source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-2601 | proteins, digestive-system
Title: Why do humans cook animal meat Why do humans "need" to cook animal meat?
It seems there's an aspect of safety to it: are other animals (eg, house cats, dogs) not vulnerable to the same diseases we get from modern food processing of meats?
But it also seems there's something else to it: is raw animal flesh is harder to digest for us, no matter how fresh or processed?
I've read so many conflicting things about it, like how cooking is really a way to avoid disease, but that the human body is capable of processing protein from raw meat just the same. An example is how other countries eat raw meats that Americans would not. But then I've also read things about how cooking meat is what allowed humans an energy advantage early in our development as a species (I'm not clear how more calories are "unlocked" by cooking) or how denatured protein plays some role in usability. I also know that my person experience with raw meats doesn't help me understand it, because sushi seems to be fine but raw eggs will upset my stomach. Humans do not "need" to cook food, but in general cooking food facilitate digestion and absorption of nutrients.
Heat cause denaturation of proteins. Once denatured, proteins are more susceptible to the enzymatic digestion. Thus, more nutrients are absorbed. There are also macroscopic phenomena in play, for example, a cooked piece of meat is more tender than the raw one, making mastication easier and less energy consuming.
The fact that you may feel your stomach upset because of raw food is probably due to the fact that you were never used to it. Your intestinal flora has been selected during the year to deal with the food you usually eat, any "new" food may cause the same symptoms. Humans that eat regularly raw food will not feel the same way.
The following is multiple choice question (with options) to answer.
What might be harder to digest? | [
"corn",
"spinach",
"water",
"eggs"
] | A | the breaking down of food into simple substances occurs in the digestive system |
OpenBookQA | OpenBookQA-2602 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which of the following is a true statement? | [
"a lizard has warm blood",
"a python has warm blood",
"a robin has warm blood",
"a rock has warm blood"
] | C | a bird is warm-blooded |
OpenBookQA | OpenBookQA-2603 | atomic-physics, geophysics, explosions
I think the most interesting diagrams are the ones labeled (e) and (f) - where the explosion happens at great depth. In that case, you get a "tight packing" of the soil above in a way that I think is similar to the mechanism that causes sugar to "settle" if you first fill a bowl to the rim, and then tap the bowl gently. The shock wave that travels through the soil (or the sugar) causes individual grains to find a more energetically favorable orientation - so they are a little more tightly packed. This can result in a crater.
Now whether you consider this "compacting voids" is a matter of opinion. But it's a real effect. Of course, very close to the nuclear reaction the heat will be so great that the rock will liquify; as a liquid it might be able to pack more tightly, although that depends on many factors.
The following is multiple choice question (with options) to answer.
Folding up rocks can happen when | [
"deer shiver",
"snakes rattle",
"birds quiver",
"bunkers shake"
] | D | earthquakes cause rock layers to fold on top of each other |
OpenBookQA | OpenBookQA-2604 | zoology, ornithology, ethology, behaviour
Title: Crow branch pecking behaviour I was walking through a small park when two crows started cawing at me, and followed me, flying from tree-to-tree as I walked. I speculate that this is a territorial or protective behaviour, but what I found different was the crows were violently pecking the branches nearby them. I have no memories coming to mind of seeing this behaviour beforehand. I speculate that this behaviour could be threat displays, but a quick search on Google did not reveal to me any authoritative studies on this phenomenon. I'd appreciate more information and sources.
This question has been added as a casual observation on iNaturalist. This is a good question. This type of behavior -- pecking at a branch, wiping the side of the beak on a branch, pulling off twigs and dropping them, or knocking off pieces of bark -- is quite common among many corvid species, particularly when they are interrupted by something or someone that they might consider a threat. This includes not only potential predators but also potentially hostile conspecifics.
It is typically considered to be a form of displacement behavior. The concept of displacement behavior, from classical ethology, posits that when an animal experiences two conflicting drives to do two different things, it doesn't know which to do and does a third thing instead to dissipate the drive or anxiety. For branch-pecking in crows, see E.g Kilham and Waltermire 1990 Ch. 12.
Referece: Kilham, L., & Waltermire, J. (1990). The American crow and the common raven. Texas A&M University Press.
The following is multiple choice question (with options) to answer.
If a bird lives in a dangerous place with fires and predators, a bird will likely | [
"live longer",
"flourish",
"thrive",
"acquire characteristics"
] | D | an organism 's environment affects that organism 's acquired characteristics |
OpenBookQA | OpenBookQA-2605 | [13]:
nutrients = pd.DataFrame(
index=[
"Vitamin A",
"Vitamin B1",
"Vitamin C",
"Calcium",
"Iron",
"Phosphorus",
"Potassium",
"Total fat",
"Carbohydrates",
"Proteins",
]
)
nutrients["DRI"] = [800, 1.1, 80, 800, 14, 700, 2000, 70, 260, 50]
nutrients["Chicken Breast"] = [0, 0.1, 0, 4, 0.40, 210, 370, 0.8, 0, 23.3]
nutrients["Milk"] = [37, 0.04, 1, 119, 0.1, 93, 150, 3.6, 4.9, 3.3]
nutrients["Pasta"] = [0, 0, 0, 22, 1.4, 189, 192, 1.4, 79.1, 10.9]
nutrients["Beans"] = [3, 0.4, 3, 135, 8, 450, 1445, 2, 47.5, 23.6]
nutrients["Oranges"] = [71, 0.06, 50, 49, 0.2, 22, 200, 0.2, 7.8, 0.7]
nutrients
[13]:
DRI Chicken Breast Milk Pasta Beans Oranges
Vitamin A 800.0 0.0 37.00 0.0 3.0 71.00
Vitamin B1 1.1 0.1 0.04 0.0 0.4 0.06
Vitamin C 80.0 0.0 1.00 0.0 3.0 50.00
Calcium 800.0 4.0 119.00 22.0 135.0 49.00
Iron 14.0 0.4 0.10 1.4 8.0 0.20
Phosphorus 700.0 210.0 93.00 189.0 450.0 22.00
Potassium 2000.0 370.0 150.00 192.0 1445.0 200.00
Total fat 70.0 0.8 3.60 1.4 2.0 0.20
Carbohydrates 260.0 0.0 4.90 79.1 47.5 7.80
Proteins 50.0 23.3 3.30 10.9 23.6 0.70
The following is multiple choice question (with options) to answer.
Which of these items contains a fat soluble vitamin? | [
"dog",
"yogurt",
"cat",
"water"
] | B | dairy is a source of Vitamin D |
OpenBookQA | OpenBookQA-2606 | botany, reproduction
Title: Are the seeds in a single capsicum fruit genetically identical? Hopefully not a too-basic question for the venue. I'm a chile pepper growing hobbyist and have spent some time searching around and reading up on pepper (angiosperm) reproduction, but I'm not getting a clear picture of the details.
It seems like flowers have multiple ovules and it seems like one pollen-grain landing on the stigma leads to fertilization of a single ovule. And it seems like that process produces a single seed.
But that fertilization also prompts fruit growth and flower death and capsicum fruits have many seeds, never just one (that I've ever seen).
So, does each seed have a potentially different father? Or are the multiple seeds generated through a reproductive/cloning process that I'm not seeing written about? Or something else? No, the seeds are not genetically identical. Each seed come from the fertilization of an ovum with a sperm from a separate pollen grain. Since each pollen grain can come from a different plant, the seeds will generally differ from one another.
Additionally, even ova from a single plant will not usually be genetically identical to one another. This is because the process that creates the ova (meiosis) shuffles the genes of the parent plant on then places only half into the ovum. The same kind of shuffling goes on in the creation of pollen grains.
In the chili pepper genus (Capsicum), plants are predominantly self-pollinating. This means the majority of the pollen for the seeds in a fruit will come from the very same plant. This generally reduces the amount of variation seen in the offspring compared to complete cross-plant pollination. Some cross-pollination can nevertheless occur if there are other varieties in the neighborhood. The fruit will not show the effects of the new genetic combinations present in its seed, but only a plant grown from the seed will make the differences evident.
The following is multiple choice question (with options) to answer.
What likely directly came from a sprouted seed? | [
"a metal lantern",
"a glass lantern",
"a jackolantern",
"a paper lantern"
] | C | seeds may sprout when buried in soil |
OpenBookQA | OpenBookQA-2607 | biochemistry, plant-physiology, plant-anatomy
Title: Why do plants store energy as carbohydrates and not as fats? In my introductory biology class, we are learning about biomolecules. The textbook says fats are a more efficient energy store than carbohydrates.
So my question is - why would plants store their energy as carbohydrates and not as fats, if fats are a more efficient energy store? There are quite some reasons for why plants prefer carbohydrates for energy storage rather than fats. I will reach some of them one at a time.
The following is multiple choice question (with options) to answer.
Which of the following is never an element used to make carbohydrates for the plant? | [
"sand",
"water",
"sunlight",
"carbon dioxide"
] | A | photosynthesis makes food for the plant by converting carbon dioxide, water, and sunlight into carbohydrates |
OpenBookQA | OpenBookQA-2608 | One can easily pot data as a scattered manner on a graph. It basically depends on the data given to us as to how can it be plotted. For prediction of values in a scattered kind of data we make use of a straight line representing an equation which is not actually displayed on the graph. This straight line is known as line of best fit. In other terms it is also referred to as the trend line.
## Line of Best Fit Definition
We can define the line of best fit as the line that represents the data of a scatter plot diagram in the best manner. The line of best fit may pass through some points of the scatter plot, may even pass through all the points or at times may not even pass through any point of the scatter plot.
## How to Find and Draw The Line of Best Fit
To find the line of best fit we can use two methods: one is the spaghetti method and the second one is using least square method. The first one is a random method according to which we get different lines of best fit as the judgment varies from person to person. The least square method gives a general and more accurate line of best fit for a given set of values. With this method the line so obtained is a common line for every person determining it for the same set of values given. Once the line is obtained by using the spaghetti or judgment method we can easily find the equation of the line using point slope formula or two point formula of finding the equation of the line. In the other method we will obtain the equation first using which we can easily draw the line of best fit of the graph via finding points lying on the equation so obtained and joining them.
## Line of Best Fit Equation
Once the line of best fit is drawn one can easily find the equation of the line using any method of finding equation of a line may it be point slope or two point method.
## Line of Best Fit Formula
Usually we can make a line of best fit by the judgment of eyes which may vary from person to person. But a more accurate way of finding the line of best fit for a particular data is to make use of the least square method to determine the line of best fit.
The following is multiple choice question (with options) to answer.
What is most easily shown by a line graph? | [
"the quantity of carp in a pond",
"the thoughts in a person's mind",
"the amount of nothingness in the universe",
"the number of gods in the universe"
] | A | a line graph is used for showing change over time |
OpenBookQA | OpenBookQA-2609 | energy, visible-light, photons, sun, interactions
Title: What are the physical processes involved in feeling warm from the sunlight? Suppose a human is lying on a beach. He/she starts to feel warm after exposing his/her skin to the sunlight. I assume that feeling is due to the ability of the human body of "measuring" the increasing in temperature of the skin.
Now I want to understand what are the physical processes involved in this increasing in temperature.
Imagine a group of photons impinging on the skin in a certain interval of time. I tried to list the possible interactions from a particle physics perspective between photons and the human tissue and I concluded that the possible interactions may be:
Photoionization
Compton scattering
Rayleigh scattering
Pair production
The first 3 seems to be reasonable, but the fourth one requires an energy threshold too high: there are no incident photons that may have that energy. I conclude that by looking at the spectrum of sunlight that actually reaches the earth's surface below the atmosphere. So I think that the pair production does not play a role in this situation.
Are there any other interaction processes between photons and tissue molecules involved in the increasing of temperature of the human tissue?
After listing the processes I wonder what actually increases the temperature: is the temperature increasing because the photons-molecules interactions lead to a transition of molecules to excited vibrational states? or maybe transitions to excited rotational states?
I thought that another possibility is that the photons interactions are increasing the kinetic energy of the water molecules in the skin or maybe are increasing the lattice vibration of other tissue (skin, bones or others). Are this processes happening simultaneously? One of this processes (for example transition to rotational excited states) is dominant over the others ?
I'm looking to a qualitative answer, without going into too much details of the Biology of the human body. I just want to create an approximate picture of this situation in my mind. I want to create a mental "video" from the instant in which a photon or a group of photons impinges in the skin to the moment in which tissue molecules are affected and the temperature starts rising up.
I thank in advance anyone who answers this question. You forgot garden-variety absorption! Here, light promotes electrons from lower energy states to higher energy states. However, skin is made of many small particles, so scattering is important as well.
Here’s the mental video:
The following is multiple choice question (with options) to answer.
A way to warm your skin with sunlight is to | [
"sit near a fan",
"sit in an igloo",
"sit under an umbrella",
"ride in a truck bed"
] | D | sunlight produces heat |
OpenBookQA | OpenBookQA-2610 | species-identification
Title: What is this (water-loving) bug? For some time we've been finding these little fellows in our apartment:
They seem harmless enough, but finding them is a bit... annoying. I found the fellow above in the bathtub, and it's not uncommon to find more than one.
Unfortunately, some started to appear near the kitchen sink as well. Or outside of the bathroom on the floor (at least that's where we noticed them).
I think this thing prefers darkness over light, and seems to be drawn towards wet places or just water. These critters are also surprisingly fast.
What is it? Should we be concerned about a pest problem, or is this just a minor, unwelcome guest?
PS. We live in Poland. It is a Lepisma saccharina or silverfish.
It is rather common and yes, it's harmless.
The following is multiple choice question (with options) to answer.
Sea hares are poisonous slugs, with tiny bunny-like tentacles, that float in water currents and ocean waves. They squirt a purple colored chemical that's sticky and smelly | [
"to attract a mate",
"to swim in deep waters",
"to ward off predators",
"to color the water"
] | C | some hares live in fields |
OpenBookQA | OpenBookQA-2611 | combustion
Title: Why is O2 the supporter of combustion? It's there in every high-school textbook: $\ce{O2}$ is the supporter of combustion. Without $\ce{O2}$ combustion cannot take place. Why? And why only $\ce{O2}$? Why not some other element?
And, what happens when a combustible gas burns in air? Say $\ce{H2}$? Oxygen is not strictly needed, it just happens to be very, very good at what it does!
Specifically, combustion requires three things:
1) Fuel: The thing that burns. This is is often a hydrocarbon, or other organic molecule. The simplest possible fuel is pure hydrogen gas.
2) Energy: What gets the reaction started, which is true of most chemical reactions. Note that this so-called activation energy is usually much less than the energy ultimately released from combustion. This is like rolling a boulder some distance in order to roll it down a hill, which releases much potential energy.
3) Oxidizer: The molecule that accepts electrons. It turns out that combustion requires the fuel to be oxidized, that is, it donates electrons. So we need something to accept the electrons, and that's the oxidizer, which is then reduced.
Oxygen is a great oxidizer because it is so electronegative, which means it really wants to accept electrons. Only fluorine is more electronegative, and fluorine is a superb oxidizer: blow fluorine gas at nearly any substance and it bursts into flames. For example, see this video: Fluorine.
Oxygen is in many ways a perfect oxidizer for supporting life: it doesn't set things on fire like fluorine, but otherwise can oxidize very many things. When you eat, oxygen is oxidizing the food (fuel) you ingested, to generate energy you need to live. So there is "combustion" going on inside you!
The following is multiple choice question (with options) to answer.
Which of the following prolongs combustion? | [
"fire extinguishers",
"water",
"smothering",
"candle wax"
] | D | lighting a candle causes that candle to burn |
OpenBookQA | OpenBookQA-2612 | hydrology, rivers, dams
Title: Do dams reduce the flow of river downstream? There is a conflict between Egypt and Ethiopia, because the latter wants to build a dam on the Nile river. Citing this article:
[Egypt] fears the Nile dam will reduce its share of the river and leave the
country with dwindling options as it seeks to protect its main source
of fresh water.
What do they mean by "reduce its share of the river"? As far as I understand, the dam will create a reservoir, which will initially divert some water to be filled, but once that is done, the flow of the river should be the same. Is Egypt worried about this initial reduction, or do dams somehow reduce the flow of a river?
If so, what is the mechanism? I would guess that this is due to increased evaporation from the river, since the reservoir has a bigger surface than the usual river, but then again, it also collects more rain. Once a dam has been constructed in a river, the natural flow of water will be disrupted.
You correctly state that initially there will be a period required for the dam to fill. Until then, little of no water will flow beyond the dam.
Dams are created for one or more of three reasons:
To supply potable water to a population of humans for domestic or
industrial purposes.
For agricultural purposes.
To generate hydro-electricity.
The following is multiple choice question (with options) to answer.
The dam was put under much more stress after the | [
"drought",
"huge rain storm",
"breakup.",
"party"
] | B | clouds produce rain |
OpenBookQA | OpenBookQA-2613 | orbit
Title: Traveling constantly towards West. That is clockwise If I travel against against the Earth's rotation. Say once around the world. I will always see sunrise and never a sunset
Is that accurate? If you travel west so quickly that you go around the world in one day (24 hours) then the sun will remain almost fixed in the sky. You will see neither a sunrise nor a sunset. At a latitude of 45 degrees north, you will need to travel at 1180 km/h (faster than a commercial jet, nearly Mach 1)
If you travel less quickly, then the sun will move from East to West, but rather more slowly. You may see multiple sunrises and sunsets, depending on your speed.
If you travel faster, the sun will move from West to East in the sky. Again, you may see multiple sunrises and sunsets, but the sun would rise in the West.
The following is multiple choice question (with options) to answer.
What might I be doing during the day cycle on earth? | [
"using magic",
"having a picnic",
"time traveling",
"driving flying cars"
] | B | the sun is the source of energy for physical cycles on Earth |
OpenBookQA | OpenBookQA-2614 | thermodynamics, visible-light, perpetual-motion
Needless to say, perpetual motion of an untouched body is useless in terms of extraction of mechanical energy.
The following is multiple choice question (with options) to answer.
What is something that would be unable transfer energy? | [
"a tire",
"copper",
"metal",
"iron"
] | A | wood is an electrical energy insulator |
OpenBookQA | OpenBookQA-2615 | weather
Title: Determining cloud cover from observer to near the horizon Does there exist a Clear Sky Chart with the following enhancements?:
1 - Actual Cloud Cover (Offered Visually and not just Colors with a Legend, Over Time/Past & Predictive)
2 - Simulate/Predict Cloud Cover taking into account the direction from Observer to Observed Object and Angle of view - Close to the horizon (May be helpful to know when you can reasonably start/end tracking something you want to catch that night that is close to the horizon)
The reason I'm curious is:
A) I wonder if it's just not feasible for any/many reasons.
B) It would be great help to know this information.
In general, does anyone know of other Earth Weather, Clear Sky Clocks and Charts or anything else that gives more information?...anything related will be helpful.
EDIT: I would love to find this lecture "You can do better than Clear Sky Chart" mentioned: http://stjornuskodun.blog.is/blog/stjornuskodun/entry/966941/ Rain Today provide a rain cloud image down to 15 minutes prior. But rain cloud doesn't always equate to total cloud cover.
I think the major drawback is that clouds can arise from clear air as the moisture condenses, and predicting where this is going to happen becomes too complicated to resolve at fine enough detail to be of much use...
The following is multiple choice question (with options) to answer.
Clear weather means | [
"rain",
"zero clouds",
"snow",
"big clouds"
] | B | clear weather means sunny weather |
OpenBookQA | OpenBookQA-2616 | zoology, pathology, herpetology
Title: How do pet gecko lizards pose a health risk? Does having gecko lizards living in your house pose any health risk? If you're referring to keeping geckos as pets, like all reptiles, amphibians and birds, they come with a small but finite risk of contracting salmonellosis. Having said this, the infection is easy to avoid if you maintain basic hygiene.
On a personal note, I know dozens (perhaps hundreds) of people who keep or have kept reptiles as pets and have yet to meet anyone who contracted salmonellosis. Basically, if you wash your hands after touching the gecko, keep it away from food preparation areas and don't put the lizard in your mouth, you should be fine.
If you're talking about geckos living free in your home, as is common in many tropical places, I have never heard of any health risks associated with them. If anything, I would think that the geckos would reduce health risks by eating insects such as cockroaches and mosquitoes that are prominent disease carriers.
The following is multiple choice question (with options) to answer.
a person bought a reptile at a store and it laid some eggs once they got home, why is this? | [
"it is a mammal",
"it is under pressure",
"it is offering egg gifts",
"it is incapable of live birth"
] | D | live birth means developing inside the mother instead of an egg |
OpenBookQA | OpenBookQA-2617 | oceanography, geochemistry
Title: Why is NaCl so hyper abundant in the ocean? Why is sodium chloride far and away the most abundant salt dissolved in ocean water? Its two constituent ions do have a very high frequency in the crust of the earth, but they are far from the most common. Chlorine is (according to Wikipedia) the 21st most abundant element, and sodium 6th.
I certainly understand that a combination of their solubility and reasonably high frequency would lead one to expect them to be abundant in sea water, but they are hyper abundant, completely dominating all other salt ions. Iron, for example, is twice as abundant, and potassium only a little less abundant, and fluorine more abundant than chlorine.
Moreover, if the salts are deposited in the ocean through weathering of rocks and deposition via rivers, why does the salinity not simply grow and grow? I understand that some is lost due to tectonic activity, but it seems extraordinarily unlikely that these two forces should be equally balanced, and so we would see a significant change in average salinity over time.
(Please note I am migrating this question from the Chemistry SE at their recommendation.) Fluoride salts tend to be not particularly soluble in water. Chloride salts are. The same goes for salts containing sodium versus those containing calcium. Sodium chloride is ridiculously easy to dissolve.
Regarding your second question, it is geological forces that keep salinity more or less constant. People formerly argued that the Earth can't be more than a few hundred million years old because otherwise the river waters running into the oceans would eventually result in an insanely high salinity. It turns out that the Earth's oceans are young (young compared to the 4.5 billion year age of the Earth). The vast majority of oceanic crust is less than 100 million years old. We see huge salt deposits sprinkled across the world because those are the dried up remnants of former seas and oceans. Salt is also drawn into the Earth at subduction zones, where it combines chemically with basalt.
The following is multiple choice question (with options) to answer.
The ocean contains large amounts of what? | [
"people",
"salty biscuits",
"fires",
"saline liquids"
] | D | the ocean contains large amounts of salt water |
OpenBookQA | OpenBookQA-2618 | star, galaxy
If you're on a farm, away from cities, in a place with reasonably low light pollution, and your eyes are good, and you've been sitting in perfect pitch black darkness for at least 30 minutes prior - when you look up you can reasonably expect to see a few thousand objects, mostly stars. Keep looking, and after a while you will distinguish one or two thousand more stars, very faint, that you could not see at first sight. Practice this steadily for a few years, and you'll add maybe another thousand; but you won't be able to see those all at once - only one at a time.
Now travel to the Cerro Tololo site in Chile, up in the mountaineous desert, zero light pollution, excellent transparency, and you'll multiply all those numbers by a factor of 2x ... 5x.
As you can see, the numbers are very flexible because there are so many factors involved. You can't just slap a 44k label on it and call it a day; that doesn't make any sense in reality. Astronomers know that the pure magnitude number doesn't mean much by itself, because it is just one factor among many.
In a place with very high light pollution (like where I live, in the middle of a large, dense, sprawling urban area in California), you'd be lucky if you can see a hundred stars at night.
Or, in a place with zero light pollution, shine a flashlight into someone's face, and you've temporarily blinded them. You've reduced the number of stars they could see by an order of magnitude for the next half hour (night vision gradually recovers, and it takes 30 minutes to fully recover, according to US military manuals and visual astronomers practice).
The following is multiple choice question (with options) to answer.
It is much harder to go star gazing in the city as opposed to the mountains due to the amount of factories doing what to the air | [
"dirtying it",
"air horns",
"candy",
"tables"
] | A | as light pollution increases , seeing the stars will be harder |
OpenBookQA | OpenBookQA-2619 | electromagnetism, electrostatics, electricity, electric-circuits
Further, to speed up the ionization of the gap, I would make the trigger spark as big as practical, i.e. the secondary gap has to be sufficiently wide (to increase the ionized volume) and the trigger pulse has to have sufficient voltage and duration to break through it.
The diagram also shows tentative lines of the E-field. Its initial value could be roughly calculated as $E=30kV/d$, where d is the width of the main gap.
Once the breakdown occurs, or, for your application, the switch is turned on, the resistance of the gap will sharply drop and a (potentially) significant current will start flowing, the magnitude of the current being limited mostly by the load and the internal resistance of the power supply.
With that, the 30kV voltage (which will likely decrease due to the internal resistance of the power supply), will redistribute, such that most of it (or at least a significant part of it) will be applied to the load and much less voltage will remain on the spark gap. As a result, the E-field in the gap will decrease accordingly, since it will remain roughly proportional to the voltage across the gap.
The following is multiple choice question (with options) to answer.
Which is likeliest to let a spark pass through? | [
"a wool sweater",
"a t shirt",
"a rubber eraser",
"a soda can"
] | D | electrical conduction is when metals conduct electricity through metal |
OpenBookQA | OpenBookQA-2620 | newtonian-mechanics, classical-mechanics, rotational-dynamics, friction, centripetal-force
Title: Does a vehicle turning on a banked road need to turn its wheels? A vehicle drives in a circle on a track at constant speed at with radius of curvature $\rho$. The vehicle's acceleration is $$a = \upsilon' T + \kappa (\upsilon)^2 N \\ = \kappa (\upsilon)^2 N.$$
The track is banked at angle $$\theta = \arctan \frac {\kappa \upsilon^2}{g}$$ so that all the force required is provided by the normal force.
Question: Does the vehicle's driver need to turn the steering wheel?
If yes: Why? Isn't all the force needed to turn provided by the bank? What additional force is needed from turned wheels?
If no: How does the vehicle roll (and not skid) if its wheels are pointed in the wrong direction?
Perhaps I am misunderstanding how turned wheels work: my assumption is that turned wheels do not skid, as long as the vehicle is moving in that direction, which would imply that for any angle that wheels turn, there is exactly one trajectory that the vehicle can take without skidding. Is that correct? How exactly do turning wheels function? It depends on what you mean by the verb "turning."
No, you don't really need to steer your vehicle to take that turn. You don't even need wheels for that. When thrown at the correct speed and angle, your car will slide through the turn without any problem. As you said, banking will provide all the forces for the turn. But it won't be a pleasant experience for the driver and the passengers, though.
The following is multiple choice question (with options) to answer.
Which is required for a sedan to run? | [
"vapor of ghosts",
"an oxidizer",
"Pistons Basketball Team",
"orange juice mixture"
] | B | a car engine usually converts gasoline into motion and heat through combustion |
OpenBookQA | OpenBookQA-2621 | weather
Yamana and Hayashi (2006) (3) explain that the SLCS are a result of regional atmospheric thermal instability, where the convective available potential energy (CAPE) is high (greater than 2000 Jkg$^{-1}$) and the shear is moderate (greater than 10 ms$^{-1}$, and that the phenomena also coincides with severe local storms across the Indian Subcontinent.
Yamana et al. (2012) (1) elaborates further on what causes the atmospheric thermal instability, with a synoptic analysis of a SLCS, describing the phenomena as a confluence of (note, the authors use AGL = 'above ground level' for the following information):
The following is multiple choice question (with options) to answer.
Sun falling on mountains and the dessert at the same time leaves the area susceptible to | [
"meltdowns",
"convection",
"earthquakes",
"power failures"
] | B | uneven heating causes convection |
OpenBookQA | OpenBookQA-2622 | audio, modulation, frequency-modulation, fsk
well, "best" is always a reduction to a single set of optimization parameters (e.g. cost per bit, durability, ...) and isn't ever "universally true".
I can see, for example, that "large" is already a relative term, and for a small office, the optimum solution for backing up "large" amounts of data is a simple hard drive, or a hard drive array.
For a company, backup tapes might be better, depending on how often they need their data back. (Tapes are inherently pretty slow and can't be accessed at "random" points)
So I figured I can store a relatively large amount of data on a cassette tape.
Uh, you might be thinking of a Music Casette, right? Although that's magnetic tape, too, it's definitely not the same tape your first sentence referred to: It's meant to store an analog audio signal with low audible distortion for playback in a least-cost cassette player, not for digital data with low probability of bit error in a computer system.
Also, Music Cassettes are a technology from 1963 (small updates afterwards). Trying to use them for the amounts of data modern computers (even arduinos) deal with sounds like you're complaining your ox cart doesn't do 100 km/h on the autobahn.
But after reading up about it for a bit it turns out that they can store very small amounts of data. With baud rates varying between 300 to 2400 something between ~200KB to ~1.5MB can be stored on a 90 minute (2x45min) standard cassette tape.
Well, so that's a lot of data for when music-cassette-style things were last used with computers (the 1980s).
Also, where do these data rates drop from? That sounds like you're basing your analysis on 1980's technology.
These guys can store 90 minutes of audio. Even if we assume the analog audio quality on them was equivalent of 32Kbps that's about 21MB of data.
The following is multiple choice question (with options) to answer.
on which of these days would it be least convenient to take fast drive? | [
"a really sleety day",
"a really hot day",
"a really clear day",
"a really cloudy day"
] | A | sleet is made of ice |
OpenBookQA | OpenBookQA-2623 | WAIT!
S=11!
Because we have 11! ways of arranging the 11 items.
Sorry about that.
5. Hello, sweeetcaroline!
Edit: Plato is absolutely right . . . *blush*
6 red beads, 4 white beads, and 1 blue bead are placed in a line in random order.
What is the probability that no two neighboring beads are the same color?
There are: . ${11\choose6,4,1} \:=\:2310$ possible orders.
Place the 6 Red beads in a row, leaving a space between them.
. . $\begin{array}{ccccccccccccc} R & \_ & R & \_ & R & \_ & R & \_& R & \_ & R\end{array}$
Place the Blue bead is any of the 5 spaces: . $5$ choices.
Drop the 4 White beads in the remaining 4 spaces: . $1$ way.
Hence, there are: . $5\cdot1 \,=\,5$ ways.
Therefore, the probability is: . $\frac{5}{2310} \;\;=\;\;\frac{1}{462}$
6. Originally Posted by sweeetcaroline
the problem: 6 red beads, 4 white beads, and 1 blue bead are placed in a line in random order. What is the probability that no two neighboring beads are the same color?
Can someone give me a line of these beads in which no two neighboring beads are the same color other than the five listed below?
$RWRWRWRWRBR$
$RWRWRWRBRWR$
$RWRWRWBWRWR$
$RWRBRWRWRWR$
$RBRWRWRWRWR$
The following is multiple choice question (with options) to answer.
If a person is selling beads every day and then zero people choose to buy more beads, the seller will | [
"make more money",
"have stalled income",
"increase profits",
"have more income"
] | B | as the sale of a product decreases , the amount of money made by the person selling that product will decrease |
OpenBookQA | OpenBookQA-2624 | newtonian-mechanics, rotational-dynamics, rigid-body-dynamics, gyroscopes, precession
Given that the two gyroscopes are on a rigid rod the tendency to rise will transfer to the center. So yeah: a scale will show a lower weight.
Of course, this does not provide a way to get lift for free: in order to push you need leverage; your feet need to be firmly on the ground. (Compare pushing a large piece of furniture: if your feet don't have grip then you will only push yourself backward instead of moving that piece of furniture.)
The following is multiple choice question (with options) to answer.
A container with a printed scale on it's side is used to | [
"measure weight",
"hold flowers",
"hear through doors",
"measure volume"
] | D | a graduated cylinder is used to measure volume of an object |
OpenBookQA | OpenBookQA-2625 | newtonian-mechanics, history
in 1670 Edme Mariotte had announced his intention to compose a major work on the impact of bodies. Completed and read to the Academy in 1671, it was published in 1673 as Traité de la percussion ou choc des corps. The first comprehensive treatment of the laws of inelastic and elastic impact and of their application to various physical problems". In order to verify his suppositions, he used " an experimental apparatus consisting of two simple pendulums of equal length, the replaceable bobs (the impacting bodies) of which meet at dead center". Here we found the real inventor of "Newton's 'cradle'. Newton cites Wrenn's experiments and Mariotte's book: ".*.veritas comprobata est a Wrenno ...quod etiam Clarissimus Mariottus libro integro exponere mox dignatus est**" (p. 37), but never Huygens'. Newton affirms that Mariotte had just divulged the findings of the British architect: ".. Wren confirmed the truth of the thing before the Royal Society by the experiment of pendulums, which Mr. Mariotte soon after thought fit to explain in a treatise entirely upon that subject." (p.90)
Huygens was certainly saddened by the fact that Mariotte did not cite him as his source, but did not respond (the silence of the lambs) his nature was so meek that only " seventeen years later, in 1690, when Mariotte was dead, Huygens responded to this slight (see below) by accusing Mariotte of plagiarism. “Mariotte took everything from me,” he protested in a sketch of an introduction to a treatise on impact never completed" (ibidem, you can read about the 'slight'):
The following is multiple choice question (with options) to answer.
When Newton was 1st hit by the apple he created his famous | [
"last stand",
"hypothesis",
"hats",
"apple pie"
] | B | hypothesis means scientific guess about the cause and effect of an event |
OpenBookQA | OpenBookQA-2626 | 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 large crevasse was carved in the western United States over many | [
"glaciers",
"mountains",
"rainstorms",
"years"
] | D | the Grand Canyon was formed by the Colorado River flowing over long periods of time |
OpenBookQA | OpenBookQA-2627 | agriculture
The primary cereals for making bread are wheat and rye, while barley and oats may be mixed in. Historically significant portions of the rural population of Europe were sustained by cereal-based food in the form of gruel and porridge rather than by bread, especially prior to the introduction of the potato. Barley can be consumed in the form of pearl barley and groats and oats in the form of oatmeal. Especially in cool and humid climates not very suitable for cultivating wheat and rye, oats were once commonly cultivated and consumed. When Samuel Johnson wrote his dictionary, he famously defined oats as: "A grain which in England is generally given to horses, but in Scotland supports the people." A major historical and modern use of barley has been as malted barley, the main ingredient in beer brewing.
In the case of Finland it is interesting to note how late the transition from slash-and-burn agriculture to the use of permanent fields occurred. According to Teija Alenius, Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish − Karelian inland area, Ph.D. thesis, University of Helsinki, 2007 (online)
The following is multiple choice question (with options) to answer.
With more people eating cereal there comes a need for more | [
"butter",
"top soil",
"water",
"corn"
] | D | as the use of a crop increases , the amount of crops planted will increase |
OpenBookQA | OpenBookQA-2628 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
In the food chain process a cattail has the role of | [
"decomposer",
"consumer",
"producer",
"trader"
] | C | In the food chain process a green plant has the role of producer |
OpenBookQA | OpenBookQA-2629 | zoology, psychology
Title: Fear in elephants It has been noted that elephants trained for war, as was done occasionally in earlier times, have still shown a tendency to panic in battle much more often when compared to a war horse trained for the same purpose. However, is this due to an innate quality of elephant behavior, or a result of poorer training methods due to humans simply having less experience training elephants than horses? Are elephants naturally more fearful creatures than horses or other beasts of war? I doubt if a comparison between these two animals in war situation is in order. These two animals serve different roles.
Here is a reference to an article in Wikipedia on War Elephants. Elephants have been used in war for thousands of years pretty effectively till the enemies discover their weakness and use it to their advantage. Making the elephant panic is one of the ways to counter them. Here is a list of methods from the above article:
Elephants had a tendency to panic themselves: after sustaining painful wounds or when their driver was killed they would run amok
One famous historical method for disrupting elephant units was the war pig......
At the Megara siege during the Diadochi wars, for example, the Megarians reportedly poured oil on a herd of pigs, set them alight, and drove them towards the enemy's massed war elephants. The elephants bolted in terror from the flaming squealing pigs.
It is for sure that many horses also panic in war situations. However a panicked elephant can cause more havoc than a horse. It appears that to prevent a panicked elephant from running amuck back into the ranks
The driver, called a mahout, was responsible for controlling the animal. In many armies, the mahout also carried a chisel-blade and a hammer to cut through the spinal cord and kill the animal if the elephant went berserk.
In recent times elephants in temple festivals in india do occasionaly panic and run amuck when the high explosive fire works are set of. However most of the elephants seem to tolerate it.
The following is multiple choice question (with options) to answer.
A horse could start trembling when | [
"it's afraid another horse will win a competition",
"a cold front is moving in",
"it gets a movie role",
"the sun comes out"
] | B | cool temperatures cause animals to shiver |
OpenBookQA | OpenBookQA-2630 | 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.
When pollution levels get higher, the gas in the atmosphere | [
"raises temps",
"dries up",
"melts away",
"cools earth"
] | A | as the amount of polluting gasses in the atmoshere increases , the atmospheric temperature will increase |
OpenBookQA | OpenBookQA-2631 | A. 1
B. 2
C. 4
D. 5
E. 6
After 17 trips, the worker has carried 17 x 4 = 68 jugs.
From those 68 jugs, 68/7 = 9 cartons have been filled, with 5 extra jugs remaining. So, the worker needs one more trip to carry 2 more jugs to fill the partially filled carton with those 2 jugs.
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A worker carries jugs of liquid soap from a production line to a packi [#permalink]
### Show Tags
15 Nov 2017, 19:26
AbdurRakib wrote:
A worker carries jugs of liquid soap from a production line to a packing area, carrying 4 jugs per trip. If the jugs are packed into cartons that hold 7 jugs each, how many jugs are needed to fill the last partially filled carton after the worker has made 17 trips?
A. 1
B. 2
C. 4
D. 5
E. 6
each trip fills 4/7 of carton
(17*4)/7 leaves a remainder of 5
7-5=2 more jugs needed
B
Manager
Joined: 08 Apr 2017
Posts: 68
Re: A worker carries jugs of liquid soap from a production line to a packi [#permalink]
### Show Tags
19 Nov 2017, 06:02
AbdurRakib wrote:
A worker carries jugs of liquid soap from a production line to a packing area, carrying 4 jugs per trip. If the jugs are packed into cartons that hold 7 jugs each, how many jugs are needed to fill the last partially filled carton after the worker has made 17 trips?
A. 1
B. 2
C. 4
D. 5
E. 6
The worker has finished 17 trips.
Hence the number of jugs transported = 17*4 = 68.
The following is multiple choice question (with options) to answer.
A person who wants to visit a desert will be sure to pack more | [
"winter boots",
"thermal underwear",
"tan shorts",
"snowsuits"
] | C | a desert environment is usually hot in temperature |
OpenBookQA | OpenBookQA-2632 | c++, game, c++17, qt
void setCountOfNeighbourMines(int count);
[[nodiscard]] int countOfNeighbourMines() const;
[[nodiscard]] bool hasMine() const;
[[nodiscard]] bool hasQuestionmark() const;
[[nodiscard]] bool isCovered() const;
[[nodiscard]] bool isFLagged() const;
[[nodiscard]] bool isPressed() const;
[[nodiscard]] bool neighbourHasMine() const;
[[nodiscard]] bool neighbourIsFlagged() const;
public slots:
void toggleColor(bool value);
void toggleNewQuestionMarks(bool value);
void increaseCountOfFlaggedNeighbours();
void decreaseCountOfFlaggedNeighbours();
void uncoverIfCoveredAndNoMine();
void uncoverIfNotFlagged();
void pressIfCoveredOrQuestionmark();
void releaseIfCoveredOrQuestionmarkPressed();
void showMine();
void setToFlaggedWrong();
signals:
void hitMine();
void flagged();
void unflagged();
void uncovered();
void uncoveredEmptyCell();
void uncoverAreaWithNoMines();
void uncoverNotFlaggedNeighbours();
void pressed();
void released();
void pressNeighbours();
void releaseNeighbours();
protected:
void paintEvent(QPaintEvent *event) override;
private slots:
void mark();
The following is multiple choice question (with options) to answer.
Candace pushed a button outside her friend's house and a buzzer went off inside the house. | [
"a circuit was closed",
"a circuit was destroyed",
"the electricity cut out",
"lightning struck the house"
] | A | pushing a button sometimes completes a circuit |
OpenBookQA | OpenBookQA-2633 | waves, electromagnetic-radiation, acoustics, interference, noise
It's two different things that are kind of analogous. I can't say it's impossible but it looks difficult.
The following is multiple choice question (with options) to answer.
Magnets in ear pieces convert sound waves into | [
"ear aches",
"radio stations",
"Brain cancer",
"direct current"
] | D | telephones convert sound energy into electrical energy |
OpenBookQA | OpenBookQA-2634 | zoology, digestive-system, pets
Title: Is it safe to feed an adult fire salamander with slime maggots? As a reminder, maggots feed of a flesh, while fire salamander consumes his prey alive, without killing it.
Can it happen that the maggot will start eating the salamander from the inside? Although I am afraid I don't know much about fire salamanders specifically, it is certainly possible for ingested fly larvae (or larvae hatching from ingested eggs) to survive ingestion and subsequently cause intestinal damage. Parasitic infestation by fly larvae that grow inside the host while feeding on its tissue is called myiasis. Enteric myiasis (also called gastric, rectal, or intestinal myiasis to indicate the affected part of the digestive system) occurs occasionally in humans following the ingestion of cheese infested with cheese fly maggots. Casu marzu, a traditionally produced Sardinian cheese, is supposed to have live cheese fly maggots in it, and cases of bloody diarrhoea following its consumption are known. If they're dead the cheese is considered unsafe to eat (although personally I'd correct that to 'more unsafe').
The following is multiple choice question (with options) to answer.
A salamander is | [
"extinct",
"bipedal",
"cold blooded",
"warm blooded"
] | C | an amphibian is cold-blooded |
OpenBookQA | OpenBookQA-2635 | rust
We can now remove Clone, but need to accept an owned ParamType rather than a reference (as in your new code) since we need an owned value to insert into the cache.
The following is multiple choice question (with options) to answer.
Which of the following is the most replaceable? | [
"the energy captured by a windmill",
"the oil from the earth",
"the iron from the earth",
"the energy provided by natural hydrogen"
] | A | a renewable resource can be replaced |
OpenBookQA | OpenBookQA-2636 | everyday-life
Title: Strange pattern on car windows
A couple of days ago I was in a friend's car, and I noticed this pattern on the windows; I took a picture of the sun through the window to make it clearly visible.
The night before had been quite cold, but I don't think that the temperature went below $0$ °C, even though I am sure that it did some days before.
I can speculate that the phenomenon originated from some condensation/freezing of humidity on the outside of the car window, so I searched the web for pictures of water condensation and frost patterns (and also water staining) on car windows, but couldn't find anything similar.
What could be the origin of this intricate pattern? From your question, I can guess that the weather is rainy in your region.
When you drive a car in the rain, the water drops pass your windows at an angle. This, plus wind and other winter stuff causes the path of the drops to twist and jiggle like in this photo
I would also guess that the rain stopped while still driving, so the water could've evaporated in this pattern. The sunlight then makes those residues more pronounced when you took the picture.
Take a look at the following picture from a google search of 'water stains on glass'. To me it looks similar to your photo, just without the effect of moving window (keep in mind that the residues in the water may differ from one place to another due to pollution and etc., so the stains don't have to look the same).
The following is multiple choice question (with options) to answer.
After a storm, a glass vial with markings on it can tell | [
"how loud a baby is",
"how wet an area got",
"how sad a puppy is",
"how bad a skunk smells"
] | B | as the amount of rainfall increases in an area , the amount of available water in that area will increase |
OpenBookQA | OpenBookQA-2637 | classical-mechanics, energy, electricity
Title: Can we imagine having a computer keyboard that recharges itself through mechanical utilization? Silly question here.
I have a debate with my father, and while I am decent at high school level physics, both he and I cannot determinate through calculus which of us is wrong.
Basically, he had the idea that perhaps, through simple mechanical utilization, a wireless keyboard can be charged and used, without any other energy source. (The keyboard can have a battery that can be recharged through the said mechanical utilization though), I have the intuition that the idea is interesting, but physically problematic.
With simple research, I have seen that an idle keyboard has a consumption of $1W$, and a used keyboard will use between $1.5$ and $2.5W$.
So, we have specific questions:
Is collecting the mechanical energy from the keyboard doable ?
And if yes, how much energy can typing on a keyboard's key produce ?
How it may impact the overall comfort of the user ?
I have multiple difficulties to answer these myself. How can I know how much a person can generate through typing, how much energy will be lost in the process of using a battery, etc..?
(This is not a concept that I try to sell or anything, this is a mere thought experiment that I wanted to share and resolve, please do not take it too seriously) What you are looking for is fairly simple. All you need to do is build a piezoelectric generator under each key. These generate electricity with each push. With this the element is stretched or vibrated with each push and this generates electricity. Do a Google search and you will find much more.
The following is multiple choice question (with options) to answer.
What would need electrical energy to function? | [
"The Sun",
"Grass",
"A Dyson",
"A lake"
] | C | electric devices require electrical energy to function |
OpenBookQA | OpenBookQA-2638 | optics, microscopy, fluorescence
$$\rho = \frac{2\,\sqrt{2}\,\lambda}{\pi\,\eta}\approx \frac{0.9\,\lambda}{\eta}\tag{6}$$
The following is multiple choice question (with options) to answer.
A microscope creates clarity by | [
"levitation",
"acceleration",
"decomposition",
"augmentation"
] | D | magnifying makes seeing small things easier through using a microscope |
OpenBookQA | OpenBookQA-2639 | There is a concept of $$C\setminus B = \{x\in C$$ but where $$x \not \in B\}$$. As we know that $$x\not \in B$$ that if $$x\in C$$ then we must have $$x\in C\setminus B$$. But $$C\setminus B$$ certainly doesn't have to be empty!
So that doesn't follow at all!
But now we have proven both $$x ∈ C$$ and $$x \not \in C$$.so we have reached a contradiction. Therefore $$x ∈ B$$.
Except we haven't proven $$x \not \in C$$. We have reached no contradiction. And $$x$$ need not be in $$B$$. $$x\in C$$ so $$x$$ could be in $$C \cap B$$ or $$x$$ could be in $$C\setminus B$$. But we have no way of telling.
The following is multiple choice question (with options) to answer.
Which of the following is true? | [
"switching from a truck to a moped will save gas",
"switching from a moped to a truck will save gas",
"switching from a car to an SUV will save gas",
"switching from a car to a truck will save gas"
] | A | as mileage per galon of gasoline increases , the amount of gasoline used will decrease |
OpenBookQA | OpenBookQA-2640 | atmospheric-chemistry
But some researchers have argued it does make a notable contribution in the lower atmosphere, but indirectly. There doesn't appear to be a consensus on how big this effect is (and the Wikipedia reference is old and obsolete). The argument for ozone being a notable contributor is based on the following. Hydrocarbon pollution in the lower atmosphere (often from vehicle emissions) leads to a variety of undesirable reactions some of which lead to the production of ozone (as well as many other irritating components of smog). We really don't want too much smog or ozone in the lower atmosphere because it is bad for health. Some have estimated that it also adds to the warming caused by hydrocarbon emissions (exacerbating the warming potential of methane, for example).
It is hard to judge the estimates of its contribution to warming not least because they rely on models of complex reactions caused indirectly by other pollutants. Also, the big issue with emissions leading to ozone are not its contribution to warming but its contribution to pollution which causes direct harm to people in the short term. In fact regulations around emissions has been striving to reduce those emissions since before we started worrying about global warming. And, many countries have sharply reduced them (this is a major reasons why most western countries insist on catalytic converters in their vehicles). We should reduce ozone pollution by reducing the other emissions that cause it and we have been doing that for decades.
I would argue that ozone is essentially irrelevant to global warming. We should strive to reduce it in the lower atmosphere even if we were not worried by global warming. So even if we can't agree on how big its contribution to warming is (which the literature isn't clear on) we should be reducing it as much as we can for more direct reasons.
And, even if we wanted to report its contribution to warming, the best place to account for it is to add it to the contribution of other emissions (eg methane) rather than to account for it separately as we don't directly emit it from anything.
The following is multiple choice question (with options) to answer.
Which pollutant is most likely caused by humans activity? | [
"bricks",
"bovine farts",
"rocks",
"oxygen"
] | B | pollution is when humans pollute the environment with pollutants |
OpenBookQA | OpenBookQA-2641 | = ",Count[Drop[branches,gen],_Real,\[Infinity]]/4" "" ""Length = ",SetAccuracy[Count[Drop[branches,gen],_Real,\[Infinity]]/4*(Norm[{{pt1[[1]],0.5},{0,0}}]^gen),3]}],18],Gray],{2.3,-1.8}]},{Inset[Style[Text@TraditionalForm@Style[Row[{"Polynomial Trees by Bernat Espigulé"}],18],Gray, Opacity[0.4]],{2.3,-2}]}},PlotRange->{{-1.7,3.7},{-2.1,1.5}},ImageSize->{1000,600},Background->Black]],{{th,0.025,"Thickness"},0.005,0.185},{{gen,12,"Generations"},Range[1,16], ControlType -> SetterBar},{{pt1,{0.5,0.5}},{-0.5,0.5},{0.5,0.5},Locator}]Jurassic Trees
The following is multiple choice question (with options) to answer.
trees will grow from | [
"rocks",
"hack berries",
"thin air",
"water lilies"
] | B | a berry contains seeds |
OpenBookQA | OpenBookQA-2642 | ecology, measurement, visualization, species-distribution
Sorry for the long-winded explanation. Any thoughts? The problem of how to infer species distributions from scattered species occurrences is common in ecology, and there exists a number of methods to construct distribution maps. As a start, you should have a look at Species Distribution Models (SDMs) using regressions models or Maxent, and the paper by Elith et al (2009) is a good starting point and a standard reference. SDMs using maxent is now a common approach, which integrates species occurrences as point data along with environmental layers (e.g. temperature, moisture and topography) to predict species distribution maps, and this can also include absence data or "pseudo-absence" data (randomly sampled data from a region of interest). The maxent software is described and can be downloaded here: http://www.cs.princeton.edu/~schapire/maxent/
A common criticism against distributions produced by Maxent is however that they ignore e.g. species interactions, and they only considers the species occurences and the environmental variables that has been included in the model.
In your "Note", you touch upon the issue of detectability, which is an important issue that has received much attention recently. The problem is largest when you only have presence data, and to have real presence/absence data is preferable. Even if you don't have real absenses (the species has been searched for but not found), an estimate of sampling effort in different areas is still very useful, since this means that you can at least evaluate whether absenses is due to "real" absense or lack of sampling. In your case, the movement paths of characters could be used as a measure of spatial "sampling effort". The main issue with detectability in studies of distribution of species trends is if there is trends or bias in detectability, which means that apparent changes over time or patterns in distribution might be due to differences in detectability and not real differences between areas or over time. This could for instance be the case if observers are more likely to spot a species in one type of habitat (open savannah) then in another type of habitat (closed forest). Useful starting points for issues of detectability are Dorazio (2014) (technical though) and Kery et al (2010).
The following is multiple choice question (with options) to answer.
Which are least likely to be seen in the wild? | [
"bird eggs",
"human eggs",
"fish eggs",
"crocodile eggs"
] | B | if an animal hatches from an egg then that animal is born |
OpenBookQA | OpenBookQA-2643 | thermodynamics, energy, temperature
The higher the temperature of the room, the quicker it cools too, so typically, I would think leaving the oven closed would be beneficial in the long term. You're keeping the heat around for longer.
One (potentially) good thing about opening the oven door is that it directs more of the heat towards the inside of the room. Some of the heat is going to go into the walls, and may be heating your neighbors rooms instead (depending on the layout, wall insulation, etc). I'm not sure how insulated the back of the oven typically is though. If it's not well insulated, opening the door may be beneficial to make sure you aren't losing a lot of heat through the walls over time, but I expect that's fairly negligible in most cases.
The following is multiple choice question (with options) to answer.
Leaving your garage door open during a storm poses the risk of having animals going in due to them needing what | [
"some shoes",
"death",
"some shelter",
"some candy"
] | C | shelter is used for protection by animals against weather |
OpenBookQA | OpenBookQA-2644 | evolution, biochemistry, mitochondria
Title: Is there any advantage of having mitochondria for aerobic respiration? If we consider the pathway of breakdown of glucose which includes glycolysis, the citric acid cycle and the electron transport chain, all these processes takes place in some prokaryotes and eukaryotes. In prokaryotes all these processes take place in cytoplasm while in eukaryotes the last two processes take place in mitochondria.
So is there any advantage of performing the last two processes in the mitochondria? Does it yield more energy? If there is no advantage, what is the point of having a mitochondria (at least for this process)? From the evolutionary point of view, the eukaryotes acquired these metabolisms (except glycolysis) from their prokaryotic endosymbionts. Not all prokaryotes have the ETC. The free living ancestor of mitohondria is supposed to be the alpha-proteobacterium.
Now, glycolysis is a common pathway in lot of lifeforms perhaps because of abundance of glucose. TCA cycle is coupled with ETC at certain steps which makes it essentially a part of aerobic metabolism.
The reason for having a dedicated organelle for respiration
ATP synthesis is a membrane process. Imagine a large prokaryotic cell- as big as an animal cell. Such a cell cannot take care of its energetic demands which primarily consists of protein synthesis with the given area of membrane i.e it needs much more ATP-synthases than it can have to cope up with the energy demands of maintaining such a huge cell (this index is approximated based on surface to volume ratio). Therefore it is wise to harbor multiple efficient organelles i.e. mitochondria which themselves have just a small essential genome and proteome to maintain.
For a better understanding, please read this article. I just loved it.
There is also a book by the same author about mitochondria called Power, Sex, Suicide.
The following is multiple choice question (with options) to answer.
A cell taking oxygen and carbs and making it into something else, which can be used more efficiently is | [
"ridiculous",
"respiration",
"breathing",
"retirement"
] | B | cellular respiration is when a cell converts from oxygen and carbohydrates into carbon dioxide, water, and energy |
OpenBookQA | OpenBookQA-2645 | solar-system, coordinate, stellar-astrophysics
Can you see either in the sky now. Do they look the same? If yes you are in the same hemisphere you normally live in. If they look strange - upside down. You are in the hemisphere opposite to where you normally live.
You've just spent the rest of the night looking at the sky and the Sun is up. Observe the path Sun, in the sky, during the course of the day. If it is low, it winter. If it is high, it's summer. The daytime temperature will also confirm this.
The following is multiple choice question (with options) to answer.
If the stars in the sky above your home vary from month to month, | [
"that is a new phenomenon",
"that is expected due to the axis",
"that is very scary",
"that is rare and unusual"
] | B | the Earth revolving around the sun causes stars to appear in different areas in the sky at different times of year |
OpenBookQA | OpenBookQA-2646 | fusion, renewable-energy
An energy "breakthrough" would be a loaded development. We already use lots of energy, and if we found it economic to use more we probably would. The last breakthrough shift in our ability to exploit energy resources rocketed the entire planet into a new geological era, the Anthropocene. We called this change the industrial revolution. Some obscure project that ARPA-E funded with $500,000 could cause the next industrial revolution. The implications of such a change would probably be beyond any of our imaginations.
The following is multiple choice question (with options) to answer.
Though fossil fuels and their byproducts will eventually be used up completely, we'll still have | [
"gasoline",
"coal",
"plastics",
"light from stars"
] | D | alternative fuel is usually a renewable resource |
OpenBookQA | OpenBookQA-2647 | # Conditional Probability of rainfall
1. Apr 26, 2012
### TranscendArcu
1. The problem statement, all variables and given/known data
3. The attempt at a solution
a) P(Pickwick has no umbrella | it rains) = $\frac{\frac{1}{3}\frac{1}{3}}{\frac{1}{2}} = \frac{2}{9}$, which is the answer according to my answer key.
b) For part b we have:
There is a rain forecast which means he will bring the umbrella. The probability that it won't rain is 1/3.
There is a non-rain forecast which means he brings the umbrella with a probability of 1/3 and it will not rain with a prob of 2/3.
P(Pickwick has umbrella | no rain) = $\frac{1}{3} + \frac{1}{3}\frac{2}{3} = \frac{5}{9}$. But the answer is apparently 5/12. What have I done incorrectly here?
2. Apr 26, 2012
### MaxManus
I got the same as you at b) and I cant see why it is not correct.That's no guarantee for that you are correct though
3. Apr 26, 2012
### Ray Vickson
The following is multiple choice question (with options) to answer.
Needing to use an umbrella could be the result of | [
"altercation",
"precipitation",
"condensation",
"evaporation"
] | B | evaporation causes amount of water to decrease |
OpenBookQA | OpenBookQA-2648 | mass, velocity, weight
Wind stroke and area of existing large flying birds (and Haast Eagles) are approximately optimum for the load.
Modern materials will allow flying-related swept area per mass to be as good as or better than nature has achieved in these large birds.
This violates the usual cube-squared law that usually requires scaled-up versions of a given creature to be substantially more sturdy and thick-boned, and scaled-down versions to be much more "delicate". This is because the volume and (more or less) the mass changes with dimension cubed but areas such as bone cross-section to change with dimension squared. So a linearly scaled-up ant of elephant size would break apart under its own weight and muscle forces and a linearly scaled-down elephant of any size would be vastly too massive for its energy and power capabilities.
Feather size scales at most linearly with dimension squared - ie a Haast Eagle scaled up to man mass size would have feathers in the same proportion to size as on the original, or smaller.
Wing design will be "something like" the best examples available in nature. While many people probably thing that they could greatly improve on current designs, the experience base is very limited compared to the competition and so far design successes are few.
The following is multiple choice question (with options) to answer.
If a raptor loses weight, then it will have an easier time | [
"eating a goldfish cracker",
"building a small house",
"circling way up there",
"leaving home at night"
] | C | as the weight of an animal decreases , that animal will fly more easily |
OpenBookQA | OpenBookQA-2649 | star, planet, telescope, light, space
Title: How do I know what I'll be able to see? So I live in a suburb in Victoria, Australia. Less than an hour away from the city and I guess there is a bit of light pollution because from my backyard I can probably only see about 15 - 20 stars (probably less), I'm wondering what these stars are, and what I'll see when I get this telescope:
https://www.opticscentral.com.au/saxon-707az2-refractor-telescope.html?___SID=U#.WXQNMtN940r
This is going to sound stupid but how do I know when there are planets in the sky that I can see? I don't think I've ever actually seen a planet other than the moon.
Thank you. Firstly, if you're planet spotting, don't worry too much about light pollution. The planets are some of the brightest objects in the sky and some (especially Jupiter) can easily be observed even with a full Moon - the full Moon (along with the Sun!) is the biggest contributor to light pollution!
Take a look at the list of brightest stars ( https://en.wikipedia.org/wiki/List_of_brightest_stars ), which also contains estimates for the brightness of the Sun, Moon and major planets. There aren't typically any stars brighter from Earth than Venus, Jupiter, Mars and Mercury and precious few brighter than Saturn. I'm going to suggest you probably have seen many of the planets - but just didn't recognise them.
+1 for Stellarium ( http://www.stellarium.org/en_GB/ ). It's free, intuitive and very visual to use. You can put in your local viewing location and it gives you a view for any time of the night, future or past. At the time of writing (23 July 2017), Saturn and Jupiter should be looking good for the Southern Hemisphere. This rotates throughout the year, and Stellarium will help with this.
Do a web search for "the sky at night in the southern hemisphere" and you'll find a number of examples of websites with highlights to look for when you get out.
Couple of final suggestions:
The following is multiple choice question (with options) to answer.
If someone wants to see the celestial bodies clearly they would use | [
"a freshly printed magazine",
"a dirty old sneaker",
"a paper towel tube",
"a lengthened glass tube"
] | D | a telescope is used for observing stars |
OpenBookQA | OpenBookQA-2650 | energy-efficiency, thermal-insulation
greater if the window is bigger
less as temperature difference get smaller
Radiative heat transfer
The main factor that is of consideration here is the solar radiation. There are three types of radiation:
Direct radiation: the direct rays of the sun. (this is zero on a cloudy day).
Diffuse radiation: this is always present and its an effect of the presence of atmosphere. In higher latitudes it tends to increase because the sun rays need to "pass through" more atmosphere.
reflected (you can neglect this)
If you can get the rays of the sun (direct radiation) into the house, this will always be a significant plus in the heat balance of the house.
Final thoughts
This problem is very instance specific depending on:
the location of the house
orientation of windows
type of blinds, etc.
Therefore, it is impossible to draw a generic conclusion. As such, only trends can be realistically observed.
At a temperature difference of 30$[^oC]$ it makes sense to close the blinds on a cloudy day. However, if you get closer to 15$[^oC]$ then the savings are diminished.
If the windows are positioned in the right angle and light shines into the room, then expect the added solar radiation will improve the heat balance in favour of open blinds.
The following is multiple choice question (with options) to answer.
More sunlight will be absorbed by | [
"a daffodil with curled leaves",
"small plant with tiny leaves",
"a plant with wide, smooth leaves",
"a daisy with thin, short leaves"
] | C | sunlight contains ultraviolet light |
OpenBookQA | OpenBookQA-2651 | The first one gives the minimum volume, so you don't want that. Take the second.
-
Thank you Jerry. :) Cheers! You get the right answer, because you actually gave me two value and described them really nice! I could follow the process very easily! – user31113 Apr 7 '13 at 11:46
You're welcome! – Jerry Apr 7 '13 at 11:47
If you cut the corner in the manner shown, by trigonometry at any corner, the new side length is smaller by $2 \sqrt3 h$. (Let me know if you have difficulty with this.)
Hence the box's volume is proportional to $\left(a-2 \sqrt3 h\right)^2 h$, which we try to maximise. Let $V(h) = \left(a-2 \sqrt3 h\right)^2 (4 \sqrt3 h)$. The value of $h$ which maximises $V(h)$ is exactly same as that maximising the volume we desire, due to proportionality. Now $V(h)$ can be looked at as the product of $3$ terms, $(a-2 \sqrt3 h), (a-2 \sqrt3 h)$ and $(4 \sqrt3 h)$, which sum to a constant $2a$. Hence the product is maximised when these three terms are equal. i.e.
$a-2 \sqrt3 h = 4 \sqrt3 h$ or when $h = \dfrac{a}{6\sqrt3}$.
-
Oh woops, yours is definitely more elegant! – Jerry Apr 7 '13 at 11:26
@Jerry Thanks. It's just that I like inequalities a lot. – Macavity Apr 7 '13 at 11:32
Thank you Macavity. :) Cheers! – user31113 Apr 7 '13 at 11:44
@Macavity Your solution is certainly neat, but I get a slight butterfly feeling when you pull that factor out of the air. I seem to get the same numbers by a method at least I find simpler. Any comments? – Brian Chandler Dec 20 '14 at 16:24
The following is multiple choice question (with options) to answer.
Which is least likely to have a constant volume? | [
"ice",
"play doh",
"food",
"car exhaust"
] | D | Matter in the gas phase has variable volume |
OpenBookQA | OpenBookQA-2652 | thermodynamics, electricity, temperature
I'm not defending either model but merely showing how different dependencies can arise from various assumptions and idealizations.
More generally, we could write the heat equation as
$$k\frac{\partial^2 T}{\partial x^2}+\frac{I^2\rho}{(\pi r^2)^2}-\frac{2[h(T-T_\infty)+\sigma\epsilon(T^4-T_\infty^4)]}{r}=pc\frac{\partial T}{\partial t}$$
(thermal conductivity $k$, Stefan–Boltzmann constant $\sigma$, emissivity $\epsilon$, all material properties dependent on temperature.) for a long fuse wire that cools by convection, radiation, and conduction to its connected ends. Note that even this more complex model ignores lateral conduction within the wire! This equation would need to be solved numerically, providing improved predictive accuracy at the expense of losing simple scaling relations.
The following is multiple choice question (with options) to answer.
What could be an example of a thermal conductor | [
"a penny",
"grass",
"a wood block",
"cotton"
] | A | a thermal conductor is made of materials that conduct thermal energy |
OpenBookQA | OpenBookQA-2653 | 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.
Where would you find a less than average amount of biodiversity compared to other biomes? | [
"a jungle",
"the arctic",
"a forest",
"a rain forest"
] | B | cold environments contain few organisms |
OpenBookQA | OpenBookQA-2654 | everyday-chemistry, cleaning, minerals
Once you've got the crystal to the cleanliness you're happy with, you can polish it with powdered polish and a cloth, given time.
If instead of nice, angular crystals you're just trying to produce something like a smooth, rounded stone, after cleaning with water you can use a series of sandpapers (start at 60-80 grit and work up to ~400 grit) and polish to gradually smooth, then polish the stone by hand. This will clear away any deposits, but it will also change the surface of the stone itself. That might be acceptable to you if you've got something like a quartz river rock, and it will make a very nice end product. Take care to keep the stone wet while working, you don't want to breathe in rock dust if you don't have to.
The following is multiple choice question (with options) to answer.
Where would rocks be the smoothest? | [
"where thunder was heard",
"where water has flowed for years",
"where wind has blown for days",
"where the human population is the highest"
] | B | contact between rocks over long periods of time causes rocks to smooth |
OpenBookQA | OpenBookQA-2655 | experimental-physics, speed-of-light, neutrinos, faster-than-light
Title: Light vs neutrino speed comparison in a real tunnel Given current accuracy of the techniques, is it possible to identify a real, existing tunnel (stright I think) to make the direct comparison of the speed of light and of neutrinos?
The hypotetical tunnel from CERN to OPERA would-be too long. If we were able to increase accuracies by two decades, then would a 7.3 Km tunnel suffice ? The 60ns difference would
become around 600ps.
Suppose there is such a tunnel, suppose it can be availabe to physicists. Apart from all the logistics problems of generating and detecting light and neutrinos at the two ends of such tunnel, are there other difficulties? Unlike neutrinos, light will be slowed down by gas in the tunnel, which would have to go through the Earth. It is much cheaper and easier to mathematically analyze the OPERA results to find their error, were they ever to release their detailed protocol, which is unlikely, because they don't seem to want the error discovered.
The following is multiple choice question (with options) to answer.
if a tunnel had a modern facility for seeing, what can we infer from this? | [
"there is water in use",
"Thomas Edison's work is in use",
"there is sunlight in use",
"there is petrol in use"
] | B | a light bulb requires electrical energy to produce light |
OpenBookQA | OpenBookQA-2656 | energy, visible-light, photons, sun, interactions
Title: What are the physical processes involved in feeling warm from the sunlight? Suppose a human is lying on a beach. He/she starts to feel warm after exposing his/her skin to the sunlight. I assume that feeling is due to the ability of the human body of "measuring" the increasing in temperature of the skin.
Now I want to understand what are the physical processes involved in this increasing in temperature.
Imagine a group of photons impinging on the skin in a certain interval of time. I tried to list the possible interactions from a particle physics perspective between photons and the human tissue and I concluded that the possible interactions may be:
Photoionization
Compton scattering
Rayleigh scattering
Pair production
The first 3 seems to be reasonable, but the fourth one requires an energy threshold too high: there are no incident photons that may have that energy. I conclude that by looking at the spectrum of sunlight that actually reaches the earth's surface below the atmosphere. So I think that the pair production does not play a role in this situation.
Are there any other interaction processes between photons and tissue molecules involved in the increasing of temperature of the human tissue?
After listing the processes I wonder what actually increases the temperature: is the temperature increasing because the photons-molecules interactions lead to a transition of molecules to excited vibrational states? or maybe transitions to excited rotational states?
I thought that another possibility is that the photons interactions are increasing the kinetic energy of the water molecules in the skin or maybe are increasing the lattice vibration of other tissue (skin, bones or others). Are this processes happening simultaneously? One of this processes (for example transition to rotational excited states) is dominant over the others ?
I'm looking to a qualitative answer, without going into too much details of the Biology of the human body. I just want to create an approximate picture of this situation in my mind. I want to create a mental "video" from the instant in which a photon or a group of photons impinges in the skin to the moment in which tissue molecules are affected and the temperature starts rising up.
I thank in advance anyone who answers this question. You forgot garden-variety absorption! Here, light promotes electrons from lower energy states to higher energy states. However, skin is made of many small particles, so scattering is important as well.
Here’s the mental video:
The following is multiple choice question (with options) to answer.
in the presence heat, which of these comes about? | [
"a piece of gum",
"a slurpy at the cafeteria",
"an ice cream cone",
"a large metamorphic rock"
] | D | extreme heat and pressure metamorphose rock into metamorphic rock |
OpenBookQA | OpenBookQA-2657 | condensed-matter, pressure, temperature
$$\alpha = \frac{1}{V}\left(\frac{\partial V}{\partial T}\right)_P $$
Therefore the result is:
$$\left(\frac{\partial T}{\partial P}\right)_S = \frac{T V\alpha}{C_P}$$
In terms of the specific heat capacity (per unit mass) $c_P$ this is:
$$\left(\frac{\partial T}{\partial P}\right)_S = \frac{T\alpha}{\rho c_P}$$
where $\rho$ is the density. For water at 20 C this is about $1.45\times 10^{-8}\frac{K}{\text{Pa}}$, so 1000 bar pressure will raise the temperature by about 1.45 C.
The following is multiple choice question (with options) to answer.
Sticking your hand in water above 100 degrees Celsius | [
"will freeze your digits",
"will lead to scalded fingers",
"will heal any sores or wounds",
"will lead to frostbite"
] | B | if liquid is boiling then that liquid is hot |
OpenBookQA | OpenBookQA-2658 | life, replication
Title: What is the name of the smallest self-replicating thing? Some time last year, I found an article on Wikipedia about the smallest something to be able to reproduce.
I don't remember exactly what it was, but I am fairly certain that after the initial discovery another of the previous organism (this one slightly smaller) was discovered.
I think that the smallest something might have been the smallest self-replicating protein, or smallest self-replicating molecule, or something like that.
It was not mentioned in this thread: Which organism has the smallest genome length?
It had a strange, stand-out name and I believe it was discovered in the 90s. You're probably thinking of the Spiegelman Monster. It was actually discovered in 1965, but it was discovered that it became shorter over time in 1997.
It also wasn't included in that thread, and it has a strange name.
http://en.wikipedia.org/wiki/Spiegelman_Monster
The following is multiple choice question (with options) to answer.
Some of shelled item containers for replication processes are use by which kind of life form? | [
"reptile",
"dog",
"plant",
"invisible"
] | A | as temperature in the environment increases , the body temperature of a reptile in that environment will increase |
OpenBookQA | OpenBookQA-2659 | climate-change, glaciology, ice-sheets
Title: Can ice caps reform if they disappear? Excuse my ignorance. I'm under the impression that there are various types of ice at the poles, but I don't know the difference or the significance of each type, so, in terms of whatever is actually melting in these areas as a result of climate change, is it possible that it could come back if greenhouse gas emissions were eliminated or something like that? Basically, I'm assuming that the ice caps are necessary in order to maintain the habitability of the planet for humans, so is there some sort of threshold of melting that would essentially count as a point of no return or is there always the possibility of seeing the ice caps return to safe levels? Yes, polar ice can melt -- significantly, if not completely, with substantial effects on human civilization. And it can stabilize and recover, but the question is at what pace relative to human civilization.
There are generally three types of polar ice:
Ice sheets: "An ice sheet is a mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles). The two ice sheets on Earth today cover most of Greenland and Antarctica."
Ice shelves: "Permanent floating sheets of ice that connect to a landmass."
Sea ice: "Sea ice is frozen ocean water. It forms, grows, and melts in the ocean. In contrast, icebergs, glaciers, and ice shelves float in the ocean but originate on land."
Sea ice is usually 1-2 meters thick; shelf ice is 100-200 meters thick; sheet ice is one to several kilometers thick.
The poles differ significantly. It's often pointed out that the Arctic is an ocean surrounded by land and the Antarctic is land surrounded by ocean. The North Pole is occupied by sea ice, about half of which melts every summer and reforms every winter.
At the other extreme are the ice "caps," more or less the ice sheets in Greenland and Antarctica that extrude ice in the form of glaciers and ice shelves that continuously flow into the ocean, breaking apart and melting.
To take just Greenland: Greenland has had some degree of glaciation for ~38 million years, but lost much or almost all of its ice during a warming period about 400,000 years ago, suggesting that the current ice sheet was created in that time.
The following is multiple choice question (with options) to answer.
The arctic can be considered what? | [
"desolate",
"A magical place",
"A city",
"A watermelon"
] | A | the arctic environment is white in color from being covered in snow |
OpenBookQA | OpenBookQA-2660 | newtonian-mechanics, conservation-laws
So generally the plate will move : it could translate and also rotate. Constraining forces (and torques) would be needed to keep it in place. If it is released it will move.
The following is multiple choice question (with options) to answer.
If a thing is going to consume something that moves it is | [
"nursing",
"birthing",
"perusing",
"grazing"
] | C | An example of hunting is an otter cracking open clams with a rock |
OpenBookQA | OpenBookQA-2661 | plant-physiology
Title: Would a plant survive if it was watered using hard-water? Hard water is water with high mineral/salt content. I'm told that a potted plant watered with a salt solution dries out sooner or later. Is this true?
If so, would a plant survive if watered using hard-water? It would depend on the content of the hard-water. If the water contained heavier metals like lead or radioactive elements like tritium (Hydrogen-3), the plant would most likely die. Most land plants cannot survive when watered with massive amounts of salt water as the salt would absorb the water from the leaves.
The following is multiple choice question (with options) to answer.
If a plant is deprived of which of these, it will die? | [
"glass",
"dampness",
"cat food",
"poison"
] | B | a plant requires water to grow |
OpenBookQA | OpenBookQA-2662 | remote-sensing, forest
Title: How is tree age estimated? I am trying to study about forest biomass and carbon amount of forest.
First of all, I studied some papers, they mentioned that age of forest is related to the biomass. So, How do we measure the age of tree? What are the practical ways used to estimate tree age? Biomass itself isn't a great measure of tree age because the size of a tree is affected by a number of factors. Assuming the same species of tree:
Soil nutrients: more nutrients in general means better growth for most species
Availability of water: scare water means less growth
Availability of light: a tree with more light grows more than one that's constrained
A tree with good soil, lots of water and light will grow more than one without those things, so the same age of tree could be very different sizes and biomasses. The only way to get an exact age of a tree is to get a core sample or cut it down and count the rings, every ring represents a growing year. A tree that grows very little will have narrowly spaced rings, a tree that grows a lot has wider space rings as it's putting more biomass. Note that wood density is also an important measurement for biomass, the denser the wood the more biomass is compacted in the same amount of space. Slower growing trees tend to be more dense, tree twice the size of another may not be twice the mass.
That's for a single tree, but you're asking about forests. It's impractical to core sample a million trees, but you can core sample a fair number of live ones or take samples of fallen ones. Along with measurements of circumference and height you can build a database and estimate the average age of the rest of the trees in the forest from their heights and circumferences. It's also possible to estimate the biomass of the forest from estimating the number of trees in and using an average biomass.
The following is multiple choice question (with options) to answer.
what is a simple way to determine the age a tree? | [
"by counting its branches",
"by counting its round inner markings",
"by counting its leaves",
"by counting its roots"
] | B | a tree growing a tree-growth ring occurs once per year |
OpenBookQA | OpenBookQA-2663 | 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.
A frog was sick because it wasn't staying warm enough. | [
"The frog was getting burned by a heat lamp",
"The water in the tank had dried up.",
"the frog was unable to regulate its body temperature without an external heat source",
"The frog was using too much ice in its drinks"
] | C | if an organism becomes too hot then that organism may die |
OpenBookQA | OpenBookQA-2664 | # Thread: physics tourist & bear problem
1. ## physics tourist & bear problem
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
2. Originally Posted by rcmango
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
The maximum value of d is such that the bear gets to the car at the same time the tourist does.
So set up a coordinate system such that the bear is at the origin and positive x is in the direction from the bear to the tourist.
Both are moving at a constant speed. The bear has to cover 27 + d meters in the same time the tourist covers d meters.
So for the tourist:
[tex]d = v_t t = 3.5t[tex]
Thus
$t = \frac{d}{3.5}$
For the bear:
$27 + d = v_b t = 6 \left ( \frac{d}{3.5} \right )$
Now solve for d.
-Dan
3. Hello, rcmango!
Another approach . . .
A tourist being chased by an angry bear is running in a straight line
toward his car at a speed of 3.5 m/s. .The car is a distance $d$ meters away.
The bear is 27 meters behind the tourist and running at 6.0 m/s.
The tourist reaches the car safely.
What is the maximum possible value for $d$?
The tourist has a 27-meter headstart.
Relative to the tourist, the bear has a speed of 2.5 m/s.
To cover 27 meters, it takes the bear: . $\frac{27}{2.5} \:=\:10.8$ seconds.
The following is multiple choice question (with options) to answer.
The bear in the wild needs to find other animals to feast. | [
"they are killers",
"they only eat",
"they never kill",
"they are docile"
] | A | lizards eat insects |
OpenBookQA | OpenBookQA-2665 | 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.
Why is it fall one month and spring another month? | [
"the moon has different phases",
"the earth is revolving",
"solar flares appear in cycles",
"the earth is in a different place in its orbit"
] | D | Earth orbiting the Sun causes seasons to change |
OpenBookQA | OpenBookQA-2666 | food, nutrition, energy-metabolism
Title: What are the bare minimum nutrients required to survive as a human? I am trying to determine the bare minimum nutritional requirements to survive as a human, ignoring energy (caloric) requirements. Another way to ask this question is: What elements can humans not live without? I am not inquiring solely about what nutrients are needed, but also their approximate amounts.
Imagine pills that a person can take that covers all their base nutritional needs and that after taking this pill the person can eat whatever they want to meet their caloric requirements. Hypothetically, this pill could have some amount (how much?) fat, carbohydrates, protein, fiber, minerals, and vitamins, and the person could subsequently eat any other food to meet their caloric requirements knowing their nutritional needs would already be otherwise met. Lets ignore the possibility of the person suffering from health issues due to eating too much of any specific food to meet their caloric requirements (e.g., taking the magic pills and then eating only butter).
A person in this situation could think "Ok I've got most of my bases covered, now I just need to ingest another 1000 calories of (almost) anything I want).
What nutrients are absolutely necessary for humans to survive indefinitely, and how much of these nutrients are required?
I am hoping for a complete list with approximate amounts (e.g., 20g fat, 20g carbohydrates, 1mg Vitamin X, .05mg Vitamin Y, 10mg mineral X). Essential nutrients include (NutrientsReview):
Water
9 amino acids: histidine, isoleucine, leucine, lysine, methionine,
phenylalanine, tryptophan, threonine, valine
2 fatty acids (alpha linolenic and linoleic acid)
Vitamins: A, B1, B2, B3, B5, B6, folic acid, biotin, B12, C,
D, E and K (and choline, which is considered a vitamin-like substance)
Minerals: calcium, chromium, chloride, copper, iodine, iron,
manganese, molybdenum, phosphorus, potassium, selenium, sodium, zinc
The following is multiple choice question (with options) to answer.
What requires nutrients to grow and heal? | [
"birds",
"computers",
"dirt",
"metals"
] | A | an animal requires enough nutrients to maintain good health |
OpenBookQA | OpenBookQA-2667 | quantum-mechanics, quantum-information, superposition
When the compass needle points north, that is like a qubit being in the state $\lvert 0\rangle$, and when the compass needle points east, that is like a qubit being in the state $\lvert 1\rangle$. But a compass needle can also point northeast. The direction northeast is neither north nor east, but it is a superposition of equal parts north and east: if you add a north-pointing vector and an east-pointing vector of equal magnitude, you will get a vector that points northeast. Similarly, the qubit state $\frac{1}{\sqrt{2}}(\lvert 0\rangle + \lvert 1\rangle)$ is neither $\lvert 0\rangle$ nor $\lvert 1\rangle$, but it is a superposition of equal parts $\lvert 0\rangle$ and $\lvert 1\rangle$.
The following is multiple choice question (with options) to answer.
When a needle points north on a compass and you are thirsty | [
"head south",
"head towards water",
"head forward",
"head north"
] | B | when the needle of a compass lines up with Earth 's magnetic poles , the needle points north |
OpenBookQA | OpenBookQA-2668 | classical-mechanics, soft-question
Title: Physics of a fixed wheel moving on a flat surface held at distance from a center point Ok, so my boss is trying to make a car turntable. In essence, he has a two boards that sit atop a rotating ring. He wants to put two wheels at the end of each board (8 wheels total). He thinks that you can angle wheels properly (2d) such that they can be flat (axis is parallel to the floor) and the whole contraption move smoothly.
Take a look at this picture (Edit: copied below - Mark)
The following is multiple choice question (with options) to answer.
Two wheeled conveyances are held together by | [
"helically ridged pins",
"tape",
"glue",
"gum"
] | A | a bicycle contains screws |
OpenBookQA | OpenBookQA-2669 | image, mathematics, svg
Beyond that feel free to move things around, change the stroke, change the margins, or change the proportions. But do try to remember that this is a code review. While I am certain that any number of people could draw a better visualization by hand or GImP, this uses SVG for that purpose. So please propose edits to the SVG rather than changes to the image. For example, a patterned fill is certainly possible, but please include how to do that rather than just saying, "The image would look better filled with a polka-dot pattern."
My plan is to use this to fix my T-shirt design on Zazzle, as the current image doesn't scale well. Wow! I’ve never reviewed an image before. Neat.
First, I’d flip your left square to align the corners of the right-most triangles in the left square with the horizontal line in the right square. This gives a visual indication that those dimensions (a and b) in both squares are the same. With the original image, your eye has to draw the line all the way across the left square to see it line up with the left triangles of the left square.
Second, both squares have the same four triangles, except in your right diagram, you have to mentally flip 2 of the triangles to make corresponding triangles in the same orientation between left and right squares. If you drew one of the diagonals between the opposite corners of the a/b rectangles, then all 4 triangles can be mentally translated from the left to the right image, without needing rotations or flips.
I’ve number the triangles in my image, below, to show you what I mean, but I’m not certain you’d want to number them in your final t-shirt design.
The SVG Code
Styling
You've used styles to assign attribute to text elements, so you don't have to specify the attributes in each <text/> element, but you continue to specify both the fill and stroke for <rect/> and <polygon/> elements. Let's add a style for these:
rect, polygon {
fill: none;
stroke: black;
}
The following is multiple choice question (with options) to answer.
One example of changing an objects shape is | [
"Making glass into a birdhouse",
"Holding another person's hand",
"Watching a bird fly",
"Watching a show on TV"
] | A | tearing an object changes that object 's shape |
OpenBookQA | OpenBookQA-2670 | human-biology, sleep
Title: Why do people look different after a long sleep? What happens during a long sleep that makes people look odd when they have just woken up? Why doesn't the same phenomenon occur in the case of a person who lies down for an extended period of time, but stays awake? I've noticed that some nights seem to make a bigger difference than others in the appearance of the sleeper, but haven't noticed a pattern. Puffy eyes are caused by fluid build up in tear ducts from extended periods of lying down. Gravity from sitting or standing slowly drains them during the day. The crusty 'sleep' that accumulates in the corner of your eyes is the residue from basal tear liquid that has seeped out of the eye and evaporated during the night.
The following is multiple choice question (with options) to answer.
Long naps increase the bodies | [
"shoe size",
"physical state",
"tan lines",
"hair color"
] | B | rest has a positive impact on a health |
OpenBookQA | OpenBookQA-2671 | everyday-chemistry, water, crystallography
Spin-off question:
I heard (not sure where) that each snowflake assumes a unique shape. How true is this?
Now, as I understand it, all processes proceed so as to maximize the "randomness" of its constituent particles. (Oversimplified version of the Second Law of Thermodynamics, yes, I know... just don't chew me out in the comments section...)
Yes. True.
This Law can easily be observed in, and verified by, natural processes.
Sure. Still with you.
Now the formation of snow is a natural process, agreed? The way my brain sees it, is that water droplets ought to freeze into random, and by virtue of its "randomness", highly unsymmetrical shapes. But this is not the case here!
The following is multiple choice question (with options) to answer.
Which of the following likely occurs in nature? | [
"pools condense",
"pools dissolve",
"pools evaporate",
"pools transpire"
] | C | evaporation is a stage in the water cycle process |
OpenBookQA | OpenBookQA-2672 | ## Property #2
The next symmetric property will require a little more finesse. Now, I don't claim that this is the easiest or most intuitive way to prove this but it does work and it is the one that I came up with. Besides, if you have a better way then it will still be good to see an alternative as that seems to broaden one's understanding. And perhaps you could be so kind as to give me a few clues in the comments.
The following is multiple choice question (with options) to answer.
A close object will seem to be | [
"miniscule",
"minute",
"puny",
"ginormous"
] | D | if an object is close then that object will appear large |
OpenBookQA | OpenBookQA-2673 | human-biology, biophysics, skin, light, uv
Title: Can UV radiation be safe for the skin? It is well known that UV radiation can damage the DNA and generally harm our skin.
We also know that UV radiation helps on the production of melanin and Vitamin D.
From what I could find, the DNA absorption spectrum goes to almost zero for wavelengths higher than 300 nm. This seems to suggest that we would be safe to use UV radiation between 300 and 340 nm in our skin (as long as the power or exposure is not too high/long to make burns), for therapeutic purposes such as the stimulation of Vitamin D production.
Is this assumption correct? Are there any evidences that we could use this UV wavelength range safely? You're talking about long-wave UV, or UV-A radiation. In the 80s, experts claimed that this was a safe wavelength. Protection against UV-A was not part of sunscreen in the early days. Consequently, UV-A was (and still is) used in tanning beds due to its perceived safety over UV-B. However, a lot of research has been done since.
UV-A is well understood now to also be unsafe in unreasonable amounts. Currently, UV-A protection is a typical feature of sunscreen and tanning beds are still not a healthy alternative to moderate, healthy doses of sun. Here is a recent review covering some of the aspects comparing different UV range effects on skin. I really suggest you put a search engine to good use here; it makes little sense for us to expound on the literature when it is so clear and easily available.
In summary,
UVA certainly contributes to the development of skin cancer.
UVA penetrates deeper into the skin than UV-B (which is largely responsible for 'burning' of the topmost layer of skin, without directly affecting the deeper layers). For this reason, UV-B is associated primarily with burning and UV-A is primarily associated with aging and aging diseases like cancer.
It is important to note that 95% of UV light in every day life is UV-A, because it does not vary seasonally and can penetrate clouds and windows. Therefore, in spite of the fact that short wavelengths carry more energy per photon, the ratios of UV-A and UV-B exposure are far from equal.
These are only a few of the explanations as to why we observe an incidence of aging and skin damage and disease upon UV-A exposure.
The following is multiple choice question (with options) to answer.
Skin can protect your | [
"emotions",
"anger",
"feelings",
"squishy bits"
] | D | skin is used for protecting the body from harmful substances |
OpenBookQA | OpenBookQA-2674 | electromagnetism
Title: Region of most and least intense magnetic field
It's a unmagnetized iron screw placed in the north pole of a U shaped magnet. I believe the region of least intense magnetic field is at the far left of the board. From what I understand the screw becomes magnetized and it's south pole is where it's touching the north of the magnetic, is it correct to assume the most intense magnetic field will be where the screw is touching the magnet due to there being direct contact between them?
Consider these images showing the magnetic field lines of a horse-shoe magnet. Magnetic intensity at any point in its field is directly proportional to its magnetic flux.So the region where the field lines are more densely packed have a higher intensity than where the field lines are loosely packed. If possible, draw the field lines for your own case and you will realize where the magnetic intensity is most and least.
The following is multiple choice question (with options) to answer.
What job site would most likely utilize powerful magnets that use electricity? | [
"a grocery store",
"a gymnasium",
"a scrap yard",
"an office"
] | C | electromagnets can be powered by electricity |
OpenBookQA | OpenBookQA-2675 | sensors, computer-vision, kinect
What good resources on the internet give you a good introduction on 3D scanning concepts (theoretically and programmatically)? I will be using C++ and OpenCV (I already worked with both a lot) and/or the API provided with the chosen camera (if applies).
Should you have a static camera capturing a moving object or a moving camera capturing a static object?
Should I use something in conjunction with stereo camera (like lasers)?
Is it profitable to use more than two cameras/sensors?
Are resolution, FPS and global shuttering really important in 3D scanning?
What camera should I get (it can also be something I didn't mention, in the range of $500 maximum if possible)? My main criteria is a camera that would be able to generate an accurate depth map from close range points.
Thanks for your help!
My favorite is the Learning OpenCV book. It has a fantastic stereo / 3D section that introduces concepts from the ground up. If you're at a university, you might be able to find the digital version available from the library website.
Depends, especially on how you are going to combine scans into a full 3D pointclound (if you need 360 degree views.) Overall, moving the camera is usually harder than moving the object in my opinion.
Lasers can help a ton. Take a look at the MakerScanner from a few years ago (disclaimer, I designed it).
Extra cameras can reduce ambiguities in stereo (from, say, horizontal symmetry). In such a controlled environment, I doubt it's worth it.
Resolution, yes, depending on your scan technique. With something like the MakerScanner, you can use sub-pixel interpolation on the laser line to get surprisingly good accuracy, reducing the need for high resolution images. If you're in a controlled environment, FPS probably isn't much of a concern (ie just scan slower.)
You might consider pairing gPhoto2 with a point and shoot camera like one of the Cannons on this page, which can give you incredibly nice images for very little money. Not much in the way of realtime, but it's unclear to me that you need that.
The following is multiple choice question (with options) to answer.
which of these environments would better support photo film development? | [
"a dense forest nook",
"a lush green meadow",
"a sparsely populated forest",
"an open sahara desert"
] | A | a dense forest environment is often dark in color |
OpenBookQA | OpenBookQA-2676 | metabolism, human-anatomy, pharmacology, liver
For drugs introduced through an injection, for example, metabolism occurs throughout the circulatory system and in the liver. Remember that it's all the same blood supply, but the first-pass effect just refers to the blood that goes to the liver before entering the systemic circulation (by which it can travel to its target).
The following is multiple choice question (with options) to answer.
The circulatory system brings oxygen to the body from where? | [
"The brain",
"The feet",
"The stomach area",
"The chest"
] | D | the circulatory system carries oxygen from the digestive and respiratory systems to the rest of the body |
OpenBookQA | OpenBookQA-2677 | newtonian-mechanics, estimation
Would the rock have created a seismic event of its own (if so, how large)?
Would the rock have created a crater? The energy of the rock at the time of hitting the earth is mgh.
No rock we know of is going to be able to survive this collision with out breaking into pieces.
Non the less it will be a big impact and depending on the geology of the location it hits a variety of reactions scenarios can happen.
If the soil is aggregate of silt and sand and gravel, it would part into several shear rupture sections which look like slices of shell pattern surfaces starting from the bottom surface of the rock and turning up exiting the earth surface a few hundred yards outside of the impact zone and probably even eject some material out like a bomb crater. This scenario will have shakes that could be recorded miles away.
The calculation of how much of the momentum of rock will be shared with the shear material and accelerating them will be involved but not impossible.
If the geology of the impact area is of very low bearing like mostly silt and loose clays, the rock my lose most of its kinetic energy by just sinking into the dirt mostly with a giant humph with a cloud of dust rising.
If the geology is hard or rocky with the 'optimal' amount of mass and resilience it could create a substantial earthquake by resonating with the impact.
The following is multiple choice question (with options) to answer.
A reason there is so much debris and damage during tornadoes is due to rocks that are getting | [
"broken apart",
"eaten",
"evaporated",
"stolen"
] | A | breaking apart rocks can cause debris |
OpenBookQA | OpenBookQA-2678 | magnetic-fields, ferromagnetism
Title: Technical Term for Material That is Only Magnetic Next to A Magnet I was wondering what the technical term is for some metal(like a refrigerator door) that is not magnetic on its own like neodymium but when there is a magnet in its vicinity, it attracts to the magnet. Neodymium has a polarity but these metals don't have one, they just stick to a magnet. Is it called ferromagnetism? As far as I know there is no single term to refer to a material that is attracted by magnetism but not a magnet. Rather, there are terms that describe a material's magnetic behaviour regardless of its magnetized state.
There are a few versions. Ferromagnetic, paramagnetic, and diamagnetic.
Ferromagnetic is like iron it will be attracted to other magnets, but can also be magnetized and turned into a permanent magnet.
Paramagnetic and diamagnetic materials can't be turned into permanent magnets. The difference might be considered nitty gritty and I'm not qualified to comment.
But it sounds like you're asking for a specific term for a material that is ferromagnetic, but not currently magnetized. I don't know of one.
The following is multiple choice question (with options) to answer.
Which is nonmagnetic? | [
"nail",
"washing machine",
"traffic cone",
"refrigerator"
] | C | iron is always magnetic |
OpenBookQA | OpenBookQA-2679 | Best Japanese Brown Rice, Air Fryer Burgers And Fries, østfold University College Vacancies, Band T-shirts Walmart, How To Become An Anglican Priest, Too Much Fennel Taste, Porter Cable Circular Saw Cordless, Utmb My Chart, Iams Large Breed Dog Food Nutrition Facts,
The following is multiple choice question (with options) to answer.
Omnivores would dine on | [
"leafy greens and steak",
"only that which inhabits the sea",
"only steaks or burgers",
"only that which grows from the ground"
] | A | omnivores eat plants |
OpenBookQA | OpenBookQA-2680 | energy, electromagnetic-radiation, radio
And why is it that one can pick up the radio frequency over the radio's own self-induced frequency?
I think you mean how is a radio able to transmit and receive at the same time. That's a complicated question but most simple radios can't. They're either transmitting or receiving and they must stop one to do the other. One somewhat easy way to transmit and receive at the same time is to use different frequencies for send and receive.
More over, how do you insert information into a wave?
The simplest way to put information in a wave is to use "amplitude modulation" (AM). Another simple way is with "frequency modulation" (FM). There is a huge branch of math and physics behind the more complicated methods.
The following is multiple choice question (with options) to answer.
What is a radio used for? | [
"radiation",
"human contact",
"energy",
"water"
] | B | a radio is used for communication |
OpenBookQA | OpenBookQA-2681 | geophysics, earthquakes, plate-tectonics, geography
Title: Why is the Ring of Fire there? The Ring of Fire goes through the places that have the most earthquakes. Why is the Ring of Fire there, not somewhere else?
Any help would be appreciated! This question is very similar to: Why does the "Ring of Fire" pretty much define "Pacific Rim"
The high levels of volcanoes and earthquakes are primarily due to subduction. So why is the Pacific surrounded by subduction zones?
Think back to Pangaea. This was a supercontinent that formed in the late Palaeozoic. Virtually all of the Earth's land masses were concentrated in one large supercontinent. When this broke up, the new continents moved away from each other. Fast forward 200Ma or so, and you find that the continents have moved so far apart that they are now converging on a point on the other side of the planet - the continents are moving towards each other! Hence the remains of the super ocean (which was actually multiple ocean plates - today's Pacific & Nazca plates, plus the Farrallon plate (RIP),etc ) is shrinking as the continental plates move towards it. This destruction of the ocean plate(s) occurs at subduction zones.
This is a big picture generalisation. Not all of the Pacific's boundaries are marked with subduction zones (e.g. North America has two large strike slip systems + a new spreading ridge). Also, not all of the continents are converging on each other. Africa is doing a pirouette, India is moving northwards, etc.
The following is multiple choice question (with options) to answer.
Magma piled on the Pacific bottom tho form | [
"Honolulu",
"los angelos",
"kansas",
"texas"
] | A | an island is formed by lava cooling on the ocean floor over time |
OpenBookQA | OpenBookQA-2682 | There is a concept of $$C\setminus B = \{x\in C$$ but where $$x \not \in B\}$$. As we know that $$x\not \in B$$ that if $$x\in C$$ then we must have $$x\in C\setminus B$$. But $$C\setminus B$$ certainly doesn't have to be empty!
So that doesn't follow at all!
But now we have proven both $$x ∈ C$$ and $$x \not \in C$$.so we have reached a contradiction. Therefore $$x ∈ B$$.
Except we haven't proven $$x \not \in C$$. We have reached no contradiction. And $$x$$ need not be in $$B$$. $$x\in C$$ so $$x$$ could be in $$C \cap B$$ or $$x$$ could be in $$C\setminus B$$. But we have no way of telling.
The following is multiple choice question (with options) to answer.
Which of the following is true? | [
"gut flora can make you more healthy",
"bacteria is always bad",
"bacteria in your brain helps digest food",
"gut bacteria always makes you sick"
] | A | bacteria can help digest food in humans |
OpenBookQA | OpenBookQA-2683 | tropical-cyclone, barometric-pressure
Also, a figure from Stull showing the difference in temperature within the hurricane core relative to surroundings:
That perhaps makes it more sensible that the warmer core air cannot continue subsiding down to the near-sea surface low at base of the core, where the air is very moist, but at lower temperature (might consider this to be a high stopping on encounter with a low).
The following is multiple choice question (with options) to answer.
As the barometer reading goes lower there is a greater chance of | [
"winning a prize",
"sunshine",
"a full moon",
"getting wet"
] | D | as air pressure decreases , the chance of rain will increase |
OpenBookQA | OpenBookQA-2684 | energy-efficiency, thermal-insulation
greater if the window is bigger
less as temperature difference get smaller
Radiative heat transfer
The main factor that is of consideration here is the solar radiation. There are three types of radiation:
Direct radiation: the direct rays of the sun. (this is zero on a cloudy day).
Diffuse radiation: this is always present and its an effect of the presence of atmosphere. In higher latitudes it tends to increase because the sun rays need to "pass through" more atmosphere.
reflected (you can neglect this)
If you can get the rays of the sun (direct radiation) into the house, this will always be a significant plus in the heat balance of the house.
Final thoughts
This problem is very instance specific depending on:
the location of the house
orientation of windows
type of blinds, etc.
Therefore, it is impossible to draw a generic conclusion. As such, only trends can be realistically observed.
At a temperature difference of 30$[^oC]$ it makes sense to close the blinds on a cloudy day. However, if you get closer to 15$[^oC]$ then the savings are diminished.
If the windows are positioned in the right angle and light shines into the room, then expect the added solar radiation will improve the heat balance in favour of open blinds.
The following is multiple choice question (with options) to answer.
To protect against the noon day sun you might use | [
"an opaque bandana",
"a short haircut",
"transparent baseball cap",
"a sunny smile"
] | A | the sun is located directly overhead at noon |
OpenBookQA | OpenBookQA-2685 | newtonian-mechanics, estimation
Would the rock have created a seismic event of its own (if so, how large)?
Would the rock have created a crater? The energy of the rock at the time of hitting the earth is mgh.
No rock we know of is going to be able to survive this collision with out breaking into pieces.
Non the less it will be a big impact and depending on the geology of the location it hits a variety of reactions scenarios can happen.
If the soil is aggregate of silt and sand and gravel, it would part into several shear rupture sections which look like slices of shell pattern surfaces starting from the bottom surface of the rock and turning up exiting the earth surface a few hundred yards outside of the impact zone and probably even eject some material out like a bomb crater. This scenario will have shakes that could be recorded miles away.
The calculation of how much of the momentum of rock will be shared with the shear material and accelerating them will be involved but not impossible.
If the geology of the impact area is of very low bearing like mostly silt and loose clays, the rock my lose most of its kinetic energy by just sinking into the dirt mostly with a giant humph with a cloud of dust rising.
If the geology is hard or rocky with the 'optimal' amount of mass and resilience it could create a substantial earthquake by resonating with the impact.
The following is multiple choice question (with options) to answer.
If a stone is broken down into sand it is | [
"glass",
"mechanically weathered",
"garden compost",
"grits"
] | B | mechanical weathering is when rocks are broken down by mechanical means |
OpenBookQA | OpenBookQA-2686 | volcanology, volcanic-hazard
In any case, if you do manage to reach the last eruption site, don't walk on the lava flow crust in the hope to see some active lava. I did it with a group of visiting volcanologists, guided by local volcanologists who had been in the field every day for six months. They knew the site very well and we just followed their tracks. It can remain dangerous for months. I hope that you'll get to see this wonder of nature, but don't risk your life for it!
The following is multiple choice question (with options) to answer.
You're most likely to encounter magma at | [
"top of iceberg",
"a cloud",
"a space station",
"an island"
] | D | magma is found below the ground |
OpenBookQA | OpenBookQA-2687 | planet, natural-satellites, nomenclature
Title: Is the satellite of a small star in a binary solar system a moon or a planet? What exaclty distinguishes a moon from a planet?
In a binary solar system that has a large star in the center and a smaller star - among some planets - orbiting that large star, and the smaller star has natural satellites - are these satellites called moons or planets?
Or asked in a different way - if Jupiter would ignite and become a star (which it can't because its mass doesn't suffice, but let's assume it was larger and could ignite), would its moons then be considered planets? A planetary mass object (also callled a planemo) is an astronomical object large enough to be pulled into a roughly spherical shape by its gravity compressing its matter. A planetary mass object must also have less than about 13 times the mass of Jupiter or about 4,131.4 times the mass of Earth.
If a planetary mass object orbits around the Sun in our solar system it is called a planet (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, & Neptune) or a dwarf planet (Ceres, Pluto, Eris, Hamaea, and Makemake, plus of number of candidate objects).
If a planetary mass object orbits around a planet in our solar system it is considered to be a natural satellite or a moon. Smaller objects which orbit around planets are also considered to be moons.
Any object smaller than a planetary mass object that orbits the Sun in our solar system is a small solar system body. They include all comets, asteroids, etc. that orbit the Sun ddirectly instead of orbiting one of the planets, moons, asteroids etc. that orbit the sun.
Any astronomical body with a mass greater than about 75 times the mass of Jupiter, or about 23,835 times the mass of the Earth, is a star are the stellar remnant of a star which has completed its "life cycle".
Any planetary mass object which directly orbits a star which is not the Sun, in another star system, is usually considered to be planet. So far there has been no effort to classify exoplanets (planets orbiting other stars) in other star systems as planets or dwarf planets. If they are large enough to be detected they are considered to be explanets. That might possibly change sometime in the future.
The following is multiple choice question (with options) to answer.
All of the following might be found on the natural satellite orbiting our planet excluding what? | [
"H2O",
"rocks",
"dust",
"footprints"
] | A | the moon does not contain water |
OpenBookQA | OpenBookQA-2688 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is the most accurate statement? | [
"a phone's brain controls its body",
"a rock's brain controls its body",
"a sloth's brain controls its body",
"a bacteria's brain controls its body"
] | C | an animal 's brain controls that animal |
OpenBookQA | OpenBookQA-2689 | energy, work, statics
With no "lossy" forces eg friction acting the body will overshoot the position $x=0$ and undergo oscillatory motion about that position.
If friction does act then the amplitude of oscillation of the body will decrease with time until the body eventually stops at position $x=0$.
The following is multiple choice question (with options) to answer.
If the world is trembling it is likely that motion is being caused by | [
"stony plates",
"giants",
"large dinosaurs",
"huge wolves"
] | A | tectonic plates being pushed together causes earthquakes |
OpenBookQA | OpenBookQA-2690 | wasps
Title: Can wasps see under moonlight? It appears that the best time to attack a wasp nest is in the middle of the night. Their venom might terrorize us (my five-day old sting remains swollen and is starting to have red bumps in an area the size of a tennis ball), but at least our eyesight is superior. If we attack while they are asleep, or at least resting, we have our best chance of escaping unscathed—or so the online pundits claim.
The nest in question is at the edge between the wall and the roof protrusion. Because it is 8 feet off the ground rather than on the ground, it would appear to be a paper wasp nest. But because it is covered with paper and the individual cells are occluded, with the entrance at the bottom the only visible path leading inside, it may well be a yellow jacket nest.
Maybe it's futile to attack the nest in September. One might as well let them be. The nest will anyway be deserted in October when the temperature starts to freeze overnight. But it's never too early to prepare for next Spring.
I could choose a night when there is absolutely no light—not even moonlight—but then I myself would need to use a flashlight, providing them with the means of pursuing me. Or I could choose a full-moon, or near full-moon, night, and then I can see and they can, perhaps, not see.
Can wasps see under moonlight? No.... probably not... wasp cannot see at night... their scotopic vision{dim light vision} is not well develop so before sunset they return back to thier nest... so at night.. probably you can get them all together... rather then hunting for each indivisually...for reference https://sciencing.com/how-to-identify-wasps-bees-13406632.html hope it helps..
The following is multiple choice question (with options) to answer.
If a person is searching for others in a forest at night, they can signal quietly to each other by | [
"falling down",
"making memories",
"flicking a lighter",
"sleeping quietly"
] | C | fire gives off light |
OpenBookQA | OpenBookQA-2691 | pathology, skin, infection
Title: What counts as a 'breach of the skin' for infections(like rabies) that spread via wounds? I've been looking at several sources on how the virus spreads and they all mention that the skin has to be broken, but does it mean broken to the naked eye?
A minor scratch where the skin appears unbroken and there was no bleeding could still have microscopic breaks of the skin, therefore it seems risky to rely on the naked eye. I believe that your books refer to 'broken' not necessarily meaning broken to the naked eye, but as in any broken epidermis.
The outer layer of your skin that protects you against infection is the epidermis. It's a water-tight layer mostly composed of keratinocytes joined together by adherens junctions. Logically, even if you can't see a breach in your skin (epidermis), there may still be one. While the chance of getting an infection from a non-visible break is less than the chance of infection from a visible scratch, it's still possible.
The following is multiple choice question (with options) to answer.
if a person has a scar on the face, at what point did they get it? | [
"after they were born",
"at the time of delivery",
"at the time of conception",
"at the time of fetus development"
] | A | a scar is an acquired characteristic |
OpenBookQA | OpenBookQA-2692 | thermodynamics, thermal-conductivity
Indeed, $1kg$ of silver would feel much closer to body temperature than $1kg$ of diamond (that's alot of diamond!) despite diamond having a higher heat capacity.
The following is multiple choice question (with options) to answer.
Which would feel hotter? | [
"a stove on the fingertips",
"a stove on the butt",
"a fridge on the butt",
"a fridge on the fingertips"
] | A | if an object is hot then the surfaces of that object are hot |
OpenBookQA | OpenBookQA-2693 | newtonian-mechanics, energy-conservation, momentum, conservation-laws
So the answer is that regardless of the current motion of $M$ it is always possible to shoot $m$ at $M$ such that it transfers all its kinetic energy to $M$ and thus the maximum amount is 100%.
The following is multiple choice question (with options) to answer.
Which is likely to have to highest kinetic energy? | [
"a beach ball",
"a tossed balloon",
"a sleeping person",
"a thrown racquetballl"
] | D | as an object moves , the kinetic energy of that object will increase |
OpenBookQA | OpenBookQA-2694 | microbiology, bacteriology, ecology, environment, freshwater-biology
Title: Does rainwater contain many fewer micro-organisms than river water? From watching many documentaries on micro-organisms, I can tell water typically contains quite a lot of them.
But what about rainwater? (before it hits the ground). I know nothing about any micro-organisms that live in the sky or clouds. Does rainwater contain fewer, and less dangerous, micro-organisms? According to a number of citations listed on Kenyon College's MicrobeWiki, rain can contain microorganisms via a process called "bioprecipitation."
Essentially, microorganisms, dust and other small particles get swept up into the atmosphere, and cold temperatures cause atmospheric water vapor to freeze around the organism/particle. Once the ice-covered particle picks up enough mass, it falls from the sky and reaches earth as precipitation (likely rain if temperature is warm enough).
Here is a schematic from Wright et al. (2104) of how an increase in relative humidity, due to a cold-frontal passage, can trigger biological ice nuclei release followed by seeding of the frontal cloud band with the lofted ice nuclei:
So How Many (and Which) Bacteria Are in Rain?
Which Bacteria?
According to Wikipedia:
The ice-nucleating bacteria currently known are mostly plant pathogens
According to MicrobeWiki, these include:
Exserohilum turcicum, Pseudomonas viridiflava, Pseudomonas fluorescens, Pantoea agglomerans and Xanthomonas campestris.
The most well described organism that demonstrates ice nucleation is Pseudomonas syringae, which was determined to specifically supply a source of ice nucleators by Leroy Maki in the 1970’s.
According to work by Natasha DeLeon-Rodriguez, Athanasios Nenes, et al. (full paper here and NPR story here), 100s of species of bacteria exist in the clouds and it's not uncommon to find almost 20 species in any given sample (60% of which on average were still living).
Here's a graph showing the relative amounts of various taxa found in their samples:
The following is multiple choice question (with options) to answer.
There is less food to feed bacteria in a puddle when it | [
"fills",
"grows",
"drains",
"overflows"
] | C | as available water in an environment decreases , the amount of available food in that environment will decrease |
OpenBookQA | OpenBookQA-2695 | thermodynamics, energy, energy-conservation, phase-transition, physical-chemistry
Title: Why is Energy change occurring during the reaction at constant temperature and constant volume given by internal energy change? When volume and temperature are kept constant, shouldn't internal energy remain constant (as it's a state function depending on state variables)? When heat is supplied, why does the internal energy increase if state variables are kept constant? For a system likely to be the seat of a chemical reaction, the variables of state are not limited to the temperature and the volume: it is necessary to add the extent of reaction.
The following is multiple choice question (with options) to answer.
As a matters state changes, what will remain constant? | [
"acceleration resistance",
"appearance",
"temperature",
"mass amount"
] | D | heat can change the state of matter |
OpenBookQA | OpenBookQA-2696 | cosmology, string-theory, quantum-gravity, theory-of-everything, poincare-recurrence
The timescale is vastly longer than anything we have a chance to experimentally test. Each 10 billion years or so, the linear distances between galaxies double and the density of normal matter decreases by an order of magnitude. In hundreds of billions of years, a vast majority of the currently active stars will be inactive and even "new generations" of the stars will already be gone or dying. In trillions or certainly quadrillion years, there will be nothing left to energize star-powered life as we know it, and similar "local, more modest" sources of useful energy will be diminishing in similar ways.
It is hard to imagine that there will be any intelligent beings in a quadrillion years. This is still vastly smaller than the Poincaré recurrence time. And this result of the comparison is no coincidence. Of course that things must have a chance to "destroy any pattern" before the chaos has a chance to reassemble itself into the patterns again.
The following is multiple choice question (with options) to answer.
If the world is shaking it will likely last for | [
"under five full seconds",
"an hour and a half",
"more than a day",
"less than a minute"
] | D | an earthquake usually occurs over a period of 10 to 30 seconds |
OpenBookQA | OpenBookQA-2697 | evolution
///
Why not have a switch between the two hemispheres to give the hand currently being used the fine motor skill located in the other hemisphere? (from comment)
I see. In my answer I only talked about one aspect. The brain doesn't have to learn skills for each hand completely independently. For example imagine if you learn to play a musical piece with your right hand only. If you try it with your left you won't be amazing but you'll definitely be better than a complete novice. Our brain can learn how to do by seeing which is vital for development. But there's a limit to that, your hands aren't completely identical so there's still a portion that needs fine tuning. Your muscles have different stregth, fatigue, resistance, recruitment patterns, places they innervate. Your hands are mirror images. The weight of your hand is different. And not only that but these variables aren't fixed, there's lots of them and they are different for different tasks. So to use your analogy, the more expensive remote can be used but it wasn't bought for use with the black plane. It'll give more control to the black plane but it still won't be the best ever until it learns what the muscle strength is etc. then it will be just as great.
The following is multiple choice question (with options) to answer.
Skills are learned characteristics. To get better at doing something, you must stretch yourself in ways that | [
"may be very uncomfortable at first",
"take very little time",
"are without learning from others and past experiences",
"are without goals and commitment"
] | A | skills are learned characteristics |
OpenBookQA | OpenBookQA-2698 | mycology, microscopy, parasitology
Cross sections of leaves (hold between two thin pieces of polystyrene or cork and slice gently with a new single-edge razor blade or craft knife). . These will show the internal structure of the leaves - veins (xylem, phloem), cells etc. You can also use clear nailpolish to paint on the surface of a leaf (try the underside), then peel off and look at under the microscope - this should let you see the pores (called stomata) in detail, they look like pairs of lips usually. The fine tissue skin (not the brown bit, it's a very thin wet translucent bit) of an onion also looks pretty nice. Moss leaves also are fun to look at.
Along with mosses - take some dry moss, let it sit in water for 30 min or so and then squeeze out - you'll hopefully find tardigrades
Edited to add:
With respect to parasites in faeces; this requires a bit of expertise to get good at. There is a lot of matter in faeces and parasites are generally low abundance. Unless you know a host is infected and are willing to mix faeces with water, filter and do a bunch of screening, you might not find any actual parasites, though you might see things that look, to the untrained eye, like parasites but are really just debris. You also run a significant chance of infecting yourself with something, be it parasitic, bacterial or viral.
The following is multiple choice question (with options) to answer.
Wax is on some plant leaves for what purpose? | [
"keep water available for predators",
"keep the ongoing hydration",
"stay moist for warm weather",
"creation of toxins in the cells"
] | C | moist means high in moisture |
OpenBookQA | OpenBookQA-2699 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
Honeybees would most enjoy some | [
"foxhounds",
"rusty knives",
"creeping buttercup",
"blackberry smartphones"
] | C | bees convert nectar into honey |
OpenBookQA | OpenBookQA-2700 | evolution, biochemistry, plant-physiology, plant-anatomy, life
Title: Plants without bacteria? is it theoretically possible? I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But it is a natural way.
But is it possible to have a world with plants (without mammals or microorganisms and without bacteria) that could exist in the long term. Saying the atmosphere of these world has already enough nitrogen, oxygen and CO2, and of course there is water.
What could break this artificially created world with such conditions (say the world created not from low-level living structures)?
Could bacteria emerge in the world? This is the sort of question that should be considered from more than one perspective. Since this is speculation, take it as a given that there is a lot of 'what if' here.
I doubt most animals and plants can do entirely without bacteria - as you say most of the essential nutrients come from bacteria, who fix nitrogen. If only plants were left on earth, eventually the plants would use up all the nitrogen and they would have to find a way to fix more.
Can bacteria emerge from just a world of plants? I don't think viruses arise spontaneously, but since genomes often have viruses embedded in them, over the course of a billion years or so, its possible since bacteria and viruses continue to be impressed upon our genomes. Would it happen in time? Most would be skeptical whether that timing could work out.
In practice it would be hard to create a world like this. I would be interested to see whether you could sterilize the microorganisms off of seeds without killing the plant for instance. If you're asking about a small sterile environment with only plants, you could do it by adding the nutrients the plants need and giving them sunlight. Such self sustaining systems have been made with cyanobacteria and i'd be surprised if plants could not be included. But these are closed systems and judged by limited amounts of time, so whether this is an answer to your question is not clear. Here it looks like some water plants and fish have been done. If there was a plant that created CO₂ at an adequate rate its possible.
The following is multiple choice question (with options) to answer.
Which is able to create its own nourishment from sunlight? | [
"roses",
"deer",
"rainbows",
"water buffalo"
] | A | animal cells can not perform photosynthesis |
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