source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-401 | 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.
as rainfall increases in an area, electricity will be less and less available for | [
"solar panels",
"energy",
"coal power plants",
"wind turbines"
] | A | as the amount of rain increases in an environment , available sunlight will decrease in that environment |
OpenBookQA | OpenBookQA-402 | atmospheric-science, boundary-conditions, chaos-theory
More generally, I am proposing that over the years minuscule disturbances neither increase nor decrease the frequency of occurrences of various weather events such as tornados; the most they may do is to modify the sequences in which they occur. The question which really interests us is whether they can do even this—whether, for example, two particular weather situations differing by as little as the immediate influence of a single butterfly will generally after sufficient time evolve into two situations differing by as much as the presence of a tornado. In more technical language, is the behavior of the atmosphere unstable with respect to perturbations of small amplitude?
The answer to this question is probably, and in some cases, almost certainly. The atmosphere operates at many different scales, from the very fine (e.g., the flap of a butterfly wing) to the very coarse (e.g., global winds such as the trade winds). Given the right circumstances, the atmosphere can magnify perturbations at some scale level into changes at a larger scale. Feynman described turbulence as the hardest unsolved problem in classical mechanics and it remains unsolved to this day. Even the problem of non-turbulent conditions is an unsolved problem (in three dimensions), and hence the million dollar prize for making some kind of theoretical progress with regard to the Navier-Stokes equation.
The following is multiple choice question (with options) to answer.
Stormy weather often leads to | [
"picnics in the park",
"moisture in rain gauges",
"dry fields and roads",
"sunny and bright days"
] | B | if weather is stormy then there is a greater chance of rain |
OpenBookQA | OpenBookQA-403 | zoology, entomology
Title: How do insects know what is edible? What is the current scientific consensus on how insects innately know what is food and not food? If they are introduced to new food sources do they experiment with eating the new food? Could you teach a preying mantis to eat beef? Insect feeding behaviour is generally triggered by one or more conditions which may include colour, shape, chemical traces or temperature.
Insects generally locate food based on some combination of olfactory, thermal and visual queues (colour and shape). If their minimum criteria are met to specified tolerance, they will attempt to feed on whatever is nearby using their usual feeding method.
When these conditions appear on the 'wrong' target, it attracts insects and triggers feeding attempts. Insects can be triggered to feed on atypical food sources if the relevant aspects of their environment match those of their normal feeding environments. For example, here is a report from a professor of entomology recollecting his observations of being bitten by pea aphids while handling plants, which he assumes is because of the scent on his hands.
We can exploit this in various ways for research. One is for artificial blood-feeding of insects: most systems, like the Hemotek membrane feeding system, warm blood to the body temperature of the host. They do not normally resemble a target host in any other way. Some blood-feeding insects have very specific requirements for temperature (for example they will only feed on blood if it is heated to the body temperature of birds; the same blood heated to mammalian body temperature will be ignored) but we do not need to make the target look or smell like the natural host. Other species may need olfactory cues, which can be provided by researchers rubbing the membranes on their forearms before placing them on the feeding system, or by breathing on cages as you add the food.
A second way we exploit this is for insect traps. Although not all traps work this way, some work by mimicking the host and attracting insects that are looking for a meal. This can be via olfactory/chemical mimicry (for example carbon dioxide baited traps - try Googling "CO2-baited traps") or visual. Different degrees of visual 'deception' may be needed; for instance to attract tsetse flies, colour is important but shape is not:
The following is multiple choice question (with options) to answer.
Venus fly traps are poor at creating their own food though photosynthesis because | [
"they are unhealthy",
"they need water",
"they require insects",
"they grow slowly"
] | C | if an organism makes food for itself then that organism does not need to eat other organisms |
OpenBookQA | OpenBookQA-404 | human-biology, plant-physiology, stem-cells
Title: Is that true that plant stem cells can be used in humans? I was reading an article (which seems very fake to me) on sensitive topics, but there was one astonishing statement:
Stem cells are obtained from certain plants that grow all over the world. Once the stem cells have been obtained, the doctor will inject them on the target organ...
I want to ask specialists if this particular statement can be true. If yes, does it imply nucleus replacement in stem cells, or anything like that?
Sorry guys, for the stupid question. https://stemcells.nih.gov/info/basics/6.htm
...
Viruses are currently used to introduce the reprogramming factors into adult cells, and this process must be carefully controlled and tested before the technique can lead to useful treatment for humans. In animal studies, the virus used to introduce the stem cell factors sometimes causes cancers. Researchers are currently investigating non-viral delivery strategies. In any case, this breakthrough discovery has created a powerful new way to "de-differentiate" cells whose developmental fates had been previously assumed to be determined. In addition, tissues derived from iPSCs will be a nearly identical match to the cell donor and thus probably avoid rejection by the immune system. The iPSC strategy creates pluripotent stem cells that, together with studies of other types of pluripotent stem cells, will help researchers learn how to reprogram cells to repair damaged tissues in the human body.
So as that all points out, no, the genetics of it will cause a plant stem cell to be genetically not a match, where it might do something for a little while, but upon that cells first interactions, it will stimulate the immune system to get rid of it, rather than incorporate it.
Anymore, I want to know about how Bone Morphinogenic Proteins (BMP-4 or above) can be injected into an organ, and if that will help stem cells for reviving an organ at all.
The following is multiple choice question (with options) to answer.
To help your body repair cells | [
"eat chicken",
"chew gum",
"eat raw sugar",
"drink soda"
] | A | protein is used to repair cells by the human body |
OpenBookQA | OpenBookQA-405 | water, materials
Title: Hygroscopic material absorption level I live in a high humidity location and every winter, mold forms on one of my walls due to water sticking on it during the cold times. This also ruins the paint.
I found out that certain materials absorb water from the air, so I decided to make my own dehumidifier based on sea salt. The problem is alleviated slightly, but not fully - the salt becomes moist, but I think after a certain point it just can't absorb any more humidity.
So I was wondering how much salt I would need to bring the humidity in my room to a normal level.
I looked for things like "hygroscopic materials water absorption levels" on Google, but I did not have much luck.
What I am looking for is a formula like:
X kg of sea salt will absorb Y kg of water at Z% humidity
I have no background in chemistry, unfortunately, so I am not even sure if I am searching for this formula using the right terms. I tried to do something similar when I had a humid car.
In chemistry, we often use $\ce{CaSO4}$ or anhydrite to serve as a desiccant. You could probably get cost-effective plaster for similar purposes. You could also get gypsum and heat it to generate plaster of Paris yourself.
As you're probably aware, people also use silica gel in products (and food) to minimize water content.
Either material should be much better as a desiccant than regular salt.
One key criteria is to increase the surface area - make sure the material is a fine powder and enclose it in something porous. I've seen people use various cloth materials, paper towels, etc.
As to how much you need, you can work out how much it will eventually absorb. If I take plaster of Paris to gypsum, each mole of $\ce{CaSO4}$ will take ~1.5 moles of water. So for every 136.14 g of anhydrite or ~145.15 g of plaster, you can absorb ~27 g of water. (I use ~ here, since I'm not convinced that regular plaster of Paris will be completely $\ce{CaSO4*0.5H2O}$.. some will likely already have extra water in it.)
The following is multiple choice question (with options) to answer.
What item is high in moisture? | [
"firewood",
"light bulb",
"wet dog",
"a book"
] | C | moist means high in moisture |
OpenBookQA | OpenBookQA-406 | homework-and-exercises, newtonian-mechanics, angular-momentum, rotational-dynamics, string
Title: A mass attached to a string rotates, string meets a nail halfway thus the rotation continues I have a ball attached to a masless string that rotates, and the string meets a nail midway thus the string with the mass now rotates around the nail with half the radius it rotated before, lets call that radius $L$, and $X$ is equal to $L/2$
I have angular velocity just a moment before the string meets the nail, when mass is at P, lets call that velocity $w_{1}$ and I need to find the Tension of the rope a moment before the rope meets the nail and a moment after it.
$T=mg+Lw_{1}^{2}m$
Now I can use conservation of angular momentum here(fix me if I'm wrong here) before and after meeting the nail and say:
$I_{i}w_{1} = I_{f}w_{2} \Rightarrow mL^{2}w_{1} = m(L/2)^{2}w_{2}$
and from that I see $w_{2} = 4w_{1}$ Is there something wrong here? Because this result says the velocity instantly changed once meeting the nail.
to sum up my question, because it is requested to find the tension an instant after meeting the nail should I use:
$T = mg +\frac{L}{2}w_{1}^{2}m$
or
$T = mg +\frac{L}{2}w_{2}^{2}m$ ?
The following is multiple choice question (with options) to answer.
A nail can attach to metals after it receives | [
"water",
"electricity",
"light",
"heat"
] | B | if battery in an electromagnet is active then the nail in the electromagnet will become magnetic |
OpenBookQA | OpenBookQA-407 | ecology, trees
Title: Why do some trees in California have dead brown leaves but also new green leaves? It's Autumn 2015, and I just saw a tree that had mainly dead brown leaves but also some new small green leaves growing. Why didn't the tree just keep its old leaves? Does it think we are in spring already?
EDIT: To be clear, I had always thought that in autumn that all the leaves of a tree would fall off together, as a preparation for winter. It seems silly that the tree would then immediately grow some new leaves when it just decided to let all those previous leaves die. Why not just use that same energy to maintain those leaves?
I've taken some photos of the leaves and the trunk for help with identification.
The following is multiple choice question (with options) to answer.
As leaves turn from green to gold, another change is | [
"darkness comes earlier",
"the sun shines",
"more rain storms",
"warmer weather"
] | A | when the seasons change from the summer to the fall , the amount of daylight will decrease |
OpenBookQA | OpenBookQA-408 | 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.
Which uses gills to breathe? | [
"hermit crab",
"human",
"blue whale",
"bluebird"
] | A | gills are used for breathing water by aquatic animals |
OpenBookQA | OpenBookQA-409 | climate-change
Source: World Meteorological Organization Press Release No. 976: 2001-2010, A Decade of Climate Extremes
The above image speaks for itself. The global temperature change over the last forty years is very real, and is not noise.
With regard to point #2, yes the climate has changed in the past, and by huge amounts. We've had everything from snowball Earth to dinosaurs roaming the Arctic. And the point is? This argument is akin to a farmer taking a trip to the Grand Canyon and upon seeing what damage nature can do decides to forgo contour plowing and other anti-erosion farming techniques.
That the farmer's field might turn into a mountain or be washed out to sea several millions of years from now is irrelevant. What's relevant is that his good or bad practices have an impact on the world food supply. That nature can do far worse does not negate those bad farming practices. Bad farming practices are bad for humanity.
Getting back to climate change, if higher global temperatures are bad for humanity, it doesn't matter matter one bit how close ice came to the equator or how far north dinosaurs roamed in the past. What matters is that modern humanity is sensitive to climate change, be it natural or induced by humans.
With regard to point #3, yes, weather becomes chaotic after ten days or so. That does not mean that climate is chaotic, and if it is, the ~ten day Lyapunov time of the weather does not mean that climate also has a ten day Lyapunov time.
With regard to point #4, it is CO2. It was amusing to follow the skeptic response to Richard Muller's Berkeley Earth Surface Temperature project. Muller was a self-proclaimed skeptic, and he was going to prove those leftist climatologists wrong. The skeptic community cheered at the start.
"He's going to prove them wrong!" A funny thing happened on the way to proving them wrong: He proved them to be correct. Muller was an honest scientist in this regard. His own work caused him to switch from being a skeptic to ascribing to AGW.
The following is multiple choice question (with options) to answer.
An example of a change in the Earth is | [
"the sands of Mars moving",
"the moon appearing larger in the night sky",
"a volcano erupting in Hawaii burning through a forest",
"a skyscraper being built"
] | C | An example of a change in the Earth is an ocean becoming a wooded area |
OpenBookQA | OpenBookQA-410 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
Fish move best through water when their fins are? | [
"Large [Collect]",
"Long",
"Small",
"Short"
] | A | large fins can be used to move quickly through water |
OpenBookQA | OpenBookQA-411 | ecology
I have tried to find explanatory texts both in this and other books without any success so my question is how's this balanced state achieved in both types of successions (the answer is hinted in the first paragraph which I don't quite understand)?
Related to my last post. The author is saying that 1) Mature ecosystems tend to have a balance between production (=P) and use (=R, respiration) of biomass. This is actually tautological because the author would probably define a mature ecosystem as one where this is true (P=R).
If it starts out P > R, the autotrophs are dominant: more biomass is being produced than used up. It is possible, for a time, that P will increase as, for example, plants grow more leaves, but R is growing too, and there is an eventual limit on P, which at maximum depends on the light available to the ecosystem. As biomass grows, so does the amount of biomass to potentially decay, so eventually R will always catch up to P, until there is balance.
If it starts out P < R, that means you are using up biomass faster than you are creating it. This case is even simpler: you will gradually run out of biomass, and R will decrease.
In either case, when the author is talking about P = R, this is going to be in relative terms; there might still be variations between them, for example seasonal variation, but on average over years or decades you would expect P = R in a mature, stable ecosystem.
The following is multiple choice question (with options) to answer.
do ecosystems remain the same? | [
"they are altered with time",
"ecosystems are always the same",
"with time they only grow",
"ecosystems experience very little change"
] | A | ecological succession means entire communities in an ecosystem change over time |
OpenBookQA | OpenBookQA-412 | biochemistry, synthesis, proteins, amino-acids
Also, assume a constant amount of amino acids always being added to the resin to couple. If only the so far correctly built sequences are available, these will ‘see’ a higher ‘concentration per site’ of their coupling partners maybe resulting in slightly increased yield, too. (Note that this paragraph used layman’s terminology.)
The following is multiple choice question (with options) to answer.
A good example of increased demand may equal increased production is | [
"soldiers eat beans, so beans are planted when there is war",
"dogs eat kibble, so stores sell it",
"cats eat mice, so mice are afraid of cats",
"people have babies, so baby clothes are made"
] | A | as the use of a crop increases , the amount of crops planted will increase |
OpenBookQA | OpenBookQA-413 | thermodynamics, perception
Title: Our Perception of Heat Our body temperature is roughly 37 degrees celsius (that is, when we measure our body temperature externally, by using a thermometer that measures the temperature of our skin usually between our arm and side torso), whereas most of us would say that 25 degrees would be a pretty hot day. Why do we perceive a 25 degree day to be hot, when thermal energy from our 37 degree bodies should be leaving out and entering our surroundings? You are correct in a sense of thermodynamics. The heat from a human body does indeed leave the body and into the surroundings. The body combats this by burning calories and producing more heat, keeping the internal body at a constant temperature.
I'm not a biologist however:
Perception of a hot day, is just because our nerves our telling our brain its a given temperature. We are warm blooded animals, our body naturally generates heat. Lets assume that the body generates the same amount of heat every day, our brain may interpret a 25C day as warm because the body is generating the same amount of heat however it is leaving the body into the surroundings at a slower rate.
Temperature sensing is a survival tool, it used as a way of keeping the body at a constant temperature. As it gets hotter, your brain is in a sense telling you that it's getting harder to cool. (Forgive my terminology)
Think of this, if the day was as hot as the human body, you would be at danger of heat stroke.
The following is multiple choice question (with options) to answer.
At what time would a person feel the most heat outside? | [
"noon",
"midnight",
"morning",
"evening"
] | A | the sun is located directly overhead at noon |
OpenBookQA | OpenBookQA-414 | 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.
Feeling sweaty is normal on the ocean because | [
"the desert is drier",
"the ocean is wet",
"there is more moisture in the air",
"the moisture is higher up"
] | C | as distance from water decreases , humidity will increase |
OpenBookQA | OpenBookQA-415 | meteorology, climate-change, gas, pollution
If you are interested in Greenhouse Gases (e.g. methane, carbon dioxide, CFCs, nitrous oxide), the EPA has a separate site for those emissions since they are not part of the same regulatory framework http://www.epa.gov/climatechange/ghgemissions/ . Greenhouse gases typically do not cause adverse health effects for plants or animals on land. However, they have long-term radiative effects (e.g. the greenhouse effect) because they stay in the atmosphere for many years and trap infrared light. These long-term radiative effects are what can change climate and consequently land cover. Furthermore, most of the excess carbon is absorbed by the ocean, which creates carbonic acid. Increased acidity of the ocean causes severe problems for marine ecosystems.
The EPA states that in 2012 the CO2 equivalent GHG emissions for the USA by sector was:
The following is multiple choice question (with options) to answer.
What is an example of protecting the environment? | [
"flushing the toilet twice",
"using water flow limiter",
"driving shorter trips more often",
"using fancy, more expensive paper"
] | B | An example of protecting the environment is reducing the amount of waste |
OpenBookQA | OpenBookQA-416 | Problem #2: A box contains 18 tennis balls, 8 new 10 old. 3 balls are picked randomly and played with (so if any of them were new, they become 'old'), and returned to the box. If we pick 3 balls for the second time (after this condition), what is P that they are all new? I broke this down into 4 pieces: P(3 new second round|3 new first round)P(3 new first round) + P(3 new second round|2 new 1 old first round)P(2 new 1 old first round) + P(3 new second round|1 new 2 old first round)P(1 new 2 old first round) + P(3 new second round|3 old first round)(3 old first round). However, I was supposed to used binomials to count this. Instead I had a feeling that I should just multiply probabilities this way: \begin{align*} \frac{5\times4\times3}{18\times17\times16} &\times \frac{8\times7\times 6}{18\times 17\times 16} + \frac{6\times5\times 4}{18\times17\times16} \times \frac{8\times7\times10}{18\times17\times16}\\ &\quad + \frac{7\times6\times5}{18\times17\times16} \times \frac{8\times10\times9}{18\times17\times16} + \frac{8\times7\times6}{18\times17\times16} \times \frac{10\times9\times8}{18\times17\times16}. \end{align*} I get the correct answer with binomials, but this equation that I constructed undercounts the possibilities. Could you tell me what I am missing? ty!
-
Let's reduce problem 1 to see where you are going wrong. Let's say that there are 7 fishes, 4 trout and 3 carp, and you want to count how many ways there are of catching 2 fishes, at least one of them a carp.
The following is multiple choice question (with options) to answer.
Beach balls contain | [
"water",
"carbon dioxide",
"sunlight",
"beach sand"
] | B | a beach ball contains gas |
OpenBookQA | OpenBookQA-417 | electric-circuits, electric-current, electrical-resistance, batteries, short-circuits
Title: The importance and the role of a switch in an electrical circuit There is this simple test:
Three identical bulbs are connected in the circuit illustrated in the figure. When switch $S$ is closed:
a] The brightness of $A$ and $B$ remains the same, while $C$ goes out.
b] The brightness of $A$ and $B$ remains the same, while that of $C$ is halved.
c] The brightness of $A$ and $B$ decreases while $C$ goes off.
d] The brightness of $A$ and $B$ increases while $C$ goes off.
For my opinion the answer to this question is D because the switch (which has a resistance of $0\, \Omega$ has a node connected before the third bulb C) that "interrupts" the circuit. But, going into detail, according to Kirchhoff's first law the current should also go on the third bulb as in the first red node it divides into two currents $I_1$ and $I_2$. The current $I_1$ goes for example in the key $S$ and $I_2$ in the third bulb. The key and the third bulb have the same potential difference. I believe that the current $I_2$ passes through the third bulb but the current passing through it is so small that it does not turn on.
I made a point. When an individual is operated on at the heart and puts a by-pass (a bridge), blood will flow on the tube that detects the by-pass and the occluded artery (the third bulb) where blood will flow slowly, over time it will atrophy.
If the circuit were like the one drawn in the picture I would answer the b).
My question is: I have not very clear the rule of a switch in a eletric-circuit.
In fact, I find it difficult to give an answer to the following image.
The following is multiple choice question (with options) to answer.
A a switch turns something with batteies on because: | [
"electrons are then disturbed",
"a piece of metal closes the circuit",
"it lets the acid free",
"the circuit is opened"
] | B | when a switch in a simple series circuit is closed , electricity will flow through the circuit |
OpenBookQA | OpenBookQA-418 | geology, rocks, mineralogy
Title: What is this Lake Michigan rock? Rock found along northern Lake Michigan, (Charlevoix, MI). Made up of very thin crystalline layers. There are small, round bubble like bumps that protrude from the surface. Doesn't show well in the picture, but the rock has a sugary appearance. I can't be definite but my three best guesses are Travertine, Agate and maybe Halite, if it fizzes in mild acid it's Travertine, a form of Limestone, if it dissolves in hot water it's Halite, or Rocksalt, otherwise if it's more or less inert it's probably Agate, an amorphous silicate. I find Halite unlikely, the other two are probably pretty equally likely in that location.
The following is multiple choice question (with options) to answer.
Michigan is the land of the great lakes, where | [
"glaciers tore out lakes",
"there are lots of swimmers",
"glaciers are in lakes",
"lakes are filled with eels"
] | A | the Great Lakes were formed by glaciers moving over the ground |
OpenBookQA | OpenBookQA-419 | exoplanet
It's probably possible to have volcanic eruptions even though dozens or maybe even hundreds of miles of exotic ice because the heat has to go somewhere, eventually, assing it's likely to build up over time, so either by circulation of eruption, the heat has push through at some point. This even happens on so called "dead" planets like Mars or even the Moon. Mars still has the occasional volcanic eruption, just not very often.
But water worlds certainly can have plate tectonics. There's nothing in the water that would prevent it from happening. Plate Tectonics is, as I understand it, primarily a factor of the size of the planet. Gas planets - different story, but planets with a hard surface, Earth sized, a tiny bit smaller to a fair bit but not much bigger are good candidates for plate tectonics (I think). There's some debate on how large, I think, still going on. But I remember reading that ocean/water worlds might even be more likely to have plate tectonics. Plate tectonics is definitely something we'd look for if we ever get a close enough look at other planets in different solar-systems (exoplanets).
Just my thoughts on this. Not meant to be complete or definitive.
The following is multiple choice question (with options) to answer.
Mountains exist on a planet next to | [
"Saturn",
"Mars",
"Neptune",
"Uranus"
] | B | the surface of the Earth contains mountains |
OpenBookQA | OpenBookQA-420 | geology, fossil-fuel, petroleum
For some transport applications, the energy density is still a winning attribute of hydrocarbons: most notably, powered flight for freight and travel.
We already have two routes to non-fossil hydrocarbons: biological sources, and direct chemical synthesis. Each involves capturing atmospheric CO2, and combining with water, to generate a blend of hydrocarbons.
Now, we already have means of creating hydrocarbons suitable for flight (e.g. Jet-A and Jet-A1 fuels). And there are already demonstration plants that have closed-loop generation of synthetic hydrocarbons, for use in electricity-grid-balancing, by using surplus electricity to synthesise methane, which is then burnt in gas turbines when required. Similarly, Tony Marmont's team have been synthesising petrol (gasoline) from air, water, and electricity.
However, none of those things mean that hydrocarbons necessarily have much of a future, beyond plastics production. Because hydrocarbon-powered aviation has a lot of environmental problems beyond just CO2 emissions, in particular it makes other contributions to exacerbating global warming. And there are lots of options for energy storage within the electricity supply chain.
The following is multiple choice question (with options) to answer.
Avoiding the use of fossil fuel is an example of | [
"Liberalism",
"Ecosystem Vulnerability",
"Conservationism",
"Protectionism"
] | C | An example of conservation is not using fossil fuel |
OpenBookQA | OpenBookQA-421 | galactic-dynamics
Title: What happens to galaxies when they die? Stars explode when they die and blast heavy elements into space. Do galaxies do the same thing? Well, it would be useful to define what a 'dead' galaxy is. Probably the most simple method would be a galaxy that is no longer producing new stars. We might also consider a galaxy that no longer produces significant light in the visual spectrum, or perhaps EMR across the entire spectrum.
Generally, there's unlikely to be a firm line between living and dead, and not nearly as dramatic as larger stars. More akin to watching a camp fire burn itself out. Star formation is largely dependent available gases, but as more and more stars fuse those gases into heavier elements, there is less gas available for star formation. For your average sized galaxy, this will eventually result in running out of gas. Eventually the galaxy will dim and go dark, a process purported to begin at the center of the galaxy, where star formation is heaviest according to research based on Hubble images of giant galaxies. (Tacchella, et al.) The matter ought to (mostly) all still be there and still orbiting the (presumed) SMBH, but with no energy coming from fusion, it's going to be a dark, cold, and barren place. Sounds dead to me.
There are some complicating factors. It's believed that encounters with nearby galaxies can affect available gases. The gravity from a larger galaxy could potentially strip the gases from a smaller one, a fatal blow for the smaller galaxy. Fortunately, it won't suffer much as the death will come (relatively) quickly. This process has been deemed 'strangulation' by a study published in Nature several years months days ago. (Ping, et al.) Note that as the study indicates, the methods of death are proposed solutions - not conclusive understanding of the exact processes that result in a galaxy's death.
The following is multiple choice question (with options) to answer.
What happens after something dies? | [
"chance",
"rot",
"luck",
"magic"
] | B | dead organisms rot |
OpenBookQA | OpenBookQA-422 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
The deforestation can be the cause of what occurrence? | [
"death of trees",
"death of oceans",
"saline solutions",
"global warming"
] | A | if a tree is cut down then that tree will die |
OpenBookQA | OpenBookQA-423 | 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.
Some animals that detect objects by emitting sound live in | [
"the arctic",
"soil",
"a tide pool",
"rivers"
] | D | echolocation is when some animals detect objects by hearing echoes by emitting sound |
OpenBookQA | OpenBookQA-424 | time-series, hypothesis-testing, causalimpact
We expect that when a product is on sale, it will see an increased number of impressions.
We have introduced a new piece of logic that identifies all on sale products and moves them up into a 'better' advertising campaign, with the aim of increasing their impressions over and above what the normal level of impressions for that on sale product would be.
Question
What is the best way to test the impact of this new piece of logic?
In particular, how can I test the impact of moving on sale products into a better campaign (in terms of impressions) relative to what we'd expect for the same on sale products without moving them up a campaign?
I imagine some sort of A/B test where I randomly take some of the on sale products and apply the new logic to them (i.e. move the products up) and compare the change in impressions to a control group of on sale products that I don't apply the new logic to.
Any insight into this problem would be great. I am looking for test that can be implemented in Python. The best way to do a comparison like this is multi-facetted.
The first component is to create an appropriate experiment which means being as completely random as you possibly can and serving an equal number of enhanced and typical advertisement campaigns.
Be super sure that you are being even and fair across times of day, demographics and all possible fronts to limit bias as much as possible.
Ideally I would prefer to have data from before and after the sales collected in both methods as well to give you a sense of how the enhancement works in both sale and non-sale periods of time.
Once you have two sets of data, you need to prepare each set of experiments as a separate time series. You can all the things one might do with time series to explore them separately.
But to do a comparison you can use a granger causality test (here in python, here in R). This test is a test of how well one time series predicts another. It looks at how well a point in set one at a given time is predictive of a value in set two at some time in the future ( some number of lag time increments in the future).
The links explain how it work pretty well and it uses an F-statistic and a p-value like many a good statistical tests.
The following is multiple choice question (with options) to answer.
As demand for product lags | [
"retailers make more money",
"retailers open new branches",
"retailers lose out on revenue",
"retailers double up on their stock"
] | C | as the sale of a product decreases , the amount of money made by the person selling that product will decrease |
OpenBookQA | OpenBookQA-425 | 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.
Seed dispersal happened when the plant's seeds were | [
"sold to a person in another country",
"genetically modified for pesticide resitance",
"destroyed by radiation during processing",
"planted in the same garden"
] | A | seed dispersal is when the seeds of a plant are spread from the parent plant to another area |
OpenBookQA | OpenBookQA-426 | forces, centrifugal-force
This acts to allows the rider to change the bikes trajectory, and pivot slightly about the rear wheel's point of contact and provide some lateral stability.
Aside: An interesting thing about the use of the front wheel to steer a motorcycle (or any bicycle for that matter) is 'mechanical trail' or 'caster'. This quantity is one thing that I was not aware of until I designed and made my own downhill racing bike many years ago. Mechanical trail is the perpendicular distance between the steering axis and the point of contact between the front wheel and the ground. It may also be referred to as 'normal trail'. This quantity is what determines how a bicycle handles when steering. See the picture below
If the trail is positive (trail shown by the green arrows), the bike will be stable. The more trail, the "heavier" the steering. If this distance is (too) negative, you cannot steer you bike (try turning the handle bars of your push bike the wrong way around [we have all done it as kids but I don't recommend it!].
For me, the reasons for trail playing such a key role in the steering stability of a bike is (very loosely) 'causality'. The trail or 'lead' allows the rider to adjust the lateral force on the front tyre as required before the point of contact of the tyre travels the trail-distance. This is a poor, on-the-fly explanation of trail and why it works the way it does and I would be interested to hear some of the other guy’s thoughts on this... but that is another question entirely!
I hope this helps.
The following is multiple choice question (with options) to answer.
when a person pushes a bike pedal it will make the bike | [
"speed to a halt",
"slow down very slowly",
"has zero effect at all",
"accelerate it forward rapidly"
] | D | force causes the speed of an object to increase |
OpenBookQA | OpenBookQA-427 | 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.
It changes from winter to spring because of a | [
"moon",
"cloud",
"star",
"sky"
] | C | the Earth revolving around the Sun causes the seasons to change on its axis |
OpenBookQA | OpenBookQA-428 | 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.
Melissa is creating a new product to quench people's thirst. She thinks it will be more popular if it is less flat. She decides to | [
"add more salt to the drink",
"add some dissolved carbon dioxide",
"shake up the drink bottles before shipping them to the stores",
"boil the drink in a large vat"
] | B | a carbonated beverage contains dissolved carbon dioxide |
OpenBookQA | OpenBookQA-429 | electricity
But in the car, the neutral return is exactly the same thing as the ground reference and so there is no way you can "get yourself between" the neutral and the ground reference.
And even if you grabbed onto the +12 volt terminal of the battery with one hand and the metal body of the car with your other, there isn't enough voltage there to push enough current through your skin and into your body to injure or kill you.
The following is multiple choice question (with options) to answer.
An electric car causes | [
"more CO2 emissions",
"equal CO2 emissions",
"electric emissions",
"less CO2 emmissions"
] | D | an electric car uses less gasoline than a regular car |
OpenBookQA | OpenBookQA-430 | food
Title: Why might food go bad in an oxygen-free environment? I was recently watching a video from the International Space Station (Making a peanut butter sandwich in space), and I noticed he mentioned that a tortilla kept in an oxygen-free environment could last up to 18 months. Impressive, but it got me thinking: Why would some foods ever spoil if kept in a state where molds would not be able to grow? Would it be that other micro-organisms in things like the moisture present in the food eventually take their natural toll? Just a curious thought I had while watching through these awesome ISS videos.
Thanks for any answers! First of all, you assumed that this tortilla went bad after 18 month, not that austranaughts just decided to eat it?
More importantly, there is thing called anaerobs. Just like your muscle don't use oxygen in times of acute stress (force requirement), so there are organisms that don't care much about oxygen. As it happens in muscle, it happens in yeast during fermentation when sugars are turned into alcohols and released energy is used to propel molecular machinery. So, if there are sugar molecules on tortilla, there are still microbes that willing to prosper on it.
The following is multiple choice question (with options) to answer.
A human who goes long periods of time without nourishment will experience | [
"Starvation",
"Perspiration",
"Fullness",
"happiness"
] | A | lack of food causes starvation |
OpenBookQA | OpenBookQA-431 | newtonian-mechanics, energy-conservation, friction, everyday-life, physical-chemistry
Title: Conservation of energy when we drive a car When we drive a car, we use gasoline as the source of energy. When we arrive at the destination, we lose some of the gasoline, used to move the car from one point to another. Then how energy is conserved, if we spend energy to move the car? What does it mean to "spend energy"? In the concrete example, the engine converts the chemical energy in the gasoline through combustion into kinetic energy of the car.
While the car is moving, it feels friction with the surface and air, so some of the kinetic energy of the car goes into friction (heat, air movement, etc).
When you stop the car, the kinetic energy completely goes into friction in the brakes, asphalt and air (again, as heat or kinetic energy of the air molecules, etc).
Conservation of energy means that in a closed system the energy stays constant. If you look just at the car and not also at the surroundings, that is not a closed system, and that principle is not applicable here. However, you can look at the surroundings too; then it all works out.
The following is multiple choice question (with options) to answer.
Why should people conserve gas when fueling their cars? | [
"because it can only be used once",
"because it is hard to find",
"because the more it is used the more it costs",
"because it can mess up their engines"
] | A | fossil fuels are a nonrenewable resource |
OpenBookQA | OpenBookQA-432 | earth-rotation, seasons, time
Title: Are the length of seasons the same globally? Is the length of time, say months, for each season the same all over the world or can it vary? As has been noted in a comment, it depends on how you define seasons (see https://earthscience.stackexchange.com/a/2603/111).
If seasons are defined in astronomical terms, then they have the same length everywhere on the planet. This is simply down to geometry.
However, the effects of astronomical seasons vary geographically in a number of ways. The magnitude of seasonal changes, for example changes in day/night lengths, is more pronounced in higher latitudes, so the effect of (for example) winter might be noticeable for a shorter time period in the tropics than the arctic, and hence some people might reasonably consider winter to be shorter there. There are other, less systematic variations that depend on local climate and weather. In weather terms, not everywhere in the world has the same 4-season cycle that temperate zones tend to experience - so when defining seasons in terms of observable effects one often has, for example, a wet season and a dry season rather than spring /summer /etc.
The following is multiple choice question (with options) to answer.
seasons change due to the earth's | [
"tides",
"size",
"weather",
"degree of angle"
] | D | Earth 's tilt on its axis causes seasons to occur |
OpenBookQA | OpenBookQA-433 | automotive-engineering
Title: What's so special about Tesla's all-electric automobiles, compared to other car manufacturers'?
Why haven't car manufacturers caught up with Tesla's automobiles?
E.g. why haven't the Chevy Bolt, Nissan Leaf, VW e-Golf driven (pun intended) TSLA out of business?
I list TSLA's advantages that don't appear grueling or covert or confidential to mimic, like its exterior appearance. Yet u/skogoa wrote that "Tesla is very good at marketing. Their technology isn't all that special but they have managed to build quite a lot of hype."
i_start_fires. 62 points 5 years ago
Well, they're the only company producing cars that can run 250+ miles on electric power alone. They are single-handedly building a network of charging stations in the US making cross-country electric travel a viable reality for the first time. They recently released their entire patent portfolio into the public domain, allowing any company to use their electric car, battery, and charger designs for free.
Turtlecupcakes. Aug 25 2013.
Their range nearly competes with gas (2-300 miles, I believe)
They look like high-end vehicles, not some pile of plastic that runs on batteries.
The entire in-car dashboard and computer system is built from the ground up so that software can control nearly every single motor, display, relay, and so on. This means that all sorts of functionality can be added at any point through firmware updates. Most existing car manufacturers just build new cars on the old computer systems that were basically hardwired to perform specific function. (So even though the AC is digitally controlled, the only way to change its behavior is to basically take the car apart, pull out the microcontroller, and reprogram it.)
NiceTryNSA. 26 points. Aug 26 2013.
The following is multiple choice question (with options) to answer.
A car can be powered by all but | [
"the push of a cat",
"fossil fuel products refined",
"the motion of atmosphere",
"the warmth of the sun"
] | A | wind is a source of energy |
OpenBookQA | OpenBookQA-434 | That would be a total of 5x30 + 3x40 + 2x60 = 390 plants (with an arbitrary factor that we'll set to 1 without loss of generality).
The amount of highbush is 5x30 = 150.
The amount of lowbush is 3x40 = 120.
The amount of hybrid is 2x60 = 120.
If the opossums didn't care, they would likely eat blueberries in this ratio (null hypothesis H0).
The total that we have observed the opossums to eat is 5% x 150 + 10% x 120 + 20% x 120 = 43.5 plants.
They eat 5% large, which a corresponding fraction of 5% x 150 / (5% x 150 + 10% x 120 + 20% x 120) = 17%
They eat 10% low for 10% x 120 / (5% x 150 + 10% x 120 + 20% x 120) = 28%
They eat 20% hybrid for 20% x 120 / (5% x 150 + 10% x 120 + 20% x 120) = 55%.
Checking... yes the total is 100%.
What we see is that the opossums prefer hybrid by far.
Small blueberries are their second choice.
Last edited:
#### anemone
##### MHB POTW Director
Staff member
Hi anemone!
What do you mean by the symbol E?
Anyway, you've found that the opossums eat 45.8% large and 54.2% small for a total of 100%.
But... what happened to the hybrid blueberries?
By the symbol E, I meant the blueberries (all 3 types of them) that are eaten by opossums...
That would be a total of 5x30 + 3x40 + 2x60 = 390 plants (with an arbitrary factor that we'll set to 1 without loss of generality).
The amount of highbush is 5x30 = 150.
The amount of lowbush is 3x40 = 120.
The amount of hybrid is 2x60 = 120.
If the opossums didn't care, they would likely eat blueberries in this ratio (null hypothesis H0).
The following is multiple choice question (with options) to answer.
A chipmunk will consume all of these things with just one that it refuses to: | [
"jerky",
"grapes",
"nuts",
"acorn"
] | A | a chipmunk eats acorns |
OpenBookQA | OpenBookQA-435 | the-moon, the-sun, earth
That explains the circular movement of the stars, the Sun and the Moon.
This is true for all locations on the Earth, except for the equator:
Is the Earth spinning? That depends, you can always choose a frame of reference that suits you. However, only one of them are non-rotating, the Inertial frame. In all the others we have fictitious forces acting, like centrifugal or Coriolis forces.
We can test if the Earth rotates by watching a pendulum throughout a day. The pendulum would then seem to slowly rotate during this period of time, meaning some fictitious "force" is acting on it. That means that we are located in a rotating frame of reference, and thus the Earth rotates.
The following is multiple choice question (with options) to answer.
What is an example of the Earth rotating on its axis? | [
"constellations are only visible in some parts of the world during certain months",
"cloud coverage varies depending on the season",
"it is always cold in Antarctica",
"the equator moves up and down around the Earth"
] | A | the Earth rotates on its axis on its axis |
OpenBookQA | OpenBookQA-436 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
Arctic animals often live on | [
"ice",
"soil",
"liquid water",
"plants"
] | A | arctic animals live in an arctic environment |
OpenBookQA | OpenBookQA-437 | the-moon, moon-phases
Title: Red cresent moon Yesterday night i witnessed something very strange when i looked outside the window. I saw the moon (crescent) but it was dull red and right on the horizon ,which is strange considering that it is usually on the upper right of the night sky and white in colour. On further inspection with my binoculars i noticed it was lowering down until it was hidden by the mountain range (5km away) next to my building, this all occurred within a few minutes (about 5).
Tonight i saw the moon (crescent) had again returned to its normal position.
Please explain the cause for this, i'm completely baffled!
(Sorry for the poor wording, i'm not familiar with all the astronomical terms!) The dull red color has been due to atmospheric causes, like the reddish sun close to sunset. There hasn't been an astronomical reason for the reddish color.
A few days after New Moon moonset occurs short after sunset, so you won't see the Moon high over the horizon at those evenings. With each day the Moon is a little higher above the horizon after sunset. It's hence less close to the horizon at the same time of the day. Less close to the horizon means less atomospheric absorption/scattering responsible for the dull red color, assuming the same weather conditions.
At Full Moon the Moon is at the opposite side of the Sun relative to Earth. Moon is then rising shortly after sunset.
The following is multiple choice question (with options) to answer.
The moon | [
"has less matter than Earth",
"orbits around the sun",
"weighs more than Earth",
"has more mass than Earth"
] | A | the earth has more mass than the moon |
OpenBookQA | OpenBookQA-438 | visible-light, photons, speed-of-light, refraction
Title: Why does light not slow down? Clearly light bounces off of things, going really really fast. I'm curious to understand how light interacts with matter in order to bounce without:
Applying force to the object
Losing speed
So my questions parts, in the interest of the one given in the title are:
What makes photons move through space and interact with matter the way that they do, down at the core level?
What might happen to a photon if we squeezed one into a photon-sized container and stopped it from even vibrating, for example?
What would speed it back up?
Furthermore, would the speed increase back to light-speed over time, or would the speed be achieved instantly?
The following is multiple choice question (with options) to answer.
What can cause light to bounce off an object? | [
"something painted black",
"surface with aluminium",
"water condensation",
"springs and coils"
] | B | when light hits a reflective object , that light bounces off that object |
OpenBookQA | OpenBookQA-439 | electricity, electric-circuits
Title: Why is it necessary for a circuit to be complete? Can electrons not flow through a load if they do not have a path to flow to the positive terminal of the battery? Why is it absolutely necessary for electrons to end up at the positive terminal? It is not that it is just necessary. Electron flow, in the first place, OCCURS due to the potential difference between the 2 terminals - negative and positive terminals.
Emf or potential difference is the driving force of the electrons in the electric circuit which causes the electrons to flow from the negative terminal to the positive terminal.
If the circuit is not closed, electrons will not flow.
EDIT: As per the comment by brucesmitherson ; In an open circuit, the driving force is not absent, it is just that it is not strong enough to make electrons jump outside of the metal, which requires a lot of energy.
The following is multiple choice question (with options) to answer.
Which of the following, when plugged into an outlet, completes a circuit? | [
"gold",
"glass",
"plastic",
"rubber"
] | A | when an electrical conductor is plugged into an outlet , a circuit is completed |
OpenBookQA | OpenBookQA-440 | human-biology, eyes, vision, human-eye
Title: Superhuman eyesight My ten year old son was reading car number plates that were too fast, too far away and at the wrong angle for any of us to read or even believe that it was possible for him to read. We thought he was lying as he reeled off the whole number plate and not just some. My husband went across the road to prove him wrong and get him to admit he was making it up but he wasn't. We even asked people in the restaurant and waiting staff for their opinion and everyone was blown away. I'm totally astonished and slightly freaked out by his sight and I'm hoping someone can explain for me.
Specifics
The following is multiple choice question (with options) to answer.
Our eyes can help us with | [
"a radio recording",
"shove from behind",
"a label",
"a loud noise"
] | C | seeing is used for sensing visual things |
OpenBookQA | OpenBookQA-441 | evolution, mammals, marine-biology
The question remains: why? The most likely explanation is that cetaceans evolved to exploit an unfilled ecological niche or adapted to new niches that formed as a result of plate tectonics or other types of environmental changes that occurred 50-55 million years ago. The niche describes all of the living and non-living resources needed by an organism to survive. Although land-based mammals were increasing in diversity, few or none were present in the oceans. The basic hypothesis is that the early whale-like artiodactyls, like Indohyus and Pakicetus were land-based (terrestrial) mammals that spent most of their time near the water's edge. Over time, they adapted to the niches in the ocean. Fossils like Ambulcetus and Rodhocetus showed clear evidence of swimming ability, with flattened tails and the enlarged rear feet. In addition, the nostrils shifted from the front of the face to the top of the head, which we recognize as the blowhole.
The shift to the aquatic habitat allowed these species to exploit resources that were not available to land-based mammals, thereby reducing competition for the resources. Reduced competition allows more individuals to survive and reproduce.
Similar scenarios are very likely for other marine mammals, such as seals or manatees. They evolved to take advantage of ecological niches that were not filled by other organisms. This basic concept, evolving to fill available niches, is a common outcome of the evolutionary process.
The of adaptation of cetaceans and other mammals to the oceans may be similar to that of the hippopotamus. Hippos spend most of their time in the water, and they show many adaptations that allow them to live in the aquatic environment. The eyes and nostrils of the hippo are high on the head, which allows them to remain almost entirely submerged but still see and smell, as shown below.
(Hippo photo by Johannes Lunberg, Flickr Creative Commons.)
Hippos feed underwaters, they are heavy enough to walk on the bottom of the river, and the mate and give birth underwater. The young can suckle underwater. Clearly, hippos seem to be another mammal that is "returning to water." Similar types of processes must have occurred in cetaceans for them to adapt to the marine habitat.
The following is multiple choice question (with options) to answer.
in order to better live in its habitat, camels have done one of these | [
"adapted long ears the size of elephant's",
"adapted a raised portion on their dorsal side",
"adapted long snouts to drink from holes",
"all of these"
] | B | An example of an adaptation is camel humps |
OpenBookQA | OpenBookQA-442 | java, performance, game, homework, processing
boolean isAlive(){
return (lifeSpan > 0);
}
}//end class
ParticleSystem class:
import java.util.ArrayList;
import java.util.Iterator;
import processing.core.PApplet;
public class ParticleSystems {
ArrayList<Particles> particlesList = new ArrayList<Particles>();
float xOrigin;
float yOrigin;
int numParticles;
ParticleSystems(float xInit, float yInit, int numInit){
xOrigin = xInit;
yOrigin = yInit;
numParticles = numInit;
while(particlesList.size() < numParticles){
addParticle();
}//end while
}//end construction
void addParticle(){
particlesList.add(new Particles(xOrigin, yOrigin,
(float) Math.random()*2 -1,(float) Math.random()*2 -1));
}// end addParticle
void display(PApplet proc){
for(Particles theParticle: particlesList){
theParticle.display(proc);
}//end for
}//end display()
void update(){
Iterator <Particles> piterator = particlesList.iterator();
int index = particlesList.size()-1;
while(index >= 0){
Particles theParticle = particlesList.get(index);
theParticle.update();
if(! theParticle.isAlive()){
particlesList.remove(index);
}//end if
index--;
}//end while
}//end update
}//end class
The following is multiple choice question (with options) to answer.
If something is alive, then it requires | [
"something to keep it interested",
"a source to propel it forward",
"something to give it hope",
"something to consider doing"
] | B | living things all require energy for survival |
OpenBookQA | OpenBookQA-443 | cellular-respiration
Title: Do cold blooded animals generate any heat? In explaining energy and work to an 8 year-old I said that all conversion of energy generates heat as a by-product. For example, cars generate heat in their engines and running generates heat in our bodies. Then the 8 year-old said, except for cold-blooded animals.
So my question is, do cold-blooded animals generate any heat in their conversion of stored energy (food, fat, etc) into motion? If they generate heat, why are they cold-blooded? They do generate heat. They just do not SPEND energy specifically on heating their bodies by raising their metabolisms. This is a form of energy conservation. The metabolic rate they need to live is not nearly enough to heat their bodies.
An example of spending energy to heat the body is seen in humans shivering. Here muscle is activated not for its usual purpose, but to function as a furnace. "Warm-blooded" and "cold-blooded" is somewhat a misnomer. The correct way to think of it is...
Endotherm or ectotherm. Does the heat primarily come from within (endo) or from the surroundings (ecto). Endothermic animals include mammals. Most of their body heat is generated by their own metabolisms. Ectothermic animals include reptiles and insects. They absorb most of their body heat from the surroundings. This is not the same as saying they let their body temperature fluctuate with their surroundings, some avoid this by moving around to accomodate themselves.
Homeotherm or poikilotherm. Homeotherms want to maintain homeostasis for their body temperatures. They don't want it to change. Poikilotherms do not exhibit this behaviour, instead their body temperatures vary greatly with the environment.
We can have endotherm poikilotherms, such as squirrels, who let their body temperature drop while hibernating. Endotherm homeotherms, such as humans, where temperature is constant by means of complex thermoregulation. Ectotherm homeotherms, such as snakes (moving into shadow or into the sun to regulate temperature), and ectotherm poikilotherms, such as maggots.
The following is multiple choice question (with options) to answer.
People shiver when they are cold and animals: | [
"sleep",
"do the same",
"pant",
"pace"
] | B | cold temperatures cause animals to shiver |
OpenBookQA | OpenBookQA-444 | everyday-chemistry
Title: How does a fire start? I know that fire in a few words is the exothermic reaction of a fuel with an oxidizing agent, but I can't fully understand what exactly happens to piece of wood when it is ignited. How do molecules start producing a flame? In other words, what is the chemistry behind the production of flame? https://www.youtube.com/watch?v=B0E4PX3e3RE It feels somewhat weird to answer my own question but I think this video describes exactly what I wanted. As it supports, when heat is applied to a piece of wood, some bonds of the molecules that make up wood, break and thus different compounds are formed. These compounds are not held back by some force and so they are released in the air. When these compounds meet atmospheric oxygen, under heat (=energy), they burn and thus more heat is released along with carbon dioxide and water. That stage can be described as ignition. Finally, this produced heat is able to preserve the fire.
The following is multiple choice question (with options) to answer.
In a forest without anyone around, a fire may be started by | [
"electricty",
"a bird",
"a landslide",
"a flash flood"
] | A | lightning can cause a forest fire |
OpenBookQA | OpenBookQA-445 | Shanonhaliwell April 8th, 2018 03:31 PM
Quote:
Originally Posted by romsek (Post 591335) outstanding, you seem to be getting the hang of things.
Thanks to you, I was able to do it.
All times are GMT -8. The time now is 12:30 AM.
The following is multiple choice question (with options) to answer.
On a clear day I should | [
"ride my bike",
"Bring an umbrella",
"Wear a coat",
"Stay inside"
] | A | clear weather means sunny weather |
OpenBookQA | OpenBookQA-446 | development
Title: How detachment/separation works in biology? It might be a strange question, but I'm interested in the mechanics of separation/detachment during asexual reproduction, for example when an organism reproduces by budding (I don't mean cellular budding like baker's yeast). When the newly formed body is fully matured it detaches itself from the parent / original body.
It might not be caused by a specific tissue, as animals with not so differentiated bodies are (also) capable of such, but I could easily be wrong. Is this (the detachment) triggered by changes in the cell membrane? I can't really think of other explanations. Reproductive budding and what you call 'cellular budding' are really highly related processes. Budding as a form of reproduction essentially partitions protein aggregates and damaged cellular components into the host or mother and builds fresh or 'young' cells on the opposite side of a partition. To begin understanding this look at Saccharomyces cerevisiae (budding yeast) which forms protein rings (from the septin proteins) at the membrane, around the bud neck which separates the mother and daughter cells Hartwell 1971. This ring acts a partition that in part, withholds protein aggregates and certain proteins from diffusing from the mother to the daughter. This protein ring is an example of how cells limit diffusion of proteins and cellular components to the daughter cell. Another good example that comes to mind is Linder 2007, though it is done in E Coli, not budding yeast, where mother cells maintain protein aggregates and age, while the daughter cells are given fresh components and are therefore more fresh and 'young'.
Now like you mention, imagine this process in a multicellular organism to be fundamentally the same. At some point the multicellular organism will start an outgrowth of cells, while restricting what materials are given to the daughter cells to maintain their youth. And eventually a new organism will have been created. Some of the details will be different, but the fundamental process is is quite similar. In that you start with an old cell that creates a new cell from scratch, but rather than splitting all cellular components equally between mother and daughter, the daughter cells is made in peak condition while the mother cell retains much of the cell 'junk' like protein aggregates.
Hopefully that starts to answer your question.
The following is multiple choice question (with options) to answer.
The part of a cell that separates the interior from the outside provides | [
"nutrients",
"support",
"food",
"energy"
] | B | the cell membrane provides support for a cell |
OpenBookQA | OpenBookQA-447 | A. 7% loss
B. 13% loss
C. 7% profit
D. 13% profit
E. 15% profit
Total cost 60*($250/1.2)=50*250; # of cameras sold is 60-6=54 total revenue is 54*250; # of cameras returned is 6 total refund 6*(250/1.2)*0.5; So, total income 54*250+ 6*(250/1.2)*0.5 The dealer's approximate profit is (54*250+ 6*(250/1.2)*0.5-50*250)/(50*250)*100=13% Answer: D. this must be kind of awkward question but i got no option other than asking you. 20% markup over the dealer’s initial cost for each camera- I made a wrong assumption , but reducing 20%from 250 & got 200 as an initial cost for each. please explain that "Total cost 60*($250/1.2)=50*250;"
(Cost per unit) + 0.2*(Cost per unit) = $250 1.2*(Cost per unit) =$250
(Cost per unit) = $250/1.2 Total cost for 60 units = 60*(Cost per unit) = 60*($250/1.2) = 50*250.
Hope it's clear.
_________________
Intern
Joined: 02 Mar 2010
Posts: 19
Re: A photography dealer ordered 60 Model X cameras to be sold [#permalink]
### Show Tags
The following is multiple choice question (with options) to answer.
as Ford lost customers it's earnings | [
"plummeted",
"raised",
"stayed the same",
"fluctuated"
] | A | as the sale of a product decreases , the amount of money made by the person selling that product will decrease |
OpenBookQA | OpenBookQA-448 | photons, material-science, absorption, optical-materials, glass
Funny thing is, as I wrote this long question, I feel like I answered my own question. Is it basically that whereas the molecules in opaque materials generally convert photons to heat after absorption, those in transparent materials such as glass/water are unable to do so and so must re-emit them? This is a really interesting question, and I worry that you are getting overly bogged down by being unable to focus individually on the different perspectives which are happening at multiple scales. First, let's tackle the more microscopic quantum scale. If we want to understand how light is (or is not) being absorbed by a material, we must first understand what would cause that absorption in the first place. You hit the nail on the head by giving an example of a process that would allow light to be absorbed; absorption of UV-visible light often leads to the excitation of electrons about the various energy levels within the material. A related phenomena might be the absorption of IR light by molecules because of the excitation of the vibrational degrees of freedom into excited states. All together, the various ways that a material may absorb light are collectively determined by the quantum mechanical structure of the material and what levels and states are available. Of course, describing these levels gets increasingly complicated the more complex the material becomes (which is why I have a job!). But there is one key thing you are missing.
While there may be levels present to allow an absorption of light, we still have to ask how likely it is that the light is absorbed! The classic example of such a calculation is Fermi's Golden Rule in perturbation theory for a two level system which relates the probability of absorption to the transition dipole moment between the two states. See MacQuarrie's Physical Chemistry A Molecular Approach, or his Statistical Mechanics for derivations and details. So we not only have to worry about whether there are levels for the light to cause transitions between, but also the probability of this happening at all. This probability analysis becomes more difficult when we then have to consider how frequently the light will actually get an opportunity to be absorbed on its journey.
The following is multiple choice question (with options) to answer.
If a substance can absorb solar energy, then what can or will happen to that substance? | [
"it will see a raising of warmth levels",
"heat levels will decrease exponentially",
"temperatures will be maintained",
"the substance will gradually cool"
] | A | if a substance absorbs solar energy then that substance will increase in temperature |
OpenBookQA | OpenBookQA-449 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
A footprint in a rock may have been from | [
"new rock formation",
"a random break",
"an optical illusion",
"very long ago"
] | D | An example of a fossil is a footprint in a rock |
OpenBookQA | OpenBookQA-450 | evolution, homework
Title: Can someone help me analyze this article? I need to read this article — "Beyond the rainbow" by
Marie-Claire Koschowitz et al., for an exam.
Following are some questions for which I could not figure the answer out after reading.
1) Why does this miniaturization necessitates insulation ? Following is quote from article: "For fast-growing, presumably warm- blooded animals , such miniaturization would only have been possible with sufficient body insulation. "
2) Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ? Why does the article mention reptiles before that ? Are birds reptiles ?
3) The article starts talking about how mammals develop fur and lost their highly differentiated color vision because they gave up structural color signaling. What is the direct connection between mammals and the dinosaurs ? I don't see the parallel here....why bring the mammals into the discussion ?
4) What is the connection between pennaceous feather and planar feathers ?
Any or all questions answered is welcome ! Thanks ! I will answer the questions one by one-
Why does this miniaturization necessitates insulation ?
An organism's volume determines the total amount of heat that can be stored. The loss (exchange) of heat between the body and external environment mainly occurs on the skin's surface. Hence, body volume determines how much heat is stored, while body surface determines how fast that heat is dissipated to the environment. Volume increases with a power of three with radius, while surface increases with a power of two. Hence, smaller animals have large surface-to-volume ratios, which decreases rapidly with body size. Hence, small animals will dissipate relatively more heat per unit of time.
Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ?
No, birds are the closest living relatives to dinosaurs, and birds can be said to have inherited tetrachromacy from dinosaurs - see the cladogram below.
The following is multiple choice question (with options) to answer.
what could it be indicative of, if an animal's fur has grown thicker? | [
"it could be up to something bad",
"the hemisphere could be facing away from the sun",
"it could be summer",
"it could be dying"
] | B | An example of a seasonal change is an animal growing thick fur for keeping warm in the winter |
OpenBookQA | OpenBookQA-451 | solar-system, mars, meteorite
Title: Are there Earth rocks on Mars? Certain meteorites found on Earth have been established to come from Mars: a giant impact ejected rocks from Mars, these rocks traveled through interplanetary space, and went through the Earth's atmosphere without completely burning up.
Might it be possible to find a meteorite on Mars that comes from Earth from the same kind of mechanism?
Earth's gravity is stronger than Mars', so I guess you would need a bigger impact to send debris into interplanetary space. And the atmosphere is thicker on Earth, so the impacting body would need to be even bigger for enough of it to touch the ground. And you also need to give the rocks more energy so that they can go outwards in the Sun's gravitational well. So I'm guessing that impacts that might be violent enough are rarer for the Earth than they are for Mars.
Might it be possible for there to be Earth meteorites on Mars? And if so, is there any chance that we might stumble upon one? Well if no one is going to answer this I will. The answer is we don't know for sure. We speculate that there should be earth rocks on mars but until we 'see' one and analyze it we will not know for sure. The comments here all point to this answer.
Mars hit with thousands of Earth rocks possibly containing life following asteroid impacte talks about the Chicxulub impact and how it probably spread rocks to all the terrestrial planets in our solar system and the moons of all the planets.
The statement comes from Penn State University researchers who have calculated the approximate number of rocks from our planet large enough to possibly carry life that have made their way into space over the past few billion years.
Said the paper’s lead author Rachel Worth: “We find that rock capable of carrying life has likely transferred from both Earth and Mars to all of the terrestrial planets in the solar system and Jupiter. Any missions to search for life on Titan or the moons of Jupiter will have to consider whether biological material is of independent origin, or another branch in Earth’s family tree.”
The article cites its source as The BBC's Dinosaur asteroid 'sent life to Mars' which cites a 2013 paper published in Astrobiology Seeding Life on the Moons of the Outer Planets via Lithopanspermia:
The following is multiple choice question (with options) to answer.
Earth is a similar material as | [
"Mars",
"Jupiter",
"Neptune",
"the sun"
] | A | Earth is made of rock |
OpenBookQA | OpenBookQA-452 | pressure
Title: Microscopic idea of sudden extreme pressure difference I'm having some issues understanding what's happening microscopic when there's sudden changes in the pressure.
The microscopic idea, is that particles randomly bounces around each other. It's even possible with entropy to state all the air can go to one side of the room, and leave a vacuum on the other side but off course very improbable.
But if particles just randomly just bounces around, why are you being sucked out of a space station, if the doors are suddenly opened into the vacuum? Why can the molecules around you feel the doors has been opened another place, if they just randomly bounces around? They are still just "randomly" bouncing around. The problem is that you've now changed the constraints for which they can randomly bounce.
Before, the odds that they could randomly bounce outside the ship are extremely limited. For the most part, bouncing is constrained to other particles and the walls of the ship itself. As soon as you introduce an easier pathway out of the ship, some of the gas will begin randomly bouncing out that hole. What's especially important is that once they start to move away, it's extremely unlikely that much of the air escaping will bounce back into the ship. Instead, they are free to start permeating space where they have very low chances of collisions that would send them back. This creates a net flow rate out of the hole compared to the essentially evenly distributed bouncing around when it is enclosed by walls and pressurized gases.
If you're facing the hole, collisions with gasses behind you are likely to send the air essentially backwards, hitting the air behind it, which cascades until it hits the wall and essentially pushes back on you. In front of you, when you push against the air, it collides with more air, which cascades; but there is no wall to push back against it, so the air just starts flowing out the hole.
The following is multiple choice question (with options) to answer.
Pressure is quite high in spaces such as | [
"the floor of a sea",
"the bottom of a house",
"the bottom of a mountain",
"the bottom of a river"
] | A | as depth increases , pressure will increase |
OpenBookQA | OpenBookQA-453 | 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.
What do steam and ice have in common? | [
"intensive properties",
"form",
"temperature",
"appearance"
] | A | as the temperature of something increases , the intensive properties of that something will not change |
OpenBookQA | OpenBookQA-454 | distance from a given point called centre. You can use the formula for the volume of a cylinder to find that amount! In this tutorial, see how to use that formula and the radius and height of the cylinder to find the volume. As you can imagine, as the discs become thinner, the volume of the sphere gets more accurate. (Assume ≈ 3. Diameter - a line going through the circle from edge to edge, dividing circle in half. The cubic volume of a cylinder is found by multiplying the radius times the radius times pi times the height. Cylinder, hollow Calculate the volume, height, inner or outer radius of hollow cylinder. Cylinder Volume Formula Calculator - How to Calculate the volume of a cylinder. Net of a Cone. Find the area of a circle when you know the diameter. When the piston has moved up to the top of its stroke inside the cylinder, and the remaining volume inside the head or combustion chamber has been reduced to 100 cc, then the compression ratio would be proportionally described as 1000:100, or with fractional reduction, a 10:1 compression ratio. Show that the rectangle of maximum area that can be inscribed in a circle is a square. The Volume of a Cylinder is. The volume of each cone is equal to ⅓Bh = ⅓(28. Volume calculator will determine the volume of the most common geometric solids. The base of the cylinder is large circle and the top portion is smaller circle. Volume of a cylinder : V = πr 2 h where r is the radius and h is the height of the cylinder. It is the same measurement for circles of any size. 25 × 6 Inches Height = 37. cm, the base ring area is 115. What is the value of pi, rounded to the nearest hundredth? 3. However (a) the statements are in the incorrect order; (b) the function calls are incorrect: (c) the logical expression in the while loop is incorrect; and (d) function definitions are incorrect. Their radius (r) is therefore 3 m. Usually the pipe line would be in the shape of cylinder. Now you see that the ratio of the volume of a sphere to the volume of a cylinder is 2/3. 14 x 9 2 x 7. Therefore, the volume of a cylinder = πr2h cubic units. Also, this is important to know that the radius of a circle is always the half of its. Calculate the volume of a
The following is multiple choice question (with options) to answer.
What would you measure in a graduated cylinder? | [
"nitrogen",
"Perfume",
"Oxygen",
"helium"
] | B | a graduated cylinder is a kind of instrument for measuring volume of liquids or objects |
OpenBookQA | OpenBookQA-455 | wildfire
There are detailed satellite imagery with PM2.5 monitor overlay at Aerosol Watch, if you would like to see how the event progressed through time.
The following is multiple choice question (with options) to answer.
After a wildfire, the surviving creatures need to | [
"find new homes",
"dig for food",
"reproduce",
"fight for leadership"
] | A | if a habitat can no longer support animals then those animals will move to another area |
OpenBookQA | OpenBookQA-456 | thermodynamics, electricity, temperature
Title: How to calculate temperature of an incandescent bulb filament? Suppose we have a light bulb, for which we know its power rating, like voltage of $12\mathrm V$, and power consumption of $10\mathrm W$. We also know it's a halogen bulb with a tungsten filament inside. Suppose we also know temperature of the surrounding air.
Is this data enough to compute temperature of the filament? If not, what should also be included? And anyway, how do we find the temperature? You really are asking two questions.
First - how do we calculate the temperature:
At the typical temperatures of an incandescent bulb, the large majority of heat loss is due to thermal radiation. Because of this, the most important factor is the "apparent size" of the filament. I say "apparent" because when you have a tightly wound coil, the parts of the coil facing other parts of the coil don't contribute to a net heat loss - they receive as much heat as they emit.
If you took for example a 5 mm long, tightly wound filament with a mean diameter (after winding) of 0.5 mm, you would have a surface area of approximately $5·π·0.5 \sim 8 \textrm{ mm}^2$. If you had 10 W of emission, you would use the Stefan Boltzmann law to get the power per unit area:
$$I = \sigma T^4$$
from which we get a temperature of
$$T = \sqrt[4]{\frac{10}{8\cdot 10^{-6}\cdot5.67\cdot 10^{-8}}} \approx 2100 K$$
This is of course for illustration only - at 2100 K the bulb is not very bright. Specifically, a real filament has emissivity less than 1.0 which would mean it would run a little hotter (though that pesky 4th power limits the impact somewhat).
Getting more accurate numbers is quite hard - there are lots of subtle effects (conduction down the support wires, heat lost due to imperfect vacuum, emissivity, and "true effective area" to name just four).
The following is multiple choice question (with options) to answer.
An incandescent light bulb requires a filament to | [
"emit illumination",
"emit radiation",
"convert mechanical energy",
"convert chemical energy"
] | A | an incandescent light bulb converts electricity into light by sending electricity through a filament |
OpenBookQA | OpenBookQA-457 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
A glacier is made of | [
"ice trays",
"solid water",
"warm water",
"buckets of oil"
] | B | a glacier is made of ice |
OpenBookQA | OpenBookQA-458 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
After extensive logging activity, a forest had less | [
"water",
"soil",
"carbon dioxide",
"biodiversity"
] | D | cutting down trees in a forest causes the number of trees to decrease in that forest |
OpenBookQA | OpenBookQA-459 | To seven decimal places, this is $r = 0.96824583$, even though the relationship is quadratic rather than linear. Now you have taken a discrete uniform distribution on $1, 2, \dots, n$ rather than a continuous one, but for the reasons explained above, increasing $n$ will produce a correlation closer to the continuous case, so that $\sqrt{15}/4$ will be the limiting value. Let us confirm this in R:
corn <- function(n){
x = 1:n
cor(x,x^2)
}
> corn(2)
[1] 1
> corn(3)
[1] 0.9897433
> corn(4)
[1] 0.984374
> corn(5)
[1] 0.9811049
> corn(10)
[1] 0.9745586
> corn(100)
[1] 0.9688545
> corn(1e3)
[1] 0.9683064
> corn(1e6)
[1] 0.9682459
> corn(1e7)
[1] 0.9682458
That correlation of $r=0.9682458$ may sound surprisingly high, but if we inspected a graph of the relationship between $X$ and $X^2$ it would indeed appear approximately linear, and this is all that the correlation coefficient is telling you. Moreover, we can see from our table of output from the corn function that increasing the value of $n$ makes the linear correlation smaller (note that with two points, we had a perfect linear fit and a correlation equal to one!) but that although $r$ is falling, it is bounded below by $\sqrt{15}/4$. In other words, increasing the length of your sequence of integers makes the linear fit somewhat worse, but even as $n$ tends to infinity your $r$ never becomes worse than $0.9682\dots$.
x=1:100; y=x^2
plot(x,y)
abline(lm(y~x))
The following is multiple choice question (with options) to answer.
When the demand for corn rises | [
"farmers grow different crops",
"farmers ask people to stop eating corn",
"farmers stop planting corn",
"farmers must harvest more corn"
] | D | as the use of a crop increases , the amount of crops planted will increase |
OpenBookQA | OpenBookQA-460 | newtonian-mechanics, fluid-dynamics, acceleration, simulations, power
For your fan, air far away is still. It accelerates as it is sucked in, and slows down as it blows away. When it is far enough away, it is going so slowly that it might as well be still.
The amount of air passing through a fan in a given time is proportional to $v$, the velocity of the air. Said another way, the time it takes a given amount of air to pass through is inversely proportion to $v$.
The kinetic energy of the moving air is $E = 1/2mv^2$. Obviously, air moves at different speeds in different places. But suppose you double the air speed. The air in the fan will double its speed. As the air leaves the fan, it spreads out. But at each place, it is approximately true that it will go twice as fast as it did before. You can reasonably expect that if you double the speed through the fan, that all the moving air will double its speed, at least to some level of approximation.
This tells us something important. We can either take some sort of average $v$, or we can consider the energy of each piece of moving air. Either way, we find that
$$Power = \frac{Energy}{Time} \propto \frac{v^2}{1/v} = v^3 $$
So to double the air speed, the fan needs 8 times the power. $Power \propto v^3$ will be the most important part of your simulation.
The following is multiple choice question (with options) to answer.
If something consumes air, then | [
"it has capacity to grow",
"it is home grown",
"it will grow into a life form",
"it was hatched from a shell"
] | A | all living things grow |
OpenBookQA | OpenBookQA-461 | gas-laws, heat
Title: How can I light a fire in this case? Is there any gas that contains oxygen so that it doesn't require oxygen from the environment in order to burn?
What I am trying to do is use LPG gas, which is fed through a pipe to a burner that is placed in an environment that has no air, somewhat like a vacuum. Is there any way to light the burner inside that vacuum environment?
A few wild ideas that I had included finding some gas that contains oxygen in itself. I may be wrong.
EDIT - The question doesn't end here. Please read the comments section below for any doubts that you might have. And if it isn't answered in comments section then ONLY comment. The most convenient solution for your question can be the Hydrooxy gas (also sometimes called the Brown’s gas). Simply put its water split into hydrogen and oxygen. Hydrogen and oxygen can be combined back by ignition and can create a maximum temperature up to 2800 °C (around 600–700 °C hotter than burning hydrogen in air), which makes it a good fuel for metal welding and cutting.
Though 2:1 hydrogen and oxygen ratio is enough to produce water via combustion, but on a practical solution you will need around 3:1 to 5:1 ratio to avoid oxidizing flames. The temperature you can achieve by burning hydrogen oxygen mix varies, depending on the ratio of both gases used.
Hydrogen and oxygen can be obtained via simple electrolysis.
$$\ce{2H2O + Energy -> 2H2 + O2}$$
and combined back as
$$\ce{2H2 + O2 -> 2H2O + Energy}$$
It might be worth noting that for all practical purposes, the energy you use to split hydrogen and oxygen will always be greater than what you can get by combining them back (like what happens in every combustion engine, humans have ever created).
If you are planning to develop an actual application, there are many precautions that you would need to consider, the most important of which would be back-fire protection (a common problem with gas based welding), so that the flame doesn’t reach back into the gas tank, which of course will explode.
The following is multiple choice question (with options) to answer.
Burning natural gas can | [
"keep you cozy on a frigid night",
"conserve valuable planetary resources",
"aid in cooling down the planet",
"keep a car running in the cold"
] | A | natural gas is a source of heat by burning |
OpenBookQA | OpenBookQA-462 | mechanical-engineering, structural-engineering, control-engineering
For example, if I wanted to setup such a facility, who would I have to consult?
You either find a consulting engineering firm with a lot of experience in designing and planning (and building!) such a plant. Or you find anexperienced hydroponics expert (the first bullet point) and a consulting firm with experience in a relevant field like wastewater.
Alternativly, you find a company specialized in building and selling hydroponics farms. This will give you less choice over the final plant - the company will want to work with their preferred components and concepts, and crucially they will want to reuse as much egnineering work from previous projects as they can.
The following is multiple choice question (with options) to answer.
Where would a greenhouse best be used? | [
"Bahamas",
"Nebraska",
"Florida",
"Mexico"
] | B | a greenhouse is used to protect plants by keeping them warm |
OpenBookQA | OpenBookQA-463 | zoology
From Scripture's research: “. . . a live frog can actually be boiled without a
movement if the water is heated slowly enough; in one experiment, the
temperature was raised at the rate of 0.002 degrees Celsius per
second, and the frog was found dead at the end of 2.5 hours without
having moved."
According to Dr. Karl S. Kruszelnicki (Australian scientist): "[T]he numbers just don’t seem right. If the water comes to a boil,
that means a final temperature of 100 degrees Celsius. In that case,
the frog would have to have been put into the water at 82 degrees
Celsius. Surely, the frog would have died immediately."
According to Dr. Victor H. Hutchinson (Herpetologist and Zoology Professor at University of Oklahoma):
"The legend is entirely incorrect! The 'critical thermal maxima' of many species of frogs have been
determined by several investigators. In this procedure, the water in
which a frog is submerged is heated gradually at about 2 degrees
Fahrenheit per minute. As the temperature of the water is gradually
increased, the frog will eventually become more and more active in
attempts to escape the heated water. If the container size and
opening allow the frog to jump out, it will do so."
Whit Gibbons (University of Georgia) says that there is an important message behind the false legend:
So where does that leave us with the boiling frog as a metaphor for
the human response to economic change or environmental degradation?
Well, it's not true that you can induce a frog to willingly remain in
boiling water by starting it off in cold water. But that does not
diminish the truth of the message that the accumulation of
imperceptible changes can have a significant effect on the economy and
the environment. We need to be aware of what changes are occurring and
to respond to them in a timely fashion. The metaphor lies in the
frog's ability to escape from the container: if there's no way out,
then the frog's fate is a foregone conclusion.
The following is multiple choice question (with options) to answer.
John's pet frog was sick because it wasn't staying warm enough. Maybe | [
"The frog was getting burned by a heat lamp",
"the frog was unable to regulate its body temperature without an external heat source",
"The frog was using too much ice in its drinks",
"The water in the tank had dried up."
] | B | an amphibian is cold-blooded |
OpenBookQA | OpenBookQA-464 | 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.
what creates no pollution? | [
"natural fuel like coal or gas",
"mills that makes energy from the wind",
"buildings that make large quantities of items",
"transportation contraptions with four wheels"
] | B | a windmill does not create pollution |
OpenBookQA | OpenBookQA-465 | javascript, performance, beginner, game, canvas
// Following code is a fix for [[obj1, obj3], [obj2, obj4]].
if (alreadyHadCollisions && (index1 > -1 || index2 > -1)) {
for (i4 = 0; i4 < this.collisions[collisionIndex].length; ++i4) {
obj3 = this.collisions[collisionIndex][i4];
if (obj3 !== obj1 && obj3 !== obj2) collision.push(obj3);
}
this.collisions.splice(collisionIndex, 1);
}
if (index1 > -1 || index2 > -1) {
alreadyHadCollisions = true;
collisionIndex = i3;
}
}
if (!alreadyHadCollisions) this.collisions.push([obj1, obj2]);
}
}
}
}
for (i1 = 0; i1 < this.collisions.length; ++i1) {
var targets = this.collisions[i1],
biggestRadius, scaleFactor;
obj1 = targets[0];
biggestRadius = obj1.getRadius();
for (i2 = 1; i2 < targets.length; ++i2) {
obj2 = targets[i2];
var density = Math.max(obj1.density, obj2.density),
area = obj1.getArea() * (obj1.density / density) + obj2.getArea() * (obj2.density / density);
The following is multiple choice question (with options) to answer.
Tearing an object changes that object's | [
"nutrition",
"biology",
"chemical composition",
"formation"
] | D | tearing an object changes that object 's shape |
OpenBookQA | OpenBookQA-466 | solid-state-chemistry
Title: Is it possible to determine the age of a building by just looking at its window? I've recently come across the fact that glass is an amorphous solid and is known as a pseudo solid or a super cooled liquid. Our teacher told us that buildings that if we were to closely observe the glass in the window panes, we would find that it's thicker at the bottom. I'm now wondering if we can calculate the difference between the width of the top and bottom of the window, would it be possible to determine an approximate age of a building? This is but an urban legend. Glass does not get thicker at the bottom. (Sure, glass is fluid to some tiny extent, and it can be demonstrated, but not in this way.) It is just that the glass panes were initially manufactured with uneven thickness. Then the people who stuck the glass into the frames would orient the thicker side down, maybe because it is more stable this way, or because it feels right, or just to mess with us. Sometimes they didn't pay attention and turned it randomly.
Supporting links: 1, 2.
The following is multiple choice question (with options) to answer.
Which is a solid? | [
"Kool-aid",
"urine",
"helium",
"ice sculpture"
] | D | Matter in the solid phase has definite shape |
OpenBookQA | OpenBookQA-467 | homework-and-exercises, newtonian-mechanics, forces, energy, work
Title: A man carries an object in two different ways. In which will work done be greater? The man is carrying a mass of 15 kg over a distance of 2 meters. I think that in case(i) the work done would be greater as both the force applied and displacement are in same direction. But the answer says case(ii). How will that be possible. Please clarify. Rather than thinking of the force applied by the man and the distance moved by the block, think of the energy difference.
You will notice that in the first case, the body is just shifted parallel to the horizontal surface i.e. its P.E does not increase. But in the second case, the potential energy increases, which invariably means that he has done work.
Now coming to your doubt, in the first case, the man exerts a force in the upward direction (to hold the weight) while displacement is perpendicular.
In the second case, the man exerts a force on the rope, and rope transfers the force to the block, in its direction of motion (upwards).
Hope you understand
The following is multiple choice question (with options) to answer.
A heavier object | [
"requires less force to move",
"requires minimal effort to move",
"requires more muscle power to shift",
"requires a light touch to move"
] | C | as the mass of an object increases , the force required to push that object will increase |
OpenBookQA | OpenBookQA-468 | thermodynamics, statistical-mechanics, entropy
Title: Breaking down of 2nd law of thermodynamics Do you know a scenario where the second law of thermodynamics breaks down? The second law breaks down when some of the assumptions underlying this law (or the thermodynamics itself) are broke.
Among what is typically cited as "violations" of the second law are:
Violation of the laws of thermodynamics in small systems. Thermodynamics and statistical physics are applicable in thermodynamic limit that is for systems with a huge number of particles. While in some cases this number may be much smaller than the Avogadro number ($N_A\sim 10^{24}$), violation of the thermodynamics in systems with a finite number of degrees-of-freedom is not surprizing. This is equally true for ratchets and billiards.
Entropy decrease in some systems, notably in living systems. This is again not surprizing, since these are open systems, which exchange energy and matter with the environment. Thus, while the entropy of the system might be decreasing, this is accompanied by the increase of entropy in the environment, and the net entropy is growing. See this answer and this answer for more background.
The following is multiple choice question (with options) to answer.
An example of breaking down is | [
"cutting an apple into slices",
"putting a jigsaw puzzle together",
"mixing cake ingredients together",
"applying coats of paint onto a wall"
] | A | break down means change from a whole into pieces |
OpenBookQA | OpenBookQA-469 | species-identification
Title: Trying to identify the tree in this picture. Shot from the Nepenthe restaurant, Big Sur, California I'm trying to identify the tree in this picture. This was shot from the Nepenthe restaurant, Big Sur, California.
Any help is appreciated!
Thanks,
Robert It's difficult to make out the leaves in the photo, but the tree in the foreground appears to be a coast live oak (Quercus agrifolia). The tree has hairy lichen growing on its branches.
The following is multiple choice question (with options) to answer.
which of these indicate non-living tree? | [
"it stands tall with flowers",
"none of these",
"it is fresh and green with strong roots",
"it lies horizontally on the park grounds"
] | D | if a tree falls then that tree is dead |
OpenBookQA | OpenBookQA-470 | research, hri, uncanny-valley
In my personal opinion, there's no doubt something like the Uncanny Valley exists, even though it may not quite take the shape Mori gave it (Bartneck et al., 2007). Artists of all ilk have long been aware of it and have deliberately used it (e.g. Chucky or any zombie movie ever) or suffered when falling into it (the Polar Express being the most notable example). Several explanations have been put forward to explain it (Brenton et al., 2005; MacDorman, 2005; Saygin et al., 2010) and it's been observed in monkeys as well (Steckenfinger and Ghazanfar, 2009), so it's very likely evolutionary in nature.
If you are interested in this area, I'd probably look at how people suffering from autism process faces in general. In this area, there have been a number of studies using real faces (e.g. Scholar search autism "facial features"), as well as artificial faces (e.g. Scholar search autism cartoon faces). This difference in decoding facial expressions might explain why they seem to not feel the effects of the uncanny valley the same way other people do.
As for Kaspar in particular, Blow et al. (2006) goes into some detail on the design decisions involved in Kaspar's face. Also, in a YouTube video, Kaspar's creators cite predictability and simplicity as some of the reasons for his particular design.
References:
The following is multiple choice question (with options) to answer.
Which of the following could make more people want to wear masks? | [
"A bicycle race with hundreds of participants",
"the use of electric lawn mowers",
"contaminated hamburger meat from the grocery store",
"a bus that uses a petroleum product for fuel"
] | D | burning gasoline is a source of pollution |
OpenBookQA | OpenBookQA-471 | human-biology, red-blood-cell
Title: How do people who have lost both of their legs produce red blood cells? As far as I know, just leg bones produce red blood cells. So, how people who lost their both legs produce red blood cells? Red blood cells are produced in the red marrow which...
"is found mainly in the flat bones, such as the pelvis, sternum,
cranium, ribs, vertebrae and scapulae, and in the cancellous
("spongy") material at the epiphyseal ends of long bones such as the
femur and humerus." - Wikipedia
So you are partly right; the femur is associated with red blood cell production, or Erythropoiesis to give it it's technical name, but there are other bones within the human body that also do this job. The process of erythropoiesis is stimulated when the kidneys detect low levels of oxygen in the blood stream and stimulate production of the hormone erythropoietin. Further, the role of the tibia and femur in erythropoiesis also decreases with age whereas...
"the vertebrae, sternum, pelvis and ribs, and cranial bones continue
to produce red blood cells throughout life." - again from the wiki page
So I'd suggest it is unlikely that loss of the legs would have a major impact on the production of red blood cells in adults. I imagine that with the loss of legs comes some reduction in functionality of erythropoiesis but also a lower requirement of red blood cell production (less blood capacity = less blood cells needed = less blood cells need to be produced). I can't find any studies which explore the ability or needs of amputees and non-amputees with regards to red blood cell production.
The following is multiple choice question (with options) to answer.
The skeletal system | [
"is made up of tissue and organs",
"is made up of the lungs and heart",
"is made up of white blood cells",
"is made up of calcified material"
] | D | skeletal system is made of bones |
OpenBookQA | OpenBookQA-472 | material-science
Title: Wood: A Naturally Occurring Composite Material? In materials science texts, I see wood used an example of a naturally occurring composite material. One of the main components of wood is cellulose, which is a polymer. But what other component makes it a composite?
Thanks for any clarification. the two components of wood-as-a-composite are cellulose fibers and lignin, the resin in which the cellulose fibers are embedded. Cellulose furnishes strength in tension and the resin furnishes strength in shear.
The following is multiple choice question (with options) to answer.
What are a source of fibers? | [
"water",
"plantlife",
"rocks",
"air"
] | B | plants are a source of fibers |
OpenBookQA | OpenBookQA-473 | neuroscience, neuroanatomy
Likewise, the spinal chord is structured into sensory and motor regions. In summary, the spinal chord consists of: 1) cell bodies (motor, sensory, inter; grey in the picture), 2) ascending axons (blue), 3) descending axons (red). Similar to nerves, axons going up or down the spinal chord are bundled into "tracts". Sensory axons are never bundled with motor axons, making it possible to create a map of the spinal chord in cross-section.
The tracts' names might be a bit confusing at first, but on second look are actually pretty self-explanatory. They usually contain where the axons come from and where they are going in order to synapse with other neurons. E.g. the spinocerebellar tract is formed of axons coming from the spine and going to the cerebellum. Given that the cerebellum is near the brain and the spine is further down, this is obviously an ascending tract - and ascending tracts are always sensory (because sensory information never needs to be carried downwards due to the brain being at the top).
Where it gets blurry
The sensory/motor separation isn't always as clear as I've described above. In fact, nerves (bundles of axons anywhere in the body outside of the CNS) will usually contain both sensory and motor pipelines. In particular, the cranial nerves (12 of the most important nerves) all include sensory and motor components for the respective part of the body that they manage. E.g. the facial nerve contains both the sensory connections for parts of the tongue and the motor connections that control facial muscles.
Another more complex example is pain sensation, where interneurons in the spinal chord can feed back onto sensory neurons and inhibit their signals, or axons can inhibit those packed in the same nerve bundle simply due to electrical effects.
The following is multiple choice question (with options) to answer.
The spinal cord contains | [
"electrically excitable cells",
"nerve gas",
"biological impulses",
"hair follicles"
] | A | nerves are made of nerve cells |
OpenBookQA | OpenBookQA-474 | human-biology, reproduction
Title: Why are animal births not taken as seriously as human births? When humans give birth, more than often medical assistance is needed. Others gather around and frantically look for any way to help. But when an animal gives birth, it is usually seen as a moment where you give the female its space and let the birth occur naturally and without any assistance. The animal is of course in serious pain just as a female human but this is more than often not taken into account. Why is it that animal births are not taken as seriously? Our heads are bigger.
There's some debate on the issue, but in essence, human brains, and therefore heads, are very large relative to our body size. This is handy for all the intelligent things we like to do, but can be rather painful during birth. Because we walk upright, the size of a newborn's head is actually a non-trivial fact during the birthing process. There are two major implications.
The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult. Evolution has (supposedly) limited the size of the hips because, while that would allow an easier birthing process, it would negatively impact our ability to walk. As such, it has to hurt.
Secondly, in order to make the process easier, humans rotate during birth. The end result is that, unlike even other closely related primates, humans come out backward in a way that is very difficult for a birthing female to attend to. This almost requires having another person or two on hand to help out. This would, of course, be a huge reinforcement for social connections.
A few books I know of touch on this. Up From Dragons deals with the brain size/hip size issue and The Invisible Sex talks about rotation during the birthing process and the social implications.
The following is multiple choice question (with options) to answer.
Humans cry when they are born, horses can walk when they are born, and birds can chirp when born because of | [
"TV",
"learning from mom",
"instinctive behavior",
"school"
] | C | an animal knows how to do instinctive behaviors when it is born |
OpenBookQA | OpenBookQA-475 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
When cutting down rain forests, it is important to keep in mind air quality. When too many trees are cut down in a given area, there may be decrease in the air's | [
"quality",
"carbon dioxide",
"helium amounts",
"carbin dioyide levels"
] | A | carbon dioxide can be found in the air |
OpenBookQA | OpenBookQA-476 | mechanical-engineering, materials, automotive-engineering
Any time you've got a hot thing that needs to be cooled by convection, the limitation is the interface between the air and the object to be cooled. A thin copper plating -- or even making the whole rotor out of copper -- isn't going to help this.
The following is multiple choice question (with options) to answer.
Which of these items was able to keep things cool thanks to electrical conversion? | [
"magic carpet",
"snowy road",
"light bulb",
"table fan"
] | D | electrical devices convert electricity into other forms of energy |
OpenBookQA | OpenBookQA-477 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
How would a location's climate be determined? | [
"look at the weather many mornings, afternoons, and evenings in different seasons",
"look at the the most extreme weather events",
"look at the weather at noon only",
"look at the weather on one day"
] | A | climate is the usual kind of weather in a location |
OpenBookQA | OpenBookQA-478 | newtonian-mechanics, newtonian-gravity, acceleration
Title: Why didn't I beat the avalanche? Yesterday, while skiing out of bounds on the south west canyons of Mt. Hood, I experienced a small and extremely mild quake. This, combined with the melting conditions caused an extremely small avalanche in the canyon region we where in.
This was extremely mild in the spectrum of what is shown on TV or from what I've seen in other videos. A snow field of a bout 100 sq.m, shifted about 100 m down hill. And while mild, this was still my first ever experience in this type of situation.
Im a fairly experienced skier and we were already traveling downhill at about 35 mph +/- (we were tracking with a racing GPS app), when the snow "gave out from under". In normal "powder" and "good" snow, it normally feel like im floating on the snow. In this situation, it felt like I was being pushed from behind, while sinking under. Maneuvering was next to impossible and the only option to accelerate was to "tuck". While initially I accelerated a little, the snow caught me and my group rather easily and rapidly. Gladly, no one was hurt, but my questing are as follows:
1) If all free falling objects accelerate at the same rate (this was on a fairly steep mountain section), why did we get "trapped" into the avalanche, when our acceleration already had 35 mph +/- accelerating it? Did the thicker snow breaking and shifting somehow create more friction between my ski and the snow?
2) Most modern ski's today have alot more "nose curve", also known as rocker, in the front and back, in order to break through thicker snow with more ease The skis I was riding have what most in the ski world would call "excessive rocker". Why was it so easy for snow to sink me down, when my ski's design is for 2+ ft of snow and I was forcefully trying to "float" above the collapsing snow? This avalanche was tiny in the spectrum of perimeter and mass traveled., And also only lasted about 3 seconds. Tl;DR: It is mainly due to the skier's positioning on the ski and how being thrown off-balance by the avalanche affects it.
Concerning the first part of the first question:
The following is multiple choice question (with options) to answer.
How can a woman's compact best help if she is lost on a mountain? | [
"She will be able to fix her appearance to be more likely to receive help",
"She can use the makeup as camouflage",
"she can use the mirror to signal someone",
"She can break the mirror to use the pieces for a weapon"
] | C | a mirror reflects light |
OpenBookQA | OpenBookQA-479 | photosynthesis, respiration, ecosystem, decomposition
Maybe you should study the metabolic processes of plants and life in general to better understand this. All life consists of chemical reactions that build up structures; in order to build them up you need energy (because of the second law of thermodynamics), and all living things create that energy by breaking down complex molecules into simpler ones. (as such it would be more accurate to say that all life consists of chemical reactions that build up and break down various structures). You might be wondering "but what about the difference between autotrophs and heterotrophs I heard about"; the difference between those is where they get the complex molecules from in the first place. Autotrophs use a different source of energy to build them up while heterotrophs get them from their environment. As such, you can think of every living thing as being made of two kind of molecules: those that actually form their structure (in humans, the molecules that make up cell membranes, bones, muscles, etc) and those that are stored in order to be broken down to power the whole system (in humans that's fat, glycogen, glucose, etc). Of course a molecule can do both; if you're starving your body may start to break down structural molecules for power. There are many different ways of breaking down those big molecules for power; the most efficient one, that starts with a big chain of carbon atoms and cuts it down into individual CO2 molecules using O2 molecules, is called aerobic respiration (i.e. respiration that uses oxygen).
Because those complex molecules are required to power all life, autotrophs (the organisms that actually make them) are very important, and the processes they use to make them are very important too. The process that makes almost all of the molecules that power almost all life on earth is photosynthesis, which uses the energy from the sun to power a reaction that converts CO2 from the atmosphere into big carbon-based molecules we'll call carbohydrates. This is called "fixing carbon", since the carbon atom is the most important one; measuring how much photosynthesis is happening is another way of measuring how many carbon atoms move from being part of a CO2 molecule to being part of a plant.
The following is multiple choice question (with options) to answer.
We have respiration in our bodies to | [
"deal with gas",
"Talk for hours",
"Thinking",
"Running"
] | A | living things require respiration to use energy |
OpenBookQA | OpenBookQA-480 | zoology, ethology, sociality
Canfield, J., Hansen, M. V., Becker, M., & Kline, C. (1998). Chicken Soup for the Pet Lover’s Soul. Deerfield Beach, FL: Health.
The following is multiple choice question (with options) to answer.
Many animals entered the city because of | [
"global warming",
"buildings",
"warm streets",
"logging"
] | D | if a habitat is destroyed then that habitat can not support animals |
OpenBookQA | OpenBookQA-481 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
What is it termed when a squirrel is inanimate | [
"death",
"inertia",
"colluded",
"emanated"
] | A | if a living thing dies then that living thing is dead |
OpenBookQA | OpenBookQA-482 | glaciology, glacier, ice
What would be a good average to take? This is a non-trivial issue. When you look at volume change of a glacier, you typically subtract two digital elevation models to obtain the difference between the two. First, you must differentiate between ice sheets where ice berg calving reduces volume and more ordinary glaciers with melt processes. There are of course calving glaciers as well so it is possible to get into great detail for any one specific glacier, so here I will just discuss the most common case which is a smaller glacier with melt-freeze conditions.
The change in elevation differs in magnitude across the glacier surface due to the movement of the glacier and accumulation-melt processes. The surface material can be (1) glacier ice, (2) snow, (3) firn snow that has survived a melt season) or (4) super imposed ice all with more or less differing densities, you need to assess what sort of material has been removed.
Ice can be approximated by a density of 900 kg/m3, firn has a density of about 600 kg/m3 but it must be remembered that the firn is converted to glacier ice by metamorphic processes so that the density changes with depth from 600 to 900 kg/m3. the transition to ice occurs at depths of about 30 m in temperate glaciers although few studies exist on the actual processes that occur. Snow have very differing densities but considering averages, I would say that it would vary between 350 to maybe 500 kg/m3 for winter (cold) conditions and around 550 kg/m3 for a melting snow pack. Super-imposed ice is closer to ice and probably varies in the upper range of 800--900 kg/m3.
To make matters worse, snow superimposes firn which in turn superimposes ice. This means that in the accumulation area, volume change can result from both a reduction in a snow cover and the firn layer. In the zone near the equilibrium line there can be a loss of both firn and ice. this is also where the superimposed ice will play a role.
So there is no simple density to use since the loss you try to estimate will involve varying types of densities spatially as well as vertically. For annual changes, you can largely ignore the vertical distribution, but with volume changes covering larger periods where climate change influences the longer term location of the equilibrium line and the size of the accumulation area, vertical layering also has to be included.
The following is multiple choice question (with options) to answer.
What can melting glaciers deposit? | [
"heaps of ice cubes",
"heaps of confused penguins",
"heaps of crystalline solids",
"heaps of coral reef"
] | C | sometimes piles of rock are formed by melting glaciers depositing rocks |
OpenBookQA | OpenBookQA-483 | python, performance, programming-challenge, time-limit-exceeded, pathfinding
Title: BFS shortest path for Google Foobar challenge "Prepare the Bunnies' Escape" This is the Google Foobar challenge "Prepare the Bunnies' Escape":
You have maps of parts of the space station, each starting at a prison
exit and ending at the door to an escape pod. The map is represented
as a matrix of 0s and 1s, where 0s are passable space and 1s are
impassable walls. The door out of the prison is at the top left \$(0,0)\$
and the door into an escape pod is at the bottom right \$(w-1,h-1)\$.
Write a function answer(map) that generates the length of the shortest
path from the prison door to the escape pod, where you are allowed to
remove one wall as part of your remodeling plans. The path length is
the total number of nodes you pass through, counting both the entrance
and exit nodes. The starting and ending positions are always passable
(0). The map will always be solvable, though you may or may not need
to remove a wall. The height and width of the map can be from 2 to 20.
Moves can only be made in cardinal directions; no diagonal moves are
allowed.
Test cases
Input:
maze = [[0, 1, 1, 0], [0, 0, 0, 1], [1, 1, 0, 0], [1, 1, 1, 0]]
Output:
7
Input:
maze = [[0, 0, 0, 0, 0, 0], [1, 1, 1, 1, 1, 0], [0, 0, 0, 0, 0, 0], [0, 1, 1, 1, 1, 1], [0, 1, 1, 1, 1, 1], [0, 0, 0, 0, 0, 0]]
Output:
11
The following is multiple choice question (with options) to answer.
The worst place to leave a candy bar is | [
"refrigerator",
"closet",
"freezer",
"sunlight"
] | D | sunlight produces heat |
OpenBookQA | OpenBookQA-484 | reaction-mechanism, safety
Title: What are the consequences of mixing Ferric Chloride Solution, distilled vinegar, baking soda and water? I was attempting to etch and blade with a ferric chloride solution. I did not have enough so I filled a glass with vinegar and water (3 parts vinegar to 1 part water) then added 2 oz. of ferric chloride solution. I added baking soda later to neutralize the ferric chloride solution, but was met with a deep red foam. I quickly added more baking soda and flushed the solution down a deep sink in my basement. I rinsed out the sink and glass with water and continued to add baking soda to neutralize any ferric chloride solution that had been spread by the red foam. What reaction occurred and is this and do I need to worry about it? I suspect the red salt you are seeing is Iron (III) carbonate, which was likely created from, as you noted, the neutralization of aqueous Iron (III) chloride with Baking Soda (in excess?) per the reactions:
$\ce{FeCl3 (aq) + 3 NaHCO3 (aq)-> 3 NaCl (aq) + 2Fe(HCO₃)₃(aq)}$
$\ce{2Fe(HCO₃)₃ (aq) → Fe₂(CO₃)₃ (s) + 3H₂O (l) + 3CO₂ (g)}$
$\ce{2Fe(HCO₃)₃ + HAc (aq) → Fe₂(Ac)₃ (s) + 3H₂O (l) + 3CO₂ (g)}$
where the last reaction could also lead to Iron (III) acetate from the vinegar presence, which is also subject to further neutralization by the Baking Soda.
The following is multiple choice question (with options) to answer.
what can baking soda and vinegar do together? | [
"they will boil",
"they turn hard",
"a combined reaction",
"they do nothing"
] | C | baking soda can react chemically with vinegar |
OpenBookQA | OpenBookQA-485 | f#, playing-cards
Suit = Diamonds;}; {Face = Two;
Suit = Hearts;}; {Face = Three;
Suit = Hearts;};
{Face = Four;
Suit = Hearts;}; {Face = Five;
Suit = Hearts;}; {Face = Six;
Suit = Hearts;}; {Face = Seven;
Suit = Hearts;};
{Face = Eight;
Suit = Hearts;}; {Face = Nine;
Suit = Hearts;}; {Face = Ten;
Suit = Hearts;}; {Face = Jack;
Suit = Hearts;};
{Face = Queen;
Suit = Hearts;}; {Face = King;
Suit = Hearts;}; {Face = Ace;
Suit = Hearts;}]
The following is multiple choice question (with options) to answer.
Cardinals | [
"have live births",
"eat only meat",
"incubate their food",
"incubate their young"
] | D | some adult animals lay eggs |
OpenBookQA | OpenBookQA-486 | combustion
But when things are that hot, plenty of other reactions can occur and this is particularly noticeable if the thing that is burning is less pure than charcoal (which is mostly carbon). Raw coal, for example, contains a lot of volatile impurities (smokeless coal is deliberately treated to reduce the volatile impurities). When the primary reaction of burning carbon happens in raw coal, those volatiles are often turned to gases and driven off the coal to combust as gases far from the solid coal. Of course this is happening at the same time as solid carbon in the coal is burning so the two effects are mixed up to give both glowing coal and gases burning some distance from the glowing coal. Old home chemistry sets used to contain experiments that allowed these effects to be separated. Raw coal is placed in a vessel connected to a tube allowing any emerging gas to be directed far away from the coal. The coal is heated with an external source (eg a Bunsen burner). The emerging volatile gases can then be lit without setting the coal on fire giving a flame a long distance away from the heated coal.
The same can be done with wood (which contains even more volatile and flammable components than coal).
So, when wood or coal burn in an uncontrolled way both the burning of the solid and the burning of the volatiles contained with the solid occur at the same time but the volatiles (as gases) can move far from the solids before they burn. This is why the position of the fame can be far from the burning solid.
Also worth noting
In addition to the volatiles being driven from the burning solid, partial combustion can also create gases like carbon monoxide which can then travel some distance away from the solids while burning (though CO tends to have not very bright blue flame). In fact a controlled version of this reaction (which sometimes also used steam to create hydrogen) was once the primary way of creating town gas (which was widely distributed to support gas lighting and cookers in cities.
If the primary goal is to create flames designed to illuminate rather than heat then burning can be designed to create a lot of small hydrocarbon particles in the flame. This is intentional for things like candles. Here the heat may come from burning the was but the light comes because that burning creates small incandescent soot particles which are heated enough to glow turning a lot of the energy into light.
The following is multiple choice question (with options) to answer.
Coal and oil directly removed from the ground are | [
"directly consumed",
"thrown away",
"made into products",
"stored underground"
] | C | if something is a raw material in a process then that something is required for that process |
OpenBookQA | OpenBookQA-487 | geology, geophysics, climate-change, carbon-cycle
We can see here in white numbers the most significant pre-industrial sources and sinks (at ~1000 years time scales). We can see that humans produce 9 Gigatons of carbon per year (GtC/yr), due to that extra inflow, photosynthesis is taking 3 GtC/yr more than before, and the ocean is taking an extra 2 GtC/yr as well. However, that is not enough to counteract the 9 GtC/yr we produce, and that is increasing the amount of carbon in the atmosphere at 4 GtC/yr. This means the level in the atmospheric "bath tub" is still rising.
If we were to keep those 9 GtC/yr we produce stable (i.e. not increasing production in the future). The concentration of $\ce{CO2}$ in the atmosphere will rise to a level high enough that the sinks will match the sources, for example with plants taking 5 GtC/yr and the ocean 4 GtC/yr, that would nicely balance the production. But that new equilibrium atmospheric $\ce{CO2}$ concentration would be high enough to rise Earth's temperature several degrees and force a whole reorganization of the Earth's climates.
Finally, we have to say that some of these $\ce{CO2}$ intakes, like the oceanic one, don't come for free, and have their own nasty consequences, like ocean acidification.
The following is multiple choice question (with options) to answer.
Changes to the earth can be done as a result of | [
"high temps",
"mild weather",
"large storms",
"snowing clouds"
] | A | natural events usually cause changes to Earth 's surface |
OpenBookQA | OpenBookQA-488 | everyday-chemistry, acid-base
Edit:
I would like to add a few details.
Assume that the acid is not concentrated but of suitable molarity to just cut the paper. I mean, to pierce through it and burning its edges to just make a nice cut. Like a glowing incense stick makes when made to touch a paper.
Also, the nip of the pen and the ink chamber are strongly inert; enough to survive the concentrated acid's attack and prevent leaking. Like, the chamber can be made of glass (in which acids are usually kept) and the nip can be made of galvanized/electroplated iron.
Or if there is still more, we can just make this into a thought experiment. You can pour anything into your pen. Is it a good idea? Most likely not. Is it dangerous? You bet! Is it a good idea to play with? NO! Whether it is legal or not to create such an object, you'll have to check with legislation in your country.
If you want paper to ignite on touch with this pen, you would need some truly strong acid (and probably undiluted). I'm certain that if this substance has the capability to burn paper, it would also corrode away the feed and nib of the pen. In the worst case, it will even eat through the ink container and leaking everywhere. In any way, this is no viable option to cut paper in a controlled fashion.
Is there a safer method? Well, there would be laser-assisted cutting of paper, but the good ol' knife or saw would still be cheaper.
The following is multiple choice question (with options) to answer.
adding a direct flame to container of acid causes a | [
"dormant cycle",
"lot of nothing",
"lower temperature",
"vapor expulsion"
] | D | adding heat to an object sometimes causes chemical reactions |
OpenBookQA | OpenBookQA-489 | photons, astrophysics, estimation, neutrinos, sun
https://en.wikipedia.org/wiki/Borexino :
... solar activity has been consistently stable on a 100,000-year scale....
Why so much variation in the estimates?
The Borexino measurements directly use this number to compare/estimate what the sunlight would have been X years ago, but the specific number used is 100,000.
It is one thing to report widely ranging numbers, it is another to use a specific number in calculations to make conclusions.
Like-wise, there are calculations on when the Sun will expand or when the light will dim out, again using some specific number given here.
The following is multiple choice question (with options) to answer.
Over a period of years in direct heat and sunlight, a large boulder may be | [
"frozen",
"catapulted",
"ravaged",
"rotted"
] | C | being exposed to heat can cause erosion of rocks |
OpenBookQA | OpenBookQA-490 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
Deer are less safe in the woods because wolves | [
"have fur",
"howl",
"have claws",
"have tails"
] | C | claws are used to catch prey by some predators |
OpenBookQA | OpenBookQA-491 | thermodynamics, energy, electricity, efficient-energy-use
Title: Cutting down on power by bypassing mechanical to electrical conversions: Why not? The only answer to this I can think of is energy portability issues.
Another modern-world insanity is converting mechanical energy to electrical, only to turn it back into mechanical. The example I like to use is a refrigerator's reciprocating compressor.
If we directly attach a steam turbine's axle to the crankshaft of the compressor, we will not need to suffer losses in heat in our conversion of mechanical to electrical (at the power plant) then back to mechanical energy (in our appliance). Long ago, a primitive factory used one big engine or turbine or water wheel to rotate a set of overhead shafts, from which leather belts were suspended at intervals to power small pieces of machinery scattered throughout the factory. This arrangement was inflexible in that when the single big engine stopped, so did the entire factory, and when electricity came into common use, this overhead shafting arrangement fell quickly out of favor.
The power losses in long-distance electrical power transmission are more than made up for by the ease with which it is performed and the flexibility it affords. This makes "local power generation" as you describe it impractical because a hundred small steam turbines are much more wasteful of heat energy than one large turbine.
The only practical exception is integrated co-generation in which a small engine running on, for example, natural gas powers a generator while also spinning the shaft of a heat pump. The waste heat from the engine's cooling system makes residential hot water, the waste heat from its exhaust goes through a heat exchanger to provide hot air for space heating, the heat pump furnishes air conditioning (or pulls heat from outside the dwelling) and the electricity from the generator powers up your small appliances in the home while also charging a set of batteries.
Overall thermodynamic efficiency of such a device can exceed 95%, and examples of this technology are just now coming onto the market.
The following is multiple choice question (with options) to answer.
An example of a simple machine requiring mechanical energy in order to function would be | [
"a light that needs a crank to be turned",
"a radio that needs four batteries",
"a computer that needs to be plugged in",
"a stove that works on gas"
] | A | a simple machine requires mechanical energy to function |
OpenBookQA | OpenBookQA-492 | human-biology, evolution
Humans are off the charts in the amount of resources we invest in our children - our lives are 1/4 to 1/3 over before we sometimes leave our parents household (in some societies of course they never leave the house, but step into an extended family). This may be one of the reasons we are so successful as a species - we live in practically every place we possibly could and have no danger of competition from any other living thing excepting ourselves.
The grandmother effect is essentially the idea that if women, who are more attached to the offspring in more cases than fathers, continue to live and help support the grandchildren and make them more successful, then this will allow post menopausal women to have a longer lifespan (which they do).
The evolutionary biologist Sara Hrdy, emeritus UC Davis, has written quite a bit about the nuances of the evolution of the role of motherhood - reading some of her articles or books might give you a deeper sense of how profoundly filial love has shaped human beings.
--- more answer this stuff may or may not be worth reading depending on how broadly you want to understand this question...
Its important to say that many of the expansions of human average human lifespan have not been genetic. Its commonly cited that sewer systems, clean water, antibiotics and plentiful food are the three most important factors in human lifespan - and before modern developed world nations, the average lifespan of human beings was somewhere in the 30s. And there are significant lifespan differences in regions where these factors and others (education of women, access to prenatal and early care etc) are available.
Studies continue to be published that examine environmental and lifestyle factors compared to genetics and it seems that environment and lifestyle can make an astounding difference.
But genetics undoubtedly has a role to play here too. There are probably some individual humans and animals which have evolved to live longer. This has been found to be genetically related in some humans by demographics and family lines.
The following is multiple choice question (with options) to answer.
Humans go through multiple stages in their life. First is infancy, last is | [
"Stage 7",
"being an adult",
"high school",
"puberty"
] | B | adulthood is a stage in the life cycle process |
OpenBookQA | OpenBookQA-493 | ros, node
Title: Suggestion for Custom Behaviour and Clarification of FollowPath Action Node in Behaviour Tree
This is a question regarding the behaviour of the FollowPath action node in the nav2 behaviour tree.
In the default implementation of the navigate to pose behaviour, the FollowPath action node has a goal checker that calls the ComputeVelocity method of the plugin controller as long as the robot is outside the goal tolerance region. Now, as soon as the robot is inside the tolerance region, the goal checker registers a success and publishes a zero twist to stop the robot. Each subsequent tick then results in the goalchecker returning a success and publishing a zero twist.
In my particular use case, I'd like to perform a final orientation behaviour once the robot is within the goal region. I have made separate plugins for this behaviour that are attached to the parent pipeline sequence control node. Once the controller returns a success, this behaviour gets ticked but the controller also gets ticked since it is attached to a pipeline sequence node. This causes the zero twist to get published repeatedly.
Is there a suggested way to work around this or modify this behaviour so that subsequent actions on the robot can be implemented while a previously ticked node is halted after completion? I'm not sure if the single trigger would work here since my understanding dictates that it would tick the controller only once and never tick it again thus not permitting it to track the path.
The following is multiple choice question (with options) to answer.
Which kind of behavior has a fixed action pattern? | [
"political",
"migration",
"food preparation",
"shopping"
] | B | migration is an instinctive behavior |
OpenBookQA | OpenBookQA-494 | python, parsing, numpy, scipy
if 'electric' in producer.energy:
recipe = self.produce(cls, producer, **kwargs)
recipe.rates['Energy'] = energy
yield recipe
elif 'heat' in producer.energy:
recipe = self.produce(cls, producer, **kwargs)
recipe.rates['Heat'] = energy
yield recipe
elif 'burner' in producer.energy:
for fuel_name in producer.valid_fuel.split('+'):
fuel_name = fuel_name.strip().lower()
fuel = all_items[fuel_name]
fuel_value = parse_power(fuel.fuel_value)
new_kwargs = dict(kwargs)
if self.title:
title = self.title
else:
title = f'{self.resource} ({producer})'
new_kwargs['title'] = f'{title} fueled by {fuel_name}'
recipe = self.produce(cls, producer, **new_kwargs)
recipe.rates[fuel.title] = energy / fuel_value
yield recipe
else:
raise NotImplementedError()
tree_re = re.compile(r'(\d+) .*?\|([^}|]+)\}')
def wood_mining(self) -> Iterable[MiningRecipe]:
miners = tuple(
ManualMiner(tool)
for tool in all_items.values()
if tool.prototype_type == 'mining-tool'
)
for m in self.tree_re.finditer(self.resource.mining_time):
mining_time, source = int(m[1]), m[2]
for miner in miners:
yield self.produce(
MiningRecipe, miner,
mining_hardness=float(self.resource.mining_hardness),
mining_time=mining_time,
title=f'{self.resource} ({miner} from {source})')
The following is multiple choice question (with options) to answer.
If something is a raw material in a process, then that something is | [
"degraded during the process",
"man made before the process",
"a required during production like labor and capital",
"only used in the final phase"
] | C | if something is a raw material in a process then that something is required for that process |
OpenBookQA | OpenBookQA-495 | temperature
Title: Lab Equipment for Monitoring Sub Zero Temperatures I am doing research on objects frozen with liquid nitrogen then seeing how they thaw.
I need to monitor objects temperatures as they thaw. Ideally getting the variance of the external and internal temperatures.
What strategy or equipment would you recommend to get this data.
Thank you. You can get thermocouples which are rated for cryogenic temperatures. These produce a voltage whcih can be calibrated to temperature and so are faily easy to connect to digiotal or analogue data logging equipment.
They are essentially just a wire so they are easy to embed in things and they can be fitted to various probes and pads for differnt mounting configurations.
The following is multiple choice question (with options) to answer.
Thermometers | [
"can tell you if you need an umbrella that day",
"can tell you which direction the wind is blowing",
"can help you decide how many layers of clothes to wear outside",
"can tell you how much rain has fallen"
] | C | a thermometer is used to measure temperature |
OpenBookQA | OpenBookQA-496 | water, freezing
Title: How can I prevent drinking water from freezing in cold weather? I'd like to keep a container of potable water in my car for when I get stuck, but in the winter it gets cold enough for bottled water to freeze.
I can't put salt in it, because then it won't be drinkable anymore (or at least, will make my condition worse if I do drink it), and I can't mix it with alcohol in case I get the car unstuck and have to drive.
What else could be added to water to sufficiently lower its freezing point without making it undrinkable?
(Or to keep it in line with physics rather than chemistry, how do I calculate the amount of pressure the water need to be under to prevent it from freezing at a given temperature, say 15-20o F?) It may not be the answer you are looking for but I recommend you get a thermos or a well insulated flask. These are what mountaineers use and you do not have to change the chemical composition of water this way.
The following is multiple choice question (with options) to answer.
if a person is unable to stand cold weather, which of these should be avoided? | [
"the arctic regions",
"all of these",
"tropical rain forest",
"the mangrove forest"
] | A | the arctic environment is cold in temperature from being at a northern lattitude below 0 degrees celsius during most of the year |
OpenBookQA | OpenBookQA-497 | c++, algorithm, strings, c++11, c++14
First, I don't think that shrink_to_fit will do what you expect it to do. When you construct result, you allocate memory and fill it with spaces, so result's size probably grew to. shrink_to_fit will get rid of the allocated but unused memory, but it won't get rid of the extra spaces that you allocated at construction.
What you can do is default-construct your std::string and use an std::back_inserter to fill it the lazy way. The std::back_inserter will perform some magic so that the result's push_back method is called whenever an element has to be added:
std::string find_intersection(std::string & first, std::string & second)
{
std::sort(std::begin(first),std::end(first));
std::sort(std::begin(second), std::end(second));
std::string result;
std::set_intersection(
std::begin(first), std::end(first),
std::begin(second), std::end(second),
std::back_inserter(result)
);
return result;
}
The following is multiple choice question (with options) to answer.
I have a shirt that is now too small, what can I do to conserve and reuse the fabric? | [
"Walk a runway with it",
"Use it to protect my body from bullets",
"Make a new wallet",
"Track the weather with it"
] | C | conserving resources has a positive impact on the environment |
OpenBookQA | OpenBookQA-498 | homework, plant-physiology, plant-anatomy
and 'Vascular Plants = Winning! - Crash Course Biology #37'
https://youtu.be/h9oDTMXM7M8?t=373
[5] Osmosis (water compensating solutes) "In Da Club - Membranes & Transport: Crash Course Biology #5"
https://youtu.be/dPKvHrD1eS4?list=PL3EED4C1D684D3ADF&t=148
Ian (and dad <= all errors and approximations are his :) ).
The following is multiple choice question (with options) to answer.
Which organism uses xylem for materials transport? | [
"saguaro cactus",
"liverwort",
"green algae",
"sphagnum moss"
] | A | xylem transports materials through the plant |
OpenBookQA | OpenBookQA-499 | Change the chapter
Question
Jogging on hard surfaces with insufficiently padded shoes produces large forces in the feet and legs. (a) Calculate the magnitude of the force needed to stop the downward motion of a jogger’s leg, if his leg has a mass of 13.0 kg, a speed of 6.00 m/s, and stops in a distance of 1.50 cm. (Be certain to include the weight of the 75.0-kg jogger’s body.) (b) Compare this force with the weight of the jogger.
a) $16300 \textrm{ N}$
b) $22.2$
Solution Video
OpenStax College Physics Solution, Chapter 7, Problem 53 (Problems & Exercises) (3:42)
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The following is multiple choice question (with options) to answer.
If I wanted to prevent a blister when running I can | [
"wear layers",
"Run barefoot",
"Walk instead",
"Wear sandals"
] | A | as the thickness of an object increases , the resistance to damage of that object will increase |
OpenBookQA | OpenBookQA-500 | logic
I'll briefly discuss “and” in linear logic, to illustrate this point. To put it in a nutshell, in everyday logic, if you have a hypothesis, you can use it at multiple points in a proof. In linear logic, a hypothesis can only be used once, unless it's marked as reusable. Linear logic can thus model processes that aren't proofs as you think of them, but more physical processes, such as “if I have a cake before eating it, then I have no cake after eating it”. Linear logic has two conjunction operators. Both say: if I have a process that produces an $A$, and I have a process that produces a $B$, then I have a process that produces an $A$ “and” a $B$. They differ in how the processes are combined:
The following is multiple choice question (with options) to answer.
What can be used more than one time? | [
"coal",
"soda bottle",
"gas",
"oil"
] | B | renewable resources can be used over again |
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