source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-101 | human-physiology, digestion, stomach
The stomach accomplishes much of its function by mechanically breaking down the swallowed food particles and mixing them with acid and enzymes into a sort of slurry. To do this, there are three major layers of muscle surround the stomach - from the outside, the longitudinal layer, the circular layer, and the oblique layer. The stomach also has two holes in it - the gastroesophageal opening, coming from the esophagus with the swallowed food/saliva mix, and the pylorus, where the food/acid/enzyme slurry exits into the duodenum, which is the beginning of the small intestine.
Due to the three layers of (rather strong) muscle, the stomach doesn't have a lot of expansion capability once it is filled completely to capacity. Fortunately, this almost never occurs (despite how we may feel after a large meal) because material is always leaving the stomach on its way to enzymatic digestion in the intestines. Additionally, once the stomach is filled to a certain extent, hormones such as leptin are secreted that give you the feeling of being sated, or full, triggering the brain to make you stop eating.
Of course, as we can see with the current epidemic of obesity around the world, the stomach can change its size over time. However, this is a rather slow process (weeks to months to years) of adapting to continuously consuming large meals.
But what would happen if you completely ignored these internal warnings, or were being force-fed, or whatever? Instead of rupturing (the biological equivalent of "exploding"), food would most likely be expelled either into the small intestine or back into the esophagus and back up the way it came down, i.e. causing vomiting.
The following is multiple choice question (with options) to answer.
Eating and digesting a large meal is guaranteed to produce | [
"disease",
"fecal matter",
"fuel",
"fertilizer"
] | B | processes sometimes produce waste products |
OpenBookQA | OpenBookQA-102 | paleontology, fossils, desert
Title: Why are many fossils found in deserts? Why are deserts famous for fossils? Is it a coincidence? Some examples:
Giant Catfish Fossil Found in Egyptian Desert
Chile's stunning fossil whale graveyard explained
Giant Dinosaur Fossil Found in Sahara Desert I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago. The fact that a location today is a desert has no indication of what the climate, or even where on the globe that location was 50 or 100 million years ago.
Do not forget about plate tectonics and climate change. One can go to places like the Judith Basin in Montana, a relatively harsh area of North American Bad Lands, desert or near desert like conditions with cold winters and find fields of fossils from animals that are believed to have lived in tropic marshes of in oceans, because at the time those animals lived, what is now Montana was not inland, and was not at a Northern location. Millions of years ago it was an undersea plate, thus it has layers of limestone made from ancient single cell sea creatures and sometimes larger objects that were entrapped and preserved as larger fossils. At other times, those plates rose from the sea floor and homed some of the large creatures, like T-Rex that lived, thrived and sometimes survive as fossils.
Later, that plate move and ended up inland, in what is not North America. Glaciers, wind, and water may have stripped off many layers of deposits and left exposed or close to exposed the layers of interest to fossil hunters. Desert regions tend to be subjected to this type of erosion and exposure making such finds easier. If those same fossils were in and area such as a rich planes area with plentiful plant growth and never subjected to glacial scouring, they could be, and may very well be, right below your feet but under many layers of soil and decaying vegetation, river sediment and other deposits rendering them out of sight and out of reach.
The following is multiple choice question (with options) to answer.
Canyons are generally old, huge, and breathtaking and are | [
"brimming to full with sand",
"filled with local wildlife",
"dirty and muddy inside",
"typically materialized with stone"
] | D | a canyon is made of rocks |
OpenBookQA | OpenBookQA-103 | evaporation, humidity
Title: Confusion understanding relative humidity levels I have difficulty in understanding how can the relative humidity of a mixture of air and water can be 100%. I understand that places like where i live have high relative humidity, so the place is more humid (rain forest) than deserts, for exemple. But an evaporator, in an air conditioning system, removes the water from the air passing in and elevates the relative humidity of it. So why does a mixture containing, for example, 50% of relat. humidity can lose water mass from it and have a highier relat. humidity level?
Thanks :) For a given temperature and pressure, there is a maximum amount of water vapor which can exist in gaseous form. Any greater concentration will cause some of the vapor to condense. Measuring the absolute amount of vapor in the air produces absolute humidity, which is not expressed in per cent.
Relative humidity, however, is the amount of water vapor relative to the theoretical maximum at that temperature and pressure - that's why it's called relative. It is defined as the ratio of the two concentrations expressed as a percentage. So if the air contains the maximum amount of water vapor that it can hold without any condensing, the relative humidity is, by definition, 100%.
The following is multiple choice question (with options) to answer.
If a room is going to be humid, or dry, depends on how much water vapor is in the air, so if a room wants to be humid | [
"run a bath",
"use a dehumidifier",
"open a window",
"hope it rains"
] | A | humidity is the amount of water vapor in the air |
OpenBookQA | OpenBookQA-104 | photons, material-science, absorption, optical-materials, glass
There are further complications to all of this as well. Will the light undergo scattering processes that may allow the light to move through a material, while changing directions and potentially even turning back on itself without being absorbed? Once light has been absorbed, does it simply dissipate the excess energy through the material as heat, fluoresce it back as visible light (and in what direction?), or even do more "forbidden" transitions such as phosphorescence? The answer to all of these questions is "yes, but in varying degrees specific to the material." It even depends on the physical size and amount of material that you have present! So your worries about the rate at which light is able to pass through different materials really just becomes a question of how likely it is for the light to become "sidetracked" as it passes through the material. The net result is an apparent change in how fast the light passes through.
So finally, we can connect all of these nuanced ideas which could each fill a book of discussion on their own (and have) to the macroscopic perspective. All of these properties, for a material like a bulky glass window pane, can be summarized with three simple parameters such as the coefficients of absorption, transmittance, and reflectance of the material. Obviously, for light moving through normal glass, there is an overwhelming victory of the transmittance effects over the absorption and reflectance effects. Of course, you have also clearly experienced that standing at an alternate angle changes the propensity of reflectance of different kinds of light, mostly because you have changed the relative orientation of the light with respect to the overarching structure of the glass itself. This is explained much more deeply within the field of chemical crystallography.
The following is multiple choice question (with options) to answer.
What impacts an objects ability to reflect light? | [
"color pallete",
"weights",
"height",
"smell"
] | A | as lightness in color of an object increases , the ability of that object to reflect light will increase |
OpenBookQA | OpenBookQA-105 | material-science
Title: Optimal material for a hammer head I was watching a TV show in which a gold hammer was mentioned. It was not serious but caused me to wonder whether gold would be a good material and, if not, what else might be. An attraction of gold is that it has a high density but that advantage is probably negated by being more malleable than steel. So, I started to wonder what properties I need to consider. Some materials may be hard but liable to shatter on impact.
Let's suppose that the dimensions of the hammer are fixed: a fixed handle and a fixed size and shape for the head. The objective is to drive steel nails into a variety of hard substances.
Cost is not a factor, nor ease of construction, nor safety. It will need to last long enough to be used so francium and various heavy elements are not suitable. If depleted uranium is a good material then this would be acceptable. It is used for armour piercing shells presumably because of its density but there are denser materials. Is it that it is cheaper than gold or osmium?
What properties should I be researching?
Additional: to make the question more manageable, I will require a homogenous pure material for the head not an alloy. I hope that this makes me more a question of physics rather than engineering. This is a thought experiment rather than a real project. What the optimal hammer head material is depends on what we are optimizing for.
A standard hammer has a hard head that has high density, held by a strong but usually light handle. If it has length $l$ and is accelerated at some acceleration $a$ set by user muscle strength it will reach a velocity $v$ after having traversed a distance $\sim l$; that is, $l=at^2/2$ gives $t=\sqrt{2l/a}$ and $v=\sqrt{2la}$. The kinetic energy will be $K_e\approx mla$. So a long and heavy hammer will be able to drive a nail more deeply (to a depth $K_e/F$ where $F$ is the resisting force). So more mass and length seems good... but obviously not too much either.
The following is multiple choice question (with options) to answer.
which of these would make an ideal object to drive in with a hammer? | [
"an iron nail",
"a metal nail",
"a steel nail",
"all of these"
] | D | iron nails are made of iron |
OpenBookQA | OpenBookQA-106 | Wisconsin Wildflowers Yellow, Adaptability Culture In Organizations, Tree Of Savior Hunting Grounds 2020, 2 Timothy 2:16 Kjv, Aristolochia Florida Native, Best Grass For Goats In The Philippines, Seymour Duncan Sh2 Bridge,
The following is multiple choice question (with options) to answer.
local plant varieties are the best for improving the local | [
"social status",
"environs",
"satellite reception",
"future"
] | B | planting native plants has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-107 | # Ampere's Law and conductor
1. Sep 10, 2014
### Tanya Sharma
1. The problem statement, all variables and given/known data
A conductor carrying current ‘I’ is in the form of a semicircle AB of radius ‘R’ and lying in the x-y plane with its centre at origin as shown in the figure. Find the magnitude of ∫B.dl for the circle 3x2 +3z2 =R2 in the x-z plane due to curve AB.
Ans (1-√3/2)μ0I
2. Relevant equations
3. The attempt at a solution
Applying Ampere’s Law ∫B.dl= μ0I for the closed loop i.e the given circle ∫B.dl turns out to be zero since there is no current flowing through the loop .But this is incorrect .
I would be grateful if somebody could help me with the problem.
#### Attached Files:
• ###### semi circle.png
File size:
3.6 KB
Views:
139
Last edited: Sep 10, 2014
2. Sep 10, 2014
### TSny
Hello, Tanya.
Ampere's law only applies to a current that is part of a complete circuit. The current can't just start at A and end at B. So, you'll have to imagine a way to complete the circuit if you want to use Ampere's law.
(Do you have a typographical error in your equation for the circular path in the x-z plane?)
3. Sep 10, 2014
### Tanya Sharma
Hi TSny
Thanks for the response .
Yes ,there was a typo in the equation for circular path . I have fixed it .
Should I join the path from B to A to complete the circuit ?
4. Sep 10, 2014
### TSny
Maybe.
5. Sep 10, 2014
### nrqed
I think you are expected to ignore any wire beside the one shown because you may take for granted that anything else will not produce any flux through your surface (for example, the remaining wire could extend away along the y axis). Just obtain the magnetic field produced by the section shown and calculate the line integral (or calculate the integral of $\int \vec{B} \cdot \vec{dA}$ and use Stokes theorem if you have seen that).
6. Sep 10, 2014
The following is multiple choice question (with options) to answer.
Electricity sent through a conductor | [
"halts the functioning of the conductor",
"moves like traffic through a green light",
"causes fire to flow through the conductor",
"flows heat back to the conductor"
] | B | sending electricity through a conductor causes electricity to flow through that conductor |
OpenBookQA | OpenBookQA-108 | nuclear-physics, astrophysics, sun, fusion, stellar-physics
Basically, the Sun is a ball of hydrogen and helium, but this is not all there is. Being a Population I star, the Sun contains heavier elements (called metals in stellar astrophysics; anything lithium and heavier is considered metal in this sense). These elements already came with the gas cloud the Sun has formed from, and were produced by previously burst older stars. Despite low abundance, the metallicity plays an important role in the Sun's core power stability.
At some depth the gas ball compresses its inner area enough to heat it up so much that hydrogen fusion into helium begins. This area is called the core. This is where practically all fusion happens, and what is responsible for the star's energy production. For a Sun-mass star and below, the proton-proton chain dominates. The pp-chain energy output is approximately proportional to $T^4$. The good news is, if reaction rate drops, then the outer layer of the star will compress the core, so it heats up, and the renewed energy output compensates for the compression. So this highly-sensitive dependency on the temperature is what gives the star its long term stability.
It is also notable that the center of the core is hotter and therefore more energetic than its periphery, and turns hydrogen into helium faster. Absent any mixing, the core would develop an inert helium ball in the middle (helium cannot be fused by a Sun-mass star, its core is too cold for that): A pp-chain core is entirely non-convective. However, there is another multistage reaction that fuses protons into helium nuclei, the CNO cycle. This cycle requires metals ($C$, $N$ and $O$, naturally) be present in the core. They are not consumed, but participate in stages of the reaction and are ultimately recycled. The rate of this reaction depends on the temperature as $T^{20}$. It's a huge dependency! The CNO-dominant core has so much temperature gradient that it's fully convective, so it mixes the material very thoroughly.
The following is multiple choice question (with options) to answer.
The sun is a source of which, first and foremost? | [
"Light",
"Energy",
"Heat",
"Nutrients)"
] | A | the sun is a source of light called sunlight |
OpenBookQA | OpenBookQA-109 | the-sun, light, distances
Title: At what distance wouldn't the Sun cast a visible shadow anymore? How far from the Sun would a (dwarf) planet have to be so that the Sun is dim enough that it doesn't cast a shadow when you're standing on the planet? What magnitude is the border in brightness beyond which a shadow isn't visible anymore? This depends on eye biology, so there's no purely astronomical answer. I'll note that Venus is just about capable of casting a shadow (at greatest elongation, with ideal conditions) so let's say that a magnitude -5 object is at about the biological limit of casting a shadow.
The sun has a magnitude -27, so that is 22 magnitudes brighter than Venus. 5 magnitudes is a factor of 100 in brightness, so 20 magnitudes is a factor of 100000000 (100 million) and 22 magnitudes is about 600 million.
But light follows an inverse square law, The square root of 600 million is about 25000. So at about 25000 times the distance of Earth, or 0.4 light-years, the sun would be as dim as Venus at its brightest and perhaps marginally able to cast a shadow for someone with acute vision, on a good matt white surface. This puts our astronaut in the Oort cloud.
There's a good deal of uncertainty in this estimate, based on eye acuity. So let's say "something between 0.1 and 1 light-years"
The following is multiple choice question (with options) to answer.
Where in the world will a person have the smallest shadow at noon? | [
"the arctic circle",
"the south pole",
"the north pole",
"near the equator"
] | D | as a source of light moves directly overhead of an object , the size of the shadow of that object will decrease |
OpenBookQA | OpenBookQA-110 | combustion, temperature, fuel
Of course a lot of other factors are involved but this crude picture gives at least some useful insight. This was discovered experimentally in the early days of engine design as the designers observed that different extracts from oil had different combustion properties in engines and refined the way oil was distilled to give them the behaviours they wanted in their engines.
The following is multiple choice question (with options) to answer.
Oil is a source of a material used for an object with | [
"wood planks",
"cardboard",
"a large stone",
"wheels"
] | D | oil is a source of gasoline |
OpenBookQA | OpenBookQA-111 | electromagnetism, magnetic-fields
Title: Why is a paramagnetic material attracted into a magnetic field? I want to start by saying I've seen this topic: Attraction and repulsion of Magnetic materials and its supposed duplicates and it hasn't helped me very much.
In the book Introduction to Electrodynamics by Griffiths, it says the following:
"In general, when a sample is placed in a region of nonuniform field, the paramagnet is attracted into the field, whereas the diamagnet is repelled away." (section 6.14, p.273, 4th ed.)
I don't understand why this should be true. The book states that the reasons for paramagnetism and diamagnetism are due to quantum mechanics, but the book seems to imply there is a classical reason as well.
The only thing I can think of is the equation that in a nonuniform magnetic field, $F=\nabla(m \cdot B)$. Now if the $B$ field is getting weaker if you continue in the direction the field is in at that point (and stronger if you go the reverse direction), then for a paramagnetic material, with $m$ lined up with $B$ the direction of $F=\nabla(m \cdot B)$ is into the field, and for a diamagnetic field, $F=\nabla(m \cdot B)$ is away from the field. But I don't see any reason why the $B$ field gets weaker as you continue along the direction of the $B$ field.
Any help would be very appreciated. I think there is some confusion here. The actual field direction does not play a role for diamagnetic or paramagnetic behavior. What is important is the field strength. What is actually ment by Griffith is: "The paramagnet is attracted into the region of higher field magnitude." In a simlified picture it goes into regions where the field lines are more dense, while a diamagnet lowers its energy by going into regions of lower field line density. You got it, hence, almost right already.
The following is multiple choice question (with options) to answer.
A magnet would attract a | [
"Wooden hairbrush",
"Oranges",
"Glassware",
"Zippers"
] | D | a magnet attracts ferromagnetic metals through magnetism |
OpenBookQA | OpenBookQA-112 | general-biology, habitat
Title: How does life change when you dig deeper? I've just realized that I have no idea what life / biotopes / soil looks like when you dig deeper than a few meters.
I know that in the first meter of soil you can find all sorts of live animals (like moles and rabbits), insects (like ants, but many more), plants, and single-celled organisms, of course.
But how does that change when you get to the depth of a metro station (below 30m)? When you plan to build a metro, do you have to consider that you might destroy a biotope?
I guess there is a point from which you will quite certainly not find animal/plant life in the soil anymore. This will, of course, depend on where exactly you are. But can you give a rough estimate of how deep we're talking? 50m? 100m? 1km? Extremophile bacteria and archea are living very deep beyond our imaginations. This is what you need for general composition at different depths. And this and this is for the deepest living organism known ! Following is image from (Manson et al 2010) which shows at what depth you will get bacteria
Even more deeper, Wold's single species ecosystem, Desulforudis audaxviator which can be found 3 km below sea level.
The following is multiple choice question (with options) to answer.
What sort of habitat would living things live in? | [
"A habitat with plenty of water",
"A habitat with varying weather",
"A habitat that most animals choose",
"A habitat with many toys"
] | A | when a habitat can support living things , living things can live in that habitat |
OpenBookQA | OpenBookQA-113 | Please press Kudos if this helped
“Going in one more round when you don't think you can, that's what makes all the difference in your life.”
Re: Two bottles are partially filled with water. The larger bottle current &nbs [#permalink] 04 Sep 2018, 22:21
Display posts from previous: Sort by
The following is multiple choice question (with options) to answer.
A person finishes drinking a bottle of water and notices that at the bottom of the bottle is a small symbol, consisting of three arrows in a triangular shape. This symbol tells the person that they should | [
"have it reprocessed",
"burn the bottle",
"reuse the bottle",
"remake the bottle"
] | A | recyclable means a material can be recycled |
OpenBookQA | OpenBookQA-114 | time-dilation
Asking about the spatial distance along the straight line is possible but requires you to chose a frame of reference in which to ask it as there is no unique answer.
The following is multiple choice question (with options) to answer.
In order to better understand the world around us, specialists | [
"watch several educational programs",
"discuss topics with laymen",
"inspect, note, and consider",
"make notes in books"
] | C | scientists make observations |
OpenBookQA | OpenBookQA-115 | hygiene, food-chemistry
Dishes and utensils are only susceptible to bacterial growth if there's traces of food on them. Washing is meant to remove traces of food and oil so bacteria can't multiple on them. The conditions must be right for bacteria to multiple. If traces of food were to be completely dry and hardened on a dish and someone ate off it, the likelihood of any bacteria present on it is close to nil. They need moisture to grow. If dishes had no oily food on them, washing and rinsing with very warm water would be sufficient. I've seen people from other cultures wash dishes with traces of food that are soluble in water. They come out perfectly clean. (As an aside, using a tea towel can often spread bacteria when they're not used properly.) Towels top kitchen contamination hazards list
Bacteria can't multiple in oil. For example, ordinary cooking oil doesn't need to be refrigerated although it can go rancid. A cast iron frying pan is properly meant for frying foods only. No watery sauces should be cooked in them. Even "scraping it clean" shouldn't be done with a sharp metal object as it can remove some of the polymerized hardened oil layer.
I have several cast iron pans that I don't wash. I wipe them out after each use, then I add a little oil nd roughly a teaspoon of salt. With a paper towel, I rub at any bits of stuck on food. If done within a few hours of being used, it effectively removes any food traces, leaving a smooth surface. I usually rinse off the salt in warm water, dry it and then apply a very thin film of oil. I've been cooking in cast iron pans for decades and have never gotten sick or had mild food poisoning (what many people call a 'stomach flu').
Cast iron pans with a layer of proper seasoning and treated like this will definitely not cause sickness. It can't support bacterial growth and as @jeanquilt mentions, the pan gets very hot - enough to blister your skin if you touch them with a bare hand.
The following is multiple choice question (with options) to answer.
A woman leaves some meat on the counter, and bacteria begins to quickly grow on the surface. This bacteria may cause | [
"turned food",
"growing beans",
"sticky toffee",
"pocked oranges"
] | A | microorganisms cause food to spoil |
OpenBookQA | OpenBookQA-116 | solar-system, coordinate, stellar-astrophysics
Can you see either in the sky now. Do they look the same? If yes you are in the same hemisphere you normally live in. If they look strange - upside down. You are in the hemisphere opposite to where you normally live.
You've just spent the rest of the night looking at the sky and the Sun is up. Observe the path Sun, in the sky, during the course of the day. If it is low, it winter. If it is high, it's summer. The daytime temperature will also confirm this.
The following is multiple choice question (with options) to answer.
Stars appear in different areas in the sky at different times of year due to what? | [
"Earths Rotation",
"Changing Weather",
"Suns Rotation",
"Time Change"
] | A | the Earth revolving around the sun causes stars to appear in different areas in the sky at different times of year |
OpenBookQA | OpenBookQA-117 | To seven decimal places, this is $r = 0.96824583$, even though the relationship is quadratic rather than linear. Now you have taken a discrete uniform distribution on $1, 2, \dots, n$ rather than a continuous one, but for the reasons explained above, increasing $n$ will produce a correlation closer to the continuous case, so that $\sqrt{15}/4$ will be the limiting value. Let us confirm this in R:
corn <- function(n){
x = 1:n
cor(x,x^2)
}
> corn(2)
[1] 1
> corn(3)
[1] 0.9897433
> corn(4)
[1] 0.984374
> corn(5)
[1] 0.9811049
> corn(10)
[1] 0.9745586
> corn(100)
[1] 0.9688545
> corn(1e3)
[1] 0.9683064
> corn(1e6)
[1] 0.9682459
> corn(1e7)
[1] 0.9682458
That correlation of $r=0.9682458$ may sound surprisingly high, but if we inspected a graph of the relationship between $X$ and $X^2$ it would indeed appear approximately linear, and this is all that the correlation coefficient is telling you. Moreover, we can see from our table of output from the corn function that increasing the value of $n$ makes the linear correlation smaller (note that with two points, we had a perfect linear fit and a correlation equal to one!) but that although $r$ is falling, it is bounded below by $\sqrt{15}/4$. In other words, increasing the length of your sequence of integers makes the linear fit somewhat worse, but even as $n$ tends to infinity your $r$ never becomes worse than $0.9682\dots$.
x=1:100; y=x^2
plot(x,y)
abline(lm(y~x))
The following is multiple choice question (with options) to answer.
Corn can sometimes | [
"be grown in arctic environments",
"be used as kindling",
"fuel a steam locomotive",
"fuel an economy car"
] | D | ethanol sometimes is made of corn |
OpenBookQA | OpenBookQA-118 | resonance, vibrations, coupled-oscillators
Title: String Vibrations Interesting thing I noticed just now playing my ukulele.
For those who don't know how a ukulele works, it has four strings: a high G followed by a lower C, E, and A. Holding down frets causes the strings to play progressively higher-pitched notes. Now, it is possible for two or more strings to play the same note. I've noticed that when this happens, playing one string will cause the others of the same pitch to vibrate, even without actually playing them. However, it's only when they are exactly the same note. If it's not the same note, it doesn't vibrate (at least not perceptibly). Why? If it's caused by the vibration from the string spreading outward, why would it matter what pitch the strings are relative to each other?
Perhaps it's a property of the nylon in the strings? After noticing this, I checked on my steel-stringed acoustic guitar, which definitely does not (perceptibly) do this. The sound of a ukulele (or any similar instrument - guitar, violin, etc) does not come from the strings themselves, but from the whole body of the instrument vibrating and moving the air which is in contact with it.
The vibrations are transmitted from the strings to the body of the instrument mainly through the bridge.
If you stop two strings so that they produce the same pitched note, the vibration of the bridge will cause both strings to vibrate if you pluck one of them.
This will also happen on an acoustic guitar, but in an electric guitar the sound is not physically produced by the body of the instrument vibrating. Instead, by magnetic pickups sense the vibration of the steel strings and the electrical signals are then amplified and sent to a loudspeaker.
The same effect happens in instruments like the piano, but the steel strings are at a higher tension than in plucked instruments and there is no visible vibration of the strings (except perhaps for the lowest bass notes) in normal playing.
The following is multiple choice question (with options) to answer.
strumming a string can cause what type of wave? | [
"Tidal",
"Pressure",
"Light",
"Dark"
] | B | strumming a string can cause that string to vibrate |
OpenBookQA | OpenBookQA-119 | species-identification, microbiology, microscopy
Title: Identification of protozoa under microscope I observed maybe Protozoa from standing FRESH water and from slowly flowing FRESH water. I am complete dilettante. Can you tell what these creatures are?
https://www.youtube.com/watch?v=6D5ck3zNJzA&t=474s
Thank you.
Added picture for to be more specific At first glance, the organisms may hold the appearance of protozoans like ciliates. However, I am of the belief that these 'totally tubular' micro organisms are in fact diatoms.
The diatoms are a diverse range of eucaryotic microalgae which comprise a large percentage of the phytoplankton group. (Diatomaceous earth is the residual remains of their calcareous walls)
They are likely diatoms because of their apparent hard membrane, and slight brown-green pigment, typical of heterokont diatoms.
I would be unable to specify the organism to family level. However, you may wish to complete your investigation by looking under the order 'Pennales'.
For general information regarding the Diatoms, you may visit https://en.wikipedia.org/wiki/Diatom
Morphology and description available from: https://books.google.co.uk/books?id=xhLJvNa3hw0C&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
Good luck
The following is multiple choice question (with options) to answer.
Coral is a type of living organism which can be identified in | [
"only in the pacific ocean",
"saltwater locations that are open",
"any where with liquid",
"water sources in america"
] | B | coral lives in the ocean |
OpenBookQA | OpenBookQA-120 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
Having reliable plant sources in a field, a rabbit may react by | [
"having larger litters",
"finding a mate",
"eating more food",
"finding new food"
] | A | as the number of sources of food increase in an environment , the population of the organisms will increase in that environment |
OpenBookQA | OpenBookQA-121 | materials
The image is a modified version of an image found at www.geology.um.maine.edu. Original credit: Passchier and Trouw, pg 33 (2005).
The following is multiple choice question (with options) to answer.
The layer of material on the bottom of the Snake River was put there by what? | [
"fish swimming",
"weather related degradation",
"global warming",
"animal movement"
] | B | sediment is formed by weathering |
OpenBookQA | OpenBookQA-122 | water, safety, hydrogen, equipment, reaction-control
Title: Creating water from hydrogen and oxygen Assuming a scientist has two canisters: One with a liter of pure gas of hydrogen (single atoms gas), and one with half a liter of pure gas of oxygen (single atoms gas).
The scientist desires to conjunct the two single atom gasses inside some instrument somehow, to create water.
I understand that the process of doing so is some kind of explosion.
What are the names of that reaction and of the instrument in which it should take place?
I ask this after I saw the film "The Martian", in which the protagonist "Mark Watney" created water from separating hydrogen from hydrazine, then burning it with oxygen in extremely low stream of gasses, creating very small amount of water in each step of a process.
Here is a video in which a youtuber seemingly creates water from burning hyrdogen and oxygen (legal note: I ask any reader not to try this without being certified as a chemist from, a internationally known academic center).
This question is for general knowledge: To know the name of the reaction and the common instrument for it. Having a single atom hydrogen or oxygen gas means having lots of free radicals just waiting to react with their own species, liberating a huge amount of energy within a fraction of a fraction of a fraction of a second. This is very unstable.
Lets say the hydrogen only reacts with oxygen and vice versa, then such a reaction would be possible. In general it is called radical addition or free radical addition when radicals react with each other.
The bond energy of a O-H bond is about 464 kJ/mol.
If we had 1 mol magic $\ce{O.}$ ( the oxygen radical) gas and 2 moles magic $\ce{H.}$ the result would be 1 mol (normal) $\ce{H2O}$ and 928 kJ energy. This is the energy delivered by 221.8 g of TNT.
This reaction should be slow or taking place in an explosion proof container.
If you did the same with ordinary oxygen and hydrogen, the energy liberated would still be high but not as big as with radicals ( the O-O and H-H bond needs energy to be opened).
The following is multiple choice question (with options) to answer.
Which converts carbon dioxide, water, and solar energy into oxygen? | [
"chrysanthemum",
"mistletoe",
"mushroom",
"mole"
] | A | photosynthesis means green plants convert from carbon dioxide, water, and solar energy into oxygen for themselves |
OpenBookQA | OpenBookQA-123 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
December is in the summer in what | [
"the southern part of cities",
"the northern part of Earth",
"the southern part of the third rock",
"the southern part of every rock"
] | C | December is during the summer in the southern hemisphere |
OpenBookQA | OpenBookQA-124 | zoology, behaviour, mammals, rodents
Title: Why do Guinea Pigs chirp / sing? Ok, so this appears to be quite a mystery. Me and my girlfriend have 2 Guinea Pigs, 1 male and 1 female.
My girlfriend once picked up the female one and took her outside into our garden. The Guinea got scared for some unknown reason and jumped out of my girlfriend's arms and fell down hard.. That night, the female Guinea woke us up with some very strange sounds. She sounded like a chirping bird.
Since then, she sometimes repeats these sounds (most often at night, but not always). Mostly, we are puzzled as to why as there is often no apparent reason for her sounds. Also, when she makes the sounds, she appears to be in a trance-like state, making no movements at all.
Looking for the answer online I found many discussions on the subject like this one or this one. Mostly, the sounds (and the often mentioned trance like behavior) appear to be interpreted as either (1) alarm sounds, (2) loneliness sounds or (3) happiness sounds.
There are also recordings of it one Youtube, like this one.
What I was wondering:
Does anybody know about some actual research that has been committed on this subject? If so, what were the results?
I'm just so very curious to find out! I found this question very interesting so I did some research. Here's a brief summary of what I've found:
Researchers have found that there are 11 different call types. Some of these include a "sharp alarm cry", "sociable clucking", chutter, whining, purring etc. Using body position and behaviour, researchers attempted to associate these vocalizations with behaviour. Some vocalizations had no apparent associated action including what researchers designated the "chirrup" ( I think this is similar to what your guinea pig might have emitted.)
For more information you can read the results section of this paper by Berryman. You can find a full description of each of the 11 calls and their assumed cause or purpose. Some involve social interaction, reproduction, and distress. Much of the research regarding Guinea pig vocalization involves communication and response between mothers and pups.
In short, it seems as though this chirping behaviour your Guinea pig is exhibiting is normal, but not of any known cause.
The following is multiple choice question (with options) to answer.
Trembling muscles spasms in animals can be caused in party by | [
"temperature in single digits",
"temperatures in triple digits",
"finding the right temperatures",
"being unaware of the temperature"
] | A | cool temperatures cause animals to shiver |
OpenBookQA | OpenBookQA-125 | algorithms, algorithm-analysis, data-structures, trees, binary-trees
The expected number of queries used by this algorithm is $\mathcal{O}(n)$.
Routine 3 Now let's make the next observation. There are $2^{k-1}$ nodes in the last level of this complete binary tree. Colour these leaf nodes with two colours, red and blue. A leaf is coloured red if it belongs in the left sub tree of the root and blue otherwise. Using Routine 2, we will try to find a pair of leaf nodes one of which is red and the other is blue in $O(n)$ queries. Here is how -
Find any leaf node using the algorithm in Routine 2. Call this leaf node $u$.
Find a different leaf node, call this $v$.
$u$ and $v$ are of different colour if and only if exactly $2k-1$ nodes can disconnect $u$ from $v$, i.e., the nodes on the path that connect $u$ to $v$ (We assume that deleting $u$ will disconnect $u$ from $v$). This can be verified in $\mathcal{O}(n)$ queries as well by iterating over all nodes once.
Repeat steps 2 and 3 till you find the desired leaf node.
The following is multiple choice question (with options) to answer.
The number of lines found in a tree bore will tell you? | [
"variety",
"sturdiness",
"the age",
"the height"
] | C | the number of rings in a tree trunk can be used to estimate the age of the tree |
OpenBookQA | OpenBookQA-126 | species-identification, entomology
Title: Big Bug from Peru I'd like to have a name for this guy. There were 5 or 6 of them zipping around the flower bed on the coast of Peru about 120 kms south of Lima. That is a hawkmoth, probably Hyles annei (Guerin-Meneville, 1839). It is one of a number of moth species commonly called "hummingbird," "sphinx," or "hawk" moths in the family Sphingidae.
Beautiful, isn't it? :)
edit - sorry, I originally misidentified this as Hyles lineata - the pattern is slightly different.
The following is multiple choice question (with options) to answer.
Hummingbirds take what with them | [
"Bees",
"energy",
"Pollen",
"Honey"
] | C | when pollen sticks to a hummingbird , that pollen will move to where the hummingbird moves |
OpenBookQA | OpenBookQA-127 | soil-science
Title: How does humanure make soil "fluffier"? This BBC article says biosolids make soil "fluffier", among other benefits. How?
Adding humanure also changes soil structure, making it more resilient, preventing erosion and balancing out moisture, says Moss. It makes dirt fluffier, so water passes through easier. Conversely, in drought conditions, this also helps it retain water. The less compact soils are also softer, enabling seedlings to take faster and grow stronger roots, producing better yields. What are Biosolids and how do they work?
a biosolid is a product of the sewage treatment processes and is a semi-solid sludge of organic matter, nutrient-rich organic compounds. Here I list several reasons as to why biosolids would make the soil 'fluffier' and and better
As I said earlier biosolids are typically made out of organic matter, organic matter is carbon-based and biosolids are usually biological material (decomposed feces, urine and et cetera).
If you are not familiar with the normal decomposition processs it is a biological material (banana, apple, feces and et cetera) that is decomposed by microbes, molds, fungi and etc
biosolids are biological and/or organic material so what I just stated above applies to biosolids as well
Think of what you flush down a toilet or what goes down a sewer drain, are those things carbon based and biological? (human feces is an organic-compound and it goes in the sewers)
So now we know that biosolids are like other organic-compounds, how does this maker the soil fluffier. When something undergoes decomposition it turns into fresh brand-new soil, and quite obviously this new soil would be much more higher-quality and better than over-used old soil.
Here it states that organic material in a landfill produce gases due to decomposition so it makes sense that the same process would happen underground where microbial decomposition can release gases in the soil thus making the soil fluffier
So I can conclude that biosolids do, in fact help soil and make it fluffier and better.
The following is multiple choice question (with options) to answer.
To naturally increase the amount of organic matter in soil add | [
"fungi",
"sunflowers",
"trees",
"voles"
] | A | decomposition increases amount of organic matter in soil |
OpenBookQA | OpenBookQA-128 | organic-chemistry, acid-base
Title: What are the predominant acids in sphagnum peat moss? I'm trying to figure out what the predominant acidic substances in peat moss are. Peat moss is said to have a pH of approximately 4.0. So, I'm curious what is making it acidic.
I know not all acids bind to various elements in the same ways. So, I'm trying to find out which acids (and/or acidic salts) are present in peat moss in order to aid me in my research to discover approximately how long it might take to acidify soils with it compared with the traditional methods of adding various forms of sulfur to soil. You don't need to tell me how long it takes, by any means. I can do more research after I find out which acids or acidic salts are in peat moss, in what levels.
I'm not familiar with this particular SE site's customs. So, if this is the wrong place to ask, or if I used the wrong tag(s), feel free to let me know. I figured people might be more likely to know here than on Gardening and Landscaping, though. This 1992 article by Gagnon and Glime suggests that the ability of Sphagnum to lower pH depends on the presence of cations in the surrounding environment and is not (contrary to prevalent belief) due to organic acids in the plant itself. Here is a more recent article from New Phytologist amplifying that cation exchange is responsible for lowering of pH.
If you want to acidify soil using sphagnum/peat--assuming the authors are right--it's more important what cations you put into the soil. The sphagnum will then exchange them for $H^+,$ lowering the pH of the soil.
This does not mean there aren't organic acids in moss. You would have to look in specialized journals to determine what acids are found in the plant, but they are not necessarily very acidic and are, according to both articles, not the cause of acidity of the soil associated with the plants.
The following is multiple choice question (with options) to answer.
Peat is an important factor when | [
"Driving a new car",
"Putting a fresh raspberry seed in soil",
"Taking the temperature for the day",
"Having a large breakfast"
] | B | being burried under soil and mud changes peat into coal through extreme heat and pressure in a swamp over a long period of time |
OpenBookQA | OpenBookQA-129 | evolution, species, molecular-evolution, species-distribution, macroevolution
Lalage leucopygialis, L. nigra, and L. sueurii: Species of triller birds that coexist on Sulawesi Island.
The existence of ring species like this can, as biologist Ernst Mayr puts it, illustrate "how new species can arise through 'circular overlap', without interruption of gene flow through intervening populations…" and offers proof of speciation through a method other than allopatric speciation: speciation that happens when two populations of the same species become isolated from each other due to geographic changes.
The following is multiple choice question (with options) to answer.
When a bird is living in a certain segment of the world, it can become part of that environment along with predators and food sources, the process being called what? | [
"animals reproduce",
"preyed upon",
"adapted to it",
"predators get it"
] | C | living in an environment causes an organism to adapt to that environment |
OpenBookQA | OpenBookQA-130 | zoology, ethology
Title: Is there a term for tool use in animals? Is there a technical/scientific term that scientists use to refer to tool making abilities found in certain types of animals?
Reference http://en.wikipedia.org/wiki/Animal_cognition#Tool_and_weapon_use Having read this article on tool use in Chimpanzees in full, I am inclined to say that if such a term existed then either the article itself or the titles of any of the 30 articles referenced would have included it.
Searching a couple of online biological dictionaries and ethology sites hasn't yielded anything either, therefore until someone else points out that I'm missing the obvious I'd say you're free to coin the term yourself!
The following is multiple choice question (with options) to answer.
Chimpanzees dig for insects with sticks; what is another example of using tools? | [
"birds using twigs to build nests",
"otters using rocks to open clams",
"anteaters using their tongue to catch ants",
"koalas using their pouch to hold infants"
] | B | An example of using tools is a chimpanzee digging for insects with a stick |
OpenBookQA | OpenBookQA-131 | geology, geophysics, climate-change, carbon-cycle
We can see here in white numbers the most significant pre-industrial sources and sinks (at ~1000 years time scales). We can see that humans produce 9 Gigatons of carbon per year (GtC/yr), due to that extra inflow, photosynthesis is taking 3 GtC/yr more than before, and the ocean is taking an extra 2 GtC/yr as well. However, that is not enough to counteract the 9 GtC/yr we produce, and that is increasing the amount of carbon in the atmosphere at 4 GtC/yr. This means the level in the atmospheric "bath tub" is still rising.
If we were to keep those 9 GtC/yr we produce stable (i.e. not increasing production in the future). The concentration of $\ce{CO2}$ in the atmosphere will rise to a level high enough that the sinks will match the sources, for example with plants taking 5 GtC/yr and the ocean 4 GtC/yr, that would nicely balance the production. But that new equilibrium atmospheric $\ce{CO2}$ concentration would be high enough to rise Earth's temperature several degrees and force a whole reorganization of the Earth's climates.
Finally, we have to say that some of these $\ce{CO2}$ intakes, like the oceanic one, don't come for free, and have their own nasty consequences, like ocean acidification.
The following is multiple choice question (with options) to answer.
Carbon dioxide exists where it does because | [
"humans expel it",
"deer eat it",
"birds use it",
"trees absorb it"
] | A | carbon dioxide can be found in the air |
OpenBookQA | OpenBookQA-132 | orbit, the-moon, apparent-motion
Title: What percentage of the celestial sphere can the Moon cover? I was solving a task that said (paraphrasing):
What percentage of the night sky can the Moon cover during the entire
year, when observed from all points on Earth (what percentage of the
night sky can be studied with the occultation method)?
The following is multiple choice question (with options) to answer.
What covers over 90% of the Earth's surface and 0% of the moon's surface | [
"a magnesium iron silicate mineral",
"chemical element with the symbol S",
"the element with the symbol Fe",
"that which contains 2 hydrogen and 1 oxygen molecules"
] | D | the moon does not contain water |
OpenBookQA | OpenBookQA-133 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
Why do berries exist? | [
"reproducing",
"food for animals",
"growth",
"food storage"
] | A | a berry contains seeds |
OpenBookQA | OpenBookQA-134 | newtonian-mechanics, forces, newtonian-gravity, planets
Well, the second bullet point says that the mass plays a role. You are much less massive than the Moon. So that factor is not in your favour. But you are much closer. That factor is in your favour. Which factor counts most is found by calculating the actual force with the formula for gravitational force, Newton's law of gravity:
$$F=G\frac{m_1m_2}{r^2}$$
We can try to plug in numbers and see if you or the Moon experiences largest force. The gravitational constant is $G=6.67\times 10^{-11}\;\mathrm{N\;m^2/kg^2}$ and Earth's mass $m_1=5.97\times 10^{24}\;\mathrm{kg}$. The Moon's mass is $m_{2,\text{Moon}}=7.35\times 10^{22}\;\mathrm{kg}$ and it is $r_{\text{Moon}}=384\;400\;\mathrm{km}$ from Earth (average distance from centre to centre) and your mass around $m_{2,\text{you}}=70\;\mathrm{kg}$ and your distance is $r_{\text{you}}=6400\;\mathrm{km}$ (from centre to you; Earth's radius):
$$F_{\text{between Earth and you}}=G\frac{m_1\;m_{2,\text{you}}}{r^2}=681\;\mathrm N\\
F_{\text{between Earth and Moon}}=G\frac{m_1\;m_{2,\text{Moon}}}{r^2}=1.98\times 10^{20}\;\mathrm N$$
We see here that the Moon is being pulled in very much more than we are being pulled in. So you are indeed right that the very large masses here have the biggest influence.
The earth should literally stick to the moon even more strongly than it will stick to me.
The following is multiple choice question (with options) to answer.
The biggest things on the moon are | [
"space stations",
"alien life forms",
"craters",
"moon rocks"
] | C | the lunar surface contains many craters |
OpenBookQA | OpenBookQA-135 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Which set of animals don't compete for food? | [
"dolphin and fish",
"hyena and bear",
"whale and cat",
"eagle and raven"
] | C | if two animals have the same food source then those two animals compete for food |
OpenBookQA | OpenBookQA-136 | thermodynamics, buoyancy, freezing, oceanography
Title: How do you calculate the rate of ascent for frozen seawater in seawater? Assuming 1m3 sphere of seawater were flash frozen at a depth of 1km, how rapidly would it start ascending to the surface given the buoyancy? Assuming we could ignore bonds between the surface of whatever actually froze the seawater and it just magically popped into the ether. Given a temperature at that depth of 5C, and the gradient of increasing temperature as the chunk floats upward, would it ever reach the surface at all before being slowly melted by the higher temperatures approaching the surface? Assume a surface temperature of 24C.
If 1m3 of seawater is not adequate to reach the surface frozen, what volume would be necessary in order to counteract the loss whilst surfacing? It won't take very long to rise. The net force is (using densities of 1000 and 934 kg/m^3 for water and ice)
$$F = \frac{4}{3}\pi * 9.8 * (1000-934) \approx 2700\,\text{N}$$
which gives an acceleration towards the surface of
$$a = \frac{F}{m} = 0.7\,\text{m/s}^2$$
So the ball will reach the surface in about
$$t = \sqrt{\frac{2000}{0.7}} \approx 1\,\text{minute}$$
ignoring drag.
The following is multiple choice question (with options) to answer.
will a glacier travel at greater speeds than a sea going vessel? | [
"maybe it moves faster",
"this is likely to be false",
"all of these",
"odds are in its favor"
] | B | a glacier moves slowly |
OpenBookQA | OpenBookQA-137 | geophysics, climate-change, climate-models
What changes with Earths precession is the position of the stars. The sky will shift depending on where Earth is in it's 22,000 year wobble. Similarly, the North star won't always be the North star. The night sky will look shifted by about 46 degrees in 11,000 years (some of the stars will have moved over that time-frame as well, but lets ignore that for now).
You've herd the term "Age of Aquarius". The astrological ages each last about 1,800-2,000 years, and the cycle of 12 ages corresponds to Earth's 22,000 year wobble. Note, that article says 25,860 years and your quoted 22,000 years. The solar system also wobbles, so how those wobbles add up can give different estimates. If you use 22,000 or 25,860 or 25,771 or 26,000 or 23,000 on average, the different numbers don't change the answer to this question. This explains the variation in the numbers used.
The following is multiple choice question (with options) to answer.
Something that shows that the earth changes is | [
"a city where a tree was",
"a lake where a tree was",
"a tree where a bird was",
"a plant where a rock was"
] | B | An example of a change in the Earth is an ocean becoming a wooded area |
OpenBookQA | OpenBookQA-138 | plate-tectonics, mountains, orogeny
Just doing some quick googling, it sounds like Arizona also has both volcanic feature and eroded remnants of volcanic features. These kinds of mountains/hills are formed via a different method again, and their heights are controlled by their own method of formation. Volcanoes can vary a lot in height. They can be very small, like the volcanoes in south-east Australia where I live, or very large, like the volcanoes in the Andes mountain range, or they can be large, but broad and flat, like Hawai'i.
Erosion can carve out softer rock and leave behind more resistant stuff, and this is how some smaller hills/mountains are formed (like Uluru in central Australia). I found this online which might lead you in some interesting directions: Geologic History of Arizona By Jan C. Rasmussen
The following is multiple choice question (with options) to answer.
A lot of people think that volcanoes may only exist in tall mountains that tower above us, but a lot of volcanoes | [
"fall into the oceans",
"are water leaking volcanoes",
"erupt into the sea",
"are found and erupt beneath the water"
] | D | volcanoes are often found under oceans |
OpenBookQA | OpenBookQA-139 | newtonian-mechanics, everyday-life, collision, spring
But if you pull the small block away from the large block slowly, then the large block will follow the small block, while the spring doesn't stretch terribly much. In this case, the low acceleration of the large mass takes place over a longer time, and so it can move more while the force is being exerted on it. This is the equivalent of going over a bump/pothole at low speed; since the wheels move up or down relatively slowly, the frame of the car will follow them. If you go over a bump at low speed, this means that the frame will follow the wheels (which follow the road surface), rather than moving in something resembling a straight line and possibly hitting the road surface.
The following is multiple choice question (with options) to answer.
A car slowed down because of | [
"bad brakes",
"the engine size",
"the wind",
"the steering wheel"
] | C | a force acting on an object in the opposite direction that the object is moving can cause that object 's speed to decrease in a forward motion |
OpenBookQA | OpenBookQA-140 | electric-circuits, electric-current, electrical-resistance, batteries, short-circuits
Title: The importance and the role of a switch in an electrical circuit There is this simple test:
Three identical bulbs are connected in the circuit illustrated in the figure. When switch $S$ is closed:
a] The brightness of $A$ and $B$ remains the same, while $C$ goes out.
b] The brightness of $A$ and $B$ remains the same, while that of $C$ is halved.
c] The brightness of $A$ and $B$ decreases while $C$ goes off.
d] The brightness of $A$ and $B$ increases while $C$ goes off.
For my opinion the answer to this question is D because the switch (which has a resistance of $0\, \Omega$ has a node connected before the third bulb C) that "interrupts" the circuit. But, going into detail, according to Kirchhoff's first law the current should also go on the third bulb as in the first red node it divides into two currents $I_1$ and $I_2$. The current $I_1$ goes for example in the key $S$ and $I_2$ in the third bulb. The key and the third bulb have the same potential difference. I believe that the current $I_2$ passes through the third bulb but the current passing through it is so small that it does not turn on.
I made a point. When an individual is operated on at the heart and puts a by-pass (a bridge), blood will flow on the tube that detects the by-pass and the occluded artery (the third bulb) where blood will flow slowly, over time it will atrophy.
If the circuit were like the one drawn in the picture I would answer the b).
My question is: I have not very clear the rule of a switch in a eletric-circuit.
In fact, I find it difficult to give an answer to the following image.
The following is multiple choice question (with options) to answer.
The lights were turned off in a room, who could find the light switch? | [
"Mice",
"Elephants",
"Raccoons",
"Hamsters"
] | C | raccoons eat waste |
OpenBookQA | OpenBookQA-141 | If you pick two points on a line --- (x1,y1) and (x2,y2) --- you can calculate the slope by dividing y2 - y1 over x2 - x1. The word “slope” in math has roughly the same meaning in math as it has in everyday language: “…a surface of which one end or side is at a higher level than another; a rising or falling surface.” In this lesson, we are going to look at the "real world" meanings that the slope and the y-intercept of a line can have, in context.In other words, given a "word problem" modelling something in the real world, or an actual real-world linear model, what do the slope and intercept of the modelling equation stand for, in practical terms? What does the slope do for us? Graphically, a positive slope means that as a line on the line graph moves from left to right, the line rises. Finding Slope Given a Graph 6. A lower positive slope means a flatter upward tilt to the curve, which you can see in Figure 6 at low levels of output. In Other words, the Slope and y intercepts have real world meanings. Strand 4: Geometry and Measurement Concept 3: Coordinate Geometry PO 6. It tells us how "steep" the diagonal line is. Graphically, that means it would shift out (or up) from the old origin, parallel to the old line. Kids Math. Figure 4. A positive slope means that two variables are positively related—that is, when x increases, so does y, and when x decreases, y also decreases. We cannot discuss rise over run here because there is no run. The concept of slope is very useful in economics, because it measures the relationship between two variables. 1. In order to understand the importance of the definition of slope, one should understand how to interpret graphs and how to write an equation. Check out this tutorial to learn about slope! Graphically, that means it would get steeper. n. 1. To cause to slope: sloped the path down the bank. It is positive as you moved up. The slope factor or Hill slope. In other words, as we increase the quantity of output produced by one unit, the total cost of production increases by \$9. Graphically, a negative slope means that as the line on the line graph moves from left to right,
The following is multiple choice question (with options) to answer.
slope is a measure of the difference in elevation from the top to the base of a | [
"penny",
"tower",
"pyramid",
"box"
] | C | slope is a measure of the difference in elevation between one part of the land and another part of the land |
OpenBookQA | OpenBookQA-142 | dna, mammals, eggs
Title: In what circumstances does a mammalian egg copy its DNA? In the 2nd episode of the new Cosmos series, the host Neil deGrasse Tyson shows how the white-furred bear could have evolved (reasonable scientific speculation, of course).
If you haven't seen that episode, here's the link. Great show, by the way.
So, it shows the bears eggs, and then goes on to show how there can happen an error in the DNA copying, that leads to the brown pigment production malfunction. Here's an excerpt from the subtitles text:
- great bears roamed the frozen wastes of Ireland.
- This might look like an ordinary bear,
- but something extraordinary is happening inside her.
- Something that will give rise to a new species.
- In order to see it, we'll need to descend down to a much smaller scale, to the cellular level, so that we can explore the bear's reproductive system.
..
- Those are some of her eggs.
- To see what's going on in one of them,
- we'll have to get even smaller.
- We'll have to shrink down to the molecular level.
..
- When a living cell divides in two,
- each one takes away with it a complete copy of the DNA.
- A specialized protein proofreads to make sure
- that only the right letters are accepted
- so that the DNA is accurately copied.
- But nobody's perfect.
- Occasionally, a proofreading error slips through,
- making a small, random change in the genetic instructions.
- A mutation has occurred in the bear's egg cell.
- A random event as tiny as this one can have consequences on a far grander scale.
- That mutation altered the gene that controls fur color.
- It will affect the production of dark pigment in the fur
- of the bear's offspring.
The following is multiple choice question (with options) to answer.
In a zoo, a polar bear exhibit will contain | [
"salt",
"cacti",
"strong fans",
"sand"
] | C | a polar bear requires a cold environment |
OpenBookQA | OpenBookQA-143 | physical-chemistry, thermodynamics, equilibrium, precipitation
Title: Why exactly does precipitation occur? In a solution, we have ions floating around but when we have a precipitate, they're arranged as they would be in a solid. This conversion should cause a decrement in the entropy of the system and cause the reaction to be non-spontaneous, but that is not the case. Data of several $K_\mathrm{sp}$'s suggests that the reactions are very spontaneous, with $\log{K_\mathrm{eq}}$ around $30-40$ for some salts. Why does this happen?
One possible explanation I could think of was that all precipitation processes are enthalpy driven instead of entropy driven but in those cases enthalpy should either be really high and all solubilities must increase upon increase in temperature. I haven't studied these enough to know if that is the case or not, so help from someone more experienced would be appreciated. Short story
Maybe it will help to think first about a ridiculous case. Say you have a large hydrophilic solid, and a small drop of water is added on top. We would not expect the entire solid to disappear into the liquid. Yes, there will be some adsorption and solubility here, yet most of the solid will remain undisturbed. In some sense, the solid 'does not fit' into the liquid droplet over a certain limit.
Similar things are true, again in a certain interpretation, for more realistic situations. What does this 'fitting' mean exactly? It definitely does not mean there is not enough physical space per se. Instead as you increase the concentration of your solute, the distances between solute entities starts to decrease on average. Hence, at a certain radii the intermolecular forces become strong enough to pull the solutes together. There is often some energy barrier to this approaching, as colloid chemists will tell you, but if the end result is some energy minimum, the process will occur at some rate.
The following is multiple choice question (with options) to answer.
Precipitation sometimes leads to | [
"mountains",
"earthquakes",
"volcanoes",
"caves"
] | D | precipitation is when rain fall from clouds to the Earth |
OpenBookQA | OpenBookQA-144 | experimental-chemistry
Pouring the copper sulfate solution into the beaker resulted in a vigorous reaction and quite a bit of heat. I stirred the reaction mixture and let it go to completion. The magnet still stuck strongly to the bottom of the beaker, indicating that there was still substantial powdered iron remaining.
The mixture was decanted to another beaker, with some mostly useless filtering (no good filter paper at hand), and allowed to settle for about an hour. The copper particles produced in the reaction are very small and settle out very slowly. Some of the supernatant solution was transferred to a sample cell, illuminated from the left via an LED flashlight and photographed. This is shown in the next figure:
Despite the light scattering, the green color of the ferrous sulfate solution is evident. The photo will be updated after more particulate has settled out.
The following is multiple choice question (with options) to answer.
When the scientist finally completed his new invention he thanked his | [
"powers of observation",
"lucky stars",
"mother",
"grandmother"
] | A | scientists make observations |
OpenBookQA | OpenBookQA-145 | kinect, turtlebot
Originally posted by dornhege with karma: 31395 on 2012-09-17
This answer was ACCEPTED on the original site
Post score: 1
Original comments
Comment by Vegeta on 2012-09-17:
Thanks for your reply, in the detailed tutorial that you mentioned , they built a 12 V regulated power supply. I will use the turtlebot board with gyro, it says that the board generates regulated power for the kinect which draws power from the create. So do I still need to make the regulator?
Comment by dornhege on 2012-09-17:
If they provide 12V regulated power, then you can use those. I'm sure there are specs for the boards available. In that case, you only need to connect the kinect power cable with the correct plug.
Comment by Ryan on 2012-09-17:
This question may also help: http://answers.ros.org/question/43830/kinect-and-turtlebot-and-xbox/
Comment by Vegeta on 2012-09-17:
thanks a lot ryan .. that answered everything..
The following is multiple choice question (with options) to answer.
When the game console's power cable was attached to the wall, electricity ended up in | [
"the plug",
"the power cable",
"the wall",
"the game console"
] | D | sending electricity through a conductor causes electricity to flow through that conductor |
OpenBookQA | OpenBookQA-146 | zoology, ornithology, ethology, behaviour
Title: Crow branch pecking behaviour I was walking through a small park when two crows started cawing at me, and followed me, flying from tree-to-tree as I walked. I speculate that this is a territorial or protective behaviour, but what I found different was the crows were violently pecking the branches nearby them. I have no memories coming to mind of seeing this behaviour beforehand. I speculate that this behaviour could be threat displays, but a quick search on Google did not reveal to me any authoritative studies on this phenomenon. I'd appreciate more information and sources.
This question has been added as a casual observation on iNaturalist. This is a good question. This type of behavior -- pecking at a branch, wiping the side of the beak on a branch, pulling off twigs and dropping them, or knocking off pieces of bark -- is quite common among many corvid species, particularly when they are interrupted by something or someone that they might consider a threat. This includes not only potential predators but also potentially hostile conspecifics.
It is typically considered to be a form of displacement behavior. The concept of displacement behavior, from classical ethology, posits that when an animal experiences two conflicting drives to do two different things, it doesn't know which to do and does a third thing instead to dissipate the drive or anxiety. For branch-pecking in crows, see E.g Kilham and Waltermire 1990 Ch. 12.
Referece: Kilham, L., & Waltermire, J. (1990). The American crow and the common raven. Texas A&M University Press.
The following is multiple choice question (with options) to answer.
Some birds have scooped beaks, but others have sharp beaks such as | [
"peregrine falcons",
"pelicans",
"toucans",
"snakes"
] | A | sharp beaks are a kind of adaptation for catching prey |
OpenBookQA | OpenBookQA-147 | human-biology, brain, endocrinology, behaviour
Title: Is there a hormone combination that makes humans grumpy? Imagine a typical situation that is likely to give rise to a bad temper within an individual: a person is awoken very early in the morning by a sound of a lawn being mowed next door.
Unlike expected awakening by an alarm clock, such unexpected awakening by a lawn mower is likely to leave the person in a bad temper, feeling grumpy or sulky.
I'm interested if there's a specific hormone or process that makes a person experience the feeling of grumpiness? Is it related to adrenaline and fight or flight instinct?
In other words, can experience of grumpiness be induced under laboratory conditions by using some combination of hormones/drugs? This is a hard question to respond to.
Many things might make someone grumpy. There are also individual temperaments, making grumpy hard to quantify - a Grumpy to one person might barely be a blip on another individual's scale. Hormones like cortisol reflect stress, and can make people in general irritable, but I doubt any one combination of hormones would always cause grumpiness.
But I thought I'd venture an answer since I did see this paper today: "Low glucose relates to greater aggression in married couples" doi: 10.1073/pnas.1400619111
Being hungry will do this for lots of people, so maybe a bit of an answer for you. There are lots of different kinds of signals that mediate hunger though, so still a tough call.
Update: here's an additional article that specifically talks about parts of the brain involved in aggression and grumpiness as response to a drop in glucose.
The following is multiple choice question (with options) to answer.
People commonly have bad reactions to what they get from a | [
"discount store",
"lawyer",
"catalog",
"pharmacy"
] | D | medicine can cause people to have bad reactions |
OpenBookQA | OpenBookQA-148 | ocean, ocean-currents, tides
Physical effects, then, are likely to include direct effects on current speed, sediment, and stratification.
The obvious possible biological effect is from collisions. This is not my field, but as I understand it no effect is likely on small fish populations from collisions, although individuals may be affected. Collision risk for large animals (e.g. sharks and marine mammals) and for diving birds is a topic of active research, and is likely (especially for mammals) to depend on their behaviour around the devices. No large animal collisions have been reported on any of the prototypes undergoing testing so far.
A good review of possible effects on benthic organisms is provided by Shields et al (2011). These may include,
The following is multiple choice question (with options) to answer.
What happens to body water when animal activity rises | [
"the water decreases",
"it stays same",
"the water increases",
"the water hardens"
] | A | as the activity of an animal increases , the amount of water in an animal 's body in that environment will decrease |
OpenBookQA | OpenBookQA-149 | geology, geophysics, climate-change, carbon-cycle
We can see here in white numbers the most significant pre-industrial sources and sinks (at ~1000 years time scales). We can see that humans produce 9 Gigatons of carbon per year (GtC/yr), due to that extra inflow, photosynthesis is taking 3 GtC/yr more than before, and the ocean is taking an extra 2 GtC/yr as well. However, that is not enough to counteract the 9 GtC/yr we produce, and that is increasing the amount of carbon in the atmosphere at 4 GtC/yr. This means the level in the atmospheric "bath tub" is still rising.
If we were to keep those 9 GtC/yr we produce stable (i.e. not increasing production in the future). The concentration of $\ce{CO2}$ in the atmosphere will rise to a level high enough that the sinks will match the sources, for example with plants taking 5 GtC/yr and the ocean 4 GtC/yr, that would nicely balance the production. But that new equilibrium atmospheric $\ce{CO2}$ concentration would be high enough to rise Earth's temperature several degrees and force a whole reorganization of the Earth's climates.
Finally, we have to say that some of these $\ce{CO2}$ intakes, like the oceanic one, don't come for free, and have their own nasty consequences, like ocean acidification.
The following is multiple choice question (with options) to answer.
More carbon dioxide is in the air in the past decade than ever before, probably because | [
"more cattle produced",
"more plant life",
"human population increased",
"less water area"
] | C | carbon dioxide concentrations in the air have increased over the last decade dramatically |
OpenBookQA | OpenBookQA-150 | thermodynamics
You can use Fourier analysis to solve this for any configuration and boundary conditions. Bottom line is that the heat that is leaving the hotter object will warm up the cooler object, and reduce the thermal gradient. This will slow down the heat flow.
If you are interested, there is quite an extensive set of cases solved in this paper.
And here is a diagram of how the heat diffusion causes an initial step function to "diffuse" with time (from this lecture):
The following is multiple choice question (with options) to answer.
What slows down the transfer of heat? | [
"a wooden wall",
"the wind",
"the sun",
"light rays"
] | A | a thermal insulator slows the transfer of heat |
OpenBookQA | OpenBookQA-151 | meteorology, snow, radar
Also note that winter precipitation adds an extra complication because the particles are lighter in weight and can thus be blown about more by vertical and horizontal winds. Raindrops (and hail) are quite likely to fall unless extreme updrafts exist because they are heavy. But drizzle, snow, and sleet may be blown around quite a bit. Without a time-intensive dual-Doppler analysis, you cannot know the wind motion in the storm thoroughly, and therefore will have varying results at times.
And finally, the big wrench is unfortunate inherent to how radars work. They measure the percentage of their sent energy that is reflected back to them. That's great because that's directly connected to the diameter of the item falling (to the 6th power). But unfortunately the grand problem is that in a storm, there is a huge variety of drop/flake sizes mixed together at once... such that we can't extract which combination of particle sizes created it (and thus can't calculate volume to actually know the rain/snow amount that falls). It could be like 6 medium size flakes causing the 10 dBZ echo... or 2 large flakes and 10 small flakes... and each combination is a different volume/snow total. (to see the nitty-gritty math details on this, read more here.) So we can never know for sure the exact rain/snow falling using just radar. The good news is we've at least done lots of experiments and come up with some fairly useful best-practice formulas for using the Z-R ratio in different scenarios. Good, but not perfect.
The following is multiple choice question (with options) to answer.
Whether a rainstorm, snow, or hail, humanity can find a way to escape it by | [
"restoring old city streets",
"creating a protected space",
"building a large community",
"sheltering all the young"
] | B | shelter can protect humans from weather |
OpenBookQA | OpenBookQA-152 | newtonian-mechanics, estimation
Would the rock have created a seismic event of its own (if so, how large)?
Would the rock have created a crater? The energy of the rock at the time of hitting the earth is mgh.
No rock we know of is going to be able to survive this collision with out breaking into pieces.
Non the less it will be a big impact and depending on the geology of the location it hits a variety of reactions scenarios can happen.
If the soil is aggregate of silt and sand and gravel, it would part into several shear rupture sections which look like slices of shell pattern surfaces starting from the bottom surface of the rock and turning up exiting the earth surface a few hundred yards outside of the impact zone and probably even eject some material out like a bomb crater. This scenario will have shakes that could be recorded miles away.
The calculation of how much of the momentum of rock will be shared with the shear material and accelerating them will be involved but not impossible.
If the geology of the impact area is of very low bearing like mostly silt and loose clays, the rock my lose most of its kinetic energy by just sinking into the dirt mostly with a giant humph with a cloud of dust rising.
If the geology is hard or rocky with the 'optimal' amount of mass and resilience it could create a substantial earthquake by resonating with the impact.
The following is multiple choice question (with options) to answer.
In a strong tempest, a large boulder may be | [
"broken",
"smoothed",
"sharpened",
"stained"
] | B | wind and rain cause erosion |
OpenBookQA | OpenBookQA-153 | electric-circuits, potential, electrical-resistance, conductors
These analogies are not exact and are only intended to give you a better feel as to what is happening.
Hope this helps.
The following is multiple choice question (with options) to answer.
The way that electrical conductors works in ways such as | [
"sticking a plug into an outlet to power a microwave",
"turning on a coffee pot in the morning",
"making sure that a hair dryer is unplugged after use",
"turning on lights in a room"
] | A | when an electrical conductor is plugged into an outlet , a circuit is completed |
OpenBookQA | OpenBookQA-154 | newtonian-mechanics, energy, friction, everyday-life
the main issue is friction and friction forces, which become torques
because of the structure of the devices considered;
talking of torque would necessarily require the description to
introduce size considerations (wheel and brakes radius), which
would complicate the analysis without bringing in any essential
insight regarding ABS;
this is just a qualitative analysis, without using any actual
figures. Developing complete formulae would of course require to
bring in size issues, and to consider torques. But I deemed it simpler
not to do that here.
To dissipate any misunderstanding and any heat that could result from
it, I should make it clear that this looked to me like an interesting
problem to work on, but that I have no particular expertise, and I did what I could with the information I could find. Comments and criticisms are welcome.
The following is multiple choice question (with options) to answer.
When wheels are squealing on a blacktop, friction | [
"works against motion",
"stops motion",
"removes forward motion",
"makes things rough"
] | A | friction acts to counter the motion of two objects when their surfaces are touching |
OpenBookQA | OpenBookQA-155 | particle-physics
Title: Explanation for self-rupture glass is needed I witnessed a phenomenon that I couldn't conclude its cause. Please bear with me for the length of the recall, for I merely want to include any details that might help us to investigate. I had a cooking glass lid sat on a wooden shelf that is away from the stove and oven and other heating objects. The shelf is nailed on the wall and is situated just above my eye level, and a counter top is also on the same side of the wall where the shelf is installed.
Now here comes the surprise. In a winter afternoon 2011, my room had almost the same temperature as an autumn morning, and while I was cutting my lettuce on that counter top which I pointed out in above passage, a pounding sound, as if a heavy car door slam or a tree trump falling on top of the roof, knocked its introduction from the shelf that was just above my eye level. First, I thought I may had knocked something around me off(which I didn't believe that for there wasn't anything around me to knock off); then I thought it may be my neighbor next door dropping a heavy box; last, I suspected somewhere my roof top collapsed.
But it was my third suspicion directed me to meet that glass lid I mentioned above, and I found it had ruptured completely like glacier creaked BUT still having all broken pieces bounded without any pieces scattering toward random direction! Only the nob of the lid popped out partially. Before this happened, I hadn't used that lid for cooking for years, and I didn't removed it from any heating object nor there was something on top of the lid that day, and I believe what the lid had maybe just an invisible layer of dust.
I was glad my face hadn't been stung by any glass residues, but ponder what really happen to that glass lid and why it ruptured without collapsed. Below, I attached 2 pictures of the scene from that day. If you have any similar experience or know the theory behind it, may you please drop me an explanation to this incidence? Thank you in advance.
The following is multiple choice question (with options) to answer.
Breaking a vase changes its | [
"center of gravity",
"shape and mass",
"chemical composition",
"speed"
] | B | breaking down an object changes that object 's shape and mass |
OpenBookQA | OpenBookQA-156 | java, reinventing-the-wheel, console, unix
With clothes the new are best, with friends the old are best.
He is truly wise who gains wisdom from another's mishap.
Beware of a dark-haired man with a loud tie.
Today is the last day of your life so far.
Flee at once, all is discovered.
Man who falls in vat of molten optical glass makes spectacle of self.
Go directly to jail. Do not pass Go, do not collect $200.
For a good time, call 8367-3100.
Those who can, do; those who can't, simulate.
Those who can, do; those who can't, write. Those who can't write work for the Bell Labs Record.
God does not play dice.
This fortune is inoperative. Please try another.
Laugh, and the world ignores you. Crying doesn't help either.
No amount of genius can overcome a preoccupation with detail.
You will feel hungry again in another hour.
You now have Asian Flu.
God made the integers; all else is the work of Man.
Disk crisis, please clean up!
You auto buy now.
Many are called, few are chosen. Fewer still get to do the choosing.
Try the Moo Shu Pork. It is especially good today.
Many are cold, but few are frozen.
The early worm gets the bird.
He who hesitates is sometimes saved.
Time is nature's way of making sure that everything doesn't happen at once.
The future isn't what it used to be. (It never was.)
Can't open /usr/lib/fortunes.
If God had wanted you to go around nude, He would have given you bigger hands.
It is better to have loved and lost than just to have lost.
A journey of a thousand miles begins with a cash advance from Sam.
Disk crunch - please clean up.
Center meeting at 4pm in 2C-543
I will never lie to you.
Spock: We suffered 23 casualties in that attack, Captain.
Your computer account is overdrawn. Please reauthorize.
1 bulls, 3 cows
It's hard to get ivory in Africa, but in Alabama the Tuscaloosa.
Waste not, get your budget cut next year.
Old MacDonald had an agricultural real estate tax abatement.
Snow Day - stay home.
Save gas, don't eat beans.
The following is multiple choice question (with options) to answer.
When looking for a good renewable resource in order to avoid wasting anything that will eventually run out, a man decides to use | [
"colored pencils",
"snow cones",
"murky river fluid",
"fresh flounder"
] | C | a renewable resource can be renewed |
OpenBookQA | OpenBookQA-157 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
A consequence of polluting could be that | [
"fish become inedible",
"water tastes gross",
"papers report it",
"trash is overflowing"
] | A | polluting means something poisonous is added to an environment causing harm to the environment |
OpenBookQA | OpenBookQA-158 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
the top layer of soil contains the most nutrients where I | [
"hike",
"wade",
"jog",
"skate"
] | A | the top layer of soil contains the most nutrients |
OpenBookQA | OpenBookQA-159 | botany, plant-physiology, plant-anatomy
Title: Caudex vs Xylopodium difference I live in Brazil and many plants from the brazilian grasslands/prairies exhibit an structure called, by the brazilian literature, "xylopodium" (or "xilopódio" in portuguese) - which are tickened, underground, lignified structures (root or stem) to store water and nutrients. I couldn't really find any work outside Brazil that mentions this kind of strucutre, and as far as I know, the structure known as "caudex" fits the very same definition. That being said, are these two terms synonyms? The New York Botanic Garden gives the definition of xylopodium as:
An underground, woody, storage organ derived from stems or roots and common in cerrado vegetation.
And the definition of caudex as:
A short, vertical, usually woody and persistent stem at or just below the surface of the ground.
I think the main difference here is the focus on the xylopodium as a storage organ, as well as the fact that it is fully underground and can be derived from either the stem or root. A caudex doesn't necessarily primarily provide storage, and as a modified stem, is at or above the surface.
*There is also a definition of xylopodium meaning the type of fruit found in Anacardium (cashews).
The following is multiple choice question (with options) to answer.
A cacti is basically an enormous stem, which means that | [
"it can be drunk from",
"it is very thin",
"it holds up bright green leaves",
"it can hide in grass"
] | A | a stem is used to store water by some plants |
OpenBookQA | OpenBookQA-160 | food, decomposition
Title: Worm compost cannot have cooked food I live in the Netherlands and it is getting fashionable to compost with worms. After investigating a few websites I noticed that most websites suggested that I cannot feed the worms leftovers from citrus fruits. This seems logical. I then started noticing that people advise against feeding the worms cooked food.
I'm no biologist but I cannot imagine a reason why cooked food is bad for the worms. Could anybody explain why this might be in layman’s terms? There are a few reasons for not feeding cooked foods to worms (Eisenia spp.) in a smaller household size worm farm. It's not because the food is cooked but what it often contains.
The earthworm used in vermiculture is usually Eisenia fetida (red wigglers) though other Eisenia species are sometimes used. All Eisenia are epigeic species meaning they live in the junction of decomposing organic matter (such as leaf litter, aging manure, rotted fallen trees) and their natural food is decaying plant matter and bacteria that are also digesting the organic matter. They don't make use of small dead animals (meat and fat).
In large scale commercial vermiculture operations, leftover and past-due-date foods from restaurants, institutions, nursing homes and schools are used along with plant matter and carboard and paper. I'm not sure how they balance cooked foods but possibly much less is used than plant matter.
The fact food is cooked isn't the problem but what's in it and/or what happens to it when added to the bin. If you have leftover vegetables and fruit that's been cooked with no added salt, it's perfectly acceptable. A certain amount of sweetened cooked fruit is also fine as the worms will eat that too. But ready-made foods usually have preservatives, salt, fats and spices added. Either worms won't eat it, leading to odour caused by mouldy rotten food, or it can make them unthrifty and even killing off your worms if it's fed them repeatedly.
The following is multiple choice question (with options) to answer.
Without reliable sources of food or water | [
"creatures experience some suffering",
"animals must make their own",
"dogs will need to be fed",
"organisms need to be cared for"
] | A | loss of resources has a negative impact on the organisms in an area |
OpenBookQA | OpenBookQA-161 | reflection
Title: Why the transmitted pulse in pulse-echo technique cannot be too long? Question. An ultrasound pulse-echo technique is used to produce an image by reflection from many boundaries. If the transmitted pulse is too long, the image produced is of poor quality. Why?
My attempt. If the transmitted pulse is too long, then the pulse contains many wavelengths. After that, I would receive pulses containing the same number of wavelengths but with lower intensity. Then I am stuck. I even wonder why the transmitted pulse cannot be replace by continuous ultrasound so that we could have continuous reflected image. Any kind of help would be appreciated! This has more to do with signal processing than physics per se. A pulse is usually a chirp, i.e. an increasing or decreasing frequency signal. You could dilate it but if you keep all subbands active all the time then you have no way to determine a start or a end to the band signal so no way to calculate delays either. Delays are what is used to compute distances using this type of imaging. The longer the sound takes to feed back the sampler, the farther the target is assumed to be located. So you need a way to precisely determine the timing of what comes in and back. Also some frequencies can be absorbed by the material so the pulse is designed to send a wide range of frequencies at once. But it has to be short so you know what pulse number you are going to listen to next. Optimizations can be made so as to send multiple pulses before the first comes back, it just gets more complicated to make sure which is which.
The following is multiple choice question (with options) to answer.
An echo is produced by what type of reflection of sound source? | [
"Direct",
"Distant",
"Varied",
"Single"
] | D | when a sound is produced inside of a room , there is sometimes an echo after the sound |
OpenBookQA | OpenBookQA-162 | food
Title: Why might food go bad in an oxygen-free environment? I was recently watching a video from the International Space Station (Making a peanut butter sandwich in space), and I noticed he mentioned that a tortilla kept in an oxygen-free environment could last up to 18 months. Impressive, but it got me thinking: Why would some foods ever spoil if kept in a state where molds would not be able to grow? Would it be that other micro-organisms in things like the moisture present in the food eventually take their natural toll? Just a curious thought I had while watching through these awesome ISS videos.
Thanks for any answers! First of all, you assumed that this tortilla went bad after 18 month, not that austranaughts just decided to eat it?
More importantly, there is thing called anaerobs. Just like your muscle don't use oxygen in times of acute stress (force requirement), so there are organisms that don't care much about oxygen. As it happens in muscle, it happens in yeast during fermentation when sugars are turned into alcohols and released energy is used to propel molecular machinery. So, if there are sugar molecules on tortilla, there are still microbes that willing to prosper on it.
The following is multiple choice question (with options) to answer.
if food has lack of immediate use for energy then it will | [
"be discarded immediately",
"kept for later",
"left to rot",
"be thrown up"
] | B | if food is not immediately used by the body for energy then that food will be stored for future use |
OpenBookQA | OpenBookQA-163 | geomorphology
Title: What causes these mound-like ground formations? Whilst riding on Mam Tor in Castleton, England I came across this scene (not my photo) and I would like to know what causes the formations which I have ringed in red. They look like piles of earth have been deposited a long time ago, but clearly that can't be the case, so what causes them?
Another image of these mounds They're landslide deposits; Mam Tor gets its name, which translates as "mother hill", from the regular landslides that come off the higher slopes and form hillocks further down into the valley.
The following is multiple choice question (with options) to answer.
Puerto Rico experienced many landslides due to Hurricane Maria in | [
"2017",
"2015",
"2012",
"2009"
] | A | storms can cause a landslide |
OpenBookQA | OpenBookQA-164 | material-science
Title: Optimal material for a hammer head I was watching a TV show in which a gold hammer was mentioned. It was not serious but caused me to wonder whether gold would be a good material and, if not, what else might be. An attraction of gold is that it has a high density but that advantage is probably negated by being more malleable than steel. So, I started to wonder what properties I need to consider. Some materials may be hard but liable to shatter on impact.
Let's suppose that the dimensions of the hammer are fixed: a fixed handle and a fixed size and shape for the head. The objective is to drive steel nails into a variety of hard substances.
Cost is not a factor, nor ease of construction, nor safety. It will need to last long enough to be used so francium and various heavy elements are not suitable. If depleted uranium is a good material then this would be acceptable. It is used for armour piercing shells presumably because of its density but there are denser materials. Is it that it is cheaper than gold or osmium?
What properties should I be researching?
Additional: to make the question more manageable, I will require a homogenous pure material for the head not an alloy. I hope that this makes me more a question of physics rather than engineering. This is a thought experiment rather than a real project. What the optimal hammer head material is depends on what we are optimizing for.
A standard hammer has a hard head that has high density, held by a strong but usually light handle. If it has length $l$ and is accelerated at some acceleration $a$ set by user muscle strength it will reach a velocity $v$ after having traversed a distance $\sim l$; that is, $l=at^2/2$ gives $t=\sqrt{2l/a}$ and $v=\sqrt{2la}$. The kinetic energy will be $K_e\approx mla$. So a long and heavy hammer will be able to drive a nail more deeply (to a depth $K_e/F$ where $F$ is the resisting force). So more mass and length seems good... but obviously not too much either.
The following is multiple choice question (with options) to answer.
What item's housing is made of metal? | [
"butter",
"cola",
"tea",
"syrup"
] | B | a soda can is made of aluminum |
OpenBookQA | OpenBookQA-165 | desert
Title: When was the first not-icy desert formed? For how long have deserts existed and which one would be the first to be created? I'm talking about arid, dry deserts, not the Antarctic or Arctic or any other icy deserts. Deserts have existed since at least the Permian period (299-251 million years ago) when the world's continents had combined into the Pangaea supercontinent. Stretching from pole to pole, this land mass was large enough that portions of its interior received little or no precipitation, according the University of California Museum of Paleontology.
Pangaea broke into smaller land masses which were moved across the surface by tectonic forces, a process that both changed global climate patterns and the climate those continents were exposed to. As a result, current desert regimes date back to no more than 65.5 million years, according to this Encyclopedia Britannica article:
The desert environments of the present are, in geologic terms,
relatively recent in origin. They represent the most extreme result of
the progressive cooling and consequent aridification of global
climates during the Cenozoic Era (65.5 million years ago to the
present), which also led to the development of savannas and scrublands
in the less arid regions near the tropical and temperate margins of
the developing deserts. It has been suggested that many typical modern
desert plant families, particularly those with an Asian centre of
diversity such as the chenopod and tamarisk families, first appeared
in the Miocene (23 to 5.3 million years ago), evolving in the salty,
drying environment of the disappearing Tethys Sea along what is now
the Mediterranean–Central Asian axis.
Which would put the oldest of "modern" desert somewhere in the region of what later became North Africa or South Asia.
The following is multiple choice question (with options) to answer.
Deserts, Jungles, and Oceans have many different | [
"organisms",
"fish",
"trees",
"grasses"
] | A | an ecosystem contains a large community of living organisms in a particular place |
OpenBookQA | OpenBookQA-166 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
If a glacier going past a dock brushed up against some large boulders there, the stones would | [
"have gouges",
"have stains",
"be frozen",
"be dirty"
] | A | glaciers cause scratches in rocks |
OpenBookQA | OpenBookQA-167 | thermodynamics, statistical-mechanics, temperature
Air is not an ideal gas. The most important factor is that air usually contains a non negligible amount of water vapor, the presence of which can greatly change its thermodynamic properties
In the atmosphere, wind is actually a large mass of air moving from regions of higher pressure to regions of lower pressure. Such a mass of air can be colder than the surrounding air, so the presence of wind can actually be linked to a decrease in temperature. The discussion becomes much more complicated in this cases, and a full understanding of it would require some knowledge of atmospheric science.
The following is multiple choice question (with options) to answer.
Air is considered to be a vehicle for..? | [
"Light",
"Wind",
"Speed",
"Sound"
] | D | air is a vehicle for sound |
OpenBookQA | OpenBookQA-168 | biochemistry, ecosystem
The main damaging effects of wood ash are if it is applied in high concentrations where it can directly enter water sources (see for example UGA extension). In this case, it can raise pH enough to be damaging to life. Large quantities from large fires can also raise pH substantially in streams and such (see for example Burton, C. A., Hoefen, T. M., Plumlee, G. S., Baumberger, K. L., Backlin, A. R., Gallegos, E., & Fisher, R. N. (2016). Trace elements in stormflow, ash, and burned soil following the 2009 Station Fire in Southern California. PloS one, 11(5), e0153372.).
Eventually, however, there are enough sources of acid in the environment that there is no way the salts are permanently alkaline from the perspective of the whole environment.
The following is multiple choice question (with options) to answer.
The removal of trees may cause damage to ecosystems such as | [
"cities",
"jungles",
"fields",
"oceans"
] | B | cutting down trees has a negative impact on an organisms living in an ecosystem |
OpenBookQA | OpenBookQA-169 | zoology, entomology, ethology, ant
Title: What happens to an ant colony when the queen dies? Does the colony collapse? Do workers keep following the last orders? Or can future queens replace the dead one? I'm guessing this might also depend on each specific sub-species. Not really my field, but I can point to this review which discusses a couple of different ways in which ants organize their communities:
Heinze. 2008. The demise of the standard ant (Hymenoptera: Formicidae)
I know that in some species there can be several queens per colony (so more robust to queen deaths). In many species, workers can start laying eggs if the queen dies, but these will develop as males (since they are unfertilized). However, in some species (e.g. Platythyrea punctata) the workers can reproduce by parthenogenesis which can stabilize the colony to some extent after the queen dies.
The following is multiple choice question (with options) to answer.
When a wolf is buried what will happen to other wolves? | [
"small change",
"learn to fly",
"less of them",
"more of them"
] | C | if an organism dies then the population of that organism will decrease |
OpenBookQA | OpenBookQA-170 | photosynthesis, respiration, ecosystem, decomposition
Maybe you should study the metabolic processes of plants and life in general to better understand this. All life consists of chemical reactions that build up structures; in order to build them up you need energy (because of the second law of thermodynamics), and all living things create that energy by breaking down complex molecules into simpler ones. (as such it would be more accurate to say that all life consists of chemical reactions that build up and break down various structures). You might be wondering "but what about the difference between autotrophs and heterotrophs I heard about"; the difference between those is where they get the complex molecules from in the first place. Autotrophs use a different source of energy to build them up while heterotrophs get them from their environment. As such, you can think of every living thing as being made of two kind of molecules: those that actually form their structure (in humans, the molecules that make up cell membranes, bones, muscles, etc) and those that are stored in order to be broken down to power the whole system (in humans that's fat, glycogen, glucose, etc). Of course a molecule can do both; if you're starving your body may start to break down structural molecules for power. There are many different ways of breaking down those big molecules for power; the most efficient one, that starts with a big chain of carbon atoms and cuts it down into individual CO2 molecules using O2 molecules, is called aerobic respiration (i.e. respiration that uses oxygen).
Because those complex molecules are required to power all life, autotrophs (the organisms that actually make them) are very important, and the processes they use to make them are very important too. The process that makes almost all of the molecules that power almost all life on earth is photosynthesis, which uses the energy from the sun to power a reaction that converts CO2 from the atmosphere into big carbon-based molecules we'll call carbohydrates. This is called "fixing carbon", since the carbon atom is the most important one; measuring how much photosynthesis is happening is another way of measuring how many carbon atoms move from being part of a CO2 molecule to being part of a plant.
The following is multiple choice question (with options) to answer.
A fundamental feature of all life produces | [
"offspring",
"auroras",
"magnetism",
"organisms"
] | A | reproduction produces offspring |
OpenBookQA | OpenBookQA-171 | thermodynamics, temperature
Layout
In the night, the outside temperature is lower compared to both Room, but since I live on top floor, the above slabs get heated and it starts radiating heat. I want to cool all my room. It seems like you want to transfer heat from Room 2 to Room 1, but you haven't mentioned the reason behind it. Are you trying to cool down Room 2 or warm up Room 1? Depending on the goal, the approach may vary.
In scenario 1, using the evaporative cooler with the vent facing Room 1 will result in the air in Room 1 being cooled down by the water flowing through the honeycomb structure. However, this may not be an efficient way to transfer heat from Room 2 to Room 1 as the cooler may not have enough cooling capacity to offset the heat generated in Room 2.
In scenario 2, using the cooler as a fan and facing the vent towards Room 2, will allow the air in Room 2 to circulate to Room 1, but again, it may not be an efficient way to transfer heat from Room 2 to Room 1. In this case, you may end up just circulating warm air from Room 2 to Room 1 without actually cooling Room 2.
There are other ways to transfer heat from one room to another, such as using a heat exchanger or a duct system. However, the best way to cool both of your rooms will depend on the specific conditions and layout of your house.
Edit
Based on the information you provided, one option that could be effective in cooling down both rooms to the outside temperature is to use a combination of natural ventilation, shading, and thermal insulation.
During the day, when the outside temperature is hotter than the inside of your home, you can close the windows and curtains or blinds on the sun-facing side of your home to keep the heat out. You can also use reflective film on the windows to reduce the amount of heat that enters your home.
At night, when the outside temperature is cooler than the inside of your home, you can open the windows and use fans to draw in the cool air and circulate it throughout your home. You can also use thermal insulation, such as ceiling insulation or insulation on the roof or walls, to prevent the heat from entering your home during the day and to keep the cool air in at night.
The following is multiple choice question (with options) to answer.
What part of the backyard is cooler than the other parts? | [
"the part by the fence",
"the part with the grass",
"the part by the pool",
"the part by the oak tree"
] | D | large trees block sunlight from reaching the ground |
OpenBookQA | OpenBookQA-172 | reproduction, asexual-reproduction
Title: can self-fertilization in flowers be called asexual reproduction? Suppose a flower having both male and female reproductive parts is self-fertilized then can this be called asexual reproduction...?I'm quite confused cause in this case the fusion of male and female gametes do take place but again the gametes are from the same parent....please help. According to this article from Berkeley, asexual reproduction is:
Any reproductive process that does not involve meiosis or syngamy
Using this definition of asexual reproduction and knowing self-fertilization involves meiosis and syngamy, it is not asexual.
The following is multiple choice question (with options) to answer.
What is an example of reproduction being a stage in the life cycle process? | [
"births can occur only after reproduction takes place",
"death is the last stage in the life cycle",
"reproduction mightn't guarantee a healthy life",
"life can end during reproduction"
] | A | reproduction is a stage in the life cycle process |
OpenBookQA | OpenBookQA-173 | experimental-chemistry
Title: How to produce Fe(OH)2? I'm interested in producing Ferrum hydroxide (II), I did some research on the internet and made a plan for myself:
Conduct electrolysis:
Conduct electrolysis producing $\ce{NaOH}$ and chlorine solution.
Produce $\ce{HCl}$:
Produce $\ce{HCl}$ from chlorine solution by exposing it to UV light.
Make iron and hydrochloric acid react:
Adding iron in hydrochloric acid makes this reaction: $\ce{2HCl + Fe -> FeCl2 + H2}$ producing a solution with $\ce{HCl}$ and $\ce{FeCl2}$, then evaporate it and be left with solid $\ce{FeCl2}$ crystals.
Produce $\ce{Fe(OH)2}$:
As we have $\ce{FeCl2}$ and $\ce{NaOH}$, we can make this reaction: $\ce{2NaOH + FeCl2 -> Fe(OH)2 + 2NaCl}$ producing a participate ($\ce{Fe(OH)2}$).
The following is multiple choice question (with options) to answer.
Iron is used to make | [
"pottery clay for kilns",
"baking sheet for cookies",
"items that fasten roofing to roofs",
"twist ties for bread bags"
] | C | iron nails are made of iron |
OpenBookQA | OpenBookQA-174 | visible-light, speed-of-light
Title: How can travelling at light speed affect light itself? ~Hypothetical Scenario:
Your driving in a car (with the headlights on high beam) and you gradually get faster until you reach the speed of light.
Raised Assumptions:
You can see in and out of the car whilst moving at the speed of light.
Ignore air resistance.
Ignore all biological affects.
The headlights on the car still work at the speed of light.
Bystanders can see objects move at the speed of light.
The car can physically make it to the speed of light.
Questions
Would the driver be able to see the high beam on in front of the car and be travelling twice as fast as the speed of light? Or will the photons produced pool up within the light bulb itself? Would there be no light produced even though the light bulb is on?
If a bystander saw the car drive by would they see the light from the headlights?
The following is multiple choice question (with options) to answer.
When car is close to the runner the illumination of the motorized entity is at a higher level because? | [
"moons gravity",
"motion",
"it is closer",
"sun rotation"
] | C | as a source of light becomes closer , that source will appear brighter |
OpenBookQA | OpenBookQA-175 | zoology, ecology, species-distribution, migration
Title: How do animals end up in remote areas? I was thinking specifically about random marshy water holes on farmers fields. It seems that you can visit just about any one of these and you will find frogs if you look hard enough.
They usually don't seem to be connected to each other. If it were any other land animal I would figure they walk from one spot to another, but in the case of frogs, I don't imagine their range is very vast. But often these marshy spots can be separated by fairly large distances to a frog.
So this brings me to my question: how do each of these spots end up with frogs in them? I don't imagine a frog is going to go hopping over a hill to get to a marsh on the other side, is it? This question pertains to organism dispersal, which is a very active field of study with relation to it's impact on conservation efforts. Much of what I will say below has been covered in this wiki.
Definition: From the Wiki
Technically, dispersal is defined as any movement that has the
potential to lead to gene flow.
It can be broadly classified into two categories:
Density dependent dispersal
Density independent dispersal
The question of frogs and fishes both refer to Density independent dispersal, while an example of density independent dispersal can be the competition for habitat space between big cats and humans (this is a WWF pdf)
From the wiki:
Density-independent dispersal
Organisms have evolved adaptations for dispersal that take advantage
of various forms of kinetic energy occurring naturally in the
environment. This is referred to as density independent or passive
dispersal and operates on many groups of organisms (some
invertebrates, fish, insects and sessile organisms such as plants)
that depend on animal vectors, wind, gravity or current for dispersal.
Density-dependent dispersal
Density dependent or active dispersal for many animals largely depends
on factors such as local population size, resource competition,
habitat quality, and habitat size.
Currently, some studies suggest the same.
This study in particular studied the movement and habitat occupancy patterns within ephemeral and permanent water bodies in response to flooding. They found that during flooding these frogs moved out to flooded ephemeral water bodies and later on moved back again to the permanent ones.
Other suggested readings for those highly interested in the subject may include this (a phd thesis) and this (a project report)
The following is multiple choice question (with options) to answer.
During a thunderstorm an animal is most likely going to relocate to a | [
"cave",
"beach",
"mountain",
"pond"
] | A | shelter is used for protection by animals against weather |
OpenBookQA | OpenBookQA-176 | species-identification, entomology
Title: I found these in my bathroom and WC Are they somehow dangerous? What are they and how can I get rid of them? These are silver fish (Lepisma saccharina) and harmless. Wikipedia says (image taken from the article):
Silverfish are nocturnal insects typically 13–25 mm (0.5–1.0 in)
long. Their abdomens taper at the end, giving them a fish-like
appearance. The newly hatched are whitish, but develop a greyish
hue and metallic shine as they get older. They have two long cerci
and one terminal filament at the tips of their abdomens; the filament
projects directly off of the end of their body, between the left and
right cerci. They also have two small compound eyes, despite other
members of Zygentoma being completely eyeless, such as the family
Nicoletiidae.
Like other species in Apterygota, silverfish are completely
wingless. They have long antennae, and move in a wiggling motion
that resembles the movement of a fish. This, coupled with their
appearance and silvery scales, inspires their common name. Silverfish
typically live for two to eight years. Silverfish are agile runners
and can outrun most of their predators (including wandering spiders
and centipedes). However, such running is possible only on horizontal
surfaces, as they lack any additional appendages, and therefore are
not fast enough to climb walls at the same speed.[citation needed]
They also avoid light.
The following is multiple choice question (with options) to answer.
How do some octopus hide? | [
"using clear ink to spread smell",
"hiding in dark, inky caves",
"expelling dark fluid for cover",
"using ink to paint camouflage"
] | C | ink is used for hiding from predators by octopuses |
OpenBookQA | OpenBookQA-177 | metabolism, ecology, photosynthesis
Title: Why isn't phosphorus or nitrogen a limiting nutrient for animals? Nitrogen and Phosphorus are usually the limiting nutrient for plants, especially for algae. Phosphorus is used for DNA, ATP and phospholipids, and Nitrogen is used for pretty much every protein a cell might want to produce. That is, their need for biological processes is not tied specifically to photosynthesis: anything that lives is going to need them, pretty much for anything it might want to do. It would make sense for them to be a limiting nutrient for almost anything that's trying to grow, plant or animal.
Yet for animals the limiting "nutrient" seems to always be energy, ie: food. Why aren't animals limited by lack of nutrients in the same way that plants are? Obviously animals need these nutrients, too. Or to reverse the question, why do plants need so much more phosphorus/nitrogen than animals do?
My best guess is that an animal's digestion of plant material is relatively inefficient energy-wise but relatively efficient nutrient-wise. So for an animal to eat enough food to have sufficient energy to survive, it's probably eaten more than enough Nitrogen and Phosphorus for its needs. But I'm just guessing and I can't find any data that would back up that guess. Phosphorus
Your suggestion that if we are meeting our calorific requirement we will be getting enough is true for phosphorus.
Most foods contain lots of phosphorus. The maximum dietary requirement occurs during adolescent growth, estimated at 1250 mg per day. Assuming a calorie intake of 2500 kcal we can calculate a 2500 kcal equivalent phosphorus content for various foods:
skimmed milk contains 7,400 mg phosphorus per 2500 kcal
roasted chicken breast contains 7,500 mg phosphorus per 2500 kcal
cooked white rice contains 3840 mg per 2500 kcal
(Calculations are based upon values obtained via this site.)
Nitrogen
Our requirement for nitrogen is met by our protein intake: inadequate protein intake manifests as kwashiorkor which is essentially due to a dietary deficiency of essential amino acids. In other words, the only way to achieve a nitrogen-deficient diet is to not eat protein, and this would not be alleviated by any inorganic source of nitrogen, even if we could consume enough of such a N source.
The following is multiple choice question (with options) to answer.
nutrients from food and water are necessary to an organism's | [
"friendships",
"habitat",
"survival",
"caloric needs"
] | C | an animal requires nutrients for survival |
OpenBookQA | OpenBookQA-178 | material-science
Title: What is the physical process behind wool shrinking when dried? Wool is a fibrous material, but other fibrous materials do not suffer the same problem.
Let us set the scene; a woollen jumper shrinking when put in the washing machine, then the dryer. This involves wetting and heating the jumper, then allowing it to cool and dry. It also tumbles as it is washed, but I do not think this is important.
What about this process causes the jumper to shrink?
Do the fibres themselves shrink, or do the become more tightly bound?
Having googled the matter, it seems the process going on is called "felting" and has to do with heat or water "shocking" the fibres - whatever that means - allowing them to settle into a tighter configuration, but I am interested in the exact physical process we are experiencing. What causes heat or water to "shock" the fibres, and why does it happen to wool much more than other fibrous materials? What is this shocking process; it sounds like the heat of the water overcoming the electrostatic attraction of the fibres, but these website are vague about the physics. It's kind of like "material memory." Wool is pretty kinky originally (as sheared), and the production processes pull the strands straight. Hot washing allows the material to revert to a tightly-wound config, which reduces the external dimensions, aka "shrinking."
The following is multiple choice question (with options) to answer.
When a microfiber towel is used to pick up a puddle of milk, the towel then | [
"is milky white",
"is partly milk",
"contains the milk",
"is now wet"
] | C | if something absorbs something else then that something will contain that something else |
OpenBookQA | OpenBookQA-179 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
Why would a species camouflage as a dangerous animal? | [
"to mate",
"to avoid crocodiles",
"to catch prey",
"to build nests"
] | B | mimicry is used for avoiding predators by animals by camouflaging as a dangerous animal |
OpenBookQA | OpenBookQA-180 | zoology, entomology
Title: How do insects know what is edible? What is the current scientific consensus on how insects innately know what is food and not food? If they are introduced to new food sources do they experiment with eating the new food? Could you teach a preying mantis to eat beef? Insect feeding behaviour is generally triggered by one or more conditions which may include colour, shape, chemical traces or temperature.
Insects generally locate food based on some combination of olfactory, thermal and visual queues (colour and shape). If their minimum criteria are met to specified tolerance, they will attempt to feed on whatever is nearby using their usual feeding method.
When these conditions appear on the 'wrong' target, it attracts insects and triggers feeding attempts. Insects can be triggered to feed on atypical food sources if the relevant aspects of their environment match those of their normal feeding environments. For example, here is a report from a professor of entomology recollecting his observations of being bitten by pea aphids while handling plants, which he assumes is because of the scent on his hands.
We can exploit this in various ways for research. One is for artificial blood-feeding of insects: most systems, like the Hemotek membrane feeding system, warm blood to the body temperature of the host. They do not normally resemble a target host in any other way. Some blood-feeding insects have very specific requirements for temperature (for example they will only feed on blood if it is heated to the body temperature of birds; the same blood heated to mammalian body temperature will be ignored) but we do not need to make the target look or smell like the natural host. Other species may need olfactory cues, which can be provided by researchers rubbing the membranes on their forearms before placing them on the feeding system, or by breathing on cages as you add the food.
A second way we exploit this is for insect traps. Although not all traps work this way, some work by mimicking the host and attracting insects that are looking for a meal. This can be via olfactory/chemical mimicry (for example carbon dioxide baited traps - try Googling "CO2-baited traps") or visual. Different degrees of visual 'deception' may be needed; for instance to attract tsetse flies, colour is important but shape is not:
The following is multiple choice question (with options) to answer.
The reason that flies can always find food is that they can smell | [
"organism decay",
"bad smells",
"dying animals",
"rotting trees"
] | A | the smell of rotting meat attracts flies |
OpenBookQA | OpenBookQA-181 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
examples of pollution include all but | [
"acid rain",
"smog",
"chemical run-off",
"laundry soup"
] | D | pollution is a source of pollutants |
OpenBookQA | OpenBookQA-182 | energy, fuel, environmental-chemistry
Title: Effect of coal and natural gas burning on particulate matter pollution I sometimes hear people talking about how we should replace coal burning plants with natural gas ones, to alleviate the case of particulate matter pollution. What exactly is the difference between coal fuel and natural gas that makes the latter seem "cleaner"?
At the same energy outcome, natural gas produces less carbon dioxide than coal. In a way, natural gas is half way between coal and hydrogen.
Coal produces smelly smoke, solid particles, sulfur dioxide and minor or trace heavy metal pollutants.
It is less known to common people, but power plants burning coal are more significant source of radioactive pollution than nuclear plants. This pollution is very diluted, but rather significant in absolute amount. Coal ash, used in past as a filler for some construction materials, has lead in some cases to significantly increased content of radium-226 in building walls. This radium is a product of long term decay of natural uranium. It further decays while producing radioactive gaseous radon-222, which is dangerous in long term inhalation because of lung cancer. As it stays in lungs as polonium-218 and its decay products.
See e.g. Uranium produced from coal ash
... the uranium concentration in the ash pile is about 150-180 parts per million, about 1/4th of the concentration often thought of as commercially viable for ISL[In Situ Leaching] mining. However, coal ash piles have some physical characteristics that might help overcome that disadvantage since they may be easier to drill and it might be easier to protect the local groundwater from contamination. ...
See Radon in building materials by Czech government agency for radiation protection.
The following is multiple choice question (with options) to answer.
This type of energy resource often results in particulates that are very toxic to breathe: | [
"wood",
"coal",
"oil",
"solar"
] | B | coal is used to produce electricity by burning in coal-fire power stations |
OpenBookQA | OpenBookQA-183 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
Seeds travel by | [
"Fish",
"Word of mouth",
"Knowledge",
"Boat"
] | A | seed dispersal has a positive impact on a plant |
OpenBookQA | OpenBookQA-184 | temperature, thermal-conduction
The TC industry is extremely well controlled, and so it's highly unlikely that any TC wire you buy will be "inaccurate." So if you buy only the wire itself, no need to worry. TC wire is very cheap, coming in all Types and diameters. It's very easy to make a TC junction from the wire itself. All you have to do is fuse the two separate wires (one + the other -) together by a hot acetylene torch, or by an electronic "TC maker" that uses a discharge from a capacitor. This is essentially fool proof. If the wires are fused, the TC is a TC. You can also imbed (drill a hole and "peen" it in) one wire in say the metal piece you want to measure the temperature of and the other wire a short distance away, and the reading will give you the average temperature of the space between. The TC Law that assures this is the Law of a Common Junction.
You mention "probes," but you didn't say what kind of probe geometry you're using. In general, TC wires are often mounted inside probes, and there, the manufacturing quality is important. There are "surface probes" to measure the temperature of flat surfaces, "point probes" that are used to stick inside things, and others with variously different probe materials suitable for different environments.
TC don't age, unless the probes become corroded or broken, but the basic TC itself never wears out or loses calibration, as long as the TC welded junction is intact.
That's about all I can do for you here, but please go to Omega.com and learn more.
The following is multiple choice question (with options) to answer.
What should my thermometer read if I want to make sure my home-made popsicles are done? | [
"212 degrees F.",
"0 degrees C.",
"39 degrees F.",
"32 degrees C."
] | B | freezing point means temperature at which a liquid freezes |
OpenBookQA | OpenBookQA-185 | power-engineering
Title: Why are hydropower plants always wheel-shaped and not flat? Question:
Why are there no flat power generators like in the picture below, that work on the surface of shallow, but steadily flowing rivers ? (As a floating micropower plant.)
The picture shows a conveyer belt with vanes/blades(?) attached to it. The water flow moves the conveyer belt. A generator could be attached to the front and back "wheel" of the belt.
Here's a video of something similar. I would just build it on a larger river.
Why would I ask this?
There are much more flat rivers than waterfall-like structures on this planet. Using them looks like a much more non-nature-inversive, cheap solution. Having a longer surface should supply better drag by flowing water. When you want to solve a problem, the best start is to look at previous attempts. To provide some perspective, I'm doing that for you now. You are not looking at a typical hydro power plant where a dam provides a high head, and the flow is ducted onto a a francis or pelton turbine. You are describing a microhydropower installation with a floating turbine.
Floating hydrpower allows capturing some power without building a dam. The turbine could be placed in or near the middle of the river, where the current is fastest. An installation with a damn will always harvest vastly more power from the same river.
Before electrical power transmission became widespread, there used to be boat mills - workshops with machinery driven by water wheels, placed on boats.
(Boat mill in Servia, 1900, Image from lowtechmagazine page on boat mills)
Improvised versions have also been used for electricity generation.
Floating hydro power is, AFAICT, an ongoing area of developement. The two most common turbine shapes appear to be a propeller hanging from buoys:
(Image source)
... Or some sort of flat paddle wheel:
Vertical axis turbines also exist.
I think Kamran explains quite well why a propeller or a paddle wheel is used, rather than a conveyor belt. I will just add this: Look at the water wheel in the direction of flow: You want to maximise area here.
The following is multiple choice question (with options) to answer.
Using wind in order to power factories is a good idea because | [
"it can be gotten continuously",
"it is free from dirt",
"it is electric and powerful",
"is uses very little gasoline"
] | A | alternative fuel is usually a renewable resource |
OpenBookQA | OpenBookQA-186 | statistical-mechanics, atmospheric-science, density
A limnic eruption, also referred to as a lake overturn, is a rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud that can suffocate wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe earthquakes, volcanic activity, or explosions can be a trigger for such phenomenon. Lakes in which such activity occurs may be known as limnically active lakes or exploding lakes.
Picture 1: one of a number of cattle killed by a limnic eruption at Lake Nyos, Cameroon.
We can occasionally prevent the buildup of carbon dioxide by degassing the body of water.
Picture 2: a siphon used by French scientists to de-gas Lake Nyos. The carbon dioxide emerges from its deposits and bubbles into the water, floating to the top.
The following is multiple choice question (with options) to answer.
A storm rages for two weeks, and the rivers and lakes swell past their holding capacity, so | [
"the area becomes damp",
"the surrounding land is underwater",
"the wind blows over trees",
"everything around burns down"
] | B | when a body of water receives more water than it can hold , a flood occurs |
OpenBookQA | OpenBookQA-187 | molecular-biology, molecular-genetics, development, sex
Quote from a Review (Yao 2005):
We have just begun to glimpse into the mechanisms underlying ovarian development. Convincing evidence challenges us to reconsider the existing paradigm that describes ovarian development as a default system. The default concept was first proposed in the early 1950s when Jost performed the groundbreaking experiments to demonstrate mechanisms of sex differentiation of reproductive tracts (Jost, 1947, 1953, 1970). The term “default” was not originally intended to describe the developmental status of the ovary. Instead, it is referred to the female reproductive tract or the Mullerian duct based on the fact that the female reproductive tract forms in both XX and XY individuals in the absence of gonads. Indeed, now it has become evident that early ovarian development is an active process involving intrinsic cell fate decisions and complex crosstalks between germ cells and somatic cells. Most intriguingly, the appearance of testicular structures in XX individuals where Sry and its downstream components are absent further raises the improbable question: Could the testicular development be default after all?
The following is multiple choice question (with options) to answer.
what process is adulthood categorized under? | [
"the living term",
"a plant feeding",
"the entertainment circuit",
"a chemical reaction"
] | A | adulthood is a stage in the life cycle process |
OpenBookQA | OpenBookQA-188 | thermodynamics, atoms, phase-transition
But let's look at how the states change. In a solid, you have a bunch of atoms that can be thought of as masses connected by springs. As heat is added to the system, the atoms begin to vibrate in the lattice of springs. As more heat is added, they vibrate enough to break the springs. This is when the solid begins to melt and turn to a liquid.
Now you have a liquid where the atoms are all moving around but they aren't free to move wherever they want. More heat is added to the system and the atoms begin to translate faster and faster. Eventually they translate fast enough to overcome the forces that are holding them together in a liquid. Now they fly free and are a gas.
So ultimately, heat is energy that makes atoms and molecules move in some way. They may translate, rotate, vibrate, or the electrons may begin moving around depending on how much heat is there and what configuration the molecule has.
The following is multiple choice question (with options) to answer.
If an object undergoes chemical change then that object will have new chemical properties, such as | [
"a drink with water in it",
"a toilet with bleach in it",
"a soda with lime in it",
"a sink with hair in it"
] | C | if an object undergoes chemical change then that object will have new chemical properties |
OpenBookQA | OpenBookQA-189 | dna, mammals, eggs
Title: In what circumstances does a mammalian egg copy its DNA? In the 2nd episode of the new Cosmos series, the host Neil deGrasse Tyson shows how the white-furred bear could have evolved (reasonable scientific speculation, of course).
If you haven't seen that episode, here's the link. Great show, by the way.
So, it shows the bears eggs, and then goes on to show how there can happen an error in the DNA copying, that leads to the brown pigment production malfunction. Here's an excerpt from the subtitles text:
- great bears roamed the frozen wastes of Ireland.
- This might look like an ordinary bear,
- but something extraordinary is happening inside her.
- Something that will give rise to a new species.
- In order to see it, we'll need to descend down to a much smaller scale, to the cellular level, so that we can explore the bear's reproductive system.
..
- Those are some of her eggs.
- To see what's going on in one of them,
- we'll have to get even smaller.
- We'll have to shrink down to the molecular level.
..
- When a living cell divides in two,
- each one takes away with it a complete copy of the DNA.
- A specialized protein proofreads to make sure
- that only the right letters are accepted
- so that the DNA is accurately copied.
- But nobody's perfect.
- Occasionally, a proofreading error slips through,
- making a small, random change in the genetic instructions.
- A mutation has occurred in the bear's egg cell.
- A random event as tiny as this one can have consequences on a far grander scale.
- That mutation altered the gene that controls fur color.
- It will affect the production of dark pigment in the fur
- of the bear's offspring.
The following is multiple choice question (with options) to answer.
polar bears are white due to an inherited | [
"characteristic",
"coat",
"snow",
"fur length"
] | A | the color of fur is an inherited characteristic |
OpenBookQA | OpenBookQA-190 | star, galaxy
If you're on a farm, away from cities, in a place with reasonably low light pollution, and your eyes are good, and you've been sitting in perfect pitch black darkness for at least 30 minutes prior - when you look up you can reasonably expect to see a few thousand objects, mostly stars. Keep looking, and after a while you will distinguish one or two thousand more stars, very faint, that you could not see at first sight. Practice this steadily for a few years, and you'll add maybe another thousand; but you won't be able to see those all at once - only one at a time.
Now travel to the Cerro Tololo site in Chile, up in the mountaineous desert, zero light pollution, excellent transparency, and you'll multiply all those numbers by a factor of 2x ... 5x.
As you can see, the numbers are very flexible because there are so many factors involved. You can't just slap a 44k label on it and call it a day; that doesn't make any sense in reality. Astronomers know that the pure magnitude number doesn't mean much by itself, because it is just one factor among many.
In a place with very high light pollution (like where I live, in the middle of a large, dense, sprawling urban area in California), you'd be lucky if you can see a hundred stars at night.
Or, in a place with zero light pollution, shine a flashlight into someone's face, and you've temporarily blinded them. You've reduced the number of stars they could see by an order of magnitude for the next half hour (night vision gradually recovers, and it takes 30 minutes to fully recover, according to US military manuals and visual astronomers practice).
The following is multiple choice question (with options) to answer.
Seeing the stars will be harder when what happens? | [
"light in an area becomes greater",
"there is a lot of rain",
"light in an area becomes lessened",
"there is a lot of snow"
] | A | as light pollution increases , seeing the stars will be harder |
OpenBookQA | OpenBookQA-191 | astronomy, astrophysics, planets, exoplanets
Title: What day/night cycles, climate and seasons would experience Alpha Centauri Bb inhabitants? Alpha Centauri Bb is an exoplanet orbiting Alpha Centauri B. It is asserted that given the close distance to the star the planet should be tidally locked.
The orbiting period of the planet is about 3.2 days.
If the planet has no atmosphere (which is very possible due to proximity to the star), its dark side should experience low temperatures like permanently-shadowed areas of Mercury do.
At the same time the planet is about 11 AU from the other star, Alpha Centauri A.
This possibly means that the planet should experience quasi-day/night cycle each 3.2 days.
My questions are:
The following is multiple choice question (with options) to answer.
A planet rotating causes cycles of day and night on that planet, like on | [
"Orion",
"the Moon",
"Jupiter",
"Pluto"
] | C | a planet rotating causes cycles of day and night on that planet |
OpenBookQA | OpenBookQA-192 | There is absolutely nothing that prevents the production of a board that is 4in wide; and even if there was, there would be nothing preventing the lumber yard from calling boards that are 3.5in wide '3.5 inch boards'.
The reason why they don't is tradition - it's a hangover from the guild system, wherein the 'mysteries' of the trade are deliberately obscure and confusing, to make it difficult for people who didn't go through the guild apprenticeship system to compete against guild carpenters.
All pre-industrial trades, from carpenters to lawyers, have deliberately imposed barriers to understanding, erected to keep their monopoly.
Of course, there remains some value in the argument that a person who doesn't have enough experience with working timber to know how wide a four inch board actually is, should be discouraged from attempting any serious carpentry work.
But now that the information is so widely available, it seems a bit pointless to keep up this silliness.
Anyone who has ever worked with "rough" lumber will happily pay for a 4 inch board and take a 3.5 board.
In any case, whatever lumber one buys in the US needs to be measured carefully. They may say a sheet of plywood is 96 inches by 48 inches, but it actually cut to the nearest centimeter past 96 and 48.
beero1000
Veteran Member
It's not tool thickness. Dimensional lumber is cut to those dimensions at the mill, then dried and planed. The drying fibers contract and the planing takes off more, so you lose some size.
Excuses, excuses.
There is absolutely nothing that prevents the production of a board that is 4in wide; and even if there was, there would be nothing preventing the lumber yard from calling boards that are 3.5in wide '3.5 inch boards'.
The reason why they don't is tradition - it's a hangover from the guild system, wherein the 'mysteries' of the trade are deliberately obscure and confusing, to make it difficult for people who didn't go through the guild apprenticeship system to compete against guild carpenters.
All pre-industrial trades, from carpenters to lawyers, have deliberately imposed barriers to understanding, erected to keep their monopoly.
The following is multiple choice question (with options) to answer.
Because a logging company has been working here the area has more | [
"calcium",
"rust",
"carbon",
"silicon"
] | C | as the population of plants decreases , carbon in the atmosphere will increase |
OpenBookQA | OpenBookQA-193 | sensors
Title: Transducer for underwater applications (passive sonar) I'm kicking around the idea of building a small passive sonar for an autonomous submarine. I've looked through the net for parts and finding a good transducer for converting the sound underwater into an electrical impulse. After looking at parts I got into the piezoelectric materials used for doing this such as barium titanate or Lead zirconate titanate. From what I've read on the web, some of these materials are toxic.
My question is, are there piezoelectric materials that one could to build a sensor from scratch that does not possess the toxic qualities? Something that could preferably thrown in a pool w/ my kids and not give them or me any defects. In general, the microphone should be covered in some sort of waterproofing material (called "potting") that would prevent its materials from ever coming in contact with the pool water. So unless you are concerned that the microphone will be smashed to pieces while in your pool, it shouldn't be a problem
That said, there are some other transducer technologies besides piezo. Ribbon microphones won't suffice, mostly because of their fragility. Dynamic microphones might also a bad idea, because they are generally larger and require more motion than the others.
I'd recommend trying a cheap electrostatic (also called electret) microphone. You should be able to cover it in silicone RTV or "plumbing goop" and still get a signal out of it.
The following is multiple choice question (with options) to answer.
what is sonar used for | [
"gathering lost things",
"disorientating enemies",
"warning others",
"helping sleep"
] | A | sonar is used to find the location of an object |
OpenBookQA | OpenBookQA-194 | thermodynamics, temperature
Title: Non uniform freezing of lakes Here's a problem from my physics textbook:
Why do lakes freeze first at the surface?
I'm not sure why this should happen, and my guess is that the only reason for this could be the temperature distribution with depth, inside water bodies. You need to know that water at $4^{\circ}$C achieve its highest density. So naturally, water at $4^{\circ}$C will tend to move to the bottom of the lake as it is heavier. When the temperature is cool enough to freeze the lake, eventually there will be some layer of ice forming at the surface but there is still liquid water below the ice layer. The ice also works as an insulation to keep the water below it from freezing to ice completely. Also, ice has a lower density than water so any ice forming will float to the surface. There are other factor like Earth's internal heating that constantly maintaining the water at the bottom of lake from freezing.
The following is multiple choice question (with options) to answer.
When a lake is exposed to enough heat over time | [
"animals leave",
"it ceases existing",
"plants dry up",
"fish grow ill"
] | B | if a body of water loses all water then that body of water does not exist any more |
OpenBookQA | OpenBookQA-195 | entomology
Title: Constantly wiggling moth pupa - will it emerge soon? Today I found a moth pupa in the soil in my garden in western Sweden. It's about 15 mm long.
I have found similar ones before, but this one is wiggling a lot more, even after I put it down and put a bit of dirt over it. It's been moving for more than an hour now, but less now than in the beginning.
I was hoping to see it emerge, but if it will take more than a day or so, I will probably put it back. So, what I'm wondering is if this wiggling is any indication of how soon it will emerge. Or if there are other ways to tell.
Update: an hour later it has stopped moving. Maybe it was just very disturbed by my presence. I'm keeping it in a jar with soil and a stick for climbing up on, and I'll decide what to do with it tomorrow.
Update: 12 hours later and it seems very still. But I'm letting the question remain since I really want to know if there are any signs to look for.
Final update: After 16 days it had turned almost black, and was still very active when handled.
And after 17 days this moth came out: I posted the same question on tumblr and got an answer:
It depends on the species. This one looks like a Noctuid. I’d give it
two weeks to a month or so. You may be able to see its wings showing
through the darkening pupal case when the time draws near! Just make
sure you give it somewhere to climb up and expand its wings when it
ecloses.
After keeping it until the moth emerged, I now know that wiggliness is not an indication of maturity, but turning dark is.
The following is multiple choice question (with options) to answer.
A pupa creates cocoons in a stage of the life cycle, and eventually the insect will | [
"adjust",
"shrink",
"burn",
"collect"
] | A | the cocoons being created occurs during the the pupa stage in a life cycle |
OpenBookQA | OpenBookQA-196 | matter
When a solid is dissolved in a liquid, is it still a solid
I want to touch on this too, because there's a useful subtlety here.
When you put salt in hot water, it dissolves. In this case the energy from the water is enough to overcome the attraction between the atoms, and it is pulled off the crystal to mix with the water. So you don't have water and salt any more, you have a mixture of Na ions, Cl ions, and water molecules. Or saltwater.
Now compare this to what happens when you salt and sugar. In this case the two happily sit together as a mixture, but they are not changed in form. They're also quite tasty, as salted caramel attests. If one of the two you mix is a liquid, like powder in water, then you have a suspension. In these cases the original materials remain in their original forms, just mixed together. This is different than the saltwater case, which is not simply salt and water in the same bottle.
The following is multiple choice question (with options) to answer.
What does water taste like after a substance is dissolved in it? | [
"watery",
"the same",
"similar to object",
"full of life"
] | C | dissolving a substance in water causes the water to taste like that substance |
OpenBookQA | OpenBookQA-197 | newtonian-gravity, mass, acceleration, earth, estimation
Title: Does Earth's Gravitational pull increase with time? Gravitational field depends on mass ($g = \frac{GM}{r^2}$) and every year many outside cosmic objects like asteroids or tiny object are hitting earth. So I think may be in a very microscopic amount the mass of Earth is increasing. But does it increase the Gravitational Pull or Gravity on Earth?
And also, does it result in decrease in height of organisms in each century? Because some older people say that people in their time or in ancient times were taller and more aged. I am just curious if it is the reason or not. Actually the opposite is true.
Quoted from Gizmodo - Did You Know That Earth Is Getting Lighter Every Day?:
Earth gains about 40,000 tonnes of dust every year,
the remnants of the formation of the solar system,
which are attracted by our gravity and become part
of the matter in our planet. Our planet is actually
made from all that starstuff.
Earth's core loses energy over time. It's like a giant
nuclear reactor that burns fuel. Less energy means less mass.
16 tonnes of that are gone every year. Not much.
And here's the big mass loss: about 95,000 tonnes of hydrogen
and 1,600 tones of helium escape Earth every year.
They are too light for gravity to keep them around,
so they get lost. Gone into space.
So, summing all these effects mentioned above,
you get a mass loss of 57,000 tonnes per year.
But this is still much too small to have a measurable effect on gravity
($g = GM/r^2$) even after millions of years,
because the mass of the earth is $M = 6\cdot 10^{24} \text{ kg}$
(i.e. 6,000,000,000,000,000,000,000 tonnes).
The following is multiple choice question (with options) to answer.
What causes the pull of gravity on a planet? | [
"people",
"plants",
"kilograms",
"air"
] | C | the mass of a planet causes the pull of gravity on that planet |
OpenBookQA | OpenBookQA-198 | the-sun, earth
Title: If the Sun got larger, but maintained its luminosity, would the Earth get hotter or colder? A recent question If the Sun were bigger but colder, Earth would be hotter or colder? asked - if the Sun got bigger and cooler, would the Earth heat up or cool down. I think the answer to that is mainly that it depends on the final luminosity.
However, what I want to know here (hypothetically), is if the Sun got larger and it's effective temperature decreased such that it's luminosity was unchanged; how would that affect the equilibrium temperature of the Earth? I suspect the answer may involve the wavelength dependence of the albedo, emissivity and atmospheric absorption of the Earth.
Another, less hypothetical, way of asking this is, if you put an Earth-like planet at different distances from stars with a variety of temperatures, such that the total flux incident at the top of the atmosphere was identical, how would the temperatures of those planets compare? The key issue is the opacity of the atmosphere, because I presume the question is about the temperature at the solid surface of the Earth. The atmospheric opacity can be seen from https://physics.stackexchange.com/questions/135260/can-someone-explain-to-me-the-concept-of-atmosphere-opacity, where you can see that the "rainbow" of maximum heat flux from the Sun happens to hit a kind of hole in atmospheric opacity. That has a significant warming effect on the Earth, and is exacerbated by the Greenhouse effect. If sunlight was further into the infrared, the graph shows that much more of it would be intercepted in the atmosphere. That would make the surface significantly colder, though certainly not a factor of 2 colder.
No doubt the question is of more than passing interest, because M dwarfs are the most numerous main-sequence stars and are therefore interesting for life. To have life near an M dwarf, the planet would need to be closer than Earth is to the Sun, but the effect of moving the planet closer and shrinking and cooling the star would be similar to leaving Earth where it is and making the star cooler and larger. So the nature of atmospheric opacity for wet atmospheres must be of great significance for understanding the prospects for life around M dwarfs.
The following is multiple choice question (with options) to answer.
If more pollution is released into the air, what happens to the planet's temperature? | [
"it falls",
"it becomes stabile",
"it climbs",
"it becomes volatile"
] | C | as the amount of polluting gasses in the atmoshere increases , the atmospheric temperature will increase |
OpenBookQA | OpenBookQA-199 | evolution, ecology, natural-selection, adaptation
Title: What are Some Classical Examples of Local Adaptation? Question
Can you please give a list of classical (textbook) examples of local adaptations?
How to answer
Examples don't necessarily need to include what evidence supports this specific example of local adaptation. A simple description of the local adaptation (e.g. coat colour changes from black on dark soil to white on light soil) and an brief explanation of the reason (e.g. because being nicely camouflaged prevents from predation from hawks) is enough.
I think a list of 10 or more such examples would be great.
Definition of local adaptation
Note that I define here local adaptation as differentially adapted subpopulation of a single species (with existing gene flow between subpopulations especially for sexually reproducing species).
Justification for the question
I found surprisingly complicated to find such list online. I think it could be a valuable post for many.
Examples
Examples of local adaptation (that you are free to add in your answer with a description) include beach mice camouflage, altitude adaptation in tibetans and peppered-moth camouflage. Adaptation is a change in a trait as a response to selection. As you ask for local adaptation I assume you want examples where sub-populations have either come under different selection and adapted differently, or cases where sub-populations have come under similar selection but not all have had the necessary genetic variation to evolve, i.e. selection has caused differentiation between sub-populations. Local adaptation can lead to varying degrees of divergence, so some for some examples it may be worth exploring speciation events. Here's some examples:
Galapagos Tortoises
There are two general shapes to the shell of tortoises on the Galapagos Islands. On islands with little low-lying vegetation the tortoises seem to have evolved long necks & limbs and different shell shapes which allow them to reach up more easily.
"The shell distortion and elongation of the limbs and neck in saddlebacks is probably an evolutionary compromise between the need for a small body size in dry conditions and a high vertical reach for dominance displays."
The following is multiple choice question (with options) to answer.
An example of adapting to survive is | [
"Putting on sunscreen in a sunny place",
"Growing grass in a field",
"Having a drink of water on a warm day",
"Going for a walk outside"
] | A | adaptations are used for survival |
OpenBookQA | OpenBookQA-200 | telescope, newtonian-telescope
http://garyseronik.com/beat-the-heat-conquering-newtonian-reflector-thermals-part-2/
Small dobs (up to 6...8"), just take it outside at least 1 hour before you observe - or better yet, 2 hours. Let it "breathe". Dobs 10" or larger, you MUST use a fan on the primary mirror to force cooling.
REFRACTORS
These instruments are very convenient and very low maintenance. Take it out of the box, and it's good to go. It's collimated from factory, and it doesn't care about thermal issues. A refractor makes a great "travelscope", and a great grab-and-go scope.
On the flip side, they are the most expensive, in terms of how much aperture you get for the money you spend. And they are typically made in small apertures; most commercial refractors are not bigger than 6" or so; those that are bigger are extremely expensive. The small aperture limits the maximum performance of these instruments.
There is this myth out there that refractors are somehow magically better for planets (and other high-resolution targets), whereas dobs, even very large ones, are not so great. This is false; load up the designs in Zemax, do a basic performance analysis, and you'll see that aperture is the dominant factor, with everything else being secondary. But there are several reasons why this myth is around, and it's instructive to see what these reasons are:
The following is multiple choice question (with options) to answer.
When would a reflector be most effective? | [
"fall",
"winter",
"summer",
"spring"
] | C | a reflector is used to reflect light especially on vehicles |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.