructions do locking). <S> Only use low-level synchronization to implement high-level synchronisation. <S> If you need synchronisation, and if you do not have high-level synchronisation, then find a good library that implements high-level synchronisation, using the existing low-level synchronisation. <S> Don't write it your self, except as an exercise (and do to it as an exercise, it is fun and you will learn a lot), as it is very hard and you will get it wrong. <A> Since the OP asked about functional programming, so I would highly recommend you to read " Learning Concurrent Programming in Scala " by Aleksandar Prokopec, (2014). <S> All the examples for this book are available on GitHub to give you some idea of the book before you purchase it. <S> C# <S> 4.0 <S> and I have no update about following editions (if any) <S> C++ <A> I have no recommendations for the theory part but since you are asking for implementation advice as well, here we go. <S> If you are looking to use C sharp (you haven't specified a specific language of choice) then, as a dot net guy myself, I would recommend you start your self learning on concurrent programming with .NET implementation of same at Threads and Threading . <S> The link provides with what you can (most of the things you have discussed can be done in C sharp Threads) and what you cannot do. <S> If you wish to dig deep, there are no specific books on threads in C sharp, but you can use the reference book I used which contains detailed implementation notes on the same at C sharp 70 483 <A> The Well Grounded Java Developer has an excellent section on concurrency. <S> The author claims that very few developers correctly implement concurrency. <S> As ctrl-alt-delor put it: concurrency is easy; synchronization is hard. <S> In fact, avoiding errors from race conditions and unexpected asynchronous behavior is so difficult that the author recommends developers always use one of the Java 7 library <S> features to implement multi-tasking. <S> I have personally found debugging asynchronous code to be very hard. <S> Errors just seem intractable and difficult to reproduce. <S> While the libraries used in the book are Java specific, the reasons for needing those libraries are not. <A> One book I have enjoyed is The Little Book of Semaphores by A. Downey. <S> It is free (in both senses of the word) and contains many problems with hints and solutions that can be used as starting points for small group projects (e.g., to implement such a solution in a modelling tool or to generalise it). <S> I have only used the conceptual chapters, but the book also contains chapters on synchronisation in Python and C.
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I would recommend you to read " Professional Parallel Programming with C# " - its based on .Net I think Pacheco's book would be my recommendation for sure Best of luck!
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Giving Students a Break My instruction time has specified breaks, but often the students do not take them, even if I urge them to. This results in them working and listening to my instruction while they are overdone. I tell them this is a marathon, not a sprint, and they will have the rest of their lives to sit in a chair in front of a keyboard, but they do not take the break, or they get a sip of water in the hallway and sit back down. This is impeding their learning and making them unhealthy ("Sitting is the new smoking", right?). Have you found any effective ways to get students out of the chair to take their full breaks, other than having them take up smoking (thus defeating the purpose) or yelling Fire? <Q> I don't understand all the hate this question is getting. <S> I'm guessing the answers depend on the context a lot. <S> Context of my answer <S> I regularly hold company trainings. <S> Adult education. <S> These are full day IT trainings, that means 9 AM to 5 PM. <S> In the contract we offer 90 minute blocks with 15 minute breaks between and a 45 minute lunch break. <S> Importance of breaks <S> A break is not a waste of time. <S> Researchers disagree on the amount of time an average human can uphold focused attention for, but all agree it is measured in minutes. <S> I have learnt 4-5 minutes at the university, and I have read some researchers claiming it to be up to 20 minutes. <S> But you can't expect an average human to uphold focused attention for hours at an end. <S> But from time to time, breaks are needed. <S> (The 8 second attention span you hear about is different, it is the burst attention span or whatever it is called.) <S> It is not just the attention though, but moving/stretching as well. <S> Most workplaces have recommendations, and though there are slight variations, most revolve around the "work for 60 minutes, get up and move for 15". <S> This is not only beneficiary to the health of the individual, but also (many studies point this out) improves work performance. <S> Answer to the original question <S> My actual answer is: explain to them why breaks are important, explain to them how getting up, stretching, moving can help them concentrate, but don't try to force them to do so. <S> If sitting is the new smoking, then dealing with it is similar: you can't just forcefully take the cigarette out of their hands. <S> They know their own bodies and what type of break refills them. <S> And they will learn the importance of breaks the hard way. <A> We do most of our work in vampire-mode, i.e. lights-off. <S> I put a 5-10 minute timer on the projector before every classroom context-switch, so a break doesn't take students by surprise. <S> (It's easy to get lost in this sort of work.) <S> But you can't enforce rest. <S> There will always be students who believe they can work forever without consequences, and should, and there will always be students who are just too excited about the day's content to slow down for every break. <S> Our reality is that students can take a break whenever they like; the primary purpose of my official breaks is to ensure students that it is <S> okay to rest; many of us have been raised with a philosophy of overwork, and I don't have a single student who is in danger of failing because of laziness. <A> Breaks? <S> I'm in highschool (not an adult) and I'd be kind of offended <S> if someone told me to go "take a break", especially in an elective - I took this course to learn, not to get told that "sitting is the new smoking". <S> You're wasting their time. <S> (Also, don't assume your students spend their whole day sitting - a not insignificant number of them probably work out or do some form of activity during their day. <S> No need to force it on them!) <S> Now, that being said - you don't need to rely on breaks to get people up and moving! <S> There's activities for illustrating different sorting algorithms by having people stand in a row and shuffle themselves according to the algorithm; there's activities for "programming" each other, there's activities for just about anything you want to do. <S> These have the bonus of helping the information stick in the mind of the student ("remember that time we programmed Joe so that he walked into a wall?") <S> and, most importantly, having actual substantive content - that is, not wasting student time. <A> If the class isn't too big or too small, you could organize some simple games. <S> You can have a tournament, possibly with prizes. <S> The prize can be as simple as a gold star sticker like the ones elementary school teachers have given out for years. <S> Darts Basketball Free Throws Baseball/beanbag: "hit a target" <S> Frisbee (Ultimate) Make a circle of people and throw a few small balls back and forth around it, calling out the name of the recipient as you throw. <S> Musical Chairs Hand slapping (Pease Porridge hot -- ) Or plan in advance and have people recite some poem - dramatically (weirdly). <S> The idea is to get them on their feet doing something together, possibly competitively, but not too competitively. <S> Find something that will make them happy and laugh. <S> Don't just make it free time. <S> Change of pace can also free the mind. <S> If they will be together as a class for a long time you could ask the students for ideas for the activity. <S> If part of their work in class involves teamwork this can have a positive effect on team building as well as getting a bit of exercise. <S> You may not even need "prizes". <S> Yes, I'm intentionally giving strange examples here, but you know a lot of this stuff from when you were a kid. <S> You can find more online. <S> Many of these games can be adapted to adults. <S> It is hardest to do with teen-agers who are often too self conscious. <S> Note that PLoP Conferences in the Patterns Community have several sessions of "Game Time" each day. <S> Fun and active. <S> It is one of the main reasons that it is a community, actually. <S> They often have a special role of "Games Master" to organize it. <S> I've used this idea in intensive courses both to break the ice at the start and to get people doing things together as a team.
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Turning the light on for breaks goes a long way towards encouraging students to rest their eyes and stretch. It is possible to renew attention, this is where the teacher comes in by changing the rhythm, the tone, the visualization, the exercise.
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What does a certification program for CS high school teachers need to include? If a high school math or science teacher was going to begin teaching computer science, what do they need to know? I know of many teachers given this responsibility without any training for it. Since most states in the U.S. do not have a computer science certification, new teachers are often left on their own to prepare. A number of one week summer courses exist, such as those provided by the college board, but this is grossly inadequate for a new computer science teacher. If we were to design an ideal course of studies to take a teacher with little to no programming experience and prepare them to teach a course like AP Computer Science, what should that program include? This question is not just theoretical since programs are currently being designed where none exist. Here I am looking for two types of answers: If you are familiar with an excellent program, what does it include? If you are teaching computer science, what courses do you wish you took before teaching CS and why? <Q> It is a four-course sequence designed to add a CS endorsement to a high school teaching certificate, though no state-issued endorsement exists yet in Minnesota. <S> The courses: Computational Thinking and Standards for the K-12 Teacher CS Principles , covering the <S> AP CS Principles course description with additional material covering pedagogy and CS pedagogical content knowledge Programming and Teaching Java , a Java-based course covering the AP CS <S> A course description with additional material covering pedagogy and CS pedagogical content knowledge CS Methods and Capstone , covering pedagogy and CS pedagogical content knowledge, CS education research, and development of a CS curriculum unit <A> As states in the US consider requirements to add a CS endorsement to a teaching certificate, the proposals vary widely. <S> The changing landscape is described in the April 2017 EDC document <S> State of the States Landscape Report: <S> State-level Policies Supporting Equitable K-12 Computer Science Education . <S> Iowa SF274, passed June 2017, allocated \$250 thousand for CS professional development. <S> This is dwarfed by \$500 million announced this week by the US Department of Ed and the tech sector, but like parallel initiatives in many US states, it led the state's Department of Ed to consider CS endorsement requirements. <S> The Department of Ed drafted recommendations as a starting point for a working group to consider. <S> Iowa DoEd is suggesting in that draft: <S> 12 semester hours of CS coursework to include Data structures Algorithms Operating Systems or Networking 3 semester hours of a CS Teaching Methods course 6 semester hours of coursework in Career and Technical Education <S> I post this draft recommendation because the crowd-sourced opinion of this community would be informative to me as a member of the working group. <S> The fact that the discussion here would be useful to someone like me as a CS educator in a time of fervent activity in legislative and executive realms is a reason not to close this question. <A> I'd be very wary of any program with a course llike "CS Principle" or "CS Principles for Educators. <S> " First, it pushes the "you take it you can teach it" model which would imply that any kid that finishes a class has enough content knowledge to teach it and that just isn't so. <S> It's also a red flag that it might follow the model of many math ed courses like "Calculus for math teachers" which purport to be about both the math and how to teach it <S> but in practice are more frequently watered down math classes with formulaic content about instruction. <S> I think the Iowa proposal submitted here is more on track. <S> Content should be somewhat beyond the highest level a student might take <S> so Algorithms / Data structures fits the bill. <S> I personally don't agree with the networking / OS part but that's neither here nor there. <S> On top of depth of knowledge you need breadth and on top of that pedagogy so you'd need some more courses there.
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The College of St. Scholastica in Minnesota has a Computer Science Education graduate certificate program .
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Pick-me-up exercises for after-lunch brain death If you ever had a class right after lunch break, you know what this question is about. (Student's stomachs full, computers murmuring, room half-lit, teacher droning about something - I don't blame them for falling asleep.) What short, fun exercises do you use to set student's arousal to the optimal level? It would be nice if it had something to do with CS. Not sure this needs a context, but where I usually meet the problem: adult education, all-day-long courses, right after lunch break. The problem is universal though, I think. <Q> Some conferences actually have "nap time" right after lunch. <S> Let people nap if they like or catch up on outside tasks. <S> Such conferences are usually residential, of course, so a nap is a real option. <S> A lecture immediately after lunch is going to lose a lot of people, as you say. <S> Your teaching should account for human nature of course. <S> If you have to hit them hard for the complete two days (no naps, no games), make sure that it isn't all just lecture and powerpoint. <S> They will be too passive and will zone out too often. <S> Break it up: lecture, discussion, exercises, role-play, feedback, pairing, group work. <S> Even a discussion session after lunch would be better than a lecture. <S> You can pose a question to the class about some related topic, preferably one that might generate some differences of view. <S> It could even be somewhat orthogonal to the topic of the course. <S> If the course is about programming, make the question about software process. <S> You don't win, nor do they, if you lecture beyond their point of caring. <A> CS Unplugged has some good active learning stuff, and all relating to computer science. <S> Computer science is as much about computers, as poetry is about pens. <S> Therefore only use the computer where it adds benefit. <S> CS unplugged, is an initiative to teach computer science, without the use of computers. <S> It is mainly focused at primary schools, but I have used it in senior school. <S> (If they are successful at teaching all pupils at primary school, then we will have to find other activities.) <S> I have use some of the activities on cs unplugged. <S> Not after lunch, but just because they are good activities. <S> I have in my teacher pack some basic materials that allow me to teach a range of these activities. <S> Example … An easy one that takes little preparation, except purchasing a pack of playing cards, is: sorting algorithms. <S> One pack of cards can be used for 4 groups of 2 to 4 students (so up to 16 students), but sometimes you want them to use more cards, see below. <S> Separate out one suit of cards for each group. <S> If they don't know cards well, then remove J,Q,K. And shuffle cards (or get students to do it). <S> Now as a class get one pupil to sort cards. <S> Watch what they do, and identify the algorithm that they used [usually insertion, or selection]. <S> Tell them that they just did … sort. <S> Then break them into groups, and get them to experiment, what algorithms can they find. <S> Tell them to sort a whole pack, this it to put enough pressure on them, to have to find a better way to do it. <A> One exercise I use sometimes <S> (when I'm desperate): <S> Scope: <S> Adult education, VBA intermediate course, 2 full days long. <S> Have students stand up, throw plush ball. <S> Whoever gets the ball, has to name a programming keyword from the morning - anything from a variable type to an Excel object to a VBA keyword - and pass the ball on to someone. <S> Must throw the ball, can't just give it to their neighbour. <S> In a minute or two this wakes them up enough for us to be able to go on, and this way we also refresh the morning part of the course a little.
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A simple strategy to start might be to elicit their experiences in development. But an active learning session - say role playing an algorithm - might work.
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How to answer questions about how I became interested in programming? I teach programming to students seeking employment as programmers who know little or nothing about programming, and I was last employed as a programmer over a decade ago. Sometimes I am asked what got me started, or what my main interest was. Students are often surprised when I explain that I last programmed professionally near the start of the millennium, and also that I have learned the language I am teaching only recently (C#, which did not exist way back when). I think that some students ask because they are trying to find a point of interest themselves, so that this can become something they desire to be, rather than just a job. When I tell them that I wanted to know how computers actually are able to function / operate / control themselves , ever since I was a child before anyone had a computer, they can understand that. I say I wanted to write Operating Systems, and although I did not achieve that, I did lots of low-level stuff from sharing modems over a Novell Network to creating a multi-threaded web server. They might not end up with those sorts of assignments when they become employed, but the point of learning to program is to understand how all this magic can happen. It is most fascinating when "The magic goes away" and we understand fully. That is what I want for my students. How do you answer such questions, and the flurry of "what languages do you know" etc? <Q> If you are doing a good job of teaching then your students probably think you are smarter than you really are. <S> They may also think that you arrived magically at your current position without effort or setback. <S> It is good for them to know the truth. <S> That what looks to them like brilliance was more likely just hard work and never giving up . <S> It is also good for them to know that the world they are entering (sometimes called adulthood, or the real world) <S> won't always offer them what they hoped it would, but that if things are bad they will probably get better. <S> But also, if they are good, they won't always remain so. <S> It is good for them to know that you are a human being who makes mistakes, admits them, and learns from them. <S> Letting them think you are perfect is probably a mistake as they may be overly disappointed if you ever falter. <S> It is especially useful if you let them know that some, perhaps many, of them are "smarter" than you are on nearly any scale. <S> Whatever "smarter" really means. <S> Just don't let them get the idea that you don't work as hard as you ask them to do. <S> You can teach these lessons in small bits without really taking much class time. <S> I wouldn't devote a lecture to it, but a stray comment now and then <S> ("I found this topic really hard when I first learned it.") might give them the confidence that "yes, it really is hard", rather than the fear that "I'm so dumb". <S> A few, at least, of your students might be inspired enough to follow a similar path to yours. <A> Centuries ago (1978) I saw a graph in Creative Computing. <S> It was the cost of writing a line of code divided by the cost of executing it and realised there was good money to be had there. <S> We were as poor as UK people get and programming, unlike the media, isn't determined by how pretty you are or in the case of the BBC who you are related to, the colour of your skin or your gender. <S> A C++ compiler simply doesn't care about those things. <S> I make references to the media here because they go on about "sexism" and "racism" in Tech when even the best of them are far worse than anything you hear about Uber. <S> I now live in a rather nice house, <S> my kids at a reassuringly expensive school. <S> Programming has been good to me. <S> Yes I enjoy problems solving, am vaguely competent at maths and can focus hard on things where necessary, but those are useful elsewhere, in coding they are well rewarded. <A> Maybe (given the opportunity) the best way to address this question is to have your students talk to someone actually working in the field right now. <S> You probably don't want to give the message to your students that it's been a while since you were working on what they regard as real projects <S> (and I venture that many teachers don't have time to work on projects in their spare time). <S> So maybe you don't think you have any particularly interesting personal examples to share. <S> In that case ask them about what tech they find cool and exciting, then explore what that might lead to. <S> There are two threads that I refer to when I'm talking about careers: <S> Technology changes <S> This is a complex thing, meaning that there are both new things to learn (smartphones now outperform the supercomputers of my youth), and that there will always be new technology along in a few years. <S> The hook can either be 'how does it work', or 'what can we do with this', and the appeal will be different for everyone. <S> There is a lot of detail Despite the apparent rapid changes, this isn't necessarily a field where skills become obsolete (assuming you view languages as a tool). <S> There are also many different levels to work at in even a niche of the field. <S> If you consider products, look at the whole supply chain. <S> If you consider applications, look at science/industry/entertainment/health. <S> Then don't forget development/support/training/marketing - technical skills are relevant to all of these roles. <S> If you want a modern example to break down into it's components, look at today's high-end VR. <S> GPU hardware, High-bandwidth data to displays, 3d-rendering, position aware audio, sub-mm resolution position tracking, nausea avoidance, let alone all of the actual applications of the technology and generating content. <S> Something that a few years ago, not many people though would be possible.
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So, my advice, even to a question that may not be the best fit for this place, is to open yourself to them as honestly as you can, letting them know that it takes effort to succeed, but also that it takes plenty of desire.
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Looking for software that would enable me to cast a screen over LAN I'm working at the university in a computer lab and I'm looking for a Microsoft Windows software, that would enable me to cast a screen of my computer (master) to all other student's computers which are in the same local network. I have already found several different solutions, but none of them enables me to force the slave computers to start the screen casting software . The idea here is, when I'm showing something on my computer I would start the screen casting software on all slave computers, and students won't be able to close this window until i'm done.Does software like this exist? <Q> I know of two bits of software that can do what you want. <S> They do what you are looking for, display stuff on their screen and do demonstrations on their screen. <S> They also lets you spy on your pupils, blank screens, lock screens (useful if they are not paying attention), and shutdown computers at end of day. <S> AB Tutor <S> I have used this software, in the schools I have worked in. <S> On the negative side it is proprietary, and expensive. <S> Veyon <S> I have not used it. <S> But it is Free Software and cheep. <S> See http://veyon.io/ <A> We've used Impero in our labs quite successfully. <S> It allowed me to broadcast my screen to 30 others as well as quickly jump in and take control of other screens if a student was stuck. <S> It is paid and we've used it throughout the school, not just for CS. <S> Network managers use it for quickly trouble-shooting pupil machines for instance. <A> TLDR; Use open broadcast system <S> and you can stream over lan quite easily. <S> Or set up nginx as an RTMP server Notes and thoughts <S> Why OBS? <S> First and foremost, I use it <S> and I love it :-) <S> It's a completely free, and fully open source software that deploys very quickly. <S> Open broadcast system is a powerful multi-platform (windows, linux, macosx) application that's super easy to configure and get going. <S> There are tons of tutorials and it's well developed and well documented. <S> It comes with built-in config's for most streaming environments e.g. YouTube, liveedu.tv, etc. <S> You can simultaneously stream and locally record your videos at different resolutions and framerates simultaneously, and has support for multiple screens, desktops, capturing individual windows and a whole host of other capabilities. <S> The audio/video/desktop-capture capabilities are more than impressive. <S> Using NGINX for RTMP <S> nginx RTMP configuration takes about 10 minutes of reading and about 5 minutes to deploy. <A> Our district has Adobe Connect. <S> It's used mostly for remote training, but any of us have access to setup classes. <S> I use it pretty much any time I demo. <S> I also project my screen. <S> Most watch on their screens while they're typing, but some like to look at the projector screen.
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You can use OBS configs and set up ffmpeg to broadcast over multicast address .
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Answering student questions as they work outside class If your students are like mine, they do a lot of their work outside my view; at home, on weekends, etc. But as they work they sometimes get stuck. They get questions for which they need the answers in order to continue. Sometimes it is a long time before the next class period or office hour. Suppose that you would like to be able to answer their questions as they arise, but without disadvantaging other students who may have the same question but didn't think to ask. Sometimes, in fact, a student finds an inconsistency in something you said or gave them, and needs a correction before they can continue. What tools and mechanisms do you find useful for letting students get necessary answers, at times you are not in class or office hours? I'm looking for actual solutions, not guesses about what might work or which make someone's life (mine) miserable. I'm pretty sure that giving out my cell phone number fails on too many levels to consider. <Q> Threaded discussion forums allow everyone to see all questions and answers and to post questions and receive answers at any time that you find convenient to check in and update. <S> I have used this in online teaching before. <S> It works very well. <S> Actually, I don't know of anything else that does or would work. <S> I would love to hear about other possibilities. <A> In my opinion, Moodle is a great tool to manage lesson-related things. <S> Usually, the school IT department installs Moodle (which is free and open-source) on a central server and makes it available for teachers to use. <S> To start, you set up a course for you and your students. <S> The access to a course can be limited (for example using a registration key you hand out in a lesson) so only authorized persons can view the course contents. <S> Each course provides a discussion forum which can be used for course participants (students and teachers) to ask and answer questions. <S> You can set up an email notification for new forum posts, with which I've made good experiences. <S> Furthermore, Moodle has a lot of other interesting features that could come in handy: <S> Distributing material : In a course, you can create sections containing links, files, images and formatted text. <S> This can be used to create a place where students can look up lesson contents after the lesson or to distribute links and resources during a lesson. <S> The sections can be hidden, if you don't want to show everything at once. <S> Assignments <S> : Moodle offers a function for students to hand in assignment results (as files) which can be evaluated by the teacher Polls : Using the "choice activity", you can create polls <S> A lot more features sounding promising <S> I haven't tested yet: Wikis , quizzes , chats ... ( <S> a list of features can be found in the Moodle documentation, further extension is possible using plugins) <A> Learning Management Systems <S> I agree that Moodle (and specifically the forum feature) may be the optimum solution, but not all institutions have this facility available. <S> Another similar option that is free and easy to set up is Edmodo or Easyclass . <S> Both are easy to set up and to share materials, as well as accept student uploads. <S> They are also FREE :) <S> and you are up and running in literally minutes. <S> All three of these options are " teacher-centric ". <S> Something that is quite popular with MOOCS is a facebook page . <S> I once got a reply to a question that was holding me up, from two people on the other side of the world- <S> it was 0300 in Ireland, and I got to go to bed by 0330. <S> Maybe they can add it to their resume- <S> those with a lot of answers are effectively acting as teaching assistants? <S> The best way to learn is to teach . <S> In any case, it would be very much " student-centric " and self-managed allowing you to spend less time answering questions outside of class. <S> Student Initiative <S> The students may elect to set one up themselves, and offer peer-support to members- maybe you could be a member <S> but it takes the onus off you to answer all questions. <S> In many ways, it is better if they help each other, as they would all benefit in my opinion. <S> Teacher Guidance <S> From my experience of student questions, either in-class or online, the question one person asks is often in the minds of others as well, but for various reasons they are reluctant to ask. <S> Perhaps offer a reward for "Question of the month" (SO guidelines being applied) or something to encourage question asking? <S> Hey, why not an "answer of the month as well? <S> It could simply be a printout, or something simple. <S> Any of the options above would provide the facility that you need. <S> Good luck! <A> I try to give them as many options as possible, without it becoming too much of pain for me to handle. <S> Here's what I've currently got working. <S> Slack <S> Trying it out this year. <S> Originally was thinking it would be a good way for the class to talk, sort of like the Facebook Groups in one of the other answers. <S> Didn't really work so well for that. <S> Only a few students are actively using it. <S> But a few do <S> and it works really well. <S> I've got the Slack app on my phone <S> so I'll get buzzed if someone messages me. <S> Canvas <S> We're using Canvas on our campus <S> and it's easy for students to message me through that. <S> This is where most students contact me outside of class. <S> Like Slack, I've got the Canvas app on my phone. <S> I post to the discussion boards in our Canvas class, but students very rarely respond and even more rarely start their own discussions. <S> Email <S> Very few students email me, although it's common for parents to email. <S> I've probably only had one or two students email me this year. <S> I do make a point at the beginning of the year that if they need me to help the only times I'm always available <S> is during class and after school tutorials. <S> I may respond outside of that, but it's not guaranteed. <S> And of the 120 or so students I have this year, there are only about 10 that have contacted me outside of school hours. <S> None of these are very intrusive, and they're all pretty easy to ignore if I'm doing something else.
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Students helping others Suggest or ask for student-leaders in the class.
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How to keep students heads from exploding from complex, interconnected topics My students will soon be learning ADO.Net in C#, adding on to the Windows programming skills that they recently gained. Just a few pages from one chapter in the textbook introduce the set of layers and interconnected objects needed to do the simplest first program: a DataGridView that allows full update of a table. I have taught this once before, so I have some idea what landmines to avoid, but the fact is that they will need to know pretty much the whole picture to do anything. As Chogyam Trungpa said (about the spiritual path), "It is like swallowing a porcupine: once you start, you have to eat the whole thing." I was able to learn and understand all of this last year because I had the fortunate accident of a very intense introduction to database programming in my first "real job" in 1989, taking over the development and support of a PC distributed database product written in C. I had no significant instruction in databases before that except to do some work with dBase III. I know the concepts that dictate the structure of the ADO.Net classes, because I learned these fundamental, invariant ideas in an entirely different context. Thus, I can also teach these concepts. But with so many moving parts to master up front, I think that the students get very deeply lost, and it is hard to disentangle their errors and help them even start on some lab exercises. Do you have any suggestions for how to introduce a subject where one must know so many new ideas all at once in order to begin? <Q> Students are better able to handle structured information when they understand, at the start, what that structure is. <S> Explain the situation to your students. <S> You are about to present a series of deeply interconnected systems, and though they form a beautiful system together, they essentially can't do anything until they're all moving in tandem. <S> That means that there are two levels of learning that the students must engage in: <S> The systems themselves; and how they play with one another. <S> I am unfamiliar with the topic that you are teaching, so I don't know if this would be possible, but an interconnected graph would be ideal for this. <S> Explain that you will be going through the systems (the nodes), and that students can make a check-mark on each node as they come to understand them independently. <S> But you will also be going over the vertices, and these are just as important. <S> They also need check-marks. <S> Over the course of the unit, students can refer to this graph as a way to measure their own progress and understanding, and to take charge of their own learning. <S> This graph has an additional benefit; your own teaching can now follow the same model. <S> You now have a structure that the students will already understand from which to spin out your lessons. <S> And if a student seems to be having trouble, pull that graph out and have that student begin explaining certain nodes or vertices back to you; it should quickly become apparent where the confusion lies. <S> Good luck! <A> This answer is a supplement to those of BenI. and ctrl-alt-delor, with a specific suggestion. <S> Call it an implementation strategy. <S> Your problem is that the topic is broad, with lots of parts. <S> You can show them the big picture by showing them a complete application that is as shallow as can be (broad but shallow). <S> It has all the parts, but each part is as simple as you can make it. <S> It could even be a dummy app with almost no functionality. <S> That is a way to implement BenI.'s solution. <S> Then have them work with it to deepen parts of it (as ctrl-alt-delor suggests) filling in gaps. <S> Pedagogical Pattern or Kerstin Voigt's Big Picture on a Small Scale <S> An alternative is to do the above but also break your solution a bit in ways that fixing it will be instructive and then give them the broken almost solution with instructions to fix it. <S> That would make it an example of the Fixer-Upper , which can be found in the book, also. <S> This might be a good place to use teamwork or pairing so that the students can help one another with understanding the parts and the connections. <A> It seems that you are not teaching a subject, but training in the use of a tool. <S> First ask what is your objective. <S> Is it to train in this tool, or to teach computing principles. <S> Then in either case, teach the principles (first or only). <S> Get them to do part of the problem/program «fill in the gaps». <S> I have been playing with couch-db / mustache / html / css, each of this can be taught separately, and some have multiple parts, and you can't really understand couch-db without it all. <S> So a similar situation. <S> I would first look for parts that could be taught independently. <S> And teach them. <S> show them the big picture <S> (See Ben. <S> I's answer ) <S> (you may do this earlier, if needed, else show a smaller big picture earlier). <S> This should involve using only one, or a few, principles at a time. <S> continue with them filling in the gaps or making improvements to your existing code. <S> You may need several projects for them to work on. <S> One for each fill in the gaps exercise.
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then look at parts that you can teach by creating most of the solution your self, and having them «fill in the gaps». If you give them a complete simple solution it is an example of the Lay of the Land I would show them a list of the systems at play in as neat of a form as I could.
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What is the pedagogical value of Conway's Game of Life? Lately I've come across Conway's Game of Life in a number of different arenas (articles, conferences, blogs, etc.). Last night I coded it up in C and was utterly mesmerized watching it. That being said, I'm trying to come up with one or two precise, concrete, engaging concepts I can use it for in the classroom. It comes up in my course (CS50 AP) as part of a lesson on simulations . The objectives from the AP Computer Science Principles curriculum are as follows: LO 2.3.1 : Use models and simulations to represent phenomena. LO 2.3.2 : Use models and simulations to formulate, refine, and test hypotheses. It is clear to me that the Game of Life works for reaching both of those objectives, but I get a sense that I'm missing something more that I could use it for. Keep in mind that these students are relatively new to computer science and programming as high school students. Ultimately, what is the pedagogical value of Conway's Game of Life for a high school CS course? <Q> I really like Ben's answer , <S> It's simple to understand, and easily leads to pretty patterns and cool animations. <S> This inspires students to want to play around with the code, which by itself is pretty valuable. <S> On top of that, it leads to some pretty interesting more advanced topics, such as: Emergence From Wikipedia : <S> In philosophy, systems theory, science, and art, emergence is a phenomenon whereby larger entities arise through interactions among smaller or simpler entities such that the larger entities exhibit properties <S> the smaller/simpler entities do not exhibit. <S> Emergence plays a central role in theories of integrative levels and of complex systems. <S> For instance, the phenomenon of life as studied in biology is an emergent property of chemistry, and psychological phenomena emerge from the neurobiological phenomena of living things. <S> Imho, emergence is one of the coolest things about computer science. <S> Swarm Behavior <S> From emergence, you also get to talk about swarm behavior , including programs like: Boids Ant colony optimization algorithms . <S> Swarm intelligence Particle swarm optimization Artificial bee colony algorithm <S> The list goes on, and the related articles at the bottom of all of the above are a vertiable black hole of fascinating stuff. <S> Artificial Life From Wikipedia : <S> Artificial life (often abbreviated ALife or A-Life) is a field of study wherein researchers examine systems related to natural life, its processes, and its evolution, through the use of simulations with computer models, robotics, and biochemistry. <S> From here you can talk about artificial intelligence, neural networks, machine learning, etc. <S> Cellular Automaton <S> The Game of Life is just one example of a cellular automaton . <S> There are a ton of other examples. <S> You could use a 1D cellular automaton to introduce the concept to less experienced students. <S> Simulations <S> The game of life (and other cellular automata) also has practical applications, such as being used in simulations of bacteria, epidemic / disease outbreak, and forest fires. <S> Do a search for "cellular automata forest fires" or "cellular automata disease modelling" for a ton of results. <A> I'm not sure that AP CS Principles has a lot of direct relation to Conway's Game of Life, but nevertheless there is real value in introducing it, and it ultimately features pretty prominently in my program. <S> First off, as you pointed out, it is plenty of fun to watch, <S> so you can spend some time creating glider guns and exploders. <S> You can ask the students to see if they can think up patterns that stay completely still (such as the 2x2 box), or patterns that flip back and forth (such as the line of 3). <S> But, of course, the system's really interesting properties are at higher levels. <S> It serves as a good introduction to the mathematicians Conway (who simplified it to its current state) and Von Neumann (who originally designed the concept), both luminaries of our field. <S> And most importantly, Conway's Game of Life is a great illustration of emergent complexity, and is also provably Turing Complete. <S> Here is a video of a Turing Machine being run in GoL, and here <S> is a video of GoL simulating logic gates. <S> So, in my own classes, I use it in AP Computer Science. <S> moment later on when you show them that GoL is Turing Complete. <A> I would use it as an introduction / teaser about Finite Element Analysis. <S> FEA is commonly used to simulate air / water flow in / around various shapes. <S> Like GoL, the math for each cell is fairly straightforward but the resulting behaviors observed are much more complex. <S> FEA is also used to map / model wave propagation through various fluids. <S> On a more coarse-grained level, this can simulate traffic jams in heavy traffic; one person taps their brakes in fast-moving, high-density traffic and you end up with a traffic jam, even if there are no accidents. <S> This might be something you could simulate on a classroom computer using cellular automata similar, but not identical, to GoL.
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but I wanted to add my two cents: Like Ben and others have mentioned, Conway's Game of Life provides a "wow" factor that's useful in and of itself. It's a great lab for arrays of arrays in APCS (not sure about Principles), and if you are to continue on into computability theory in a later course, letting kids play with it in the earlier class sets up this totally beautiful hook for a really big, "oh, cool!"
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Toy Databases for Class Examples/Homeworks I am familiar with the Northwind database and Chinook database as good toy databases for allowing students to practice writing queries. Are there other databases in a similar vein that are available? I want something with a sensible real-world data model and enough data to be interesting. In particular, I'm interested in databases that can be downloaded/built from a set of SQL statements in a script - building the tables, adding the foreign key relationships, inserting the data, etc. That way, students can add data under the constraints of the database (e.g., foreign keys). Thus, I am looking for databases that are downloadable in formats compatible with major RDBMS implementations (e.g., MS SQL Server, MySQL, SQLite). This differentiates this question from the previous question regarding datasets, which focuses on flat files, or databases available as flat file. <Q> I stil think this is basically a duplicate of this question: Good datasets for intro CS courses? <S> You're asking for a database of interesting data. <S> The other question is asking about interesting data. <S> The only thing you need to do to get from the answers in that question to the answers to your question is to write a little bit of processing code that outputs the data in a format that's compatible with a database. <S> In other words, you're going to have to massage the data. <S> This might require writing a program that calls an API to get data, and then outputs that data to .sql <S> files or more basic .csv <S> files or something. <S> Then the students would take those files and work with them to create their databases. <S> I think as soon as you accept the fact that you're going to have to massage the data, you'll open yourself up to a lot of cool data sets. <S> I think restricting yourself to data that's already in the exact format you need is very limiting, and isn't how things work in the real world. <S> In the real world, data is always in the wrong format. <S> You always have to convert it to something you can use. <S> Stop looking for data in the format <S> you want it in. <S> Start looking for interesting data, and then figure out how to get it in the format you want it in. <A> I see more of sqlserver, oracle, and db2 in enterprise apps. <S> Download some free demo instances of Openmaint, Maximo, redmine, or other apps that are backed by a serious database,. <A> You can check out the WorldWideImporters db (from Microsoft): https://github.com/Microsoft/sql-server-samples/releases/tag/wide-world-importers-v1.0 Or the AdventureWorks db (from Microsoft as well): https://github.com/Microsoft/sql-server-samples/releases/tag/adventureworks <S> (links at the botto still work) <A> You can look at the datasets used for TPC benchmarks. <S> You can find the tools and instructions needed at http://www.tpc.org/tpc_documents_current_versions/current_specifications5.asp <S> The advantages of the TPC benchmarks are: <S> The data is generated and loaded by scripts. <S> The schema is also created by SQL scripts (like you have asked). <S> The size of the database you want to create is configurable. <S> The benchmarks are used widely and hence knowledge of their structure and usage will come in handy. <S> The main disadvantage of the dataset is that most of the data generated is random data and hence may not make much sense to human readers.
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Look into demo instances for real products that run on various databases.
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Search for a useful interactive programming environment More interactive environments are easier to learn, but the text based ones I have seen lately don't let you change your mind. I have used Read–Eval–Print Loop (REPL) environments. However these are not suitable, as it is not possible to edit or view code that one wrote earlier. In [1]: a=5In [2]: b=a/3In [3]: bOut[3]: 1.6666666666666667In [4]: they are of some value. However it becomes less useful when creating something big, when creating routines. I want to be able to create sub-routines interactively, and then be able to inspect them, and edit them. It also needs to be easy enough for teaching beginners. In [4]: def double(a): ...: return 3*a ...:In [5]: show double def double(a): return 3*a In [7]: show --all def double(a): return 3*a def oneMoreThan(a): return a+1 I am not too worried about language. I am just looking for a nice interactive learning environment, that combines the best of REPL and editing. Can you tell me of anything that you use or know of? I will add an answer that shows what I have found, but it is not an acceptable answer as I don't think it is easy enough. <Q> I am not too worried about language. <S> I am just looking for a nice interactive learning environment, that combines the best of REPL and editing. <S> Can you tell me of anything that you use or know of? <S> It also has a slider so that you can go back to earlier versions of your source code to review and run. <S> In addition to activecode, you can also execute Python code with the assistance of a unique visualization tool. <S> This tool, known as codelens , allows you to control the step by step execution of a program. <S> It also lets you see the values of all variables as they are created and modified. <S> There is a lot more to the web site but is what I use to help others learn Python 3 and the nicest part is that once the students get the hang of the e-books they tend to take off at their own pace. <A> Expanding on hotpaw2's answer : <S> If you have a Mac , you can use Swift Playgrounds in Xcode. <S> It allows you to type code and see the results immediately, like this: <S> It only supports Swift, Apple's new language for making Mac and iOS applications. <S> You can find out more about it over here . <S> It's a good language for small things like learning programming, but it scales up to entire applications. <S> This all comes with Xcode , which you can download for free from the App Store . <A> For Python you can also check out Thonny. <S> All have a repl section and a code section. <S> Write your definitions in the code section and interact in the repl section. <S> Emacs can also be configured this way for a whole host of languages. <A> DrRacket combines a coding window with a REPL environment. <S> It would mean moving out of the imperative paradigm into a functional one, but the setup is really quite nice: <S> The top window is called the Definitions Window , and the bottom is called the Interactions Window . <S> Work in the bottom window for as long as you like, <S> but once you have something built up, copy the all-important function definition into the top. <S> Be warned that when you press the run button, the interactions window is cleared. <S> However, you can now freely utilize any functions that have been defined in the top area. <A> Repl.it REPL.it supports several languages. <S> It also supports manual and automatic testing (unit tests). <S> When students complete task they can see instructor model solution. <S> Google currently supports Jupyter Notebooks https://colab.research.google.com which would allow you some pedagogical tools in terms of embedding code within explanations. <A> What I have found so far. <S> I don't think this is suitable for teaching a class of beginners, as it is too complex. <S> In ipython , you can display the code of a function/procedure, variable…, by typing its name followed by two ? . <S> In [10] <S> : double??Signature: double(a)Source:def double(a): return a*2File: ~/<ipython- <S> input-8-4a40aa4fc91f <S> > <S> Type: functionIn [11]: a=5In [12]: a??Type: <S> intString form: <S> 5In [13] <S> : %ed double <S> Now the terminal switches to an editor, when I quit the editor the new definition is invoked, and I return to repl mode.
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Runestone Academy has a component called ActiveCode that allows you write Python code and run it. In addition to Racket, check out drjava for Java and drpython for Python.
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