source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-2801 | electrochemistry, metal
Title: Corrosion of a galvanic couple made with silver and gold If a bangle is made out of gold and silver, connected with each-other would there be corrosion happening?
If so, can it be explained using the galvanic series?
Also do those metals undergo oxidation under normal conditions? As you state, though silver is not very reactive, silver jewelry would corrode more rapidly when in contact with gold and a bit of sweat as electrolyte. Though the difference in electronegativity of pure gold and pure silver is 0.15V, and is considered acceptably corrosion resistant, commercial jewelry contains copper and other metals in the alloys. There is clearly evident corrosion in photos of copper/silver jewelry. According to the Victoria and Albert Museum staff, "All metals, with the exception of 24 carat gold, suffer the effects of corrosion."
However, in a bangle, physical abrasion is likely to cause more damage and loss of material than galvanic corrosion. Wear the jewelry and enjoy it, but it will not last forever.
The following is multiple choice question (with options) to answer.
A tongue can adhere to metal if what occurs? | [
"condensation",
"self-stimulation",
"evaporation",
"conduction"
] | D | when a cooler object touches a warmer object , thermal conduction occurs |
OpenBookQA | OpenBookQA-2802 | memory-hardware
Title: Without Rare Metals One often sees assertions that these are "necessary" for modern military and consumer computing applications. I presume that without these rare metals, the devices could be manufactured, but would be larger and/or more expensive. Is this true? Sort of, it seems.
First, I am not an expert at this topic at all. I started to use google and first found this article Computers without rare earths are huge which suggests that computers CAN be build without the use of rare earths, but would be significantly bigger. This may have a huge impact as today every vehicle, airplane or device is packed with multiple tiny computers. Large computers mean we can't utilize computational power to support/improve navigation, life support, etc. on airplanes and surely cant carry our smartphone with us. Furthermore the article suggests, that rare earth also improve efficiency of computing devices.
Then I found these articles Alternatives to rare earths More alternatives which suggest that one can indeed achieve the same or a similar level of size reduction and efficiency with alternative materials. As the supply of rare earths is not guaranteed long term (mining is not environmental friendly, there are territorial disputes etc.) researchers are working on the two obvious possibilities:
Develop the current technology to work without rare earths (or materials not yet considered rare earths)
Engineer new elements that have a similar effect (i.e. in magnets)
To sum it up: it seems like its not possible at the moment, but might become feasible in a few years (or decades).
Disclaimer: please be aware that neither this answer nor the articles provided are scientific evidence.
(I am also not sure if this is the right forum to ask this)
The following is multiple choice question (with options) to answer.
Neodymium can hold a car without being in it's | [
"proximity",
"relocation services",
"talking",
"seeing each other"
] | A | magnetism does not require contact between objects to act |
OpenBookQA | OpenBookQA-2803 | earth-rotation, geologic-layers
Title: Do Earth's layers move at different speeds? I don't have a background in Geology but this question popped in my head the other day and can't find an answer anywhere else.
If I remember science class correctly, Earth's layers have different element compositions. Would it be correct to assume that they have different densities and different frictions as a result? And if they do, does it follow from it that they rotate at different speeds?
Thanks. Im am currently doing my masters in geophysics (last semester) and before that I did a bachelor in geoscience.
I assume by layers you mean the crust, the mantle and the core.
These all have different composition and also different densities. But the earth rotates as a whole, not the individual layers, all layers have the same angular velocity. That means they all make one rotation per day.
These layers are also not the perfect boundaries we like to imagine, but more a change in properties around a finite depth. This depth can even change at different places.
The following is multiple choice question (with options) to answer.
A portion of the earth, and other planets is a layer which is composed of | [
"large limestone bunkers",
"thick stone piles",
"mostly solid clay",
"silicate rocky shell"
] | D | the mantle is a layer of the Earth |
OpenBookQA | OpenBookQA-2804 | co2, oxygen
Title: Could earth run out of O2? Death in a closed environment due to lack of O2 is actually not that bad:
https://www.youtube.com/watch?v=kUfF2MTnqAw
And as far as I know as we are cutting down our life saving woods and jungles less $O_2$ is being produced and more $CO_2$ is not converted back to $O_2$.
Greenpeace and others tell us how bad this fact is.
But: If it continues like this, is it possible for humanity to extinct itself because we run out of $O_2$ and breath in too much $CO_2$?
Wouldn't it be much nicer than like burning to death if the $O_2$ would disappear? No, that will not happen. There is just too much oxygen in the atmosphere.
Over 20% of our atmosphere is oxygen.
Only about 0.04 % of our atmosphere is CO2, so too much CO2 would kill us much sooner than the lack of oxygen.
If you reduced the oxygen concentration in the atmosphere from 20.8% to 19.8%, you wouldn't even feel the difference. If you reduced it to 15 %, you would still survive it. You could even survive 10 % for short time periods.
However, let's see what would happen if you added CO2 as a replacement for the oxygen you removed: at 1%, you would feel extreme dizziness. At 5% you would lose consciousness and die.
But the real danger in CO2 lies elsewhere. Even an increase from our current 0.040 % to 0.045 % could cause a lot of damage to the climate, and an increase above 0.055 % could be disastrous. Unless you are locked in a small room, the reason why the increase of CO2 and decrease of oxygen will be dangerous won't be because you wouldn't be able to breathe. Changes significantly smaller than those required to make breathing difficult, would be enough to wreck the ecosystem, cause drought, desertification, starvation, and economic collapse.
Also note, that trees are very important for the water cycle, as a habitat for many species, and for preventing soil erosion, but they play an insignificant role in producing oxygen. Most of our oxygen is produced by algae.
The following is multiple choice question (with options) to answer.
If we cut down trees from the rainforest what will suffer more? | [
"Buildings",
"Cars",
"Space",
"Cats"
] | D | cutting down trees in a forest causes the number of trees to decrease in that forest |
OpenBookQA | OpenBookQA-2805 | 1. all chicks peck to the left. 0% of chicks are unpecked.
2. all chicks peck to the right. 0% of chicks are unpecked.
3. all chicks, divided in pairs, peck each other, 0% of chicks are unpecked.
4. chicks are divided in groups of 4, where the pair in the middle pecks each other, while chicks on the edge peck this pair in the middle. 50% of chicks are unpecked.
There are however other possible probability distributions. Two new patterns emerge from this.
1. chicks are divided into groups of 3, where a pair of chicks pecks each other and one chick from this pair is double pecked by a chick on the LEFT. This chick on the left is unpecked which makes a total of 33%. The last, 100th chick can peck randomly left or right but remains unpecked itself as in example 4). This gives 34 unpecked chicks.
2. chicks are divided into groups of 3, where a pair of chicks pecks each other and one chick from this pair is double pecked by a chick on the RIGHT. The last, 100th chick can peck randomly left or right but remains unpecked itself as in example 4). This gives 34 unpecked chicks.
A mixture of all those sets of outcomes are, of course, also possible. Now we can calculate the median of these 6 possible outcomes: (0+0+0+50+34+34)/6=19.666 somewhat lower than the original solution.
The following is multiple choice question (with options) to answer.
If a duck lays seven eggs and last year they laid zero eggs, this year they are | [
"male",
"increasing young",
"producing zero",
"producing live young"
] | B | as the number of eggs laid by an animal increases , the number of eggs that hatch will increase |
OpenBookQA | OpenBookQA-2806 | botany, terminology, trees
Title: Branch taking over a tree trunk I stumbled upon a birch growing in sandy soil in a coniferous forest in central Russia.
It looks like over time the tree trunk got bent towards the trail and one of the branches became the new trunk as it now grows straight up, whereas the old trunk is pointing sideways.1
The tree isn't dead, I visited that place during summer time and it was covered with green foliage.
I'm wondering what's the name of such phenomena, how common it is and what usually causes the tree "to change it's mind"?
The following is multiple choice question (with options) to answer.
The tree trunk is what holds up the | [
"sky",
"roots",
"sky",
"leaves"
] | D | a stem is a source of support for a plant |
OpenBookQA | OpenBookQA-2807 | atmosphere, carbon-cycle
Title: For a tree over its entire existence, does it actually have a net negative effect on atmospheric CO2? A tree while alive converts CO2 + water -> carbohydrates + O2. However, once the tree dies, it decays, releasing CO2 back into the atmosphere. My question is, over an individual tree's overall existence, does a tree actually contribute to a reduction in atmospheric CO2?
I'm aware there's other pathways a tree could end up as a more long term carbon store (carbonaceous rocks), but mostly interested in if a tree were to die and fall in a forest, decay in 50-150 years, would it have contributed to a net reduction in CO2, or does a tree typically act as more of a temporary 100+ year store of CO2? A brief review of recent non-paywalled available literature indicates that such an effect likely exists but that it is difficult to quantify based on currently available data.
Some amount of carbon from trees can be sequestered in the soil for periods time significantly longer than the typical above-ground decomposition time of organic matter, potentially for millennia. This clearly lengthens the carbon cycle time, but it is not clear to me whether this represents carbon storage, as there does not seem to be a well established minimum cut-off time for this. The primary source for soil-sequestered carbon are tree roots, with leaf litter constituting a secondary source.
The following paper (preprint online) addresses the question in the specific context of agroforestry, i.e. cropland interspersed with trees. The paper notes multiple times that the processes involved in soil sequestration are not well understood and that quantitative measurements and estimates vary widely, as one would expect based on differences in climatic and soil condition. Note on units: A Mg corresponds to a metric ton.
Klaus Lorenz and Rattan Lala, "Soil organic carbon sequestration in agroforestry systems. A review." Agronomy for Sustainable Development, Vol. 34, No. 2, April 2014, pp. 443-454.
The following is multiple choice question (with options) to answer.
If an oak seed is placed in a compost pile in a garden, the garden's ecosystem will | [
"be negatively disrupted forever",
"be made much worse",
"be altered in damaging ways",
"adjust in positive ways"
] | D | planting trees has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-2808 | java, role-playing-game
//This is where the critter attack goes
/*
* d100();
*
* if (d100Result >= 0 && d100Result <= 20) {
*
* } else if (d100Result >= 21 && d100Result <= 40) {
*
* } else if (d100Result >= 41 && d100Result <= 100) {
*
* } else {
* System.out.println(there is an error here!");
* }
*
*/
d3();
switch (d3Result) {
case 1:
critterOffensive = true;
critterDefensive = false;
critterEvasive = false;
System.out.println("The " + critterName + " charges!");
System.out.println("Your children and the " + critterName + " are evenly matched!");
break;
case 2:
critterDefensive = true;
critterOffensive = false;
critterEvasive = false;
System.out.println("The " + critterName + " protects itself!");
System.out.println("Your children crush the " + critterName + "'s defenses!");
System.out.println("The " + critterName + " takes damage!");
critterHealth -= 1 * missionWorkerDrones + (missionWarriorDrones * 2);
break;
case 3:
critterEvasive = true;
critterDefensive = false;
critterOffensive = false;
System.out.println("The " + critterName + " moves quickly!");
System.out.println("Your children are outflanked by the " + critterName + "!");
System.out.println("One of your drones falls from it's wounds!");
d2();
switch (d2Result) {
case 1:
if (missionWarriorDrones > 0) {
killWarrior();
} else if (missionWarriorDrones <= 0) {
killWorker();
}
break;
case 2:
The following is multiple choice question (with options) to answer.
A person can bring harm to an animal habitat by | [
"avoiding it",
"leaving it alone",
"building in it",
"ignoring it"
] | C | humans changing animal habitats usually causes harm to those animals |
OpenBookQA | OpenBookQA-2809 | newtonian-mechanics, forces, friction, free-body-diagram
How do you know your legs were pushing back against the earth? Did you have a force meter?
What you would actually find, were you to measure the situation properly, is that you did not actually push back against the earth. You only pushed up and down, effectively jogging in place.
The human body is a mighty complicated structure, and our intuition is surprisingly incomplete, given how much time we spend with that body. When you say "my legs were pushing the earth back," what you actually mean is that you felt as if your legs were pushing the earth back. This is proprioception, the word for our feeling for where our body is and what it is doing. It's an astonishingly powerful system, but it has flaws based on how it goes about measuring things. You can indeed fool yourself into thinking you are pushing on the earth. How? Well, you observe that for your current body position, contracting a particular set of muscles should push against the earth. However, our muscles come in pairs. If the antagonistic element of that pair fires at the same time, your muscle will tense as usual, but it will not generate any force on the ground. Instead, it will simply oppose the forces applied by the antagonist.
If you wanted to prove this, one thing you could do is try to repeat the experiment on ice, where the coefficient of friction is much lower. If you find that you can indeed do it on ice (which you should be able to), and feel "the same" as you did on solid ground, then you know the backwards force is insufficient to break the static friction on ice... which is pretty weak. This would quickly demonstrate that there was indeed no backwards force on the earth in the first place, and leave us with biological reasons for the feeling you experience.
Edit: The above answer was provided before the OP edited in the fact that they were letting their feet slip. In the case where the feet slip, the situation is actually more intuitive. When the feet stuck, one had to explain why there was the feeling of motion when there was no motion. In this case, there is motion.
The following is multiple choice question (with options) to answer.
A foot uses force on spheres in | [
"baseball",
"kickball",
"golf",
"hockey"
] | B | if an object is kicked then force is exerted on that object |
OpenBookQA | OpenBookQA-2810 | ocean, glaciology, ice, ecology, cryosphere
Title: Do icebergs have any impact on ecology? Are icebergs neutral actors in the environment, or do they have any impact on the local ecology. Do they have any environmental impacts that might influence any part of the biosphere? Yes, they have many impacts:
They provide a substrate for algae to grow and they can have whole ecosystems under them. You might think that such substrate is transient because it is melting, but Arctic and Antarctic waters are often below zero degrees Celsius, therefore, freshwater ice doesn't melt. You can find many articles about such ecosystems (here is one).
They transport sediments and nutrients into the ocean.
They provide safe rest areas for animals like seals, birds and penguins.
They impact the temperature of surface waters, specially in fjords.
They stir the sea floor in shallow waters
And there must be more ways they impact the environment and ecosystems but those are the ones I can think about right now.
The following is multiple choice question (with options) to answer.
Which is a positive impact on the bio environment? | [
"dumping toxic waste in rivers",
"contaminating the ground with poison",
"building cars in large numbers",
"making sure trash is reused for new reasons"
] | D | landfills have a negative impact on the environment |
OpenBookQA | OpenBookQA-2811 | machine-learning
We're thus mostly concerned with the small categories which might be present in the train set but absent from the test set and/or present in the test set but absent from the train set.
One way of dealing with such situation is merging small categories (e.g. under 2% of all observations) into a single category. That way you treat any new category level as part of the merged category.
Below I share how I implement the above in python, in a way that can be combined in scikit learn pipelines:
from collections import Counter
import pandas as pd
The following is multiple choice question (with options) to answer.
Classes and categories are both part of | [
"distraction",
"confusion",
"control",
"designating"
] | D | classifying is when one sorts something by type |
OpenBookQA | OpenBookQA-2812 | equilibrium, entropy, free-energy, mixtures
The reaction entropy rules usually taught first are about the physical state of the pure substances. If you go from a condensed state (solid or liquid) to a gas, the molecules are less constrained. Similarly, if you open up a ring, the molecule itself has more conformational freedom, and this is also reflected in an increase in entropy.
There is a second, concentration-dependent contribution to the entropy of reaction. This is the entropy of mixing. A mixture has more microstates than the separate two pure substances. This is behind the experience that ideal mixtures (when the intra- and intermolecular interactions have the same strength) don't unmix. Entropy increases whem you mix something. This strangely is the case when you go from pure reactant to a mixture of reactant and product as the reaction proceed. Similarly, there is some "unmixing" when all the reactant turns into product.
This entropy of mixing is where the $R \ln(Q)$ (or $R T \ln(Q)$) comes in. This is what makes the reaction entropy and the reaction Gibbs energy concentration-dependent.
Theoretically, shouldn't dS be negative as number of gaseous moles decrease on going forward?
Yes, going from pure reactants to pure products, the entropy change is negative. However, if reactants and products are in the same phase, you have a very high positive change in entropy as the first couple of reactant molecules turn into product. If you want, you can explain this with kinetics as well, with no back reaction (no product yet) and a robust forward reaction.
[OP in comments: What if they are in different phases? Like gases combining to form a liquid?]
The following is multiple choice question (with options) to answer.
If a thing changes through a chemical process, it will have different and new chemical properties, such as | [
"adding cats to a home",
"adding cream to tile",
"adding lemon juice to milk",
"adding salt to sand"
] | C | if an object undergoes chemical change then that object will have new chemical properties |
OpenBookQA | OpenBookQA-2813 | thermodynamics, temperature, everyday-life, phase-transition, humidity
Title: Steam from a cup of coffee I observed that, in winter there is more visible steam from a cup of coffee than in summer. Is there any phenomenon taking place here. The amount of water that air can take up before the water creates fog or visible steam depends on temperature. The colder the air, the less water it needs to create fog/steam. It is the same principle when hot air rises, for example when pushed up a mountain and then it starts to cool down drastically --> It will rain.
For more have a look at: Relative humidity in https://en.wikipedia.org/wiki/Humidity
The following is multiple choice question (with options) to answer.
If steam chills then the vapor will | [
"burn",
"melt",
"boil",
"thicken"
] | D | water vapor cooling causes that water vapor to condense |
OpenBookQA | OpenBookQA-2814 | javascript, datetime
// a simple helper function
function nextDay(date) {
return new Date(date.getFullYear(), date.getMonth(), date.getDate() + 1);
}
// as long we're in the same year, keep adding 1 day,
// and store the ones that match the weekday we're looking for
while(current.getFullYear() === year) {
if(current.getDay() === weekday) {
dates.push(current);
}
current = nextDay(current);
}
return dates;
}
No need to build ranges, map, and filter them. Just a while loop and push.
Incidentally, if you want to learn more about why programming calendar and time things are just hideously complex, check out this video on youtube
1) Happy Guy Fawkes day everyone
The following is multiple choice question (with options) to answer.
If a day has passed, so has | [
"most of a month",
"most of thirty hours",
"most of a week",
"most of a year"
] | B | one day is equal to 24 hours |
OpenBookQA | OpenBookQA-2815 | dna, human-genetics, dna-sequencing, genomics
Title: Is it possible to deduce facts about a person's parents just by studying his/her genome? As an example, suppose Anne had abusive parents. Is it theoretically possible to deduce this from her genome even if she didn't inherit this quality (of being an abusive parent)? It might seem pernickety but you often can't deduce from a genome; you can only infer from it. For many characteristics about a person, there are only rough, probabilistic associations between genotype and phenotype. Not one-to-one relationships.
You can take an educated guess that someone with a certain genotype could be a social person of European ethnicity with a low risk of psychosis, which might suggest things about their parents. But there are likely many genes that influence those characteristics and still more non-genetic factors. So you couldn't be certain.
For a factor like whether the persons parents had abusive personalities, I think the genetic differences would be so subtle (if existent) and there would be so many other factors (such as the habits and choices of the parents) that you would be very unlikely to be able to draw any conclusive associations. Articles and studies about linking human genetics with a person's characteristics are listed below. If any of the genes in question are linked with those characteristics then the parents of someone with the gene could possibly have those genes and characteristics too.
Personality types including belligerence, charisma, cynicism, housekeeping, lack of personality, obsessive-compulsive behaviour and gullibility.
Psychosis and Schizophrenia risks.
Ethnicity and European ethnicity, which in turn correlate with geographical location, language and certain phenotypes.
Height.
If anyone would like to suggest additions to that list, I'll happily add them.
The following is multiple choice question (with options) to answer.
A child will share a physical trait such as this with parents due to DNA: | [
"hair length",
"vacation days",
"nose shape",
"pet preference"
] | C | DNA is a vehicle for passing inherited characteristics from parent to offspring |
OpenBookQA | OpenBookQA-2816 | species-identification
Title: What bird / animal has this call? USA MA NE
I have a bird / animal coming to the trees in the backyard making this call (see link to audio file), which does not really sound like a bird - it's fairly low frequency. I have not seen it. Sometimes it sits in a young tree, where you can almost see through to the trunk. But I cannot make it out, so it's not very big (like a turkey). It comes at late afternoon and stays around until ~11PM. It switches trees fairly quickly, so I assume it can fly. The call is always the same. Sometimes another one of its kind answers.
Bird_animal_call_mp3
You don't need dropbox. Ignore "suspicious link". Close login popup. Click download arrow. Direct download.
I added a Soundcloud link:
Bird_animal_call_mp3 It is a grey tree frog's mating call. See youtube link:
Grey tree frog mating call
Source for finding the answer: Audubon Society
The following is multiple choice question (with options) to answer.
a bird builds a nest in a tree before the forest was lumbered down. Which of these is a result? | [
"the bird gets a bigger home",
"the bird gains more space",
"the bird loses its home",
"the bird is happy"
] | C | if a habitat is removed then that habitat is destroyed |
OpenBookQA | OpenBookQA-2817 | classical-mechanics, energy, electricity
Title: Can we imagine having a computer keyboard that recharges itself through mechanical utilization? Silly question here.
I have a debate with my father, and while I am decent at high school level physics, both he and I cannot determinate through calculus which of us is wrong.
Basically, he had the idea that perhaps, through simple mechanical utilization, a wireless keyboard can be charged and used, without any other energy source. (The keyboard can have a battery that can be recharged through the said mechanical utilization though), I have the intuition that the idea is interesting, but physically problematic.
With simple research, I have seen that an idle keyboard has a consumption of $1W$, and a used keyboard will use between $1.5$ and $2.5W$.
So, we have specific questions:
Is collecting the mechanical energy from the keyboard doable ?
And if yes, how much energy can typing on a keyboard's key produce ?
How it may impact the overall comfort of the user ?
I have multiple difficulties to answer these myself. How can I know how much a person can generate through typing, how much energy will be lost in the process of using a battery, etc..?
(This is not a concept that I try to sell or anything, this is a mere thought experiment that I wanted to share and resolve, please do not take it too seriously) What you are looking for is fairly simple. All you need to do is build a piezoelectric generator under each key. These generate electricity with each push. With this the element is stretched or vibrated with each push and this generates electricity. Do a Google search and you will find much more.
The following is multiple choice question (with options) to answer.
if a television stayed on for a prolonged period, what kind of energy might be a byproduct? | [
"it will produce hydroponic energy",
"it will produce warmth",
"it will produce kinetic energy",
"it will produce hydro energy"
] | B | electrical devices convert electricity into other forms of energy |
OpenBookQA | OpenBookQA-2818 | astronomy, everyday-life, popular-science, climate-science
Title: Why is the summer, in the temperate latitudes, in average, hotter that the spring? It is common knowledge that the transition from the Spring to the Summer season occurs in the Summer Solstice when the "Sun reaches its highest excursion relative to the celestial equator on the celestial sphere" (as stated in Wikipedia).
It is also stated in Wikipedia' Summer page:
"Days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring."
My question is: why is the summer, in the temperate latitudes, in average, hotter that the spring? A major part of the reason for this is due to the temperature of the ground. While the length of days in the Summer are effectively a mirror of those in Spring, you must take into consideration more than that.
When Spring commences in temperate climates, it is (usually) immediately preceded by winter. Due to the Winter, the ground and/or surrounding bodies of water are very cold. This has the effect of cooling the air for the first part of Spring while the ground/water begins to thaw/warm up. Furthermore, it takes much longer to warm or cool a body of water than a mass of air; even longer to warm or cool the ground and water. Therefore, as Spring progresses and the days become longer (also meaning the Sun is higher above the horizon, thus providing more heating power), the sunlight must first overcome the cooling effects of the ground and water bodies. Near the end of Spring - when the days are sufficiently long and the Sun is much higher above the horizon - you should notice the weather becoming hotter. This is because the ground and water has had time to warm up, which means it is not constantly cooling the air and making it feel colder.
When you then transition to Summer, the ground is already sufficiently warm but the days are still long and the Sun is still high in the sky. This means the Sun can heat the ground, water, and air even more and without any cooling effects. This allows the Summer temperature to be easily higher than that of the Spring temperatures. If Summer were immediately preceded by winter, you might notice the weather getting warmer much more quickly, but the average temperature would be very close to that of the Spring.
The following is multiple choice question (with options) to answer.
If an island is experiencing a hot summer it is because | [
"of the water",
"of the axis",
"of the shade",
"of glaciers"
] | B | summer is when a hemisphere is tilted towards the sun |
OpenBookQA | OpenBookQA-2819 | electrical-engineering, power-electronics, temperature
I would not recommend messing around with cooling if you want the temperature to be very constant. I would operate the unit at the high end above your highest environmental temp. Perhaps something like 40C as your constant temp and use a heating element surrounding the unit to hold the temperature up in cold environments. Heating also takes less power and equipment than cooling.
If your space constraints are not too tight, some high quality insulation would be the easiest start. Closed cell foam or ceramic fiber would work well. Vacuum insulated like a thermos beverage container might be good too look at too.
If you cant increase the form factor you will need to add a uniform heating element around the outside of the unit and control it with microcontroller and thermistor using a pid loop. This will obviously cost some additional power.
Alternatively, most temperature dependent sensors and systems don't attempt to modify their environmental temperature, but instead use a micocontroller to digitally measure the temperature and compensate the value for that temperature.
The following is multiple choice question (with options) to answer.
This keeps animals warm but it is possible to have too much | [
"comfort",
"body fat",
"shelter",
"protection"
] | B | fat is used to keep animals warm |
OpenBookQA | OpenBookQA-2820 | reinforcement-learning, ai-design, control-theory
Without any proximity reward, you will rely on the wolf literally bumping into the rabbit through random behaviour, before it will have any data example that getting the vector between itself and the rabbit close to (0,0) is a good thing. You may need to have a relatively large capture radius, plus limit the area that the wolf (and eventually rabbit) can explore, in order to avoid very long sequences of random behaviour where nothing is learned initially.
The following is multiple choice question (with options) to answer.
Why does a wolf eat rabbits? | [
"to show rabbits they should stay away",
"to get the energy it needs to survive",
"because it hates rabbits",
"to show other wolves it is strong"
] | B | living things all require energy for survival |
OpenBookQA | OpenBookQA-2821 | botany
Title: Greyish spots behind a peach's stone, what could they be? I'm sorry if it's a silly question, but what are those greyish spots behind the stone of this peach (or whatever this is)? What are they for? Are they safe to eat? The fruit is ok from the outside Callus can develop inside peaches (https://www.tasteofhome.com/article/peach-callus-tissue/), between the mesocarp and the endocarp. Callus is edible and harmless. It's a tissue composed of unorganised parenchyma cells, which in turn are multi-purpose cells that can be found in a number of "soft" tissues with metabolic purposes including, but not limited to, the mesocarp and the endosperm. Callus' main purpose is to seal damaged tissues, see for instance:
this blogpost that explains the difference between mold and callus in a peach where there actually is a mold infection (which you should not eat)
its counterpart where there is no mold, but a considerable amount of callus (way more than you have there) was produced because the stone had split open; this one would be safe to eat, once you've ascertained that there is no mold, although callus may contain pieces of hard tissue from the stone.
Small quantities of callus can appear as leftovers form older and smaller lesions.
The following is multiple choice question (with options) to answer.
A peach pit holds the beginning | [
"nutrients",
"high school students",
"water",
"pocket change"
] | A | a seed is used for storing food for a new plant |
OpenBookQA | OpenBookQA-2822 | atmosphere, ocean, hydrology, climate-change
Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.
Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.
Waves come about from wind, so they're a twice-indirect form of solar power.
Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.
How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of about 1400 Watts per square metre. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.
So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$
The following is multiple choice question (with options) to answer.
Wind energy is | [
"unreal",
"careless",
"re-useable",
"noneffective"
] | C | a windmill converts wind energy into electricity |
OpenBookQA | OpenBookQA-2823 | ocean, waves
Title: What causes waves to form the characteristic "breaking" shape as they approach the shoreline? We all know that as waves approach the shallow shores, the waves begin to form a characteristic shape. The upper portion of these breaking waves appears to curl forward and downwards over the bottom segment of the wave, before breaking into "white wash". The image below illustrates what this characteristic shape looks like:
The following is multiple choice question (with options) to answer.
The mounds at the beach are made of | [
"heavily buttered bagels",
"sauteed mushrooms",
"silica",
"high school students"
] | C | sand dunes are made of sand |
OpenBookQA | OpenBookQA-2824 | electromagnetism, magnetic-fields, electric-fields, electromagnetic-induction
Consider as an example : Sinusoidal field applied to the coil. (Suppose the field to be in $z$-direction and coil to be in $xy$-plane.
$$\vec{B}=B_0\sin(\omega t)\hat{k}$$
As an exercise find $\vec{E}$ using the symmetry of the system and
$$\nabla \times \vec{E}=-\partial_t\vec{B}$$
(Otherwise, See Example (Sinuaoidal B field) Page 358 Chapter 7 In Electricity and Magnetism Purcell)
$$\vec{E}=-|E_0|\cos(\omega t)\hat{\varphi}$$
$$\rightarrow \mathcal{\vec{S}}= -|E_0|B_0\cos(\omega t)\sin(\omega t)\hat{r}$$
More specifically, see the direction of the poynthing vector which is inward and thus showing the there is a flow of energy into the system. Also as an exercise find
$$\partial_t\mathcal{U}=??\rightarrow \text{Verify}\ =-\nabla \mathcal{\vec{S}}$$
Which confirms the energy conservation.
The following is multiple choice question (with options) to answer.
An example of electrical energy is | [
"air",
"audio speakers",
"candles",
"grass"
] | B | a light bulb converts electrical energy into light energy when it is turned on |
OpenBookQA | OpenBookQA-2825 | meteorology, tropical-cyclone, extreme-weather
Title: Why would Google's map of areas affected by Hurricane Harvey have advisories for the west coast and other far away areas?
What behavior of this hurricane would lead to advisories for the west coast and even parts of Canada and Alaska, when the hurricane is in the South?
I have little experience in meteorology or any of the earth sciences really, so I am interested in how this would affect the weather or other conditions far away from where the hurricane is severe. It seems like there is more than just a hurricane going on. According to the National Weather Service there are excessive heat advisories, gale warnings, etc.
The following is multiple choice question (with options) to answer.
When a hurricane glides over a continent it | [
"runs for president",
"becomes an earthquake",
"increases in strength",
"decreases in strength"
] | D | when a hurricane moves over land , that hurricane will decrease in strength |
OpenBookQA | OpenBookQA-2826 | geology, mineralogy, minerals, weathering
To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.
My suggestion to use the term weathering or weathered.
The following is multiple choice question (with options) to answer.
Weathering can | [
"release a best selling album",
"create a black hole in the desert",
"turn a sculpture to dust",
"create a time traveling vortex"
] | C | sediment is formed by weathering |
OpenBookQA | OpenBookQA-2827 | thermodynamics
Based on this page in a “Blaze” book, my six year old asked “which would win?” between water and lava. On further investigation, we refined the question to: which would turn solid first in similar conditions, a liter of room temperature water or a liter of volcanic lava? You've got the right idea — you want to simplify the problem — but I don't think you're using quite the right simplification. Take a look at the book's set-up of the situation, and ask yourself how the water is stopping the lava. You'll see the idea is that we're using liquid water, not ice, to solidify the lava.
So your question should really be: How much heat do we need to absorb from a liter of lava to turn it into a solid, and how much heat can a liter of water at room temperature absorb before it turns to steam? If the latter is larger than the former, then a liter of water can cool a liter of lava to the point where it solidifies before the water all changes into steam.
[I'm using "heat" when I should really be using "thermal energy", but this is for a $6$ y.o., so I'm keeping it simple.]
First, let's do the calculation for water. Here (since it's for a $6$ y.o.), I'm not going to show all the steps in the calculations:
Energy to heat $\pu{1 L}$ liquid water at room temp ($25 \,\pu{^{\circ}C}$ ) to $100 \,\pu{^{\circ}C}$ = $\pu{75 kcal}$
Energy to turn $\pu{1 L}$ liquid water to steam at $100 \,\pu{^{\circ}C}$ = $\pu{533 kcal}$
Total = $\pu{608 kcal}$
According to https://en.wikipedia.org/wiki/Lava, lava is typically $700 \,\pu{^{\circ}C}$ to $1200 \,\pu{^{\circ}C}$, so let's call it $1000 \,\pu{^{\circ}C}$.
The following is multiple choice question (with options) to answer.
What happens when molten lava comes into contact with a car? | [
"it freezes into a solid",
"it turns into a gas",
"it reaches its melting point",
"it flies up into the sky"
] | C | melting point means temperature at which a solid melts |
OpenBookQA | OpenBookQA-2828 | climate-change, climate
In this case, as it is an area that it is almost constantly cloudy with high humidity, temperature is varying just a little bit, and except the first day of the period, it seems that there is no relationship. In fact, on the second day there was a storm (I am living now at Singapore) and it is reflected in a quick change in temperature (both) and solar radiation.
Conclusion: It is not as simple as it seems.
Hope it helps!
The following is multiple choice question (with options) to answer.
The temperature changing may produce | [
"daisies",
"black holes",
"magic",
"time travel"
] | A | temperature changing can cause phase changes |
OpenBookQA | OpenBookQA-2829 | humidity, air-pollution
Title: Does usual city pollution have effects on relative humidity? I've noticed that in a rural area with low pollution the relative humidity is constantly lower than the humidity in a high polluted city. Is there any correlation between pollution and humidity? By way of reference, "humidity depends on water vaporization and condensation, which, in turn, mainly depends on temperature".
From the information you have supplied in your comments. There are waters in Bucharest and forests in the suburbs, but no waters or forests where the country house is located.
From your information, Bucharest has a number of sources of atmospheric water vapour, the river that flows through it (evaporation of water) and the forests in the suburbs (transpiration of water). Additionally, motor vehicle exhausts will increase the humidity as water vapour is one of the products of the combustion of hydrocarbons.
The warmer the air, the greater its capacity to hold moisture. Cities tend to be warmer than rural areas due to the heat island effect, which is the result of modifying land surfaces and the generation of waste heat.
Humidity in the rural location will arise from evaporation of water in the soil and transpiration from crops or grasses. Such transpiration will produce less water vapour than forests. Additionally, the rural location will have significantly fewer cars producing water vapour in their exhausts. Consequently, the rural location will be less humid than the city.
The reason why Bucharest is more humid that the rural location has more to do with the greater availability and vaporization of water in Bucharest and the temperature of Bucharest than the amount of pollution in Bucharest.
The following is multiple choice question (with options) to answer.
A pollution source in a county may be | [
"compost pile",
"grass seeds",
"recycling center",
"trash heap"
] | D | an landfill is a source of pollution |
OpenBookQA | OpenBookQA-2830 | electricity, electric-circuits, electric-current
I was wearing flip flops from the time I stripped off my neoprene wet suit at the car until the time I started getting shocked (my wife was wearing Birkenstocks).
I had been snorkeling for about an hour in the Pacific Ocean wearing a full body wet-suit, booties, and gloves (no hood).
I had been camping the night before and consumed quite a bit of Gatorade.
My wife had only been wearing a spring suit and gloves, no booties.
There was another receipt that had been left in the machine (maybe someone else had been shocked as well and decided it wasn't worth the risk of going after it?)
I can't think of anything else relevant. Any insights into what was going on here would be welcome. I tried calling the maintainers of the machine but couldn't get through (this was before I found out that I seemed to be the only one affected).
Thanks!
She tried touching the machine in various places, again nothing. I inadvertently touched her hand while she was touching the machine and then suddenly she felt it too.
From this it is evident you were a good conductor to the ground.
You later say :
We came back out 15 minutes later after drinking our hot chocolate and tried to reproduce the phenomenon with no luck.
So no charge was passing through you any longer?
15 minutes is too little a time to change your conductivity. It could be a combination of an intermittent fault in the circuit and your conductivity at that time. You should alert their maintenance to be on the safe side.
The following is multiple choice question (with options) to answer.
if a person gets a shock from a faulty system, which of these surfaces were likely touched? | [
"a paper lined surface",
"a steel lined one",
"a wood lined one",
"a cotton line surface"
] | B | metal is an electrical energy conductor |
OpenBookQA | OpenBookQA-2831 | evolution
bacteria
cyanobacteria
archaea
protists
fungi
algae
plants
nematodes
arthropods
vertebrates
Bacterial and archaean colonisation
The first evidence of life on land seems to originate from 2.6 (Watanabe et al., 2000) to 3.1 (Battistuzzi et al., 2004) billion years ago. Since molecular evidence points to bacteria and archaea diverging between 3.2-3.8 billion years ago (Feng et al.,1997 - a classic paper), and since both bacteria and archaea are found on land (e.g. Taketani & Tsai, 2010), they must have colonised land independently. I would suggest there would have been many different bacterial colonisations, too. One at least is certain - cyanobacteria must have colonised independently from some other forms, since they evolved after the first bacterial colonisation (Tomitani et al., 2006), and are now found on land, e.g. in lichens.
Protistan, fungal, algal, plant and animal colonisation
Protists are a polyphyletic group of simple eukaryotes, and since fungal divergence from them (Wang et al., 1999 - another classic) predates fungal emergence from the ocean (Taylor & Osborn, 1996), they must have emerged separately. Then, since plants and fungi diverged whilst fungi were still in the ocean (Wang et al., 1999), plants must have colonised separately. Actually, it has been explicitly discovered in various ways (e.g. molecular clock methods, Heckman et al., 2001) that plants must have left the ocean separately to fungi, but probably relied upon them to be able to do it (Brundrett, 2002 - see note at bottom about this paper). Next, simple animals... Arthropods colonised the land independently (Pisani et al, 2004), and since nematodes diverged before arthropods (Wang et al., 1999), they too must have independently found land. Then, lumbering along at the end, came the tetrapods (Long & Gordon, 2004).
Note about the Brundrett paper: it has OVER 300 REFERENCES! That guy must have been hoping for some sort of prize.
References
The following is multiple choice question (with options) to answer.
Plankton can be the food as well as the creator of | [
"water",
"magic",
"nourishment",
"alcohol"
] | C | In the food chain process some types of plankton have the role of producer |
OpenBookQA | OpenBookQA-2832 | 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.
Most of the pollutants in the air and in our world are there due to | [
"wolves attacking deer",
"dolphins under water",
"man made reasons",
"naturally occurring reasons"
] | C | humans cause pollution |
OpenBookQA | OpenBookQA-2833 | reproduction
Title: Why are so many species reproducing late this year? Hope this question is OK for this site, couldn't see where else to ask it.
We've spent a few days out in the countryside recently, and have been very surprised at how many species appear to have very young offspring so late in the season. I was always under the impression that the vast majority of animals and fish produced young in the spring (March/April).
For example, we saw tadpoles, fluffy (ie obviously very young) coots and weeny minnows. I would have expected that all of these would have been born/laid a good 3 or 4 months ago, and so would be more mature by now.
Caveat: We didn't do a scientific study, this is just a strong impression we got from days out in north west England. It's hard to say without more information, but one substantial possibility is that you are mistaken that species are reproducing late - that's a problem with anecdotal rather than scientific data!
Additionally, species you mention like the common coot can attempt multiple broods where the season is long enough. Wikipedia specifically mentions Britain:
Eurasian coots normally only have a single brood each year but in some areas such as Britain they will sometimes attempt a second brood
The same could be true for species of frogs/toads and fish, so without knowing specific species it can't be known whether these are species reproducing again or species reproducing late.
The following is multiple choice question (with options) to answer.
Beavers producing offspring after Winter impacts their life | [
"neutrally",
"negatively",
"very little",
"positively"
] | D | an animal being born when food is available has a positive impact on that animal 's health |
OpenBookQA | OpenBookQA-2834 | botany, mathematical-models, statistics, biostatistics, migration
Title: Biostatistics: Pollen dispersal directionality What Information am I looking for?
Think about a tree that is sending pollen all over the place. Because of wind, most pollen grain will go toward one direction. Imagine, we split the 2D area around the tree where pollen grains fall into two half disks of equal size. We chose the disks so that the number of pollen grains falling into one half-disk is minimized and the quantity of pollen falling in the other half-disk is maximized.
The information I need is what proportion of pollen grain falls into each disk? Is it $\frac{0.5}{0.5}$ (in which case the wind would have no effect) or is it something like $\frac{0.8}{0.2}$?
Where to get the information from?
I was reading this paper about pollen dispersal directionality and was trying to extract the info I need.
On pages 4 and 5 they explain their analysis under the section statistical procedure. More specifically, in the first paragraph of the 5th page, they seem to describe the meaning of the parameters that are trying to estimate. One of them is the so-called directionality parameter $\delta$. I don't understand how to interpret this parameter $\delta$. This parameter is part of a logistic regression I think (although the authors do not characterize it as such) of "mating success" $y$ against variables $d$ ("distance") and $h$ ("height") and an angular variable $a = \cos(\alpha_0 - \alpha)$. ($\alpha_0$ is the "presumed prevailing direction of effective pollen dispersal," which apparently is not estimated from these data.) The corresponding parameters of the model are $\beta$, $\gamma$, and $\delta$, respectively, hence
$$\phi_j = \Pr(y_j = 1) = \frac{\exp\left(\beta d_j + \gamma h_j + \delta a_j\right)}{\sum_{k=1}^r \exp\left(\beta d_k + \gamma h_k + \delta a_k\right)}$$
The following is multiple choice question (with options) to answer.
Hummingbirds contribute to seed dispersal by | [
"consuming flower sustenance",
"eating pizza",
"swimming in bleach",
"going to space"
] | A | An example of seed dispersal is is an animal gathering seeds |
OpenBookQA | OpenBookQA-2835 | 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.
A person can eat a seed if they are consuming raw | [
"soup",
"elk",
"fish",
"duku"
] | D | humans sometimes eat seeds |
OpenBookQA | OpenBookQA-2836 | botany, plant-physiology
Title: Can any plant regenerate missing tissue? I have not yet found a plant that, when an insect eats a hole in one of its leaves, it can regenerate the lost tissue. Many plants will grow a new stem if the old one is cut, but it is not a perfect regeneration, and has no likeness in form to the previous stem. Are there any plants that can, even to a degree, regenerate missing tissue? In general, plant cells only undergo differentiation at special regions in the plant known as meristems. Two of the primary types of meristem are the root apical meristem (at the tips of roots) and the shoot apical meristem (at shoot tips)^. Within the shoot apical meristem the plant cells divide and begin to differentiate into different cell types (such as different cells of the leaf, or vascular cells). Later growth (of, say, a leaf) is largely a result of cell expansion (although cell division does still occur, but drops off as the leaf expands). Therefore, if you punch a hole in a leaf, it probably won't be filled in because the cells in that leaf have finished growing and dividing.
However, as a shoot grows, more meristems are created. These are found in the axillary buds, just above where the leaf meets the stem. The meristems in the axillary buds can grow to form branches. Different plants obviously make different numbers of branches, but there is a common control mechanism known as apical dominance, where the meristem at the tip of the shoot suppresses the growth of the lower axillary buds. This is why a shoot with no branches can be made to grow branches by cutting off the tip (gardeners often do this to make "leggy" plants more bushy).
All of that was a long explanation to say, no, a plant doesn't normally^^ regenerate in the sense of filling in cells that have gone missing. However, if you cut off a shoot, the next remaining bud might begin to grow and, in a sense, replace the part that was lost. In that case, an existing bud is recruited to form a new branch and replace lost functionality, but I wouldn't say that qualifies as regenerating missing tissue.
^There are other types of meristem as well.
The following is multiple choice question (with options) to answer.
Undifferentiated cells in plants allow it to grow | [
"in clouds",
"taller",
"without sunlight",
"without water"
] | B | specialized tissues at the ends of plant stems are used for growing taller by plants |
OpenBookQA | OpenBookQA-2837 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
If a person is navigating then they are most likely | [
"sitting indoors",
"holding a wheel",
"reading a book",
"laying in bed"
] | B | An example of navigation is directing a boat |
OpenBookQA | OpenBookQA-2838 | In mathematics, we say that two objects are similar if they have the same shape, but not necessarily the same size. In other words, if two figures A and B are congruent (see Fig.1) , then using a tracing paper, Fig-1. if it is can you please explain how you know its true. If 2 squares have the same area, then they must have the same perimeter. Two geometric figures are called congruent if they have … You should perhaps review the lesson about congruent triangles. This wouldn't hold for rectangles. Ex 6.4, 4 If the areas of two similar triangles are equal, prove that they are congruent. Recall that two circles are congruent if they have the same radii. For example, x = x or -6 = -6 are examples of the reflexive property. They both have a perimeter of 12 units, but they are not the same triangle. 13. Dear Student! And why does a $1 \times 1$ square have an area of $1$ unit?) They have the same area of 36 units^2, but they are not congruent figures. False i True Cs have equal areas If the lengths of the corresponding sides of regular polygons are in ratio 1/2, then the ratio of their areas … Yes, let's take two different rectangles:The first one is 4 inches by 5 inches.The second is 2 inches by 10 inches.Both of these have an area of 20 square inches, and they are not congruent. (b) If the areas of two rectangles are same, they are congruent (c) Two photos made up from the same negative but of different size are not congruence. Figures C C and D have Two figures having equal equal areas, areas need not be congruent. Two circles are congruent if they have the same diameter. If you have two similar triangles, and one pair of corresponding sides are equal, then your two triangles are congruent. ALL of this is based on a single concept: That the quality that we call "area" is an aspect of dimensional lengths and angles. If two squares have equal areas, they will also have sides of the same length. If two triangles have equal areas, then they are congruent. If two angles of a triangle have measures equal to the measures of two angles of another
The following is multiple choice question (with options) to answer.
if a person needed two objects to be more alike in appearance, they could | [
"burn both objects in fire",
"dip both objects in water",
"apply identical layers of pigmentation",
"destroy both the objects"
] | C | painting an object a color causes that object to be that color |
OpenBookQA | OpenBookQA-2839 | species-identification, zoology, entomology
Title: Species identification; clusters of big plump red bugs in Taipei I saw these red insects in Taipei near XinBeitou MRT station in the last week of April 2017, around lunch time. They were fairly active and would keep checking each other out with their antennae for a moment and then move on to the next. What struck me was the wide range of sizes and development in the groups. I didn't notice any feeding or mating that I could recognize, just a lot of walking around and checking each other out.
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
I've also included a screenshot from google maps so you can see the location and the trees growing in these concrete structures.
The body of the largest individual is probably 2.5 centimeters long. I'm fairly certain these true bugs belong to the species Leptocoris vicinus, and carry the nickname of "soapberry bugs", which is specific to the subfamily Serinethinae. They're quite common in urban areas of Southeast Asia, which coincides nicely with where you encountered them.
Also, you had mentioned,
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
Soapberry bugs, as well as many other types of insects, are able to freely congregate in large numbers, and in such exposed places, due to their bright coloration. Having such a bright color may indicate to some predators that the prey in consideration is toxic, a phenomenon referred to as aposematism.
source
source
And then, here's a map of their distribution, with Taipei holding marker #37. (source)
An interactive version of this map can be found here.
The following is multiple choice question (with options) to answer.
The building of a hotel caused many species to be | [
"acclimated",
"celebrated",
"hunted",
"destroyed"
] | D | humans changing an environment sometimes causes that environment to be destroyed |
OpenBookQA | OpenBookQA-2840 | aqueous-solution, carbohydrates, organic-oxidation
Title: Why might a prepared 1% solution of glucose take 2 hours to give maximum, stable reading on a glucometer? I put 1.000g of glucose powder into a 1 L volumetric flask and filled the flask to the 1L line with room temperature distilled water.
I then inverted several times for 10 minutes to mix until there was no visible glucose crystals left and tested the solution using an oxidase glucose strip. Even though the glucose was all clearly dissolved, the reading I got after 10 minutes were only around 40 mg/dl. I waited an hour and the readings were now about 65 mg/dl. After 2 hours the readings were averaging about 125 mg/dl, a value that remained stable after 4 hours, and after 12 hours.
First off, the actual concentration was 100 mg/dl, but the test strip and glucometer estimate blood glucose, and real blood has other components that will effect that reading, so the reading of about 125 was not unexpected, but WHY might it take 2 full hours to achieve a peak and stable glucose reading from the solution?
The only ideas I had were that 1) the "dextrose" powder (lab grade) that I used MIGHT have been in polysaccharide form, maybe some monomers combining to make di- or tri-saccharides in the container which were able to hydrolyze in distilled water at room temp. I don't think this can happen without enzymes though. Perhaps some yeast enzymes in the air could have gotten in and done the job. 2) The glucose molecules had some degree of oxidation which made them un-affective to the test strip, but that the oxidation reversed in solution over time. This also doesn't make sense since I don't expect oxygen to spontaneously bond to a glucose molecule nor reverse without a catalyst. 3) maybe the glucose molecules bond loosely to something like carbon dioxide or nitrogen that comes off gradually in the solution.
The following is multiple choice question (with options) to answer.
dissolving sugar in water will cause it to | [
"turn bitter",
"evaporate faster",
"slightly warm",
"become sweet"
] | D | dissolving a substance in water causes the water to taste like that substance |
OpenBookQA | OpenBookQA-2841 | 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.
Animals eat food for the taste but also because without it, they would | [
"Smile",
"TV",
"Shoes",
"expire"
] | D | an animal needs to eat food for nutrients |
OpenBookQA | OpenBookQA-2842 | optics, atmospheric-science, weather
Title: Explanation for an unexpected rainbow Yesterday, I observed an unexpected rainbow in the sky. There was no forecast for rain, neither was it raining anywhere nearby. I have been trying to find an explanation but don't seem to find any. Can someone please explain what this rainbow is?
Note:the colours were way more vivid as compare to the picture I have taken These are tropospheric Iridescent Clouds
According to AtmosphericOptics:
When parts of clouds are thin and have similar size droplets, diffraction can make them shine with colours like a corona. In fact, the colours are essentially corona fragments. The effect is called cloud iridescence or irisation...
The usually delicate colours can be in almost random patches or bands at cloud edges. They are only organised into coronal rings when the droplet size is uniform right across the cloud. The bands and colours change or come and go as the cloud evolves...Iridescence is seen mostly when part of a cloud is forming because then all the droplets have a similar history and consequently have a similar size.
I've saturated the image so the interesting part can be appreciated
And here you have a very similar observation I quickly found by google image search:
The following is multiple choice question (with options) to answer.
A sky that is mostly this color will likely be precipitating: | [
"yellow",
"gold",
"blue",
"gray"
] | D | grey clouds are a source of precipitation |
OpenBookQA | OpenBookQA-2843 | thermodynamics, absorption
When you want to boil water efficiently, you do two things: cover the pot (limit loss due to evaporation) and put the heat inside if you can: for example the submerged heater element in electric kettles. Other forms of boilers also put the heat in the middle of the water (think water heaters for homes) so most of the hot gas gets to give off its energy to the water.
But if you have a flame, the best you can hope to to is transfer all it's internal energy to the water - so when the water is hotter a flame is always less efficient.
Very efficient systems use counter flow - the hot air moves left to right, and the water to be heated right to left: in that way the colder gas meets even colder water so when the gas finally is exhausted it has no heat left. Same principle is used in efficient gas furnace for homes, etc.
The following is multiple choice question (with options) to answer.
Who is likeliest to overuse hot water? | [
"a rabbit",
"a squirrel",
"a bird",
"the Johnson family"
] | D | a shower is a source of hot water for washing |
OpenBookQA | OpenBookQA-2844 | organs, lifespan
Title: Organs lifespan out of the body What organ can be conserved outside of the body for the longest time and still function when reimplanted? Depends what you consider an organ. Typically though it's the cells which require the most metabolic activity which have the shortest life span. The kidney is the most of the major internal organs with up to 36 hours with liver coming second at up to 16 hours.
The following is multiple choice question (with options) to answer.
The organ most made of muscle is the | [
"one pumping blood",
"brain",
"liver",
"kidney"
] | A | the heart is mostly made of muscle |
OpenBookQA | OpenBookQA-2845 | orbit
Title: Traveling constantly towards West. That is clockwise If I travel against against the Earth's rotation. Say once around the world. I will always see sunrise and never a sunset
Is that accurate? If you travel west so quickly that you go around the world in one day (24 hours) then the sun will remain almost fixed in the sky. You will see neither a sunrise nor a sunset. At a latitude of 45 degrees north, you will need to travel at 1180 km/h (faster than a commercial jet, nearly Mach 1)
If you travel less quickly, then the sun will move from East to West, but rather more slowly. You may see multiple sunrises and sunsets, depending on your speed.
If you travel faster, the sun will move from West to East in the sky. Again, you may see multiple sunrises and sunsets, but the sun would rise in the West.
The following is multiple choice question (with options) to answer.
As our globe makes a complete quick cycle it can and does see the passage of | [
"multiple hours",
"eons",
"several years",
"decades"
] | A | a Rotation of the Earth on itself takes one day |
OpenBookQA | OpenBookQA-2846 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
Hawks eat | [
"eggs",
"eagles",
"dogs",
"geckos"
] | D | hawks eat lizards |
OpenBookQA | OpenBookQA-2847 | geophysics, seismology, instrumentation
Title: How can I calculate the sensitivity of a seismometer? I would like to know if a specific seismometer can measure 1 micron/sec velocity. I have a few specs from the datasheet but I'm not a seismologist and am trying to figure out how to relate the specs to one another.
I have:
Velocity output band: 30s (0.03Hz) to 100 Hz
Output Sensitivity: 2400 V/m/s
Peak/Full scale output: Differential: +- 20V
Sensor dynamic range: 137 dB @ 5 Hz
Thanks in advance! This is a partial answer because I'm not an expert and because I don't know what the dynamic range of 137 dB means. Hopefully you can add a little more information.
tl;dr: if 137 dB is the dynamic range in power, then it's 68.5 dB in voltage and velocity which sounds more plausible, and makes the velocity sensitivity well below 1 micron per second. However we don't yet know what the noise and bandwidth of your signal are yet so we can't evaluate that.
I have a few specs from the datasheet...
The more information you share from the data sheet the better although I've now just noticed that the question is about three years old.
Also, there may be some helpful insight at How sensitive are typical seismometers?
The following is multiple choice question (with options) to answer.
A seismograph will be able to tell how much which thing is quivering? | [
"bird",
"bunker",
"lemonade",
"jello"
] | B | a seismograph is a kind of tool for measuring the size of an earthquake |
OpenBookQA | OpenBookQA-2848 | everyday-life, ice
Title: Why are some parts of this ice block cloudy and other parts clear? I had a sprain in my leg a few days back. The doctor recommended dipping my foot alternately in ice-cold and hot water to aid blood circulation. It is here that I discovered something interesting.
The picture above shows the piece of ice that was put in the bucket. The above picture shows the ice cube from above.
If you look at the large piece of cube from the side (see below), you can see that the upper part of the cube, that was near the open surface of the container in which the ice froze, seems to be almost transparent and has a crystalline appearance. The lower part does not have this appearance, and it is white and opaque.
Why is there a difference in the layers of ice in the large cube? Is it because the water was from tap and not completely pure? The water was put in the refrigerator for a period greater than 12 hours, so the ice has frozen properly. Can anyone explain this unique structure of ice? I've never seen this before.
Update:
This update is to simply demonstrate the bubble formation in the ice,which causes the cloudiness. Out of the two answers, I had accepted the one by @IliaSmilga . Today, the ice formed demonstrated this idea clearly. Given below are the pictures in which the bubbles of dissolved gas are clearly visible.
The following is multiple choice question (with options) to answer.
Ice might be formed by | [
"upper hemisphere",
"a flowing river",
"a temperature higher",
"hot reaction"
] | A | as temperature during the day increases , the temperature in an environment will increase |
OpenBookQA | OpenBookQA-2849 | 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.
If a warm potato is left on a steel sink, the potato will | [
"burn",
"lose heat",
"get hotter",
"warm up"
] | B | if a hot substance is touches a cold object then that substance will likely cool |
OpenBookQA | OpenBookQA-2850 | everyday-life, water, physical-chemistry, surface-tension
I understand there are complaints about image quality. I cannot fix these as I do not have access to photography equipment to take higher quality images. (This photo was taken with a flagship 2023 smartphone).
The best text description that I can give is that the droplets appear as oil droplets do in water. However, presumably because the index of refraction difference is not as great (between warmer and cooler water?), it is more difficult to make out the droplets (which might be why it's hard to take a good photo with a smartphone camera).
The video here contains a link to a short clip, which might be more helpful than a static image. Note the droplets in the top left, they are liquid water of the same composition as that of which they are contained in. When I pan to the right in the video, one can observe fast moving droplets that are further upstream. Clearly they have managed to travel from the shower head all the way through the higher velocity stream of the middle of the tub before settling near the drain where the water is moving more slowly. The lifetime of these droplets is on the order of seconds.
It is difficult for me to reproduce this effect as I must angle the shower head (it is detachable) and position it specifically to generate this phenomenon (and getting a good camera angle whilst doing this is very hard for me).
Additionally, I notice this phenomenon occasionally when urinating (as a male), and when pouring hot cooking water down a sink that already has a small amount of water.
My assumption is that this phenomenon is similar to that of liquid water droplets floating on the surface of a larger body of water (this can happen when smaller droplets formed from the collision of a drop of water with a water body reach the surface of the body). There is air in the case, and I don't immediately see air in this case, which is why I assume it might be a different phenomenon and warrants asking a question. Great question! I have observed this effect too while watering plants in my garden. When I direct the water spray to a water puddle at an angle, the water droplets seem to bounce up and down! (I didn't have to use warm water though, but I guess the effect will be stronger when you have more vapors) There is a Smarter Every Day video on this exact phenomenon.
The following is multiple choice question (with options) to answer.
A faucet drips | [
"lava",
"air",
"sand",
"melted ice"
] | D | matter in the liquid state drips |
OpenBookQA | OpenBookQA-2851 | 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.
A large thing that spews out destructive materials can | [
"make babies",
"eat sandwiches",
"level planets",
"create towering hills"
] | D | mountains are formed by volcanoes |
OpenBookQA | OpenBookQA-2852 | # Logic problem
##### Active member
Consider the following sequence of statements:
$$S_1: \text{at least 1 of the statements }S_1-S_n \text{ is false}\\ S_2: \text{at least 2 of the statements }S_1-S_n \text{ are false}\\ \vdots \\ S_n: \text{at least } n \text{ of the statements }S_1-S_n \text{ are false}$$
Where $n$ is some integer.
Question: for which $n$ are these statements self-consistent? In those cases: what is the truth value of each statement?
I got this off of a blog I tend to frequent. I will wait before posting the solution this time.
EDIT:
Changed the question; I had written the statements wrong
Last edited:
#### Klaas van Aarsen
##### MHB Seeker
Staff member
Suppose $k$ out of $n$ statements are true.
Then $S_1$ up to $S_k$ have to be true and the rest has to be false.
This appears to be consistent for any $n$ and any $0\le k \le n$.
##### Active member
Suppose $k$ out of $n$ statements are true.
Then $S_1$ up to $S_k$ have to be true and the rest has to be false.
This appears to be consistent for any $n$ and any $0\le k \le n$.
Sorry about that, you were absolutely right about the question as phrased.
However, this new version should prove to be a bit more interesting. This is what I had meant; I had accidentally written "true" instead of "false".
#### Klaas van Aarsen
##### MHB Seeker
Staff member
If $S_n$ is true, then $n$ statements are false, including $S_n$.
Therefore $S_n$ is false.
We now know that at least $1$ statement is false.
Therefore $S_1$ is true.
For $n=1$ this is a contradiction, and for $n=2$ this is a consistent solution.
The following is multiple choice question (with options) to answer.
Which of the following statements is true | [
"biofuel releases CO2 but is better than oil",
"biofuel is without flaws",
"biofuel can single-handedly end CO2 production",
"biofuel is perfect for the environment"
] | A | biofuel releases carbon dioxide into the atmosphere |
OpenBookQA | OpenBookQA-2853 | fluid-dynamics, pressure, fluid-statics
Altitude
Today's astronomical observatories are constructed at locations where the altitude is 4 to 5 kilometers, such as on the highest mountain tops of the Hawaiian islands.
Astronomers have to acclimatize in order to work at an altitude like that. The acclimatization period allows the body to adapt to the lower air pressure (higher amount of red blood cells per unit of volume of blood.) Without acclimatization people are prone to getting altitude sickness.
This illustrates that with height above ground level there is a rapid decline in air density.
Air is compressible, and at ground level the air must have sufficient pressure to carry the entire column of air above it.
So we have that the case of atmospheric pressure is quite intuitive. Gradient in density and gradient in pressure going hand in hand.
In the case of a fluid column we have that the fluid is hardly compressible. So it's harder to get a feel that that there is a significant pressure gradient all the same.
In a column of fluid the pressure (as a function of height) is definitely not uniform. There is a gradient in pressure, consistent with the weight of the fluid column above it.
A fluid
As you mention: a fluid (be it a gas or a liquid) exerts a pressure by way of the constituent molecules bumping against the surface of the object that is immersed in the fluid.
The molecules of a gas (at 1 atmosphere of pressure) have a lot of room to travel.
Water does not compress much under pressure, but it does compress a little.
Water at 1 atmosphere of pressure will have its molecules bumping against the surface of an immersed object at a rate such that the pressure exerted is 1 atmosphere of pressure.
Pressurizing the water reduces how much wiggle room there is for the thermal motion of the water molecules.
Imagine you are pacing back and forth in a room, using the walls of the room to reverse your direction of motion. Pacing from wall to wall is like the life of an air molecule.
Imagine you are a molecule of liquid: you can no longer do any pacing; you are down to a vibration in place. Now increase density: less wiggle room, so the amplitude of your vibration is smaller. But you still have the same velocity from bump to bump, so the amount of bumps per unit of time is larger. This higher frequency of bumps is the higher pressure.
The following is multiple choice question (with options) to answer.
Water molecules descending from a high elevation in liquid form are known as | [
"brimstone",
"fire",
"hail",
"rainfall"
] | D | precipitation is when water falls from the sky |
OpenBookQA | OpenBookQA-2854 | 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.
If a cow eats only plants, it will avoid eating | [
"hay",
"roots",
"thistles",
"venison"
] | D | herbivores only eat plants |
OpenBookQA | OpenBookQA-2855 | metallurgy, nuclear-chemistry, geochemistry
Title: Why are rare earth metals and platinum group metals are often found clustered together in ores Rare earth and platinum group metals are often found clustered together in the earth's crust. Mining for platinum, for instance, also yields Rhodium and Ruthenium belonging to the same group. Likewise, rare earth elements such as Neodymium, Europium and Samarium also cooccur in the same ore, so much so, that they are difficult to chemically separate.
It could be reasoned that it's the result of nucleogenesis where elements are formed consecutively based on their atomic number. While it might explain the first row and the second row of each group, where each metal is only one atomic number apart, it doesn't explain why metals from both rows are found together which are much further apart.
Alternatively, the similar chemistry of each group could explain the clustering. The two groups are the only group with this property. It fails to explain, however, how these metals found each other in a molten soup of heterogeneous elements. There may be some geological factors in the clustering, but it's unclear.
Why are the two groups of elements found clustered together? The factors that generate mineral concentrations are complex and often only partly known
Introduction: geology is complicated
The one thing we can be very certain about is is that the distribution of minerals in the earth's crust has very little to do with the primordial origins of the component elements (that is where they came from in the early solar system and how they were originally generated). Most "heavy" elements are originally formed in the cores of supernovae and not in either the big bang or in normal stars.
The distribution of elements in the earth is mostly unrelated to the cosmic origins of elements because the earth's crust is not static but is frequently churned up by a variety of processes on a geological timescale. If we go back far enough in the history of the planet, everything was molten and this allowed some of the denser components to separate out before the surface cooled enough to be solid. The led to the core being mostly metallic (and consisting of mostly iron and nickel). Higher layers contain less dense minerals containing a lot of silicate minerals. At the top there is a thin layer, the crust, which is where we find useful minerals and it is even more concentrated in silicate minerals and even less dense.
The following is multiple choice question (with options) to answer.
You can find ferrous metals in | [
"Glass",
"Grass",
"Vehicle scraps",
"Wood"
] | C | rocks often contain large amounts of metal |
OpenBookQA | OpenBookQA-2856 | 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.
In addition to a slippery road, blizzards can be dangerous to drive in because | [
"you may only see a car in front of you when it's too late",
"snow might break your windshield",
"a lot of deer like to travel during blizzards",
"a tornado is likely to pick up your car"
] | A | bad weather decreases visibility while driving |
OpenBookQA | OpenBookQA-2857 | botany, methods
I think it really depends on the type of plant whether its stems will root or not and how long the stem will retain its rooting potential after being cut.
If possible, you can try the following. Put the cut stem in a small plastic pot (they are very cheap) with soil and see if it roots (leaves will begin growing). If it does, transfer it into a larger pot later once it has grown. Wait for it to grow big enough to spread its roots thoughout the pot, then shift it into a big pot.
I believe if a plant roots, then all stems of that plant will root. Plus, congratulations on your first plant.
The following is multiple choice question (with options) to answer.
If you mow over a weed, it will just grow back. Pulling them by the root will make them | [
"cry",
"perish",
"eat",
"laugh"
] | B | if a weed is pulled then that weed is destroyed |
OpenBookQA | OpenBookQA-2858 | audio
Title: What audio effects, filters, distortions, etc. create a "vinyl" effect? I want to make any song sound like it's being played on a gramophone record in the 1920s. What specific filters would I apply to make this happen?
I'm looking for technical details, not some magical program that does it for me. I'm trying to create a programming interface that does this, so a user interface doesn't work. I'm a Math major with understanding of FFTs, but I don't know all the lingo. I don't know the precise formula for 1920's gramophone, but this is the general process for audio antiquing and should get you started. Depending on the exact settings, you can get vinyl, telephone, etc.
Convert to mono.
Add white noise.
Bandpass. I would start with a HP at 80 HZ and a steep LP at 8 kHz, but that's a guess. You'll have to use your ears until it sounds like the gramophone. You should try Chebychev and Butterworth filters if available.
You may also want to add "clicks" and "Pops". You can model those in a variety of ways. One way to start is with a Dirac function and filter it with bandpass functions. Depending on how strict your bandpass in step three is, you might be able to just add the clicks and pops as Diracs at the same time you add white noise, but then all your clicks and pops will sound about the same, which isn't very realistic.
Some other things you may want to try for more realism:
applying compression and saturation after step 1.
applying wow and flutter emulation either before step 2 or after (or, for most accuracy, two stages of white noise before and after the wow and flutter emulation).
You may want to ask on https://video.stackexchange.com/ to see exactly what filter settings they would recommend for 1920's gramophone in particular.
For tips on implementing basic audio filters, I have a blog post: http://blog.bjornroche.com/2012/08/basic-audio-eqs.html
The following is multiple choice question (with options) to answer.
What might make a more musical sound | [
"a bug",
"electrocution",
"a chopstick",
"space"
] | C | musical instruments make sound when they are played |
OpenBookQA | OpenBookQA-2859 | experimental-physics, dark-matter
Title: Distribution and detection of dark matter I feel in the dark (no pun intended :),
I'm sure most of you are familiar with this image I pulled from wikipedia:
The following is multiple choice question (with options) to answer.
A way to illuminate a dark study is to | [
"spread a good idea",
"introduce a spark to a wick",
"open a small box",
"put a book down"
] | B | a candle is a source of light when it is burned |
OpenBookQA | OpenBookQA-2860 | 1. ## Vector Intersection
Hi, I have a mechanics question here I can't quite get.
A destroyer sights a ship at a point with position vector 600(3i + j)m relative to it and moving with velocity 5j m/s. The destroyer alters course so that it moves with speed v m/s in the direction of the vector 4i + 3j. Find v so that the destroyer intercepts the ship and the time to the interception.
Any help would be greatly appreciated.
Thanks
2. Hello steve989
Originally Posted by steve989
Hi, I have a mechanics question here I can't quite get.
A destroyer sights a ship at a point with position vector 600(3i + j)m relative to it and moving with velocity 5j m/s. The destroyer alters course so that it moves with speed v m/s in the direction of the vector 4i + 3j. Find v so that the destroyer intercepts the ship and the time to the interception.
The following is multiple choice question (with options) to answer.
A tugboat maneuvers a ship to help | [
"watch for sharks",
"load passengers",
"hold their anchor",
"increase their speed"
] | D | a force continually acting on an object in the same direction that the object is moving can cause that object 's speed to increase in a forward motion |
OpenBookQA | OpenBookQA-2861 | genetics, botany, reproduction, dendrology
So why I don't get the apple-tree of the scion kind if I plant the seeds from an apple which has grown on such a tree? I would expect that the genes in the apple seeds must be the same. However if I plant the seeds, I have to graft the new seedling again. The reason most apples are produced from grafted trees is that apples don't breed true.
In a large number of crops, you have "lines" of crops. Basically, if you breed two plants of the same cultivar together, their offspring are similar enough to both parents that it performs like the parents. The reason for this is that these crop lines have been interbreed with each other for long enough that the population is self consistent, and the important alleles are present in frequencies that mean all progeny are likely to inherit them.
However, the types of apples which are sold commercially are not from these sorts of cultivar lines. Instead, they've been obtained from "sports". That is, the chance production of either a particular hybrid gene set, or sometimes from random mutations that happened on an adult tree of another apple variety. For example, the Granny Smith occurred from a chance seedling which was discovered by Maria Ann Smith.
These apples don't necessarily have "consistent" alleles. For example, it may be heterozygous for certain genes. If you have Aa alleles at one gene, if you self-pollinate the plant, you're going to get a mix of AA, Aa and aa genes in the offspring, the last of these isn't going to be the same phenotype as the parent. Now recognize that this is happening at multiple genes across the entire genome, so there are many chances to get non-parent-like allele combinations. Add to this the issue of co-dominance, where the heterozygote has a different phenotype than either homozygote (that is, BB isn't like Bb), and the chances that an offspring has a gene with a non-parent like allele combination is pretty high.
There's a further complication that some apple varieties like Honeycrisp are self-sterile. Even if Honeycrisp could theoretically breed true, there's no way for it to fertilize itself, meaning that all fertilization events are hybridizations.
The following is multiple choice question (with options) to answer.
If an apple tree wanted to spread it's seeds via another entity, it would | [
"plant trees",
"feed birds",
"attract birds",
"drop seeds"
] | C | birds sometimes eat insects |
OpenBookQA | OpenBookQA-2862 | air-pollution
Title: Less pollution: moving hurricane debris to other regions for use, or burning? When a big hurricane hits, it can create debris on the scale of $\mathrm{10^8 yd^3}$. Cities in Florida, Texas, and other affected areas are struggling to hire enough trucks and drivers to pick it up quickly. But aside from that, I noticed many of the areas have started to burn the debris once it starts building up.
Got to wondering... typically mulch comes in modestly pricey, and when free mulch is offered, it often goes quickly.
So assuming a fair portion of debris is mulchable and is of interest to other areas, and that we can acquire typical transportation resources, then we'll set up transfer from collection sites to those other regions rather than burning it. What would be the net pollution result?
If removed for mulch and such: trucking pollution + decomposition (- trees saved locally??)
If burned: the burning pollution.
Obviously it's about approximation rather than exacts, it's probably hard to appraise the different byproducts from burning versus decomposition, and a lot probably depends upon the way it is burned. But as a whole, can we get a rough estimate of comparable quantities/damage done... is it less pollution/damage even to truck it an average of 3000 miles? 1000 miles? 100 miles? 10 miles? Should it be burned on the spot (if done safely)? Would think there's got to be some way to get a very rough idea.
Certainly the best option if viable might be leaving it in place to decompose. But considering how upset people are getting at having debris around these parts a month later, exclude that option from the possibilities.
Trucking or burning, how do they compare? As the question was changed, my answer attempts to evaluate only the difference between burning and transporting. Please correct my values if my quickly found sources are inaccurate or you find more representing. I know there is quite a few unwritten assumptions that simplify this problem.
The following is multiple choice question (with options) to answer.
Keeping shopping bags out of the dump affects the earth | [
"neutrally",
"positively",
"negatively",
"very little"
] | B | recycling resources has a positive impact on the environment |
OpenBookQA | OpenBookQA-2863 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
Bluebirds have a strong sense of what? | [
"Magic",
"Imagination",
"Family",
"Justice"
] | C | bluebirds live in grassy spaces |
OpenBookQA | OpenBookQA-2864 | newtonian-mechanics, centripetal-force
To move the device, no further energy would be required, yet we would neither violate the conservation of momentum, nor the conservation of energy, while the center of mass would remain at the same place for this closed system, at all times.
Sounds too good to be true, so what did i get wrong? Or would this "UFO" actually work? Your question is very confusing, so I will first attempt to answer the spirit of your question with a cleaner scenario.
It is possible to "move" from one place to another if there is minimal friction. You can do so with yourself, a large box, and a bag full of baseballs. But it isn't as cool as it sounds (that is why I had to put quotes around move).
If you sit at one end of the box with your baseballs, then in your frame everything is at rest.
If you throw a baseball at the back wall then for a bit both you and the box move in the forward direction and the box will not slow down until after the ball hits the other side. After which point everything can come to rest again. But meanwhile you and the box have moved! And there is no propellant because the baseball stays inside the box.
However the baseball moved in the opposite direction. Eventually you run out of baseballs. And the center of energy doesn't move, not ever, not for an instant not even a little bit.
That last result is a general theorem in the absence of gravity or other external forces, the total momentum stays constant and the center of energy moves at a constant velocity. So if you started with everything at rest, the center of energy can't move.
It's called the center of energy theorem.
If you have two people, one at each end, and each with a bag of baseballs, you can shuttle back and forth. If that's what you want. Nothing deep.
So now we can look at your setup. Originally everything was at rest. So the center of energy was stationary. So it must stay stationary.
Therefore as you activate your motors some energy must go one way for some energy to go the other way. And there is simply no way to end up with the center of energy in a new location. In the case with the box, the box could move one way because the baseballs move the other way.
The following is multiple choice question (with options) to answer.
Tom and Bill were both pushing on a large plastic ball but it stayed in one place. Why? | [
"the ball was being stubborn",
"the ball was large and made of iron",
"they were pushing from opposite sides using the same muscle power",
"the ball was 2 miles across"
] | C | if two equal forces in opposite directions act on an object then that object will stay in the same place |
OpenBookQA | OpenBookQA-2865 | 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.
Small animals will leave their habitat and look for new shelter when there is a | [
"less animals around",
"too much food",
"destruction",
"better food"
] | C | rocks are a source of shelter for small animals in an environment |
OpenBookQA | OpenBookQA-2866 | geography, earth-system, astronomy, orbit, geodesy
(the vertical axis is logarithmic)
We can see that around 10 km away from the subsolar point, ~10 meters are enough to be closer than it to the Sun. ~30 meters at 20 km, ~800 meters at 100 km, ~3,000 m at 200 km, and if you go further than 340 km, not even Mount Everest will get you closer to the Sun.
So, the closest point to the Sun will be whatever geographical feature that maximizes the value $\text{Altitude}-\Delta H$, where $\text{Altitude}$ is the altitude of the geographical feature. Let's call that point “proxisolar” point. I just made up that name, but it will be handy for the following discussion.
Now that we understand the basis to establish what is the closest point to the Sun at a given moment, we can tackle the question that probably most people meant when asking this question:
What is the point on Earth that gets closest to the Sun over a year?
The most important fact to keep in mind, is that the variations of the distance between the Earth and the Sun over the year dwarf any topographical feature and even the diameter of the Earth itself. Earth’s distance from the Sun (center-to-center) varies from 147,098,074 km at perihelion (closest) to 152,097,701 km at aphelion (most distant). Therefore, the difference is 5 million kilometers!.
The perihelion happens around January 4th, when the solar declination is about -23°, therefore, the latitude of the subsolar point is around 23° South. That rules out Chimborazo, Cayambe and Everest, because they are too far to be the “proxisolar” point. In contrast, Sairecabur (5,971 m at 22.72° S) and Licancabur (5,916m at 22.83° S) are reasonable contestants.
The problem is that the perihelion happens on different days of the year and at different times of the day every year, so the point that gets closest to the Sun on a given year is just the one that happen to be the “proxisolar point” at the time of the Perihelion.
The following is multiple choice question (with options) to answer.
When would the days be the longest 1000 miles north of the equator? | [
"the same time that the nights are the longest",
"in the month of March",
"6 months after Christmas",
"in the fall season"
] | C | the amount of daylight is greatest in the summer |
OpenBookQA | OpenBookQA-2867 | 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.
Rain storms and blizzards can be very dangerous to drive in due to the amount of precipitation they produce, which will do what to the roads visibility? | [
"make it worse",
"Make it tasty",
"make it better",
"make it hot"
] | A | a decrease in visibility while driving can cause people to crash their car |
OpenBookQA | OpenBookQA-2868 | safety, equipment
Finally, make sure someone doesn't get the idea that the hood will stop all fumes and try to do a perchloric acid experiment using that hood--that will go badly.
Now, all this being said...
What you really need isn't to make this safe, what you need is to convince administration that you're doing things safely. This may have nothing at all to do with whether things are actually safe or not.
At my old school (where I was briefly president of the local ACS chapter), I could have put an experiment into a fume hood with no filter, not plugged the thing in, and gotten an okay from the administrators because they believed that fume hood = safe and no fume hood = unsafe no matter what else was going on.
I say this not to encourage you to try to trick your way out of this, but to point out that, unless your administration is scientific (i.e. actually understands science), then it's fairly likely you're going to have to jump through a few silly hoops in order to satisfy them.
Best of luck!
The following is multiple choice question (with options) to answer.
if a place has clean air, food, water and safe shelter for an animal, what would happen? | [
"the species would have to emigrate",
"the species would thrive",
"the species would die off",
"that animal type would be depleted"
] | B | when a habitat can support living things , living things can live in that habitat |
OpenBookQA | OpenBookQA-2869 | botany, species-identification
Title: Plant identification? Can anyone identify the plant below? It's in a backyard in Pennsylvania, and the photo was taken today. Those flowers don't come from the same plant as that big leaf in the front do they? Cant help you with the leaves, but the flower looks like a daylily. source: I know nothing about plants, but happen to have a mom who got a degree in horticulture :)
The following is multiple choice question (with options) to answer.
which one of these items might have been a flower at some point? | [
"a quartz stone in a ring",
"a bowl of chicken soup",
"an apple in the fridge",
"a piece of cake"
] | C | some flowers become fruits |
OpenBookQA | OpenBookQA-2870 | species-identification, ornithology
Why would a mother do that to her young? Does she hates the little one? Not at all. It’s just that those little birds were made to fly, and they don’t know it, so she is going to push them out of the nest. She never lets them hit bottom, but she does let them fall, because they have to learn something they don’t know.
The next time the mother bird comes back she decides to clean house, and so she stands on the edge of the nest. The first things to go are the feathers inside; she drops them over the edge. Then the leaves go over the edge—heave ho! While this is going on, she’s not very talkative, either. ("Mom, what are you doing?") She pays no attention. Since she built the house, she knows how to take it apart.
Next she decides to take the sticks out of the middle of the nest, and with her great strong beak and feet, she’s able to break them off and stand them straight up. ("Mom, it’s not comfortable in here anymore.") Then she takes certain key sticks out of the nest and throws them over the edge. ("What are you doing, Mom? You are wrecking my room.")
She seemingly pays no attention to the concerns of her young as she prepares to pull the nest apart, for she is determined that those little ones will fly, and she knows something they don’t. She knows they will never fly as long as they remain in the nest.
The following is multiple choice question (with options) to answer.
A baby chick hatches and recognizes the mother bird above it from | [
"the worms it ate",
"the birds it discovered",
"the warmth it provided",
"the leaves it saw"
] | C | female birds sit in nests |
OpenBookQA | OpenBookQA-2871 | physiology, ichthyology
Salmon use to deal with the NaCl fluxes driven by the gradients between the salmon and its surroundings. In their gill epithelial cells, salmon have a special enzyme that hydrolyzes ATP and uses the released energy to actively transport both Na+ and Cl- against their concentration gradients. In the ocean, these Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the salmon's blood into the salt water flowing over the gills, thereby causing NaCl to be lost to the water and offsetting the continuous influx of NaCl. In fresh water, these same Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the water flowing over the gills and into the salmon's blood, thereby offsetting the continuous diffusion-driven loss of NaCl that the salmon is subject to in fresh water habitats with their vanishingly low NaCl concentrations.
Reference
Reference
The following is multiple choice question (with options) to answer.
In saltwater, a squid's method of locomotion results in water being | [
"pushed in front of it",
"sung about by Jethro Tull",
"displaced in the Great Lakes",
"displaced directly behind it"
] | D | a squid produces thrust by pushing water out of its body |
OpenBookQA | OpenBookQA-2872 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
Natural resources come from nature, so if humans are reckless when working with nature, the amount of resources will | [
"go down",
"laugh",
"go up",
"fly away"
] | A | nature is the source of natural resources |
OpenBookQA | OpenBookQA-2873 | mycology, microscopy, parasitology
Cross sections of leaves (hold between two thin pieces of polystyrene or cork and slice gently with a new single-edge razor blade or craft knife). . These will show the internal structure of the leaves - veins (xylem, phloem), cells etc. You can also use clear nailpolish to paint on the surface of a leaf (try the underside), then peel off and look at under the microscope - this should let you see the pores (called stomata) in detail, they look like pairs of lips usually. The fine tissue skin (not the brown bit, it's a very thin wet translucent bit) of an onion also looks pretty nice. Moss leaves also are fun to look at.
Along with mosses - take some dry moss, let it sit in water for 30 min or so and then squeeze out - you'll hopefully find tardigrades
Edited to add:
With respect to parasites in faeces; this requires a bit of expertise to get good at. There is a lot of matter in faeces and parasites are generally low abundance. Unless you know a host is infected and are willing to mix faeces with water, filter and do a bunch of screening, you might not find any actual parasites, though you might see things that look, to the untrained eye, like parasites but are really just debris. You also run a significant chance of infecting yourself with something, be it parasitic, bacterial or viral.
The following is multiple choice question (with options) to answer.
Tiny nits may be seen best when using a | [
"vision enhancing aid",
"series of mirrors",
"toothpick",
"glass eye"
] | A | microscope is used to see small things by making them appear bigger |
OpenBookQA | OpenBookQA-2874 | javascript, beginner, game, dom
Title: Lights on: playing with buttons in Javascript First play with the game a little bit, and it is quite fun (a little hard but very satisfying when you win, be sure to put it full page):
<!DOCTYPE html5>
<head>
<title>Lights on</title>
<script>
document.addEventListener('DOMContentLoaded', randomize_and_color, false);
function random_zero_or_one() {
return Math.floor(Math.random() * 2);
}
function color_single_button(id) {
var number = parseInt(document.getElementById(parseInt(id)).innerHTML);
if (number == 0) {
document.getElementById(id).style.background = '#CC0000';
} else {
document.getElementById(id).style.background = '#00FF00';
}
}
function color_following_numbers() {
for (var i = 1; i <= 9; i++) {
color_single_button(i);
}
}
function randomize() {
for (var i = 1; i <= 9; i++) {
document.getElementById(i).innerHTML = random_zero_or_one();
}
}
function randomize_and_color() {
randomize();
color_following_numbers();
}
function invert_text(id) {
button = document.getElementById(String(id));
button.innerHTML = String(button.innerHTML) === "1" ? "0" : "1";
}
function invert_text_and_colour(id) {
invert_text(id);
color_single_button(id);
}
The following is multiple choice question (with options) to answer.
Toggling a light switch on | [
"completes a circuit",
"makes black holes",
"opens a circuit",
"breeds contempt"
] | A | when electricity flows to a light bulb , the light bulb will come on |
OpenBookQA | OpenBookQA-2875 | optics, geometric-optics
EDIT:::Clarifications
This question is the result of a debate with my friend, who says the room would be dark and me who says otherwise.
Now being said that let's move to specifics...let's assume that the room is a cuboid and the light source is say a light bulb i.e. an isotropic source like a typical room at ceiling. and the observer with infinitesimally small view port looking from one of the wall presumably neither the ceiling nor floor.
I hope this suffices. You use the verb "to be," which is rather deceptive in this situation (and in questions of optics generally). The room itself would not "be dark" or "be light," it would be a collection of various particles, some of which would be photons in the visible spectrum. It really only makes sense to ask how the room would appear to an observer looking through the viewport.
Even if you had completely reflective surfaces, the way the room appeared would depend significantly on the orentientation of the mirrors, the orientation of the viewing hole, the focus of the light, and perhaps most importantly, the refractive and diffusive properties of the mirrors. Ultimately, the appearance of the room would be a result of the light that falls upon the viewport. While there are an infinite variety of possible arrangements, the two extremes roughly align with the two possibilities you suggest.
For the room to look completely dark, no light paths fall on the viewport. A laser perpendicular to two parallel mirrors with the line of sight also parallel to the mirrors would produce this effect.
For the room to look completely bright, all (or however much you require to meet that definition) light paths fall on the viewport. A room in the shape of a truncated paraboloid with the viewport at the focal point would produce this effect.
Edit
I decided to move these up to my answer to avoid a prolonged comment conversation.
The following is multiple choice question (with options) to answer.
If a light needs to be relocated to another room without leaving that room physically, a person could | [
"turn off all lights",
"throw it in the yard",
"get a new lamp",
"redirect it with reflections"
] | D | a mirror is used for reflecting light |
OpenBookQA | OpenBookQA-2876 | human-biology, toxicology
Title: Is nicotine toxic to humans? More specifically, is nicotine in the concentrations that smokers receive when smoking cigarettes toxic? I know that in great enough concentrations it can be toxic (but then, so can just about anything else, including oxygen) and I know that in plants it is used as a defense against insects and can even be used as an insecticide. However, it has always been my understanding that nicotine is irrelevant as far as the harmful effects of smoking go.
I recently had a conversation with another biologist who had just quit smoking and had done quite a bit of research on the subject. He said that nicotine itself is in fact bad for you and, therefore, that tobacco-less alternatives to cigarettes (such as electronic cigarettes) are still harmful because of the nicotine alone.
Does anyone have any more information on this? Perhaps some references? Or, even better, a detailed explanation of the pathways involved? Again, I stress, not about nicotine's toxicity in general but about its harmful effects on vertebrates (preferably human) at the kinds of concentrations one could expect to ingest when smoking. I think its useful to say that nicotine is not very toxic to humans - cells don't die or get sick for typical smoking habits. Secondary health effects are possible, but here is a toxicological profiles.
Nicotine is a toxin in large enough quantities and nicotine has an LD50 (lethal dose for 50% of individuals) of 0.5-1 mg Nicotine / kg of body weight. So even a small spill on your skin of the chemical can be life threatening, but for smokers the nicotine itself is not dangerous.
Individuals who smoke intake about 1 mg per cigarette smoked. So a small adult (110 lbs) can smoke 25 cigarettes in a short period of time (or all at once!) and just barely get to the bottom end of that limit. Nicotine is water soluble and clears out through the urine at a fast rate though - half of the nicotine from a cigarette is cleared from your system within 2 hours, which means that 4-5 pack a day smokers are not really killing themselves (from nicotine).
That being said, children are about 5-10 times more sensitive than adults, so even 5-6 cigarettes in an hour can be toxic. That's quite a bit of smoking though.
The following is multiple choice question (with options) to answer.
Which is most harmful to a human? | [
"dynamite going off",
"reading email",
"balloons popping",
"opening a soda"
] | A | explosions can cause harm to an organism |
OpenBookQA | OpenBookQA-2877 | materials
Title: Making Lyophilized Cake Lookalike using household ingredients I'm working on a machine learning model to identify flaws in vaccines in lyophilized cake form. To train the model, I need a number of samples that look something like this:
I have vials, but I'm having trouble making a suitable cake – I need something that will stick to itself when dried...
What I've tried so far:
Salt dissolved in water/isopropyl alcohol
Baking soda dissolved in water/isopropyl alcohol
Both of these turned back into powder (instead of caking) when dry.
Next, I'm considering using powdered detergent, adding water, then letting it dry...
How would you recommend making this using common household ingredients? You may want to consider whey. Looks like Karen Smith, Dairy Processing Technologist at the Wisconsin Center for Dairy Research, already did some of the work for you. The result depends on the specific type of whey (a high score of 4 or 5 on the caking test means the material cakes readily, forming a gummy crust):
Whey – (Scored 2-5) – whey exhibited a wide range of caking scores. How the whey is processed has a very large effect on the tendency of the resulting powder to cake as evident in this result. Clearly, two of the samples had large amounts of amorphous lactose and without the presence of significant amounts of protein the samples readily caked.
The following is multiple choice question (with options) to answer.
Cake tastes sweet because of | [
"sweet and low",
"sucrose",
"flour",
"honey"
] | B | sugar causes food to taste sweet |
OpenBookQA | OpenBookQA-2878 | organic-chemistry, physical-chemistry, biochemistry, alcohols
Title: Storage of Urine Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at times, peeing in a 3 Quart Poland Springs water bottle. If you take offense at this, please do not continue reading except to be helpful in the scientific goal. I know this subject won't suit many types of people, so just ignore it if that is your case.
I noticed first of all that urine is not at all as sterile as people say that it is. The rate of growth of bacteria is relatively slow, but as a precaution, I found the need to use additional measures to prevent the growth of bacteria. I settled on the following method: I have two bottles and I add to each bottle about enough salt as can be soluble in the urine and sometimes maybe a little more. The one bottle then fills up throughout the day and is emptied, washed, and refilled with salt. The salt helps to kill the bacteria which would be lingering in the empty bottle. The next day, the bottle stays empty and the other is used.
I would add that I discovered that the bacteria (without the salt) does not usually grow unless the bottle is left with urine for two days. After this, however, that same bottle (without the salt) would retain the bacteria and immediately grow, if used again.
This system works relatively well, so long as it is done every day. It will even withstand 2 days with only moderate growth. (If I should leave it by mistake for longer it can get ugly). Nevertheless, I am still looking to improve upon this. One reason is that, if I drink less water or relieve myself normally, the bottle does not fill in one day. I am looking for someone with knowledge of chemistry to help me find a substance that can be added to this solution which fits a number of common sense criteria. I will also add a list of the substances that I have tried or already considered.
Necessary qualities
The following is multiple choice question (with options) to answer.
If a puppy is given only water for a very long time, it will | [
"starve",
"need to hydrate",
"dehydrate",
"be thirsty"
] | A | lack of food causes starvation |
OpenBookQA | OpenBookQA-2879 | water, everyday-life, geometry, evaporation
Title: How would one calculate the amount of water contained in a cloud? So I was looking out the sky one day and I wondered how I would go about calculating how much water was contained in a cloud. I figured the following simple outline
1) We need to roughly know how big it is. We'll also be figuring out how high the cloud is. Use some sort of geometric method? Triangles?
2) We need to relate its color to its density. (Darker clouds more dense) (White fluffy clouds less dense)
3) Correction factors due to lighting conditions during different parts of the day.
Can some body help me figure out the relevant calculations needed? Or how much water does a cloud contain based on its category? If you are just standing on the ground and looking up, you will be able to see the base of the cloud. I suggest that your estimate for a cloud more or less directly overhead (and closer) will be more accurate than for distant clouds visible on the horizon. The altitude to the base of the clouds is called the ceiling, and can be measured using a instrument such as a Ceiling Projector. If you observe some horizontal limit to the extent of your cloud, and have measured the altitude of its base, you can use an instrument such as an alidade and then trigonometry to calculate lateral dimensions. From the ground, you won't be able to see the top of the cloud very easily (being obscured by the intervening cloud,) so you will need to estimate the maximum height of the cloud based on an informed guess. A practical way to guess the maximum height of the cloud is to make observations of its appearance and then classify the cloud by qualitative type. Much has been learned and documented about the physical characteristics of the qualitative cloud classes through observational meterology.
Before cloud-physics, there was the natural-science of clouds. I recommend the book: The Invention of Clouds: How an Amateur Meteorologist Forged the Language of the Skies if you are interested in "every-day life physics."
Once you have the extrinsic size of the cloud in mind, you need to know how much liquid water and how much water vapor each cubic meter contains. (Because a cloud is only visible because it contains liquid droplets or ice crystals) You can find some characteristic data for this as well. For example for the liquid water content (LWC):
Cloud Type LWC (g/m3)
The following is multiple choice question (with options) to answer.
if a cloud deposits its contents to the earth, which of these may be true? | [
"the moon will shine brighter",
"the open fair will be a success",
"the river will dry up",
"the farmers would rejoice"
] | D | rain is a source of water |
OpenBookQA | OpenBookQA-2880 | ornithology
Title: How do birds learn their tunes in isolation from their own species? I wonder what a bird would sing if it didn't have its parents around (or any other birds for that matter) to learn its chirping sounds from.
I'm interested in how a bird would sing...
in complete isolation from creatures communicating through sound;
in isolation from its own species, but with other birds;
in isolation from all birds (other animals and creatures are there for it)
For example,
Would a bird even feel the need to speak up if there wasn't any other vocalizing creature around?
Would a bird learn other species' signals? Would it only learn from one species, the one which it would think of a fitting mate?
Would a bird try to mimic a non-flying creature's signals?
These are similar questions, but if you think they should be separated, let me know in the comments. Birds have to learn their song patterns.
They are able to chirp, but the songs with "meaning" are learned from their parents or whatever they learned to be their "parent".
Here is a paper that related bird song learning to human learning (of speech, for example).
Birds brought up by parents from another species learned to sing their songs.
There are many birds that learn to imitate other animals or sounds, so in isolation from all birds they will probably do this.
I can't recall where, but I read a paper once, where little finches brought up by humans developed a song resembling the "Hello there, now there's food", their caretaker always greeted them with. (Not the speech, but the overall sound pattern.) They might not understand the signals, but they try to communicate nevertheless. Some birds use sound from other species to mock others, scare them off or lure them into thinking they might be more powerful than they are.
Birds brought up in total isolation do sing, but not the typical songs you know from their species. Deaf birds who can't hear themselves, though, do not (always) sing.
The following is multiple choice question (with options) to answer.
Two birds in completely different houses can discuss something by | [
"sitting",
"thinking",
"vocalizing",
"sleeping"
] | C | sound can be used for communication by animals |
OpenBookQA | OpenBookQA-2881 | human-biology, biochemistry
Title: Pasteurization and Bioavailability of Antioxidants in Beet Juice What are the effects of pasteurization on the antioxidants found in beet juice ? Does the process render most of the beneficial nutrients (betaine) useless and make them unable for the body to process as efficiently as it would with raw beet juice? Also, does the pasteurization process do this to most fruit and vegetable juices ? I appreciate any insight, I've seen a lot of conflicting reports and am curious of anyones thoughts. Thank you So, when they subjected "ready to drink" beetroot juice to thermal pasteurization, they found the betacyanin and betaxanthin (our major antioxidants, and pigment molecules) content to be 39.9 and 42.28% degraded, respectively (1). Their conclusion was as follows:
Standardization of process condition and
quality degradation of beetroot juice due to thermal
pasteurization was studied. The standardized T2
batch
with total heating time (fh) of 720 s thermal in-pack
pasteurization leads to the minimal degradation of
color, betalain content (Betacyanin and Betaxanthin),
antioxidant activity and complete inactivation of
micro flora of beetroot juice. The color, betalain
content (Betacyanin and Betaxanthin) antioxidant
activity and sensory of the beetroot juice was
significantly (p < 0.05) reduced during 180 days
ambient (27-30°C) storage, but still the quality of the
juice was adequate upto 180 days. We concluded that
thermal pasteurization of 96 °C for a total heating time
(fh) of 720 seconds with P-values of 11.16 would be
a good method to produce microbiologically stable
beetroot juice with the retention of quality attributes.
So our goal is to get a juice that retains as many "good" attributes as possible, while producing a product that isn't going to get anyone a foodborne illness. As for the net effect of pasteurization on fruit juice in general, im still coming to a conclusion there. The process shouldn't render too much of the fruit/vegetable ineffective, though I'd still expect some degradation either in storage or processing.
The following is multiple choice question (with options) to answer.
Which beverage can you thank Louis Pasteur for making possible? | [
"iced tea",
"water",
"ginger ale",
"strawberry milk"
] | D | Louis Pasteur invented pasteurization |
OpenBookQA | OpenBookQA-2882 | Here is one solution in $12$ pieces.
• Six of the pieces here only have crust on one corner, but didn't the problem say absolutely none? – Trejkaz Sep 2 '13 at 5:29
• @Trejkaz: The requirement is only that the measure of crust included in some piece $A_i$, i.e. $\lambda(A_i \cap \partial D)$, be 0. A single point of idealized zero-thickness crust is OK since that has measure 0. – The_Sympathizer Sep 2 '13 at 5:43
• Someone has to ask this: What if we really require $A_i\cap \partial D = \emptyset$ for at least one $i$, that is at least one piece, including its boundary, must lie entirely in the interior of the disk? – Jeppe Stig Nielsen Sep 2 '13 at 21:48
• @JeppeStigNielsen: that appears to be an open problem – Robert Israel Sep 2 '13 at 22:22
• @mike4ty4 It's fair enough to have ideals, but someone who is thinking more about the pizza than the semantics will probably consider a 0-width crust to be less than ideal. Illustrating the danger of stating mathematical problems in real-world terms which people might relate with. :D – Trejkaz Sep 3 '13 at 6:45
If this violates the parameters in a clear way, consider this a teaching opportunity. Would this count:
The following is multiple choice question (with options) to answer.
A crust is a portion of | [
"a shoe",
"a world",
"a cat",
"a knife"
] | B | the crust is a layer of the Earth |
OpenBookQA | OpenBookQA-2883 | meteorology, severe-weather
The lack of rich low-level moisture is due in large part to the lack of accessibility from warmer moisture sources, particularly the Gulf of Mexico; the Rockies provide a barrier to much of the moisture reaching further west.
As you note, parts of Wyoming and Montana do see supercells and tornadoes a bit more often... but on a good topographic map, fair parts of those states are east of the Continental Divide, and so still on an "upsloping" area and thereby not blocked by sinking regions which prevent full moisture progress. They're still less-tornado prone due to elevation and increased distance from moisture, but it does happen.
The desert southwest also does manage to get monsoon moisture sneaking around the terrain further south... but further north that monsoon moisture sees additional blocking by the more elevated terrain across Nevada and Utah. (And in the southwest, a different key ingredient in tornadic supercell development is typically missing in the summer monsoon: upper-air winds sufficient for supercell development)
The Pacific Coast does see a few occasional tornadoes. But from what I've seen, they typically form from smaller storms with much less classical and intense mesocyclones. As you mention, they're a bit more in line with cold-core setups, which usually produce weaker short-lived tornadoes than classic supercells of the Plains and on east. If you plug in the events you speak of into SPCs Severe Weather Events archive, [pick the date, then click Obs and Mesoanalysis on the left, then use the dropdowns to find various parameters]
you can see that CAPE was typically very meager (well short of 1000 J/kg) and the storm structure quite weak in reflectivity in comparison to a classic supercell, more indicative of such cold-core setups.
Capping inversions may be helpful to "keep the lid on the pot" if you have strong CAPE (and therefore quality moisture) and intense updrafts to erode the cap during the day. But as it is, there isn't enough moisture typically for the cap to be a positive factor.
The following is multiple choice question (with options) to answer.
Wildfires are exacerbated in part due to dangerously low moisture content in light fuels, commonly brought on by | [
"periods of less than usual precipitation",
"torrential rains across the plains",
"too many firefighters with McLeods and Pulaskis",
"high moisture content on incident commanders' heads"
] | A | drought may cause wildfires |
OpenBookQA | OpenBookQA-2884 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A person who is trying something out for the first time that will have unpredictable reactions will | [
"want zero protection",
"want safety goggles",
"want naked skin",
"want bare hands"
] | B | safety goggles are used for protecting the eyes during experiments |
OpenBookQA | OpenBookQA-2885 | One important takeaway here is that we're not thinking of "implies" in terms of causality or possibility. If you want to talk about such things, we have to go beyond propositional logic - modal logic is a good place to set up shop.
Any if-then statement beginning with "If" and then something that has a value of False (not P in this case) is what's called "vacuously true". In some sense, it doesn't matter whether or not the implication would have held if that false statement after the if were true, because it isn't.
Your reasoning is fine ... but it's just that within the context of logic, any kind of 'if .. then ..' statement is analyzed using the mathematically defined material conditional ... and that can lead to some unexpected results since thate material conditional does not always quite match the English conditional.
So, you didn't "screw up" ... in fact, you were right to question this very result, but there are also excellent reasons for analyzing 'if .. then..' using the material conditional, so you better get used to the material conditional in the context of logic.
If you want to know more about this very issue, I suggest you look up "paradoxes of material implication"
You need to go back to the definition of the implication :
$$\begin{matrix} P & Q & P \Rightarrow Q \\ true & true & true\\ true & false & false\\ false & true & true\\ false & false & true \\ \end{matrix}$$
Now let's adapt it to the proposition ' If (not P) then (not Q)', i.e. $not(P) \Rightarrow not(Q)$:
$$\begin{matrix} P & Q & not(P) & not(Q) & not(P) \Rightarrow not(Q) \\ true & true & false & false & true\\ true & false & false & true & true\\ false & true & true & false & false\\ false & false & true & true & true\\ \end{matrix}$$
The following is multiple choice question (with options) to answer.
Which is likely true? | [
"two negatively charged iron ingots pull together",
"two negatively charged lemons pull together",
"two negatively charged rats pull together",
"two negatively charged dogs pull together"
] | A | magnetic attraction pulls two objects together |
OpenBookQA | OpenBookQA-2886 | ecology, biodiversity
One of the advantages of bamboo over wood is that bamboo contains some silicon in both inner surface (pith-ring) and outer surface (rind) of the bamboo culm.
--Calcium phosphate formation induced on silica in bamboo
As I say I remain very skeptical. There's no evidence shown that this has actually happened. Is it telling that all these claims come from the same general region (India and Burma)? My guess is that this is an old wives' tale that's been written down and uncritically accepted, but if someone has actually seen this happen I'd be happy to be proven wrong, because the idea of plants sparking out flames in the wind is a pretty cool one.
Edit to add a link claiming that bamboo-on-bamboo generates sparks due to the silicates:
The method consists of striking sparks out of the culm of Schizostachyum bamboo with flint, broken pottery, china or even another piece of bamboo. The sparks that occur by striking the Schizostachyum bamboo are presumably generated by the high silica content in this genus of bamboo.
--Bamboo Strike-A-Light, by Tom Lourens, Ash Kivilaakso and Ed Read (My emphasis)
Edit to add that the overall concept of plants starting their own fires has been seriously looked at; the author is skeptical:
Individual plant traits (such as leaf moisture content, retention of dead branches and foliage, oil rich foliage) are known to affect the flammability of plants but there is no evidence these characters evolved specifically to self-immolate, although some of these traits may have been secondarily modified to increase the propensity to burn. ... It is more parsimonious to conclude plants have evolved mechanisms to tolerate, but not promote, landscape fire.
--Have plants evolved to self-immolate?
Notably, in his list of factors potentially allowing self-immolation, he does not list silica, and horsetail isn't mentioned at all.
The following is multiple choice question (with options) to answer.
Which likely sustains a bamboo shoot? | [
"darkness",
"bees",
"nutrients",
"pandas"
] | C | a living thing requires nutrients to grow |
OpenBookQA | OpenBookQA-2887 | general-relativity, astrophysics, dark-matter, dark-energy, galaxy-rotation-curve
The reason photons make a much lower contribution to the Solar System than to the universe as a whole is because mass is much more concentrated in the Solar System than in the universe as a whole.
The following is multiple choice question (with options) to answer.
Which is considered least important in the solar system? | [
"Earth",
"Pluto",
"Mars",
"the Sun"
] | B | pluto has not cleared its orbit |
OpenBookQA | OpenBookQA-2888 | 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.
An example of an instinctive behavior is | [
"doing a cartwheel outside",
"singing on a stage",
"eating a large pizza",
"a mother feeding the kids"
] | D | An example of an instinctive behavior is a baby bird pecking at its shell to hatch |
OpenBookQA | OpenBookQA-2889 | In the next move you therefore:
Should press on the tile right or right-down of the bottom 3. Haven't calculated what could happen in the next step to decide which of these would be better.
• Another point to consider is how much useful information one would gain from picking a square that doesn't have a mine. Picking a square in the middle of noplace might not be very helpful if it comes up with a 2 or greater, but a square two squares to the right and one down from the upper-right 3 might be helpful whether it has a low number or a high number (since a high number would influence the probable placements for the 3's). – supercat Apr 13 '17 at 18:43
• @supercat Well, the tile you mentioned would be quite irrelevant if it is 2-4 or maybe even 5, meaning you need to be quite lucky to not get this outcome (haven't calculated, but I guess you have ~20% chance of success). Picking number right to bottom 3: 2 is very helpful outcome, as you know right 3 tiles next to it cannot be bombs, and can give you additional information. As probable as "no bombs next to corner" - 50%. But yeah, other 50% is getting 3, 4 or 5 there = useless. – Zizy Archer Apr 13 '17 at 20:40
• Three spaces neighboring the spot I described would be addressed by two "count" squares. If bombs are uniformly distributed, the five other neighboring squares should on average contain one bomb. If that square were to show a 4, that would suggest that it would be unlikely that none of the squares to its left held a bomb, which would suggest in turn that it would be unlikely that the top or fourth square in the column between the new square and the existing squares would have a bomb. – supercat Apr 13 '17 at 20:48
This is a probability game now.
Pressing random tile that is not in the 5*8 square of the visible space (+1 tile near) gives only around 20% to land on mine. Next step is to optimize that choice. One of the corners is always a good choice (Since it reduces that chances of having another probabilistic option later on), I would pick the leftmost down corner - Since after a few steps it can give us a hint to what to do in the current visible corner.
The following is multiple choice question (with options) to answer.
Which is the best thing to do for a neighborhood? | [
"growing local daffodils and weeding",
"spreading trash and garbage",
"planting fast spreading plants",
"introducing a new species"
] | A | planting native plants has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-2890 | newtonian-mechanics, education
Something that might be worth trying is getting the children to push a goodly size toy wagon around with varying quantities of sand and ask them how hard it is to stop it once it gets moving. This is something that a child learns "kinetically": they may not have noticed before that it's exactly when something is hard to get going that it is also hard to stop once going.
The Third Law
How do we teach children this one - the subtlest of the three? Actually, the six year old mind can grasp this at one level really well through the following experiment. My picture speaks better than words:
The following is multiple choice question (with options) to answer.
A person wanting to learn something new when they are very young will often try | [
"running with the bulls",
"skydiving from a plane",
"swimming with great white sharks",
"rotating feet on pedals"
] | D | a human can pedal a bicycle |
OpenBookQA | OpenBookQA-2891 | motor, underwater, auv, protection
Title: Preventing leaks in motor shafts for underwater bots Whenever building an aquatic bot, we always have to take care to prevent leakages, for obvious reasons. Now, holes for wires can be made watertight easily--but what about motors? We can easily seal the casing in place (and fill in any holes in the casing), but the part where the axle meets the casing is still left unprotected.
Water leaking into the motor is still quite bad. I doubt there's any way to seal up this area properly, since any solid seal will not let the axle move, and any liquid seal (or something like grease) will rub off eventually.
I was thinking of putting a second casing around the motor, maybe with a custom rubber orifice for the shaft. Something like (forgive the bad drawing, not used to GIMP):
This would probably stop leakage, but would reduce the torque/rpm significantly via friction.
So, how does one prevent water from leaking into a motor without significantly affecting the motor's performance?
(To clarify, I don't want to buy a special underwater motor, I'd prefer a way to make my own motors watertight) I'm not sure if an 'aquabot' is a fully submersible vehicle, or a surface one.
If it's a surface vehicle, then you just need to look at RC boats. They've got this solved pretty well.
The following is multiple choice question (with options) to answer.
A boy is playing with his toy boat in his wading pool. His mother comes along and sprays more water into the pool. | [
"the boat flies",
"the boat swims",
"the boat drowns",
"the boat rises"
] | D | as the amount of water in a body of water increases , the water levels will increase |
OpenBookQA | OpenBookQA-2892 | zoology
Title: Can my dog really understand me? Are dogs capable to understands human language ( for example after order sit it sit because he know that word) Or can sence our order by body language and intonation if so why this type of communication developed only at dogs? Some researchers say that dogs have the intelligence of a two-year old.
Many dogs can understand more than 150 words and intentionally deceive other dogs and people to get treats, according to psychologist and leading canine researcher Stanley Coren, PhD, of the University of British Columbia.
He is a reasonable and serious scientist who is biased towards overstating dog intelligence. he sais:
The average dog can learn 165 words, including signals, and the “super dogs” (those in the top 20 percent of dog intelligence) can learn 250 words, Coren says. “The upper limit of dogs’ ability to learn language is partly based on a study of a border collie named Rico who showed knowledge of 200 spoken words and demonstrated ’fast-track learning,’ which scientists believed to be found only in humans and language learning apes,”
Dogs can also count up to four or five,
http://www.apa.org/news/press/releases/2009/08/dogs-think.aspx
The following is multiple choice question (with options) to answer.
A seeing eye dog is able to do this better than his master: | [
"open a door",
"speak out loud",
"talk to friends",
"observe visually"
] | D | seeing is used for sensing visual things |
OpenBookQA | OpenBookQA-2893 | Decide the seating order of the people, starting from one of the brothers, say Ivan. Then position the other brother, Alexei, in one of the two slots (fourth and fifth) that fulfill the "separated by two others" condition - $2$ options. Then with Ivan and Alexei resolved, order the remaining five people in one of $5!=120$ ways. Finally add the empty chair to the right of someone, $7$ options, giving $2\cdot 120\cdot 7 = 1680$ options.
$\underline{Get\;the\;bothersome\;empty\;chair\;out\;of\;the\;way\;\;as\;a\;marker\;at\;the\;12\;o'clock\;position}$
• Brother $A$ has $7$ choices of seats
• Brother $B$ now has only $2$ choices (one clockwise and one anticlockwise of $A$ )
• the rest can be permuted in $5!$ ways
• Thus $7\cdot2\cdot5!\;$ways
The following is multiple choice question (with options) to answer.
A boy that has two legs and two arms has parents that have | [
"nearly an arm and a leg",
"the same number limbs",
"their left arms only",
"one right leg each"
] | B | the number of body parts of an organism is an inherited characteristic |
OpenBookQA | OpenBookQA-2894 | reinforcement-learning, rewards, intelligent-agent, learning-algorithms, environment
What happens if you continue training after the agent has learnt the environment? Will it perform by reaching its goal every time or will there be failed episodes?
If you include training episodes, then RL learns mainly by "trial and error". So you should expect an agent to make deliberate mistakes as it tests to see what happens. In some environments these could be critical mistakes leading to failed episodes.
If you ignore the training episodes and are interested only in performance without exploration - e.g. testing every few hundred episodes - then you can expect performance to vary depending on the type of agent and environment. Some agents even exhibit "catastrophic forgetting", which as the name implies causes performance to drop significantly - this can be caused by a successful agent over-fitting to all the recent successful episodes without errors it just experienced, and losing the ability to predict the true lower value of incorrect actions.
Neither failed episodes during training nor catastrophic forgetting are inevitable. It depends on the environment and type of agent.
The following is multiple choice question (with options) to answer.
What is a learned behavior? | [
"a child eating",
"a child's sight",
"a child's hearing",
"a child swearing"
] | D | animals learn some behaviors from watching their parents |
OpenBookQA | OpenBookQA-2895 | 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.
Digestion is when stomach acid breaks down | [
"a pizza",
"a house",
"a rock",
"a car"
] | A | digestion is when stomach acid breaks down food |
OpenBookQA | OpenBookQA-2896 | 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.
Who would refrain from eating a salad? | [
"horses",
"cows",
"wolves",
"rabbits"
] | C | carnivores only eat animals |
OpenBookQA | OpenBookQA-2897 | plant-physiology, movement
To test this, you could take 2 paper-strips, of slightly different lengths. Now, stepple their end-portions (so-that no-one lag-behind the other, and whole length of long strip (here 10 cm) interact with whole length of short strip (here 8 cm)). Now if you gently try to stretch the whole thing, you will obtain a bent structure. Longer strip outwards and shorter strip inwards.
We see a similar situation when one side of a masonite-board or a cardboard is wiped with wet cloth, the wet surface soon bent-out, this is plausibly because the wet surface expands.
Now , for continuously growing structure, such as a plant's axis, the all sides grow in almost same speed, if one side grow/expand slightly faster than its opposite side, then faster side will accumulate some more length. Now since all the layers of plant-tissues are tightly attached, no-side will be lagged from the other's but the whole thing will become bent. The "faster" side will try to stay "outer" of the curve, and the "slower" side will try to stay "inner" face of the curve.
A more-similar situation is bi-metallic strip which is made up of 2 layers of separate metals. The 2 metals have difference in their linear thermal expansion coefficients, so, when the strip heated/ cooled, the 2 sides of the strip expands/contracts in separate rate with temperature change; as a result, the strip bents (or if it was already bent, then change its curvature).
Image source wikipedia.
The following is multiple choice question (with options) to answer.
If a plant's extended portion is larger, it will | [
"soak up more light",
"put out less pollen",
"be wilting very soon",
"fold in on itself"
] | A | as the size of a leaf increases , the amount of sunlight absorbed by that leaf will increase |
OpenBookQA | OpenBookQA-2898 | 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.
A small pile of worms can do what to a yard of dirt with dead squirrels in it? | [
"blow it up",
"make it glisten",
"pull it apart",
"set it ablaze"
] | C | decomposition is when a decomposer breaks down dead organisms |
OpenBookQA | OpenBookQA-2899 | 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.
the availability of soil nutrients in the food chain can be explained by which of these? | [
"the soil emanates nutrients into the air",
"the primary producers depend on the soil",
"all living things eat sand",
"the water we drink is from the soil"
] | B | if some nutrients are in the soil then those nutrients are in the food chain |
OpenBookQA | OpenBookQA-2900 | evolution, mammals
Title: Why haven't land animals evolved beyond urination? It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is it about the chemistry of urine and the waste products eliminated that make urination necessary as opposed to eliminating them through defecation and recovering the water on the way out? It is probably true that toilets and other resting-ish area are always a great place to think about biology, I agree $\ddot \smile$.
Why do we urinate?
In short, urine contains the waste from our blood while defecation is just the stuff that we haven't digested. Kidneys are the organs responsible for draining wastes (mostly nitrogen-containing, or nitrogenous, wastes) from our blood.
Trade-off: energy cost vs. water loss
You're correct that the loss of water through urination is a considerable cost for an organism (especially those living in dry environments). But the amount of water used to excrete nitrogenous wastes is negatively correlated with the energy it costs to perform this excretion. In other words, there is a trade-off between water and energy loss during nitrogen excretion. Also, the question of toxicity is important.
Three ways to excrete nitrogenous wastes
Animals basically have three choices to excrete nitrogenous wastes:
Uric acid (excreted by uricotelic organisms)
Solid (crystal) with low water solubility
Low toxicity
Little water is needed
Lots of energy is needed
Ammonia (excreted by aminotelic organisms)
Highly soluble in water
High toxicity
Lots of water is needed to dilute it because of the toxicity
Not much energy is needed
Urea (excreted by ureotelic organisms)
Solid but highly soluble in water
"medium" amount of water is needed
"medium" toxicity
"medium" amount of energy is needed
The following is multiple choice question (with options) to answer.
The desert rat has evolved traits that help it live with low supplies of water, what is this an example of? | [
"acquired heuristics",
"acquired characteristics",
"acquired interests",
"acquired statistics"
] | B | the condition of the parts of an organism are acquired characteristics |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.