source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-1001 | thermodynamics, electromagnetic-radiation, blackbody
What generally happens is that after an e.g. visible photon comes in and gets absorbed, the energy is converted to heat, and it is later emitted by a thermal emission as described above.
This thermal emission may be in the infra-red range (for practical temperatures), which you can't see with your eyes.
That's why an object which is both a good absorber and a good emitter looks black when it's at thermal equilibrium near room temperature.$^{[d]}$
Note that this means that black objects are actually radiating more power than white ones, you just can't easily tell because that power is in a wavelength you don't see.
More information
A hypothetical object which perfectly absorbs all incoming radiation is called a black body.
Using quantum mechanics and statistical mechanics you can compute the amount of radiation power a black body at a given temperature should emit at each wavelength.$^{[b]}$
Interestingly, if you look at the plot of the sun's emission, you see that it's pretty close to an ideal black body.
Ever notice that thermal blankets are shiny?
Shiny materials are weakly coupled to the electromagnetic field.
They're shiny precisely because they reflect incoming radiation instead of absorbing it.
Since bad absorbers are bad emitters, this also means that when you wrap yourself in a shiny blanket you will radiate away your body heat more slowly, keeping you warmer in a cold environment.
Of course, wearing a shiny blanket would also prevent you from warming up in the sun light.
The way to think about it is that the shiny thing isolates you from the surroundings: it prevents you from getting warmed by incoming radiation, and it keeps you from getting cold from outgoing radiation.
This is also why thermos bottles are shiny.
$[a]$: Note that the peak radiation power from the sun is at around $500\,\text{nm}$ wavelength, which is right in the middle of the the visible spectrum. Coincidence?
The following is multiple choice question (with options) to answer.
The property of fur that is a result of the way that it reflects or emits light is | [
"an inherited characteristic",
"a fabricated characteristic",
"a manufacturing characteristic",
"an age characteristic"
] | A | the color of fur is an inherited characteristic |
OpenBookQA | OpenBookQA-1002 | species-identification, zoology, ornithology
Title: Identification by tail feather I saw the remains of a bird today I did not recognize, and it was pretty mangled so it was hard to describe it. It was about the size of a robin. However, it had a dark brown mottled body like nothing I have ever seen. I have included below a tail feather from the bird which is 5 inches long. I am sure it is not a thrush or a woodcock or a kestrel. So what was it?
Location is Great Bay, Portsmouth, New Hampshire, United States. I believe this is a tail feather (or retrix) from an adult male eastern whip-poor-will (Antrostomus vociferus). See right image below (click to zoom):
.
Source: USFWS Forensics Laboratory
Details:
The brown, mottled appearance and the size (~12 cm) match that of the OP's specimen.
A great resource for exploring bird feathers: https://www.fws.gov/lab/featheratlas/
The whip-poor-will's breeding grounds include the OP's location (i.e., New Hampshire), and according to All About Birds this species could still be present even late in the year ("they seem to leave between early September and late November.").
Orange is breeding. Source: All About Birds.
The whip-poor-will is a medium sized bird and similar in size to an American robin.
Whip-poor-will: 22-26 cm ; Robin: 20-28 cm
Eastern whip-poor-will, (c) Paul Cools, source: inaturalist
The following is multiple choice question (with options) to answer.
What body covering does the animal that clucks have? | [
"Skin",
"Feathers",
"Scales",
"Fur"
] | B | chickens cluck |
OpenBookQA | OpenBookQA-1003 | environmental-protection, natural-disasters
Title: The impact of red mud near Hamburg On October 4, 2010 a disaster started at a site in Ajka, Hungary. A red mud reservoir near an alumina plant broke, and the toxic material moved through nature and on into the northern half of Devecser village and killed 10 people, injured 406 others, and destroyed a lot of trees and animals.
I calculated the area of that reservoir to be about 25 hectares using this site.
Also, I calculated the maximum length and width of the flown red mud to be about 3 miles and 1 mile respectively (using Google Maps).
On the Wikipedia page for the Ajka disaster it's also stated that the volume of red mud was about 1,000,000 m$^3$, and the total area affected was about 40 km$^2$.
That got my attention looking at a red mud reservoir near Hamburg. It has an area of about 1.45 km$^2$, and it is 28 miles far from Hamburg. Also, it's near an alumina plant in Stade.
The following is multiple choice question (with options) to answer.
What location that had a disaster in 2017 was caused by heavy rains? | [
"San Francisco",
"Houston",
"Mexico City",
"Tokyo"
] | B | heavy rains cause flooding |
OpenBookQA | OpenBookQA-1004 | dating
Title: Can we carbon-date the remains of homo floresiensis found in 2003? According to the Wikipedia article on the species Homo floresiensis, the remains discovered in 2003 consist of unfossilized bones. I would assume that means they are still composed of the original organic material left behind when the human specimen died thousands of years ago. Shoudn't that mean radiocarbon dating would be a good method to date the reamains?
Many articles on Homo floresiensis also discuss how the remains were originally dated to ~12,000 years ago, but that this estimate was later revised to 60–100,000 years ago. However, everything I can find indicates that mostly geological dating methods were used, not radiometric dating.
Why not? The Wikipedia entry on carbon dating says that it can only be used reliably to date specimens up to ~50,000 years, but could carbon dating then at least place a lower limit on the age of these remains? And why wouldn't it have been used back when they thought the specimens were only ~12,000 years old? ScienceMag says:
The following is multiple choice question (with options) to answer.
Something that died millions of years ago can still be relevant | [
"because we drive cars",
"because they are in our memories",
"because we still see them",
"because we miss them"
] | A | heat and pressure change the remains of prehistoric living things into natural gas |
OpenBookQA | OpenBookQA-1005 | inorganic-chemistry, decomposition
Title: Why doesn't CaO decompose into Ca and O2? Many metal oxides decompose into the free metal and oxygen gas at high temperatures, but why doesn't $\ce{CaO}$ do that? What happens to $\ce{CaO}$ at high temperatures?
This is from problem 2 of the 2011 USNCO local exam:
Oxygen gas can be produced by the decomposition of all
of the following substances EXCEPT
(A) calcium oxide. (B) hydrogen peroxide.
(C) mercury(II) oxide. (D) ozone.
The following is multiple choice question (with options) to answer.
Decomposition results in the production of which element? | [
"Silicon",
"Phosphorus",
"Carbon",
"Hydrogen"
] | C | decomposition increases amount of organic matter in soil |
OpenBookQA | OpenBookQA-1006 | meteorology, mesoscale-meteorology
In a sense, the fact pressure at one elevation induces changes\motion in another elevation maybe shouldn't seem any less weird than the fact that a low-level low pressure system can affect the wind and weather hundreds of miles away from it horizontally. This isn't spooky action at a distance, this is a continuous fluid where changes to one part of it causes impacts on another part.
The following is multiple choice question (with options) to answer.
At high elevations, there is little risk of flooding, but at low elevations, what will happen? | [
"water damage will be more apparent",
"flood damage will be decreased",
"flooding will be less of a risk",
"more floodwater will be clean"
] | A | as elevation of a place decreases , how much a flood will affect that place will increases |
OpenBookQA | OpenBookQA-1007 | magnetic-fields, earth
Title: Would a compass on its side point at the ground? From a point just north of the equator, A straight line to the Magnetic North would be through the earth. If a compass was turned on it's side, would the north pointing arrow point toward the ground along that straight line? A compass is usually used to find the direction of the horizontal magnetic field of Earth at that point. The needle of a compass is very light and thus its efficiency decreases when the compass is not in the horizontal plane at that point (due to gravity).Therefore, where the compass would point will become unpredictable. But, yes, in ideal conditions, the compass would point along the straight line joining that point to the north pole.
The following is multiple choice question (with options) to answer.
A boy is lost in a heavily forested area, and the only help he has is a small compass. He knows that his house is to the south of him, but in the direction he is facing, the arrow on the compass is showing that he is currently walking due north. Therefore, the boy | [
"turns right",
"turns left",
"turns around",
"keeps straight"
] | C | when the needle of a compass lines up with Earth 's magnetic poles , the needle points north |
OpenBookQA | OpenBookQA-1008 | 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.
if you see little wet spots on your windshield, what might have happened? | [
"the sun is setting",
"vapor transformed into droplets",
"the moon is rising",
"the windshield is dissolving"
] | B | beads of water are formed by water vapor condensing |
OpenBookQA | OpenBookQA-1009 | human-biology, reproduction, human-genetics
Title: Very frequent multiple births in humans 18th century Feodor Vassilyev is said to have had children by two wives, each of whom only ever had twins, triplets or quadruplets. His first wife has 16 sets of twins, 7 of triplets and 4 of quads; his second had 6 sets of twins and 2 of triplets. Is there any known plausible biological explanation for this, or do we have to dismiss it as a fabrication?
I could understand a woman's body being unusually susceptible to multiple births. I can't find information on whether these women tended to have monozygotic or polyzygotic offspring, but neither option seems unviable to me. However, since it's unlikely two of Feodor's sexual partners would share such a trait, one would think to attribute it to him. Presumably there would have to be a mechanism by which paternal DNA can trigger embryo fissions, in which case I imagine the offspring would be polyzygotic. Risk factors for dizygotic twinning are related to multiple follicular development, and include maternal family history, ethnicity, geography, maternal parity, maternal age, and, of course, use of assisted reproductive technology. There may be a genetic component to monozygotic twinning as well, but that rate is fairly consistent across populations. Other risk factors, such as diet and supplementation, have been proposed, but the data are less robust. There are some interesting studies demonstrating geographic clusters of twinning, but these tend to be demographic clusters that are associated with other risk factors.
Though a higher risk of twinning can be transmitted from a father to his daughters, the father's family history of twinning is not a significant risk factor (for his own children to be twins). To clarify -- if a man has a family history of multiple births, his children are no more likely to be twins than the general population, but his daughers are more likely to give birth to twins. This study is one example of the studies that have shown a significant independent association between maternal family history and twinning, with no significant independent association with paternal family history.
The following is multiple choice question (with options) to answer.
A kangaroo can have multiple babies at various stages of life at the same time. These joeys can show remarkable instincts, in that they | [
"hallucinate",
"nurse",
"scream",
"are born"
] | B | An example of an instinct is the kangaroo 's ability to crawl into its mother 's pouch to drink milk |
OpenBookQA | OpenBookQA-1010 | spectroscopy
Title: Why does the tungsten filament in a lightbulb produce a full(ish) spectrum instead of tungsten's emission spectrum? I only roughly understand how a spectroscope works, so that may be part of the problem. I don't understand what is different about what causes the materials to emit light. The light emitted by a tungsten filament light bulb is due to heating the tungsten filament to a very high temperature. Tungsten has a high melting temperature so the filament can get very hot. The light is like heating a piece of metal till it glows, and then keep heating it until it is 'white' hot. The light is not due to atomic transitions.
The melting point of Tungsten is around 3410°C (6170°F) and the temperature reached in a light bulb is around 3,000°C
The following is multiple choice question (with options) to answer.
Tungsten is a metal which is found in large amounts in filaments, which are used in incandescent light bulbs. These light bulbs work because | [
"light bulbs get very warm",
"filaments are able to freeze",
"the filament glows warmly",
"the filament catches fire"
] | C | an incandescent light bulb converts electricity into light by sending electricity through a filament |
OpenBookQA | OpenBookQA-1011 | human-physiology, digestion, stomach
The stomach accomplishes much of its function by mechanically breaking down the swallowed food particles and mixing them with acid and enzymes into a sort of slurry. To do this, there are three major layers of muscle surround the stomach - from the outside, the longitudinal layer, the circular layer, and the oblique layer. The stomach also has two holes in it - the gastroesophageal opening, coming from the esophagus with the swallowed food/saliva mix, and the pylorus, where the food/acid/enzyme slurry exits into the duodenum, which is the beginning of the small intestine.
Due to the three layers of (rather strong) muscle, the stomach doesn't have a lot of expansion capability once it is filled completely to capacity. Fortunately, this almost never occurs (despite how we may feel after a large meal) because material is always leaving the stomach on its way to enzymatic digestion in the intestines. Additionally, once the stomach is filled to a certain extent, hormones such as leptin are secreted that give you the feeling of being sated, or full, triggering the brain to make you stop eating.
Of course, as we can see with the current epidemic of obesity around the world, the stomach can change its size over time. However, this is a rather slow process (weeks to months to years) of adapting to continuously consuming large meals.
But what would happen if you completely ignored these internal warnings, or were being force-fed, or whatever? Instead of rupturing (the biological equivalent of "exploding"), food would most likely be expelled either into the small intestine or back into the esophagus and back up the way it came down, i.e. causing vomiting.
The following is multiple choice question (with options) to answer.
When the digestive system is working | [
"it is bad to eat",
"it is dismantling nutrients",
"food is cleared out",
"it is time for dinner"
] | B | the digestive system breaks food into nutrients for the body |
OpenBookQA | OpenBookQA-1012 | zoology
Title: Can my dog really understand me? Are dogs capable to understands human language ( for example after order sit it sit because he know that word) Or can sence our order by body language and intonation if so why this type of communication developed only at dogs? Some researchers say that dogs have the intelligence of a two-year old.
Many dogs can understand more than 150 words and intentionally deceive other dogs and people to get treats, according to psychologist and leading canine researcher Stanley Coren, PhD, of the University of British Columbia.
He is a reasonable and serious scientist who is biased towards overstating dog intelligence. he sais:
The average dog can learn 165 words, including signals, and the “super dogs” (those in the top 20 percent of dog intelligence) can learn 250 words, Coren says. “The upper limit of dogs’ ability to learn language is partly based on a study of a border collie named Rico who showed knowledge of 200 spoken words and demonstrated ’fast-track learning,’ which scientists believed to be found only in humans and language learning apes,”
Dogs can also count up to four or five,
http://www.apa.org/news/press/releases/2009/08/dogs-think.aspx
The following is multiple choice question (with options) to answer.
A dog can learn how to do something that it is taught to do, called learned behavior, such as | [
"eat food when it is hungry",
"lean back and accept having nails trimmed",
"bark when it wants to",
"urinate when its bladder is full"
] | B | if an animal is trained to do something then that something is a learned behavior |
OpenBookQA | OpenBookQA-1013 | human-biology, evolution, reproduction, human-physiology, sexual-reproduction
Hypothesis 1: Profet (1993) hypothesized that shedding the endometrium may be an effective way to get rid of sperm-based pathogens. The accompanying bleeding, Profet hypothesizes, delivers immune cells into the uterine cavity that can combat pathogens.
Hypothesis 2: Strassmann (1996) surmises that the endometrial microvasculature is designed to provide the blood supply to the endometrium and the placenta, and that external bleeding appears to be a side effect of endometrial regression that arises when there is too much blood and other tissue for complete reabsorption. The relatively large blood loss as seen in humans and chimpanzees can be attributed to the large size of the uterus relative to adult female size and to the design of the microvasculature in the uterus wall.
References
- Crawford (ed), Handbook of Evolutionary Psychology: Ideas, Issues, and Applications, Psychology Press (1998)
- Profet, Quarterly Rev Biol (1993); 68(3): 355-86
- Strassmann, Quarterly Rev Biol (1996);71(2): 181-220
The following is multiple choice question (with options) to answer.
Using a menstrual cup instead of pads or tampons can help avoid | [
"pills",
"waste",
"blood",
"flu"
] | B | An example of avoiding waste is using an object more than once |
OpenBookQA | OpenBookQA-1014 | electrophysiology, ichthyology, bioenergetics, energy, limnology
Containment
They also, as an aside, have to be careful to not electrocute themselves and stop their own hearts, and they have to take care not to electrocute each other. The father will keep his fry in his mouth, and signal them as to where they should go to be safe, when he performs a shock.
For those reasons, if you did use electric eels for power, you'd have to be careful how you contained them, so they had enough space to not electrocute themselves or each other.
The following is multiple choice question (with options) to answer.
To prevent electric shock | [
"masonry will come in handy",
"use all copper wire",
"aluminum should be useful",
"use all silver fillings"
] | A | brick is an electrical insulator |
OpenBookQA | OpenBookQA-1015 | bacteriology, food, hematology, toxicology, parasitology
Title: Blood consumption Is consumption of blood more "dangerous" compared to meat?
There was a news-article about unnatural chemicals found in the blood of mothers. This reminded me about a question I have pondered upon from time to time. Now, I am not a vampire, but curious as to the nature of blood vs meat in animals. More specifically unhealthy components.
There are various examples of viruses being in danger of spreading by consumption of raw blood like ebola, H5N1 etc. (But then also meat etc.)
Perhaps easier if I throw out some questions to show what I am asking:
Are there more of such in blood then meat?
Are there other things that can be worse in blood even after preparing? Like cooking, conservation etc.
Are parasites etc. more frequently found in blood?
Are there organisms that are highly resilient to heat treatment found in blood?
Are there more heavy metals in blood then meat? (Which I assume cooking does not give much of a difference.)
Other toxins?
Some references:
http://www.eufic.org/article/en/food-safety-quality/animal-health/expid/review-animal-diseases/
http://www.fao.org/avianflu/en/qanda.html
Is consumption of blood more "dangerous" compared to meat?
Actually yes, a simple high dose of blood is enough to kill. The cause is, though it is most important thing to live when flowing the vessel, it's highly toxic when consumed. There are high chances of getting haemochromatosis or Iron overload.
Source and More on this:
http://www.livescience.com/15899-drinking-blood-safe.html
Composition of Blood
(source: snmjournals.org)
The following is multiple choice question (with options) to answer.
What can can cause more harm then good when used? | [
"hiking boots",
"hybrid cars",
"anti bacteria soap",
"bike"
] | C | good bacteria grow on the skin |
OpenBookQA | OpenBookQA-1016 | meteorology, weather-forecasting, barometric-pressure
Title: Do high pressure systems draw air towards them? I refer to the this very recent article, which quotes Andrew Watkins (Manager of Climate Prediction Services at the Australian Bureau of Meteorology).
My understanding has always been that air flows away from high pressure towards lower pressure, so the following quote from the referenced article confuses me. Can anyone explain it for me?
"There's been a big high pressure system drawing air in off the ocean,
keeping it a bit cooler for Sydney," Dr Watkins said. As Fred said, it's just an unfortunate word choice that makes you think the professor is suggesting air flows towards the high.
Indeed, a surface high pressure south of Sydney would be the circumstance to have the air circulate around it in such a way as to "draw" air onshore from off the shore... even as it's actually really flowing somewhat away from the high.
There's a long-range model forecast showing exactly this setup building after a strong low potentially passes by this week... and so Sydney may be held cooler again just in time for Boxing Day:
from www.pivotalweather.com
(This is only one model's long-range forecast, and the skill in such forecasts is quite low. I present it to show this scenario, not to make any forecast as to whether it'll actually happen next week)
You can see the green arrows are bringing air onshore. This link suggests current ocean surface temperatures are around 23°C (73°F). So that would likely reduce the temperature slightly (if you explore the plots at pivotalweather.com for Australia, it currently shows a forecast high closer to 23°C for the day, rather than nearer the 30s many spots in the area see tomorrow).
The following is multiple choice question (with options) to answer.
If you fly from Europe to Australia in December, when you arrive you will most likely want to wear: | [
"heavy coat",
"mittens",
"shorts",
"ski mask"
] | C | winter in the Northern Hemisphere is during the summer in the Southern Hemisphere |
OpenBookQA | OpenBookQA-1017 | thermodynamics, absorption
When you want to boil water efficiently, you do two things: cover the pot (limit loss due to evaporation) and put the heat inside if you can: for example the submerged heater element in electric kettles. Other forms of boilers also put the heat in the middle of the water (think water heaters for homes) so most of the hot gas gets to give off its energy to the water.
But if you have a flame, the best you can hope to to is transfer all it's internal energy to the water - so when the water is hotter a flame is always less efficient.
Very efficient systems use counter flow - the hot air moves left to right, and the water to be heated right to left: in that way the colder gas meets even colder water so when the gas finally is exhausted it has no heat left. Same principle is used in efficient gas furnace for homes, etc.
The following is multiple choice question (with options) to answer.
Water can be boiled in a pot over a | [
"ice cube",
"car tire?",
"embers",
"bathtub"
] | C | a hot substance is a source of heat |
OpenBookQA | OpenBookQA-1018 | homework-and-exercises, newtonian-mechanics, forces, string
Title: How could a cord withstand a force greater than its breaking strength? How could a 100 N object be lowered from a roof using a cord with a breaking strength of 80 N without breaking the cord?
My attempt to answer this question is that we could use a counter weight. But I don't really understand the concept behind counterweights so I hope someone can clear that up for me and if there is a better answer I'll love to know it. Breaking strength refers to the maximum tension in the cord. Now, from the sounds of this problem, you've probably been doing force diagrams involving cords. What happens when you attach two cords to a single 100N object (and keep it stationary)? Is the tension in both of those cords 100N? Or is the combined force 100N, so that each just has 50N?
Put another way, most ropes you see will be made of many individual little threads. Each one of them is much weaker than the whole rope. See what I'm getting at?
The following is multiple choice question (with options) to answer.
The easiest thing to break is | [
"a notebook",
"a pair of glasses",
"a wall",
"a hardcover book"
] | B | as the thickness of an object increases , the resistance to breaking will increase |
OpenBookQA | OpenBookQA-1019 | newtonian-mechanics, momentum, everyday-life, collision
Title: Why do the pieces of breaking objects scatter? If I were to drop most objects to a level floor, they would land with a thud or bounce a few times without gaining any lateral velocity.
But a fragile object will not only break into two or more pieces, but the pieces will usually move laterally across the floor.
I suppose the center of mass of the system probably remains at the location where the object broke, but I don't see any reason for the pieces to behave any differently than a typical object that bounces or thuds. Or to put it another way, I can't determine a force that would provide the acceleration by which the pieces gained their lateral velocity.
Why does this happen? Generally, when an object collides with the floor there will be some sort of asymmetrical deformation of the object before it ultimately fails. This deformation puts a rather large amount of strain on the localized region of the object that can be considered as a sort of potential energy. When the object breaks, this energy is converted into kinetic energy, which sends part of the object flying. The part that goes flying will obviously be related to the part when the deformation caused a mechanical failure. There can, of course, be a sort of cascade of failures as well. To the degree that the system is conservative (i.e. we are ignoring things like sound waves, friction, etc.), the other pieces will tend to fly apart in a way that will conserve the linear momentum of the whole collection of parts. This gives the typical “scatter” effect that you observe.
The following is multiple choice question (with options) to answer.
If you scrape an object, small pieces or particles may break off of the object; what's an example of this? | [
"rubbing an emery board across your nail",
"rubbing a cloth over a counter",
"using a towel after you shower",
"wiping your chin after drinking some milk"
] | A | scraping an object may cause small particles to break off of that object |
OpenBookQA | OpenBookQA-1020 | electricity
Title: Why does this automatic night light advertise money savings? I just bought a night light to light the hallway since it receives no outside light. The one I bought advertises that it saves money because it turns on only during the night or (dark hours). I did the calculations and I am confused as to why it is even advertised because I did the calculations to find the cost per month to run it and as it turns out the money savings are absolutely miniscule.
The power information on the night light is 120v, 60hz, and 0.15w.
To find the cost to run it per month:
0.15w * 1kw/1000w * 24 hours * 30 days = 0.108 kwh per month.
At a cost of 9 cents per kwh, the total cost comes to less than 1 cent per month. The fact that the night light is automatic does not make a big difference on my wallet--why with a dollar I could run it for 8.3 years. Am I missing something or is this just an example of advertising? This is pure marketing, but not a lie... 0.036cents/mo is less than 0.108 cents/mo.
The following is multiple choice question (with options) to answer.
If John wants to save a little every month, what can he do to help with his water bill? | [
"dripping the sink at night",
"taking a bath twice a day",
"flushing the toilet more",
"repairing all his pipes"
] | D | using less resources usually causes money to be saved |
OpenBookQA | OpenBookQA-1021 | meteorology, tropical-cyclone, extreme-weather
Title: Why would Google's map of areas affected by Hurricane Harvey have advisories for the west coast and other far away areas?
What behavior of this hurricane would lead to advisories for the west coast and even parts of Canada and Alaska, when the hurricane is in the South?
I have little experience in meteorology or any of the earth sciences really, so I am interested in how this would affect the weather or other conditions far away from where the hurricane is severe. It seems like there is more than just a hurricane going on. According to the National Weather Service there are excessive heat advisories, gale warnings, etc.
The following is multiple choice question (with options) to answer.
A hurricane is growing on the east coast, and it's coming off of the ocean, as they do. By the time the hurricane hits the east coast, it will have built up quite a bit, and this is because of | [
"the salt from the ocean",
"the ocean being quite wet",
"seas have humidity from raised temperatures and fluid",
"the sea being cool and calm"
] | C | an ocean is a source of heat and moisture for a hurricane |
OpenBookQA | OpenBookQA-1022 | 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.
Bears dine on the some of the same things as | [
"plants",
"eukaryotes",
"apes",
"amoebas"
] | C | bears eat insects |
OpenBookQA | OpenBookQA-1023 | astronomy, everyday-life, popular-science, climate-science
It is for much the same reason that Winter is colder than Autumn, even though they have the same amount of daylight hours.
The following is multiple choice question (with options) to answer.
The air was cold, so all night the sheep kept | [
"sleeping",
"shaking",
"jumping",
"running."
] | B | shivering is when an animal creates heat by shaking to keep the body warm |
OpenBookQA | OpenBookQA-1024 | newtonian-mechanics, momentum, everyday-life, collision
Title: Why do the pieces of breaking objects scatter? If I were to drop most objects to a level floor, they would land with a thud or bounce a few times without gaining any lateral velocity.
But a fragile object will not only break into two or more pieces, but the pieces will usually move laterally across the floor.
I suppose the center of mass of the system probably remains at the location where the object broke, but I don't see any reason for the pieces to behave any differently than a typical object that bounces or thuds. Or to put it another way, I can't determine a force that would provide the acceleration by which the pieces gained their lateral velocity.
Why does this happen? Generally, when an object collides with the floor there will be some sort of asymmetrical deformation of the object before it ultimately fails. This deformation puts a rather large amount of strain on the localized region of the object that can be considered as a sort of potential energy. When the object breaks, this energy is converted into kinetic energy, which sends part of the object flying. The part that goes flying will obviously be related to the part when the deformation caused a mechanical failure. There can, of course, be a sort of cascade of failures as well. To the degree that the system is conservative (i.e. we are ignoring things like sound waves, friction, etc.), the other pieces will tend to fly apart in a way that will conserve the linear momentum of the whole collection of parts. This gives the typical “scatter” effect that you observe.
The following is multiple choice question (with options) to answer.
if a person smashes an object, and it cracks, is that good or bad? | [
"it is always a positive thing to the object",
"the object fails to be impacted",
"all of these",
"the item suffers a negative impact"
] | D | cracking something usually has a negative impact on that something |
OpenBookQA | OpenBookQA-1025 | water, spectrometry
Title: How much oxygen did the Warwick/Cambridge study find in the rocky debris around white dwarf GD 61? There are several articles out saying that a Warwick/Cambridge study of ultraviolet spectroscopy data from the Cosmic Origins Spectrograph on the Hubble Space Telescope found a large amount of oxygen in rocky debris around the white dwarf GD 61. They say that this amount of oxygen is indicative of a larger mass (asteroid), that was once composed of the rocky debris, which was 26% water.
(source: sciencedaily.com)
Image credit: copyright Mark A. Garlick, space-art.co.uk, University of Warwick and University of Cambridge
What I cannot seem to find is how much oxygen the spectroscopic examination found. Also, what methods did they use to determine how much water there would have been based on the level of oxygen? In Farihi et al. (2013) (it's a Science paper, unfortunately I'm not sure its content is freely accessible), they actually measured metal excess in the white dwarf GD 61 (for an astronomer, everything that is nor hydrogen neither helium is a metal). Due to high surface gravity in white dwarfs, any heavy element should sink rapidely in its atmosphere; therefore, they infer that, if you find traces of metals, it means that it comes from accreted material, "polluting" its atmosphere.
So if you find oxygen in a white dwarf spectrum, you know that it has to come from somewhere else, and if the white dwarf has a circumstellar disk, it has to come from planetesimals that are accreted from the disk.
Now, what they did was to measure abundances (or upper limit for their abundance) for a bunch of chemical elements (O, Mg, Al, Si, Ca, Fe) and carbon. Then, they could infer different things to determine the total oxygen budget:
The following is multiple choice question (with options) to answer.
What substance covers more than sixty nine percent of the third rock from the sun? | [
"Desert",
"Cities",
"Ocean",
"Forest"
] | C | oceans cover 70% of the surface of the earth |
OpenBookQA | OpenBookQA-1026 | organic-chemistry, everyday-chemistry, aqueous-solution, ions
How and why do they get released from tea leaf? Since you don't usually see any "big" differences between tea leaf and a soaked tea leaf? (I'm not looking for the how of solution)
If your tea leaves are crushed or broken in any way, this really is just simple dissolution. If you have whole tea leaves, the oxalate and citrate are migrating into and out of the plant cells. The cell wall is permeable, so the ions (or corresponding acids) can simply flow through it. The cell membrane is semipermeable, and the diffusion of the ions across it is a biologically controlled process that I honestly don't have the background to explain.
What makes the color of water change? Why does the color vary with pH alteration?
The pH and color are not related properties. The pH is affected by the citric acid and oxalic acid associated with the anions previously discussed, as well as other minor components that are likely present. The color comes from some of the many other compounds that are extracted into the water, which number in the hundreds, if not thousands. Some of these compounds are inherently colored - no reaction is required to produce color in the solution.
The following is multiple choice question (with options) to answer.
When the acid spilled on the plant, the plant began to | [
"smoke.",
"sing",
"flower",
"grow"
] | A | chemical reactions cause chemical change |
OpenBookQA | OpenBookQA-1027 | c++, object-oriented, database
void Client::getSmallestLectureHallForGivenStudents() {
int students;
while ((students = input<int>("Enter Students (>0): ")) <= 0)
;
LectureHall* r = rbs->getSmallestLectureHallByStudents(students);
if (r->getChairs() > 0) {
cout << "The required Lecture Hall is:" << endl;
r->printRoom();
} else {
cout << "No such Lecture Hall." << endl;
}
}
void Client::getLeastEquipmentDensityLab() {
int choice = -1;
while ((choice = input<int>("Enter 1 to get the lab with least equipment density and 2 to increase equipment density of a lab.")) < 1 || choice > 2)
;
switch (choice) {
case 1: {
Room* r = rbs->getLabByLeastEquipmentDensity();
if (r->getArea() > 0) {
r->printRoom();
} else {
cout << "No such Labs." << endl;
}
}
break;
case 2: {
Lab* l = (Lab*) getRoom(LABS);
cout << "The selected lab is:" << endl;
l->printRoom();
int newEqu = -1;
while ((newEqu = input<int>("Enter the new Lab Equipments.")) < 0)
;
l->setComputers(newEqu);
break;
}
}
}
void Client::getNearestRoom() {
int x = input<int>("Enter Position X:"), y = input<int>("Enter Position Y:");
Room* r = rbs->getNearestRoom(x, y);
if (r->getArea() > 0) {
r->printRoom();
} else {
cout << "No such Labs." << endl;
}
}
The following is multiple choice question (with options) to answer.
The teacher at the front of the classroom was reading from a laptop. For a student in the middle of the class, the teacher's laptop looked larger than | [
"the projector screen behind the teacher",
"a laptop held by a student walking outside the window",
"the student's own laptop",
"a neighboring student laptop"
] | B | as distance to an object increases , that object will appear smaller |
OpenBookQA | OpenBookQA-1028 | $7|61$ gives $61=7\cdot 8 +5$
He would have 5 cows left over. So 61 can't be an answer
5. Hello, swimalot!
A cowboy was asked how many cows were on the ranch.
He replied that he was unsure, but he knew that when he counted them
by twos, threes, fours, fives, or sixes, he always had one left over.
When counted by sevens, he had none left over.
What is the smallest number of cows on the ranch?
Let $N$ = number of cows on the ranch.
The LCM of 2, 3, 4, 5, 6 is $60$
. . Hence: . $N \:=\:60a + 1$ ... for some integer $a.$
Since $N$ is divisible by 7: . $60a + 1 \:=\:7b$ ... for some integer $b.$
Solve for $b\!:\;\;b \:=\:\frac{60a+1}{7} \;=\;8a + \frac{4a+1}{7}$
Since $b$ is an integer, $4a + 1$ must be divisible by 7.
The first time this happens is: $a = 5$
Therefore: . $N \;=\;60(5)+1 \;=\;\boxed{301}$
6. Originally Posted by TheEmptySet
we know that it needs to be a multiple of 7 from all of the other clues we know it can't be even (because two can't divide it) and the last digit need to be a one because when divided by 5 it needs one left over.
here is our list,
56,63,70,77,84,91
If you check all the other conditions you will see that they hold.
I hope this helps.
Hello Tessy
91 doesn't work for ... four
91=88+3
7. You could use the Chinese Remainder Theorem, Topsquark has a lovely example in post #5 here http://www.mathhelpforum.com/math-he...nt-modulo.html
8. I will do the Chinese Remainder Theorem for you:
The following is multiple choice question (with options) to answer.
A herd of cattle is slowly making its way through a large field. The shepherd realizes that he forgot to bring grain for the cattle, yet the cattle will survive just fine in the field, because | [
"they eat roughage",
"they hunt meat",
"they eat insects",
"they eat prey"
] | A | cows only eat plants |
OpenBookQA | OpenBookQA-1029 | solvents, solubility, melting-point, phase
Similarities:
In each case, forces between the particles that comprise the solid are disrupted and that takes energy. (Whether it’s chemical bonds or intermolecular forces depends on the process and on the solid and on your definitions. (See this question.) But melting (rare exception noted in previous comments) is endothermic and dissolving can be either endo- or exo-thermic.
In each case you end up with a liquid. Macroscopically, if you walked into a room and saw the liquid on the table, it would be difficult to say whether this liquid came from a solid that had melted or a solid that had dissolved in a solute and made a solution.
But it would be very easy to determine which you had experimentally in a “dozen” different ways.
Both melting and dissolving require interaction among groups of atoms, molecules, or ions.
There are probably more differences that could be given (how to handle thermodynamic calculations, complexity of the system etc.), and possibly more similarities, but that's enough for me on this topic.
The following is multiple choice question (with options) to answer.
An example of how melting is achieved is seen in | [
"cooking stew in a crockpot",
"using an oven to heat a pizza",
"using a stove to warm frozen vegetables",
"using a hairdryer to turn ice to water"
] | D | melting means changing from a solid into a liquid by adding heat energy |
OpenBookQA | OpenBookQA-1030 | newtonian-mechanics
I should add that the above is simply what I, as a physicist with a fairly long experience, suspect is what is going on. It is not something I have read about and I am sure there is somewhere a more thorough discussion. So I hope I am right; I think I have a good argument. As I have described it above, I have in mind mainly the last part of the process where the wood only moves a little relative to the metal. In the earlier part, when the wood moves through a larger distance, it is inertia that is the main consideration, just like in the party trick where you abruptly whisk away a table cloth and the dishes on the table stay where there are. The more abrupt the better.
Added remark
It occurred to me that there is another thing worth mentioning here, that makes this method preferable to resting the axe head on something, or supporting the handle on a work top and hitting the head. It is that by hitting the end of the handle, with the head just hanging, you are going to deliver the force more accurately at the join, because it travels along the handle in exactly the direction you want. If instead you strike the head then there is a danger it will be knocked slightly obliquely, introducing a random tilt with each blow, which is liable to deform the wood and thus loosen the fit.
The following is multiple choice question (with options) to answer.
If a head is exceptionally round | [
"that is an unusual feature",
"most heads are round",
"a parent probably had a round head",
"there is fluid on the brain"
] | C | the shape of body parts is an inherited characteristic |
OpenBookQA | OpenBookQA-1031 | human-biology
Title: Why do we sweat after drinking water and running? Why do we sweat after running?
Also we sweat sometime after drinking lots of water. Why it is so?
Can someone please enlighten me in this regard? Exercise, such as running, increases muscle activity. This increases the energy demand of these tissues, which increases the rate of cellular respiration. Respiration releases heat as a by-product, therefore the body is hotter during and after exercise.
Sweating is a homoeostatic mechanism to keep core body temperature constant. It is a response to lower the body temperature. When the body becomes too hot, sweat is released onto the surface of the skin. The water from the sweat then takes some of the excess heat energy from the body and uses it to evaporate. Because water has a relatively large specific heat capacity a lot of heat can be carried away by this method.
The following is multiple choice question (with options) to answer.
What action does sweat take once it forms? | [
"it contracts",
"it falls",
"it expands",
"it rises"
] | B | matter in the liquid state drips |
OpenBookQA | OpenBookQA-1032 | visible-light, sun, weather
Title: Why are clouds lighter than the sky during the day but darker at night This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during sunset but apparently it's common in bigger cities).
Basically what I'm wondering is why clouds during the day appear lighter than the sky (white vs light blue) while clouds at night and during the evening appear darker than the sky (see image).
Image quality is low because I took it with my phone through my window.
I guess the clouds could be blocking the light and therefore appear darker but in that case, shouldn't the same thing be happening during the day? There could be quite a few things going on.
Off the bat there's no incoming light for them to scatter: during the day, clouds are white because the water droplets are big enough for all visible light to cause Mie scattering, but if you don't have much light falling on them, you can't observe the scattering and you can't observe light passing through either.
Then you could consider the fact that in some places, it rains more in the evening/night than during the day (if you have hotter surface temperatures during the afternoon, you see cloud formation and precipitation during the late evening, and with the lower temperatures in the night, the air is more likely to become saturated, see Dew Point), and clouds which precede rain are thicker and denser. They don't allow much light pass through.
And lastly, there's less ambient light which they can reflect back towards you.
The following is multiple choice question (with options) to answer.
On a cloudy day | [
"the clouds are thin",
"the sky is dark",
"the wind is strong",
"the sun is obscured"
] | D | cloudy means the presence of clouds in the sky |
OpenBookQA | OpenBookQA-1033 | 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.
If the trees in an area are growing in soil rich with a certain vitamin, what might happen? | [
"the vitamin would evaporate",
"the vitamin would leak back into the ground",
"the trees would mutate and die",
"the squirrels would have that vitamin in their system"
] | D | if some nutrients are in the soil then those nutrients are in the food chain |
OpenBookQA | OpenBookQA-1034 | acoustics
Title: Amplified Sound in another room I was sitting in my room with my door open, because I have a cooler in my room that has a lot of noise when turned on. I was watching a video on my phone, but because of the noise from the cooler, I couldnt hear it and I had to increase the volume. However, my brother comes from the adjacent room and tells me he can hear the sounds from my phone very clearly and loudly, although his door was closed. I cant seem to understand this phenomenon. How can he hear sounds from my phone clearly, when I myself cant hear it clearly due to the cooler? Several reasons are at work here, as follows.
First, if the cooler fan is closest to you, then you will be bothered by it more than your brother, who is farther away.
Second, the noise made by a cooler fan is well-blocked by walls and doors, whereas music and speech is less-well blocked.
Third, random noise (as from a cooler fan) is fundamentally less bothersome than speech and music, to which your hearing "software" is far more sensitive.
A practical application of these effects is called masking, where the sound system speakers in a busy, open office are fed a random whoosh noise which renders speech in an adjacent cubicle inaudible to you. In fact, after several days in such an office, you get used to the whoosh noise coming from the speakers and you stop hearing it altogether. The office seems to your ears to be perfectly quiet, even though it is not!
The following is multiple choice question (with options) to answer.
When a sound is produced inside a room, sometimes there is a | [
"light",
"electric charge",
"delayed reflection",
"video"
] | C | when a sound is produced inside of a room , there is sometimes an echo after the sound |
OpenBookQA | OpenBookQA-1035 | species-identification, zoology, entomology
Title: Species identification; clusters of big plump red bugs in Taipei I saw these red insects in Taipei near XinBeitou MRT station in the last week of April 2017, around lunch time. They were fairly active and would keep checking each other out with their antennae for a moment and then move on to the next. What struck me was the wide range of sizes and development in the groups. I didn't notice any feeding or mating that I could recognize, just a lot of walking around and checking each other out.
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
I've also included a screenshot from google maps so you can see the location and the trees growing in these concrete structures.
The body of the largest individual is probably 2.5 centimeters long. I'm fairly certain these true bugs belong to the species Leptocoris vicinus, and carry the nickname of "soapberry bugs", which is specific to the subfamily Serinethinae. They're quite common in urban areas of Southeast Asia, which coincides nicely with where you encountered them.
Also, you had mentioned,
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
Soapberry bugs, as well as many other types of insects, are able to freely congregate in large numbers, and in such exposed places, due to their bright coloration. Having such a bright color may indicate to some predators that the prey in consideration is toxic, a phenomenon referred to as aposematism.
source
source
And then, here's a map of their distribution, with Taipei holding marker #37. (source)
An interactive version of this map can be found here.
The following is multiple choice question (with options) to answer.
Some birds find locations with | [
"landmarks",
"road signs",
"eggs",
"magnetic patterns"
] | D | Earth 's magnetic patterns are used for finding locations by animals that migrate |
OpenBookQA | OpenBookQA-1036 | energy, phase
Title: How can melting point equal freezing point? I don't understand how the freezing point of a substance is the same temperature as the melting point of the same substance.
For example, if liquid water freezes at 0 °C how can ice also melts at 0 °C? Because melting point and freezing point describe the same transition of matter, in this case from liquid to solid (freezing) or equivalently, from solid to liquid (melting).
What you may not realize is that while water is freezing or melting, its temperature is not changing! It is stuck on $0\ \mathrm{^\circ C}$ during the entire melting or freezing process. It is easier to see this for boiling points. if you put a thermometer in water and heat it, the temperature will rise until it reaches $100\ \mathrm{^\circ C}$, and then it starts boiling. And while it boils, it will stay at $100\ \mathrm{^\circ C}$! All the way until the water has all boiled away. Now if you could somehow trap the steam (gaseous water) and keep heating it, the steam could have a temperature higher than $100\ \mathrm{^\circ C}$.
So to sum this all up, when matter is transitioning from solid to liquid (melting) or liquid to solid (freezing), its temperature is fixed at the melting/freezing point, which is the same temperature.
The following is multiple choice question (with options) to answer.
Freezing point refers to: | [
"the temperature below which gas turns to liquid",
"the temperature above which liquid stops being liquid",
"the temperature below which solid turns to liquid",
"the temperature below which liquid stops being liquid"
] | D | freezing point means temperature below which a liquid freezes |
OpenBookQA | OpenBookQA-1037 | organic-chemistry, catalysis, green-chemistry
Title: How does the work that won the 2012 Sustainable Chemistry Award contribute to sustainable chemistry? I'm seeking a lay explanation for how the work of Dr Marc Taillefer that won the 2012 European Sustainable Chemistry Award, contributes to sustainable chemistry.
From the press release, Dr. Taillefer
is being recognised for his seminal contribution to the field of
homogeneously catalysed coupling reactions leading to C—C, C—N, C—O, C—P bonds. His team at
the Institut Charles Gerhardt, ICG (Montpellier, France) is investigating for a decade the
environmentally sustainable conversion of small molecules into more valuable substances
catalysed by copper and iron molecular complexes. This renaissance of “Ullmann type arylations” is now often used at the academic or industrial level and avoids the use of more expensive catalysts based on palladium.
The objectives of the award are (to quote from this press release) to:
Recognise individuals or small research groups which make an outstanding contribution to sustainable development by applying green and sustainable chemistry.
Promote innovation in chemistry and chemicals that will deliver clear improvements in the sustainable production and use of chemicals and chemical products.
Demonstrate that chemistry and chemicals can play a central role in delivering society’s needs, while minimizing and solving environmental problems. His work is about developping new catalysts based on copper and iron, to replace to traditional catalysts based on palladium. Copper and iron are both very common elements in nature, while palladium is considered a high supply risk (see the 2012 British Geological Survey risk list for details).
The new RSC Visual Elements Periodic Table can be used to check this kind of information.
The following is multiple choice question (with options) to answer.
A girl wants to help to protect the environment, so she decides to | [
"drive to work",
"quit her job",
"walk to work",
"visit a friend"
] | C | An example of protecting the environment is reducing the amount of pollutants |
OpenBookQA | OpenBookQA-1038 | meteorology, tornado, coriolis
And then conversely, Australia doesn't have a lot of land Poleward yet is still a reasonably busy tornado spot.
Mountain ranges Poleward also generally aren't a big deal... even pretty large ones; one of the biggest tornado areas is Bangladesh\India, despite the disruption the Himalayas presents. Because enough cold air can filter into the region in spite of the blockage.
The only thing that would be a real large scale geographic issue to the needed cold air would be a warm sea Poleward that modifies the incoming cold air significantly.
But that's pretty tough to have geographically. Perhaps more possible in the Autumn... maybe the Great Lakes serves as a slight dampener on fall season tornadoes in parts of the US? Though their effect is still mostly pretty small overall. Bring too near any large body of water, in any direction, is really a downer on supercellular tornadoes, as it modifies temperature gradients and instability.
To your direct question... there actually is a very good example of what Tornado Alley would look like in the Southern Hemisphere already: the Pampas Lowlands of Argentina.
It has that big mountain range to the west, in the midlatitudes, and does have fairly warm water a ways northward.
But it doesn't have quite as large of a region east of the mountains to have the tornadoes in, the cold air (and storm system strength) is probably modified due to the closed nature of the Antarctic vortex and the widespread oceans of the SH modifying air masses, and the source water isn't probably as well located being so far north (and is it warm?).
But even still, Pampas area might be the second most consistent tornado region on Earth. Such that some US storm chasers have traveled down there in our winter.
In the end, local effects play a huge role too, creating mesoscale ingredients (seabreezes\temperature boundaries, upsloping, local vortex flow, etc) to add plenty of rotation to the ledger (see Florida, one of highest tornadoes per square mile in US, in large part due to seabreeze water spouts and hurricanes). But all things equal, being east of mountains in the midlatitudes is a jackpot ingredient to climatological tornado formation (regardless of hemisphere).
The following is multiple choice question (with options) to answer.
storms can do what to seeds via high altitudes | [
"disperse them",
"plant them",
"destroy them",
"drown them"
] | A | a disperser disperses |
OpenBookQA | OpenBookQA-1039 | glaciology, glacier, ice
What would be a good average to take? This is a non-trivial issue. When you look at volume change of a glacier, you typically subtract two digital elevation models to obtain the difference between the two. First, you must differentiate between ice sheets where ice berg calving reduces volume and more ordinary glaciers with melt processes. There are of course calving glaciers as well so it is possible to get into great detail for any one specific glacier, so here I will just discuss the most common case which is a smaller glacier with melt-freeze conditions.
The change in elevation differs in magnitude across the glacier surface due to the movement of the glacier and accumulation-melt processes. The surface material can be (1) glacier ice, (2) snow, (3) firn snow that has survived a melt season) or (4) super imposed ice all with more or less differing densities, you need to assess what sort of material has been removed.
Ice can be approximated by a density of 900 kg/m3, firn has a density of about 600 kg/m3 but it must be remembered that the firn is converted to glacier ice by metamorphic processes so that the density changes with depth from 600 to 900 kg/m3. the transition to ice occurs at depths of about 30 m in temperate glaciers although few studies exist on the actual processes that occur. Snow have very differing densities but considering averages, I would say that it would vary between 350 to maybe 500 kg/m3 for winter (cold) conditions and around 550 kg/m3 for a melting snow pack. Super-imposed ice is closer to ice and probably varies in the upper range of 800--900 kg/m3.
To make matters worse, snow superimposes firn which in turn superimposes ice. This means that in the accumulation area, volume change can result from both a reduction in a snow cover and the firn layer. In the zone near the equilibrium line there can be a loss of both firn and ice. this is also where the superimposed ice will play a role.
So there is no simple density to use since the loss you try to estimate will involve varying types of densities spatially as well as vertically. For annual changes, you can largely ignore the vertical distribution, but with volume changes covering larger periods where climate change influences the longer term location of the equilibrium line and the size of the accumulation area, vertical layering also has to be included.
The following is multiple choice question (with options) to answer.
Glacier melt | [
"is an effect of too many polar bears",
"is an effect of an abundance of CO2 in the environment",
"is an effect of deforestation",
"is an effect of oxygen saturation"
] | B | if the atmospheric temperature rises then the glaciers will melt |
OpenBookQA | OpenBookQA-1040 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
What is a renewable resource? | [
"Plastic",
"Metal",
"Concrete",
"Rain"
] | D | renewable resources can be used over again |
OpenBookQA | OpenBookQA-1041 | human-biology, cardiology
Title: How quickly can the human heart rate rise and fall? How quickly can the human heart rate rise and lower?
For example lets say a human heart rate is rested and is at 60BPM and that person is suddenly scared to trigger their fight or flight reaction. Lets say their heart rate rises to double (120BPM).
From the above example their rate has gone from 1000ms between beats to 500ms between beats. Can the human heart instantly in one heart beat go from the 1000ms to 500ms between beats or does it need to ramp up? If yes how quickly can the heart rate ramp up?
I understand that each human heart is different, and that the speed increase and decrease will be different from person to person. What I'm looking for is a value that I can safely say the human heart won't exceed.
Similarly the same question goes to your heart going lower. According to the Wikipedia page on Supraventricular tachycardia the heart can go to a new faster rate in the space of a single beat, and then come down again just as quickly, as shown in this image taken from the Wikipedia page.
The following is multiple choice question (with options) to answer.
Pulse rate increases | [
"the quicker the pace of a runner",
"when a person falls asleep",
"as a runner slows down",
"while holding yoga poses"
] | A | as energy required for an activity increases , pulse will increase |
OpenBookQA | OpenBookQA-1042 | rotation, habitable-zone, weather, astrobiology
One of the interesting historical facts of life on Earth, at least to me, is how long it took what we might consider advanced life to develop. One celled life in various forms was around for over 3 billion years but the first fossils are about 650 million years old. It took life a very long time on earth to get from too small to see to large enough to leave a footprint . . . but, I digress.
I agree 100%, one celled life or Tardegrades could live on a planet with no tilt or 90 degree tilt. Easy. Ocean life in general should be fine cause oceans are more adaptive. Evaporation keeps ocean surfaces colder than land gets during peak heat and while a completely frozen over ocean isn't great for life, cold oceans hold more oxygen and CO2 which can be good for life. Oceans also circulate as an effective means of temperature moderation and fish don't really care how windy it is or how much or little it rains. The tilt question, I think, is really just about life on land.
Land life could be more vulnerable to high wind, extreme temperature shifts, droughts or floods, which could be driven by greater axial tilt, but I find it hard to believe that Axial Tilt is the be-all and end all. Day length and year length are key factors too.
One point I agree with the article on, is that a close to 90 degree tilt might not be ideal with one part of the planet always facing the sun and the other part never facing it but outside of extreme tilts, I don't see why it would be a big deal.
A thick cloud cover, for example, reduces seasonal changes. There's a number of factors.
The following is multiple choice question (with options) to answer.
the earth's tilt controls the | [
"seasons",
"tides",
"sunset",
"clocks"
] | A | winter in a hemisphere occurs when the Pole located in that hemisphere is tilted away from the Sun |
OpenBookQA | OpenBookQA-1043 | ##### Motivating Questions
• In a setting where a situation is described for which optimal parameters are sought, how do we develop a function that models the situation and use calculus to find the desired maximum or minimum?
Near the conclusion of Section 3.3, we considered two examples of optimization problems where determining the function to be optimized was part of a broader question. In Example 3.3.4, we sought to use a single piece of wire to build two geometric figures (an equilateral triangle and square) and to understand how various choices for how to cut the wire led to different values of the area enclosed. One of our conclusions was that in order to maximize the total combined area enclosed by the triangle and square, all of the wire must be used to make a square. In the subsequent Activity 3.3.4, we investigated how the volume of a box constructed from a piece of cardboard by removing squares from each corner and folding up the sides depends on the size of the squares removed.
Both of these problems exemplify situations where there is not a function explicitly provided to optimize. Rather, we first worked to understand the given information in the problem, drawing a figure and introducing variables, and then sought to develop a formula for a function that models the quantity (area or volume, in the two examples, respectively) to be optimized. Once the function was established, we then considered what domain was appropriate on which to pursue the desired absolute minimum or maximum (or both). At this point in the problem, we are finally ready to apply the ideas of calculus to determine and justify the absolute minimum or maximum. Thus, what is primarily different about problems of this type is that the problem-solver must do considerable work to introduce variables and develop the correct function and domain to represent the described situation.
Throughout what follows in the current section, the primary emphasis is on the reader solving problems. Initially, some substantial guidance is provided, with the problems progressing to require greater independence as we move along.
##### Preview Activity3.4.1
According to U.S. postal regulations, the girth plus the length of a parcel sent by mail may not exceed 108 inches, where by “girth” we mean the perimeter of the smallest end. What is the largest possible volume of a rectangular parcel with a square end that can be sent by mail? What are the dimensions of the package of largest volume?
The following is multiple choice question (with options) to answer.
A person wants to use raw materials to make things. Considering the want to create with raw materials, the person | [
"makes books out of trees",
"makes rocks out of wood",
"makes corn out of dogs",
"makes fur out of tableclothes"
] | A | if something is a raw material then that something comes directly from a source |
OpenBookQA | OpenBookQA-1044 | electromagnetism, electric-circuits, electric-fields, potential, potential-energy
Once the energy flows through $a$ we no longer know if the fields inside $a$ are conservative. But that is not required because we are only concerned about the currents, voltages, and power entering and leaving $a$.
The following is multiple choice question (with options) to answer.
Generally, electricity cannot flow through | [
"incomplete conductive paths",
"complete conductive paths",
"closed circuits",
"low-resistant electrons"
] | A | electricity can not flow through an open circuit |
OpenBookQA | OpenBookQA-1045 | thermodynamics, heat-conduction
However, the dependency of $c$ on starting temperature and pressure can often be ignored in practical contexts, e.g. when working in narrow ranges of those variables.
After looking up the tables for $\kappa$, $c_p$, etc. for the materials involved, they don't seem to vary much more than one percent or so in this 60-100°F range of interest, so it seemed safe to rule that facet of the problem out. (To compensate, maybe I should expect +12°F over ambient instead of +11?)
So, ignoring that aspect, is the rest of this a safe way to conduct a "how hot could it get" analysis? Does it sound like I've missed anything important?
(At this point it's mostly academic curiosity, although I do expect to install a custom parabolic'ish reflector inside the fixture, made from an intentionally high-temperature epoxy resin. I'm pretty sure I've got a safety margin on the order of 100°C but I got caught up in the question itself along the way.)
Thanks! Yes it will follow ambient.
There may be a slight lag, but you can expect the interior temperature to track towards a fixed offset from ambient.
You seem to have found all the details already youself
Barring upsets like the introduction of phase-change materials (eg snow melting or rain evaporating) it will follow the fixed offset.
The following is multiple choice question (with options) to answer.
A screw will increase in temperature when set in the sun's path, why? | [
"heating element",
"building device",
"conduction",
"convection"
] | C | if an object is exposed to a source of heat then that conductor may become hot |
OpenBookQA | OpenBookQA-1046 | 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.
Sleet is made out of water that is | [
"vapor",
"hot",
"liquid",
"cold"
] | D | sleet is made of ice |
OpenBookQA | OpenBookQA-1047 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
Replacing a natural resource can be | [
"refilling a lake that evaporated",
"planting a flower in a garden",
"growing a bush in a yard",
"planting a berry patch"
] | A | An example of replacing a natural resource is planting new trees where a forest once stood |
OpenBookQA | OpenBookQA-1048 | 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.
Humans contribute to environmental pollution | [
"by purchasing products made from recycled products",
"by switching to energy efficient appliances",
"by leaving behind refuse on public beaches",
"by frequently recycling paper and plastic"
] | C | pollution is when humans pollute the environment with pollutants |
OpenBookQA | OpenBookQA-1049 | visible-light, electromagnetic-radiation, frequency, sun
(Note, there are other possible emission spectra, but those are associated with different materials doing the emissions and, for the purposes of this discussion, they aren't too important. We can just claim the emissions are all blackbody)
If you notice, as you get hotter, a larger portion of the energy is emitted in the blue, violet, and ultraviolet. That's how you get a sunburn from the sun. It's harder to get a sunburn from an artificial light, not because it's artificial, but because those lights are almost always cooler than the sun. They don't have as much UV content. Instead, they have more red and yellow, which incidentally is why pictures taken indoors look very yellow. If you use a strobe, however, all those yellow hues go away because a strobe light is very warm, with lots of blues.
You can get a sunburn from artificial light, of course. Tanning beds are the obvious example, but there are other interesting ones. When you're a jeweler working in platinum, for instance, you need to wear UV protective gear (like glasses or even sunscreen). Platinum's melting point is so hot that it actually emits quite a lot of UV light and can give you a sunburn!
Other than these spectra, there is nothing different between light from an artificial source and light from the sun. Photons are photons.
The following is multiple choice question (with options) to answer.
Light that can burn skin is produced by a | [
"flashlight",
"laser",
"light bulb",
"fluorescent light"
] | B | a laser is used for producing light |
OpenBookQA | OpenBookQA-1050 | geochemistry, chemistry-in-fiction, minerals
They look like extremely poor sources of metals like aluminum, lithium, iron, sodium, calcium, magnesium and potassium.
Now micas. Micas are described by the formula
$\ce{X_2Y_{4–6}Z_8O_{20}(OH,F)_4}$
in which
X is K, Na, or Ca or less commonly Ba, Rb, or Cs;
Y is Al, Mg, or Fe or less commonly Mn, Cr, Ti, Li, etc.;
Z is chiefly Si or Al, but also may include Fe3+ or Ti.
Of interest in this formula are Rb and Cs, no matter how rare, because these are rare by definition. So, adding to the same elements as the above described amphiboles, micas have the advantage of also containing barium, rubidium (!), caesium (!!), manganese, chromium, Titanium and Lithium.
So my question is, what would be a lightly realistic approach to obtain usable compounds from granite? I'm sure real techniques do not exist, but what about science-fictional approaches? Chemists probably have unachievable dreams of tapping this or that potential source for obtaining huge amounts of a substance (until recently, one of those fancy dreams was a way to obtain drinkable water from sea water). I would love to hear any input from this (almost always) lovely community.
The following is multiple choice question (with options) to answer.
Which is a source of raw materials? | [
"a power plant",
"a factory",
"a shopping mall",
"an oil field"
] | D | if something is a raw material then that something comes directly from a source |
OpenBookQA | OpenBookQA-1051 | orbit, earth
Title: Average amount of annual daylight at any place on earth If this is the wrong group please direct me to the correct one.
It seems intuitively obvious that the amount of daylight per annum should be the same for any latitude on earth. For example, 12 hours per day at the equator. The poles have daylight for half the year and darkness for the other half (crudely).
Is there any way to get an answer to this apparently simple question - is the annual amount of daylight the same at any point on earth? Wikipedia strikes again:
The naive expectation is that, for every place on Earth, the Sun will
appear to be above the horizon for exactly half the time. Thus, for a
standard year consisting of 8760 hours, apparent maximal daytime
duration would be 4380 hours. However, there are physical and
astronomical effects which change that picture. Namely, atmospheric
refraction allows the Sun to be still visible even when it physically
sets below the horizon line. For that reason, average daytime
(disregarding cloud effects) is longest in polar areas, where the
apparent Sun spends the most time around the horizon. Places on the
Arctic Circle have the longest total annual daytime of 4647 hours,
while the North Pole receives 4575. Because of elliptic nature of the
Earth's orbit, the Southern Hemisphere is not symmetrical: Antarctic
Circle at 4530 hours receives 5 days less of sunshine than its
antipodes. The Equator has the total daytime of 4422 hours per
year.
Further details here on astronomical causes of average daytime variation, and here on Insolation, the solar radiation received at the top of the atmosphere and its effects on the energy received at ground level.
The following is multiple choice question (with options) to answer.
The most daylight is two months after | [
"October",
"July",
"January",
"April"
] | D | the amount of daylight is greatest in the summer |
OpenBookQA | OpenBookQA-1052 | zoology, ecology, species-distribution, migration
Title: How do animals end up in remote areas? I was thinking specifically about random marshy water holes on farmers fields. It seems that you can visit just about any one of these and you will find frogs if you look hard enough.
They usually don't seem to be connected to each other. If it were any other land animal I would figure they walk from one spot to another, but in the case of frogs, I don't imagine their range is very vast. But often these marshy spots can be separated by fairly large distances to a frog.
So this brings me to my question: how do each of these spots end up with frogs in them? I don't imagine a frog is going to go hopping over a hill to get to a marsh on the other side, is it? This question pertains to organism dispersal, which is a very active field of study with relation to it's impact on conservation efforts. Much of what I will say below has been covered in this wiki.
Definition: From the Wiki
Technically, dispersal is defined as any movement that has the
potential to lead to gene flow.
It can be broadly classified into two categories:
Density dependent dispersal
Density independent dispersal
The question of frogs and fishes both refer to Density independent dispersal, while an example of density independent dispersal can be the competition for habitat space between big cats and humans (this is a WWF pdf)
From the wiki:
Density-independent dispersal
Organisms have evolved adaptations for dispersal that take advantage
of various forms of kinetic energy occurring naturally in the
environment. This is referred to as density independent or passive
dispersal and operates on many groups of organisms (some
invertebrates, fish, insects and sessile organisms such as plants)
that depend on animal vectors, wind, gravity or current for dispersal.
Density-dependent dispersal
Density dependent or active dispersal for many animals largely depends
on factors such as local population size, resource competition,
habitat quality, and habitat size.
Currently, some studies suggest the same.
This study in particular studied the movement and habitat occupancy patterns within ephemeral and permanent water bodies in response to flooding. They found that during flooding these frogs moved out to flooded ephemeral water bodies and later on moved back again to the permanent ones.
Other suggested readings for those highly interested in the subject may include this (a phd thesis) and this (a project report)
The following is multiple choice question (with options) to answer.
What separates animals that thrive and those that go extinct are | [
"the type of animal",
"lacking ability to conform",
"ability to stay in one place",
"the ability to adapt"
] | D | changes in an environment cause animals to adapt to survive |
OpenBookQA | OpenBookQA-1053 | charge, electric-current, flow
http://amasci.com/miscon/eleca.html#cflow
Energy, however, is not transmitted by one electron moving all the way around the circuit to the load, but rather through waves in the electrons and more importantly, the associated electric field. It's the same way that mechanical energy is transmitted in, say, a pole that is pushed from one end. The pole compresses slightly, and a sound wave thus appears, initially containing all the energy within your "push", and then travels down it, progressively distributing that energy amongst all the atoms within the pole until they are all moving in a single direction (here I imagine the pole pushed in a vacuum, as in interstellar space, with no other forces acting). The same goes with electrons in the circuit - though I should point out the following model is a bit simplistic but is more to convey the point of how the energy is transmitted than to detail the actual behavior of the electrons, which involves quantum mechanics and is subject to many of the same caveats as one sees within in an individual atom or molecule. But in this loose sense, when you throw the switch, now an electromagnetic wave travels down, setting the electrons ahead in motion and thus distributing its energy throughout the circuit. Of course, the core atoms of the metal are relatively fixed despite the electron motion, so the latter will tend to lose that energy to collision with them, unlike the pole where everyone, atoms and electrons together, start going in synchrony, and thus you have to keep supplying energy to them with a power source like a battery or generator which effectively keeps "pushing the pole" and thus keeps energy going into it - now think about a pole that is now not in vacuum but in molasses, and you have to keep pushing it to keep it moving. This pushing on atoms, of course, is how electrical devices can use electrically transmitted energy to do useful tasks.
Electromagnetic waves, and sound waves, thus energy, travel much faster than the electrons and the atoms in both the circuit and pushed pole. Energy is what lights up your light bulbs, and energy is what makes your computer operate. Since energy travels fast, these devices start operating "at the flick of a switch".
The following is multiple choice question (with options) to answer.
Energy may be transferred to an object without being plugged in, such as with | [
"an electric grill",
"an electric stove",
"an electronic torch",
"a microwave oven"
] | C | a battery is a source of electrical energy |
OpenBookQA | OpenBookQA-1054 | phase-transition, biophysics, medical-physics, glass, amorphous-solids
313 6003 pp573-5 (1985).
This outcome was identified as early as the 1960s by electron microscopy of thawed cells, which revealed many puncture holes in the membrane.
Both freezing and rethawing are opportunities for damage, as recrystallization can occur during the latter regardless of how carefully the former was performed.
Freezing into the crystalline phase of ice (and many other materials) produces sharp dendrites because some crystal orientations exhibit very fast growth kinetics. This issue doesn't arise with amorphous freezing.
For an early discussion, see, for example, Mazur's "Cryobiology: the freezing of biological systems" Science 168 3934
pp939-49 (1970) and the references within.
The following is multiple choice question (with options) to answer.
Ice wedging can be explained by pointing to | [
"roads in wintery areas need constant fixing after winter",
"houses are falling down soon",
"some trees split after they start to grow tall",
"ice is cold enough to kill"
] | A | ice wedging is when ice causes rocks to crack by expanding in openings |
OpenBookQA | OpenBookQA-1055 | 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 could a person eat to avoid starvation? | [
"Akvavit",
"Jeggings",
"Carmex",
"Floss"
] | A | lack of food causes starvation |
OpenBookQA | OpenBookQA-1056 | reproduction, nutrition, ornithology
Title: Do chickens always lay eggs? http://de.wikipedia.org/wiki/Hühnerei says it takes up to 24 h for a chicken to produce an egg.
Is that dependent on the chickens nutrition, i.e., if it does not get enough food or the wrong kind, meaning it can survive on the food but it does not have everything to produce an egg?
Do we have data on this? In short; yes. It depends on the breed (not all lay up to 1 egg/day), the age of the bird and on nutrition. High yielding breeds of chicken are e.g. dependent on supplements of calcium to be able to produce new shells rapidly (e.g. in the form of ground-up shells). Some information on the nutrient requirements of chicken can be found at Feeding the Laying Hen. Egg production will also fluctuate over the year, and will generally decrease e.g. during molting, since energy and nutrients are then diverted to the production of feathers (see info at e.g. The Poultry site).
The following is multiple choice question (with options) to answer.
A bird is about to lay an egg, so it needs to construct a safe, round place to place the egg in. The bird constructs using | [
"sticks",
"gum",
"rocks",
"tape"
] | A | a nest is made of branches |
OpenBookQA | OpenBookQA-1057 | species-identification, zoology, ornithology
Title: Identification by tail feather I saw the remains of a bird today I did not recognize, and it was pretty mangled so it was hard to describe it. It was about the size of a robin. However, it had a dark brown mottled body like nothing I have ever seen. I have included below a tail feather from the bird which is 5 inches long. I am sure it is not a thrush or a woodcock or a kestrel. So what was it?
Location is Great Bay, Portsmouth, New Hampshire, United States. I believe this is a tail feather (or retrix) from an adult male eastern whip-poor-will (Antrostomus vociferus). See right image below (click to zoom):
.
Source: USFWS Forensics Laboratory
Details:
The brown, mottled appearance and the size (~12 cm) match that of the OP's specimen.
A great resource for exploring bird feathers: https://www.fws.gov/lab/featheratlas/
The whip-poor-will's breeding grounds include the OP's location (i.e., New Hampshire), and according to All About Birds this species could still be present even late in the year ("they seem to leave between early September and late November.").
Orange is breeding. Source: All About Birds.
The whip-poor-will is a medium sized bird and similar in size to an American robin.
Whip-poor-will: 22-26 cm ; Robin: 20-28 cm
Eastern whip-poor-will, (c) Paul Cools, source: inaturalist
The following is multiple choice question (with options) to answer.
Birds go south to look for | [
"Vacation",
"Friends",
"Insurance",
"a different climate"
] | D | An example of migration is birds flying south in the winter |
OpenBookQA | OpenBookQA-1058 | predators (y2) die of natural causes (Reaction 3). At the same time , a trio of coming-of-age Predators have arrived to collect the skulls of the aliens as trophies , and the humans are caught between a deadly battle between the Spectacular and decent Aliens/Predators movie set in Antarctica where a motley group takes on extraterrestrial monsters. In The Lotka Volterra Predator-prey Model, The Changes In The Predator Population Y And The Prey Population X Are Described By The Following Equations: Δxt=xt+1−xt=axt−bxtyt Δyt=yt+1−yt=cxtyt−dyt Write A Function Simulatepredatorprey (x,y, A,b,c,d, T) That Takes In The Initial Population This problem has been solved!. The main objective was to investigate the spatio-temporal pattern of diffusive prey-predator model and the emergence of irregular chaotic pattern as a result of prey-predator interaction. Eigenvalues and eigenvectors. This project results in a Lotka-Volterra model which simulates the dynamics of the predator-prey relationship. In this study, the approximate solutions of the predator–prey system with delay have been obtained by using the modified Chebyshev collocation method. To understand how predators optimize foraging strategies, extensive knowledge of predator behavior and prey distribution is needed. The number of predators is represented by y, the number of prey by x. Yang, Yong S. (This Malthus-type equation gives. a discrete time predator prey model specified by Neubert et al[9] which utilises the Ricker model to simulate prey growth. Open the first file for this module by typing on the Matlab command line: ppmodel1. 1 Introduction. If algae and plankton communities are threatened, the entire food web may change. In this work, we investigate numerically a system of partial differential equations that describes the interactions between populations of predators and preys. This paper investigates a dynamical predator-prey interaction model that incorporates: (a) hunting cooperation among predators; (b) Allee effect in prey. At the other extreme,. b) The rabbits eat grass and breed. function to be a Di erence sequence and study the convergence of the model. (5 stars rating will be given =). In the notes, the author
The following is multiple choice question (with options) to answer.
When a predator population decreases in an environment, what happens to other populations? | [
"prey numbers will boom",
"the amount of prey will go down",
"new predators will arrive",
"all populations will increase"
] | A | as population of predators decreases , the population of prey will increase in an environment |
OpenBookQA | OpenBookQA-1059 | python, object-oriented, random
def start_delay(self):
'''Return random delay within <start_delay_range>.'''
return random.randint(start_delay_range[0], start_delay_range[1])
def run(self):
'''Turn on the light to <brightness> after <start_delay> for <duration>.'''
if self.dimmable:
# Turn on light
indigo.dimmer.setBrightness(self.device_id,
value = self.brightness(),
delay = self.start_delay())
else:
# Turn on light
indigo.device.turnOn(self.device_id,
self.start_delay())
# Turn off light after <delay>
indigo.device.turnOff(self.device_id,
delay = self.duration())
# List of Light() objects to randomize
lights = [
Light(name='Breakfast Room', device_id=1222428814, dimmable=True),
Light(name='Kitchen Cabinet', device_id=18462733, dimmable=False),
Light(name='Hallway', device_id=93680547, dimmable=True),
Light(name='Living Room Recessed', device_id=7507220, dimmable=True),
Light(name='Stairs', device_id=1842915774, dimmable=True),
Light(name='TV Room', device_id=1569858222, dimmable=True)
]
def main():
for light in lights:
light.run()
if __name__ == '__main__':
main() This code looks good! But I still have some notes to clean it up a bit.
First, all your constants (start_delay_range, brightness_range, and duration_range) should really be part of the Light class since they're used specifically in there. If that's where they're relevant, keep them there. Plus this makes it easier to do from light_tools import Light and not be caught without necessary values.
class Light():
'''
Define a light object.
The following is multiple choice question (with options) to answer.
A television may turn on at the push of a button because | [
"the circuit has shorted out",
"the television is pretty short",
"the path of electricity is completed",
"the button was plastic"
] | C | pushing a button sometimes completes a circuit |
OpenBookQA | OpenBookQA-1060 | 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.
the arctic area is full of | [
"white powder",
"ice cold drinks",
"warm water",
"fluffy white dirt"
] | A | the arctic environment is covered in snow |
OpenBookQA | OpenBookQA-1061 | human-biology, reproduction
Title: Why are animal births not taken as seriously as human births? When humans give birth, more than often medical assistance is needed. Others gather around and frantically look for any way to help. But when an animal gives birth, it is usually seen as a moment where you give the female its space and let the birth occur naturally and without any assistance. The animal is of course in serious pain just as a female human but this is more than often not taken into account. Why is it that animal births are not taken as seriously? Our heads are bigger.
There's some debate on the issue, but in essence, human brains, and therefore heads, are very large relative to our body size. This is handy for all the intelligent things we like to do, but can be rather painful during birth. Because we walk upright, the size of a newborn's head is actually a non-trivial fact during the birthing process. There are two major implications.
The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult. Evolution has (supposedly) limited the size of the hips because, while that would allow an easier birthing process, it would negatively impact our ability to walk. As such, it has to hurt.
Secondly, in order to make the process easier, humans rotate during birth. The end result is that, unlike even other closely related primates, humans come out backward in a way that is very difficult for a birthing female to attend to. This almost requires having another person or two on hand to help out. This would, of course, be a huge reinforcement for social connections.
A few books I know of touch on this. Up From Dragons deals with the brain size/hip size issue and The Invisible Sex talks about rotation during the birthing process and the social implications.
The following is multiple choice question (with options) to answer.
What is a way to be born besides live birth? | [
"coming through a tough shell",
"digging out of the sand",
"cooking up an egg",
"living in a nest"
] | A | if an animal hatches from an egg then that animal is born |
OpenBookQA | OpenBookQA-1062 | power-engineering, inductive-charging
Title: Efficiency of wireless charging for moving cars The UK is about to start trials of wireless charging for moving cars.
What kind of power transfer efficiency is likely to be achievable in such a system, compared to just plugging in the car directly? This is not exactly a comprehensive answer, but I found an interesting article on The Institution of Engineering and Technology's website. It is fairly interesting, if not incredibly technically detailed, and I encourage you to check it out for projects to learn more about. I'll talk about the most interesting parts here.
It has many interesting projects listed. Some are for bus routes, and rather than charging along the whole route, they use 'opportunistic charging' to charge at key places (presumably bus stops and traffic lights) to rapidly transfer energy. This is intended to minimize the disruption and possibly cost of construction (imagine having to dig up an entire busy road to add charging coils). This is called "semi-dynamic charging" by Transport Scotland, who are working on one such project.
However, it sounds like in Korea, a more full route system has been operating.
[T]he Korea Advanced Institute of Science and Technology (KAIST) is running two online electric vehicle (OLEV) buses on a 12km continuous charging route in the city of Gumi. It claims 85 per cent maximum efficiency in power transfer.
You're question is focused on the pure efficiency of the charging capacity, but I think also interesting to consider (or possibly implied in the question) is for what cases these technological limitations make actual use a practical exercise. On that note, I will add that this technology may prove of more usefulness on highways, where range is of particular concern in the arena of electric vehicles, leading to projects going to great lengths to provide very close charging stations (25 to 50 miles) like West Coast Green Highway.
The following is multiple choice question (with options) to answer.
if a man's new car can be charged at a charging station, what is this termed? | [
"all of these",
"battery operated",
"getting energy",
"alternative fueling"
] | A | alternative fuel is usually a renewable resource |
OpenBookQA | OpenBookQA-1063 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
If an environment experiences a long drought | [
"ponds may dry up and kill off the fish population",
"plants will continue to flourish",
"animals will experience a boom in reproduction",
"tadpoles will mature faster into frogs"
] | A | the decrease of something required by an organism has a negative impact on that organism 's survival |
OpenBookQA | OpenBookQA-1064 | species-identification, zoology, entomology
Title: Species identification; clusters of big plump red bugs in Taipei I saw these red insects in Taipei near XinBeitou MRT station in the last week of April 2017, around lunch time. They were fairly active and would keep checking each other out with their antennae for a moment and then move on to the next. What struck me was the wide range of sizes and development in the groups. I didn't notice any feeding or mating that I could recognize, just a lot of walking around and checking each other out.
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
I've also included a screenshot from google maps so you can see the location and the trees growing in these concrete structures.
The body of the largest individual is probably 2.5 centimeters long. I'm fairly certain these true bugs belong to the species Leptocoris vicinus, and carry the nickname of "soapberry bugs", which is specific to the subfamily Serinethinae. They're quite common in urban areas of Southeast Asia, which coincides nicely with where you encountered them.
Also, you had mentioned,
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
Soapberry bugs, as well as many other types of insects, are able to freely congregate in large numbers, and in such exposed places, due to their bright coloration. Having such a bright color may indicate to some predators that the prey in consideration is toxic, a phenomenon referred to as aposematism.
source
source
And then, here's a map of their distribution, with Taipei holding marker #37. (source)
An interactive version of this map can be found here.
The following is multiple choice question (with options) to answer.
a student notices a large number of hawks in the playground, what will likely happen to the lizards? | [
"they will flourish and thrive",
"their kind will dwindle",
"they will become predators",
"all of these"
] | B | hawks eat lizards |
OpenBookQA | OpenBookQA-1065 | fluid-statics
Title: Is this watering with gravity concept possible with physics?
I was thinking of putting together a auto watering scheme for my plants. Main objective is to just have one place to fill water, and it will disperse to several cups equally. I might have the physics wrong but i remember some force which creates suction with gravity and keeps the containers equally filled. I tried to draw the idea, and i'm wondering if anyone have any feedback on if this is possible?
The idea here is that the gravity will bring the water from the top container which stands taller, and then fills the small containers with water. The sketch is of a high reservoir, with multiple level-controlled smaller tanks.
So, it implies that the (lower level) tanks are equipped with a valve that
shuts off the water when a target level is reached: it's just like the
shutoff mechanism in the tank of a toilet. There's a float, which operates
the valve. It doesnt equalize gallons per day, though, just level-in-a-tank.
So, you can definitely find items at a hardware store to build such a system.
If, on the other hand, you want to partition a water source to multiple
destinations based on delivered water volume being equal, the usual
approach is to use a timed valve to a pressurized manifold, and use
matched emitters (i.e. drip irrigation controlled-flow drip fittings).
The physical principle of these emitters is the Bernoulli effect, they
are fabricated so that too-fast water flow in the valve pulls the
aperture shut (this sounds hard, but it isn't). Over a range
of water pressure, the drip rate stays nearly constant. They usually
require pump pressure (or water-utility pressure) though, would clog
if you just used a few feet of gravity-driven flow.
The following is multiple choice question (with options) to answer.
When a plant is water the liquid goes from the soil area to where it is needed using what system? | [
"sprinkler",
"xylem",
"flowering pistols",
"leaves"
] | B | xylem carries water from the roots of a plant to the leaves of a plant |
OpenBookQA | OpenBookQA-1066 | fluid-statics, surface-tension
So, it would be very helpful if you could explain why does a metal paper clip float even though it has an acute contact angle with water.
Please note that the question Surface tension: the paper clip experiment is not same as this one. It doesn't discuss about the obtuse contact angles observed between metal paper clip and water which is the central theme of this question. When there is no wetting, the contact angle is obtuse. When wetting takes place, the contact angle becomes acute. A certain amount of pressure is needed to break the surface of the liquid so that wetting takes place. If wetting were to take place, the paperclip would sink (likewise it would sink if there were no surface tension).
When wetting does not take place, the contact angle is obtuse. The paper clip can float because wetting does not take place (or only a small amount of wetting takes place) - the clip is light enough that does not push hard enough on the surface of the water to break surface tension. This is undoubtedly helped by contaminants, such as oils picked up from fingers (it is opposite to capillary action, in which wetting does take place).
The following is multiple choice question (with options) to answer.
A paper clip is often made of | [
"cobalt",
"wood",
"styrofoam",
"paper"
] | A | a paper clip is often made of ferromagnetic metals |
OpenBookQA | OpenBookQA-1067 | orbit, the-sun, earth
Notes:
It takes the Earth 365.256363004 days to revolve around
the Sun with respect to the fixed stars, but the time
between vernal equinoxes is slightly less (365.242190402
days) because the position of the vernal equinox moves
(precesses) with respect to the stars. Source:
http://hpiers.obspm.fr/eop-pc/models/constants.html
The Gregorian calendar's average day length of 365.2425
is much closer to 365.242190402 days than the Julian
calendar's 365.25 average day length, but it's still not
perfect. As noted in
Do solstices and equinoxes shift over time?
if we continue using the Gregorian calendar in the far
future, the equinoxes and solstices will drift
backwards. By 17090 (the limit of DE431), they will look
like this:
EQU 476198945887.238159 A.D. 17090-02-22 08:56:59
SOL 476207018540.040894 A.D. 17090-05-26 19:21:11
EQU 476214808218.146362 A.D. 17090-08-24 23:09:09
SOL 476222655067.609985 A.D. 17090-11-23 18:49:59
about a month behind their "regular" times.
MY EARLIER PARTIAL ANSWER FOR REFERENCE:
Since HORIZONS (http://ssd.jpl.nasa.gov/?horizons) and SPICE (http://naif.jpl.nasa.gov/naif/tutorials.html) can compute the ecliptic and solar position back that far, it should be possible to compute equinoxes and solstices with reasonable accuracy. However, I haven't been able to find a site that actually lists these dates (I'm pretty sure USNO did this at one point, but I can't find their list). Other possibly helpful sources/questions:
The following is multiple choice question (with options) to answer.
how much time does it take the third planet from the sun to make a full turn? | [
"23 hours",
"twenty-one hours",
"twenty-four hours",
"22 hours"
] | C | one day is equal to 24 hours |
OpenBookQA | OpenBookQA-1068 | entomology
Title: Constantly wiggling moth pupa - will it emerge soon? Today I found a moth pupa in the soil in my garden in western Sweden. It's about 15 mm long.
I have found similar ones before, but this one is wiggling a lot more, even after I put it down and put a bit of dirt over it. It's been moving for more than an hour now, but less now than in the beginning.
I was hoping to see it emerge, but if it will take more than a day or so, I will probably put it back. So, what I'm wondering is if this wiggling is any indication of how soon it will emerge. Or if there are other ways to tell.
Update: an hour later it has stopped moving. Maybe it was just very disturbed by my presence. I'm keeping it in a jar with soil and a stick for climbing up on, and I'll decide what to do with it tomorrow.
Update: 12 hours later and it seems very still. But I'm letting the question remain since I really want to know if there are any signs to look for.
Final update: After 16 days it had turned almost black, and was still very active when handled.
And after 17 days this moth came out: I posted the same question on tumblr and got an answer:
It depends on the species. This one looks like a Noctuid. I’d give it
two weeks to a month or so. You may be able to see its wings showing
through the darkening pupal case when the time draws near! Just make
sure you give it somewhere to climb up and expand its wings when it
ecloses.
After keeping it until the moth emerged, I now know that wiggliness is not an indication of maturity, but turning dark is.
The following is multiple choice question (with options) to answer.
A moth can metamorphosize when | [
"it releases itself from a self-made chamber",
"it is entirely reborn",
"it is fully recreated",
"it becomes a winged creature"
] | A | a moth undergoes metamorphosis |
OpenBookQA | OpenBookQA-1069 | human-biology, breathing
Our lungs work off of pressure. Specifically our lungs inflate by using "negative pressure" (a word I've always hated). The pressure is not actually negative it is simply lower than the surroundings. Since there is less air in your lungs the air from the atmosphere rushes in because the pressure is higher outside your lungs. This is Boyle's Law (not the pressure outside being higher, but what happens when your lungs expand). Where an increase in Volume means a decrease in Pressure (if all else remains unchanged). In fact plants pull water up using negative pressure.
However to push out the air from our lungs we supply pressure using our muscles that overcomes the outside pressure and forces the air out.
The reason you feel your breathing change is because when that train passes by you correctly observed the strong gust of wind. This gust of wind has some force behind it that normally is not in the air you are breathing from the atmosphere. It has more force which increases the air's velocity. This actually decreases the pressure, but there's no need to get into that here (Bernoulli's).
The reason it feels like your body is "fighting to breath" is because the air is traveling in a direction with some force that you need to overcome by opening up your lungs just enough to "suck" the air in with negative pressure. This is more than the pressure you usually need to produce in order to breath in air that is "still".
What is funny to think about is we don't really have a muscle that "pulls" air in, even though it feels like you are actively doing that. The air actually rushes in on its own. All you do is expand your rib cage, which your lungs are attached to (look up on how, it's actually pretty cool), thereby making inhalation occur.
Now an interesting question for you to ask yourself is why is cold air harder to breathe?
The following is multiple choice question (with options) to answer.
If something breathes, it | [
"uses unusable byproduct",
"lives in trash",
"scraps unusable byproduct",
"moves around frequently"
] | C | all living things eliminate waste |
OpenBookQA | OpenBookQA-1070 | soil, moon
Title: What is the difference between lunar and earth soil I know that the moon has lunar regolith and earth has earth soil, but what is the difference between them? The single biggest difference is the lack of chemical weathering in lunar soils which are subject to physical weathering almost exclusively. If you exclude biological processes, terrestrial rocks undergo significant weathering from water and atmosphere, which the moon lacks.
For example, both earth and moon contain feldspar-rich rocks, however, clays, the result of chemically altered feldspars, are not found on the moon. Neither are oxidized minerals, as the moon has no oxygen-rich atmosphere to speak of.
The following is multiple choice question (with options) to answer.
Which of the following can be found on the moon? | [
"Non-volcanic Mountains",
"Life-filled Oceans",
"Volcanic Mountains",
"Multiple Land Masses"
] | A | the surface of the Moon contains mountains |
OpenBookQA | OpenBookQA-1071 | fluid-dynamics, states-of-matter
Title: Why does sweetness of coke change after freezing completely I freeze my coke in a freezer completely to solid and then keep it out to melt and as it melts portion by portion I starts to drink, initially It will be very sweet and later it wont be sweet at all. why does this happen?
We know that all sugar in coke will be dissolved (Solid solution) but how a major portion of this melts faster than water in the juice their by getting more sweet? How these sucrose can escape through the crystals formed by the ice and join in the water.
I measured the sweetness (Brix) and found it varies. Substances in solution have the effect of decreasing the temperature of the freezing point of the liquid they are dissolved in. This is called freezing-point depression. This is one of the reasons why adding salt to ice helps it melt.
Your coke is a complicated solution + colloid and sugar is one of the main substances dissolved in it.
During freezing:
What happens is that during the freezing process, as the coke cools a lot of sugar is pushed out of solution which allows the less-saturated water to freeze first. The last bit of liquid to freeze has much more sugar in it and takes a while to freeze because it is a concentrated solution and the freezing point has been lowered a lot.
During melting:
The last portion of the coke to freeze has the bulk of the sugar and the lowest freezing point and will melt first when warmed. When you allow the coke to start melting the most saturated portions melt the fastest and you consume most of the sugar in this stage. Later when the drink continues to warm the rest of the water starts melting with much less sugar in it, thereby making the remaining portion less sweet.
More information about sugar solubility:
One common way to grow sugar crystals is by slowly cooling the solution to push the sugar out of solution. There is some information about this here and they provide a nice sugar (sucrose) solubility versus temperature graph too:
As you can see the temperature dependence for solubility is dramatic. I haven't been able to find a curve for fructose (the primary sugar in coke in the United States) but I suspect the curve is very similar.
The following is multiple choice question (with options) to answer.
When sugar is added to water, it blends in such as in which drink? | [
"milk",
"lemonade",
"juice",
"tea"
] | B | sugar dissolves in water when they are combined |
OpenBookQA | OpenBookQA-1072 | geophysics, plate-tectonics
Title: Equatorial bulge and tectonic plates It is well known that the Earth is not a sphere, but rather it bulges at the equator. Also it is well known that the Earth's crust is composed of 7 or 8 (depending on definition) major tectonic plates, which are able to move on top of the asthenosphere, the upper layer of the Earth's mantle.
Due to the equatorial bulge, it would seem as though plates near the equator should not be able to drift away from the equator, and plates away from the equator should not be able to drift near the equator, since they will not be of the right shape to fit over these portions of the Earth. So how are the plates able to drift to and from the equator when the surface of the Earth is shaped differently there? The plates are not as rigid as you think. You seem to be imagining the situation as something like this: I boil an egg and take the shell off in pieces, but I can't take a piece of shell from the end and make it lay flat on the side of the egg. However, rock is not that rigid on scales of thousands of kilometres and millions of years (I don't think there exists any material which would be that rigid). Also, Earth's equatorial bulge is tiny relative to its diameter -- less than 50km. Tectonic plates move very slowly, and there is plenty of time for them to deform as they move.
The following is multiple choice question (with options) to answer.
Tectonic plates move along | [
"planar fractures",
"error lines",
"triangular fractures",
"defect line"
] | A | a tectonic plate moves along a fault line |
OpenBookQA | OpenBookQA-1073 | orbit, the-moon, earth
Title: What is the distance of the Earth's orbit around the Moon? I realize the Earth and the Moon both orbit around their shared center of mass, and that in the case of the Earth and Moon this center is "inside" the Earth. However, I'm looking for an approach to determine the distance the Earth travels in one "orbit around the moon" (as small as it may be). The mass of the Earth is about 81 times that of the Moon and the distance between their centres of mass is typically 384 400 km, so the centre of mass will be about 1/82 of this distance from the centre of mass of the Earth, which is about 4700km.
The orbits are not too far from circular, so the Earth travels about $2 \pi$ times that each month, so a little under 30000km.
The following is multiple choice question (with options) to answer.
During the time the moon orbits the Earth 13 times the Earth orbits the sun | [
"once",
"twice",
"three times",
"four times"
] | A | the moon orbiting the Earth approximately occurs 13 times per year |
OpenBookQA | OpenBookQA-1074 | seismology, earthquakes, seismic-hazards, drilling
Title: Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes? The velocity of p-waves emanating from earthquakes is in the range of 5-8 km/s (link)--let's assume it is 5 km/s. The earthquake depth is up to hundreds of kms deep underground (link)--let's assume it is 100 km.
That said, if a seismic station is installed at a depth of 50 km, and there are many of them in any given metropolitan area, then we can have a warning that is tens of seconds before the earthquake reaches the surface.
While I realize that drilling down to 50 kn is no easy task, I would have imagined that saving human life is well worth the efforts. Why hasn't this been done so far? Is it that such a short notice (10s of seconds) isn't worth it? The simple answer is that you can't drill to 50 km depth.
The deepest holes ever drilled were to a little more than 12 km, one is named the Kola Superdeep Borehole in Russia, which was a scientific drilling project. The very few others were oil exploration boreholes.
Drilling that deep is extremely expensive and hard. If you go and ask anyone who ever worked on a drill rig, drilling the second 100 metres is always harder than the first 100 metres. And we're talking about kilometres here! There are several problems with drilling that deep. It's extremely hot down there, and the drilling equipment just breaks and stops working. You also need to pump cooling water in and pump out the stuff you're drilling and it gets harder with depth.
This is simply not feasible. Now let's say that you did somehow manage to drill a hole to that depth. How would you put monitoring equipment inside? That equipment has to sustain heat and pressure and still keep working, while being able to transmit whatever it's reading back to the surface. This is not going to happen, not at 50 or 10 km depth.
Another problem is that not all earthquakes are that deep. Some earthquakes originate near the surface, or just several km deep. Having a monitoring station down there isn't going to help. The 2011 Tohoku earthquake (the one that triggered the tsunami at Fukushima) was only 30 km deep. Same thing for the 2004 Indian Ocean earthquake.
The following is multiple choice question (with options) to answer.
During an earthquake, piles of earth can | [
"crash through car windows",
"shift on top of one another",
"pile up on houses",
"kill small animals and birds"
] | B | earthquakes cause rock layers to fold on top of each other |
OpenBookQA | OpenBookQA-1075 | evolution, human-evolution
Apes
The split between the line leading to modern humans and the line leading to modern chimpanzees occured somewhere around 4 to 7 million years ago. The clade is called Hominini. The split between those and the line leading to modern gorillas occured around 8 to 19 million years ago (yes, the dates are getting fuzzier). A fossil coming close to this ancestor may be Nakalipithecus nakayamai, however, we only have a fossil jaw from that species.
Going back, we get to the split between modern-day humans/chimpanzees/gorillas and modern-day orang-utans. This is the "ape" family, Hominidae. The largest ape that we know of, Gigantopithecus, that grew to about 3 meters, is classified as an orang-utan. Note that this is not a direct ancestor of humans. Even if our ancestors were larger than modern humans at this point it's unlikely that we are talking about anything larger than a big gorilla.
Primates
Going a bit in the reverse order here: The first true primates evolved around 55 million years ago. Fossils from that time are about the size of squirrels. Humans are "old world monkeys" who first appeared around 40 million years ago - the fossils from that clade we know, for example Apidium or Aegyptopithecus are a bit larger, some as large as a dog.
Primate-like mammals
The first primate-like mammals, called Plesiadapiformes appeared around 60 million years ago. We don't know all that much about them, but the most famous Purgatorius was the size of a rat or mouse.
Mammals / placenta mammals
Going back even further, things become even murkier, but early mammals were small. Placentalia, placental mammals appeared around 90 million years ago. They were small, arboreal (tree-dwelling) animals. Early mammals appeared around 160 million years ago and fossils we have from that time place them around the size of a shrew.
Now, is it possible that there were larger mammals in there somewhere, that then "shrunk" again? Sure. Just unlikely.
Therapsid
The following is multiple choice question (with options) to answer.
A long time ago, the Grand Canyon was | [
"wider",
"deeper",
"grander",
"less deep"
] | D | the Grand Canyon was formed by the Colorado River flowing over long periods of time |
OpenBookQA | OpenBookQA-1076 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
In southern Africa we are more likely to see snow in | [
"January",
"November",
"March",
"July"
] | D | snow falls during the winter in some environments |
OpenBookQA | OpenBookQA-1077 | In the beautiful diagram above, we have a ball on the end of a string being swung around a center point.
Baby Devsman did not understand. Baby Devsman reasoned that if there is a force $T$ supplied by the string, then the ball must be getting closer to the center point except for this mystical magical force $F_c$ which is pulling it away by virtue of it going in a circle. Then, $F_{net} = ma$ as satisfied as the ball stays a constant distance from the center point. Why did scientists say it was directed toward the center? It clearly couldn't be, or else the ball would move closer to the center really fast.
$$0 = T + F_c???$$
This is wrong! Baby Devsman had much difficulty understanding many concepts as a result of wrong thinking. Baby Devsman would later learn that centripetal force is not a thing. Electric force is a thing. Electric charges attract each other and a force pulls them together. Normal force is a thing. The ground pushes back against stuff that sits on it.
Centripetal force, though, is not a thing. Nothing exerts centripetal force. Moving in a circle does not cause a force to be exerted. Centripetal force is a requirement of circular motion. Now I understand that centripetal force does not oppose $T$ in the beautiful diagram, but that the required centripetal force to satisfy the assumed scenario is provided by $T$. The ball does not get closer to the center point, true, but the ball's circular motion requires a particular $F_c$. That is, if an object is going to move in a circle,
$$F_c = F_{net}$$
Which in the case above, means $F_c = T$.
What does this have to do with Earth?
When you stand on the ground, your assertion that the weight of your body is matched by the ground's normal force is only approximately true. In reality, the centripetal force required for your body to move around the Earth is satisfied by the net of your body weight and the ground's support force:
$$F_c = W - N$$
The following is multiple choice question (with options) to answer.
A baby wants to move a ball, so it looks at the ball and it refuses to move. The baby takes its hand and touches the ball and | [
"motion occurs",
"babies whine",
"movement stops",
"people cry"
] | A | pushing an object requires force |
OpenBookQA | OpenBookQA-1078 | earth, amateur-observing, fundamental-astronomy
Title: Does weight influence Earth's spin? If put enough weight on a particular point on Earth's surface disturbing the balance between hemispheres, is it possible that the Earth's spin could change like an unbalanced spinning top? The Earth does spin like an unbalanced top. The Earth's rotation axis is not fixed. It instead moves in a complex manner due to a combination of external torques exerted by the Moon and Sun, a torque-free nutation due to the oblate shape of the Earth, and also due to changes on and in the Earth.
The torque-induced motions are called precession and nutation, distinguished by period. The largest and slowest of these motions is the axial precession. This causes the Earth's rotation axis to trace out a cone over the course of 26000 years.
(source: nasa.gov)
The torque-induced nutations are also cyclical motions induced by the Moon and the Sun. These are much smaller in magnitude and have a much shorter period. The largest of these has a magnitude of about 20 arc seconds and a period of 18.6 years. All other nutation terms have much smaller magnitude and have shorter period.
The torque-free nutation would have a period of about 305 days if the Earth was solid. The oceans, the atmosphere, and the outer core alter this. The Chandler wobble has a period of about 433 days and a magnitude of less than an arc second. Because the Chandler wobble isn't as predictable as are precession and nutation, it's lumped into a catch-all category called "polar motion." The redistribution of water over the course of a year (e.g., snow on Siberia in the winter but not in the summer) results in a yearly component of the polar motion.
There are lots and lots of other factors, all small. Polar motion is observed after the fact.
The following is multiple choice question (with options) to answer.
how many hours will it take the planet to complete a spinning motion? | [
"22",
"24",
"twenty hours",
"twenty one hours"
] | B | a Rotation of the Earth on itself takes one day |
OpenBookQA | OpenBookQA-1079 | thermodynamics, water
Title: Energy efficiency: better to heat hot tub constantly or twice a day for a longer period? I've got a hot tub in my garden with 1,500 litres of water in it and the target temperature is 38° centigrade.
The tub has two operating modes:
Economy: circulate water twice for 3 hours within 24 hours (at 4AM and 4PM). While circulating, heat if necessary.
Standard: same circulation but heat whenever temperature is dropping below 38°
Outside temperatures over here very between -15° at night (winter) and all the way up to +35° during the day (summer).
Usage of the hot tub is typically during the evening hours, the rest of the time the tub is covered with an insulated lid.
I observed that on warm days the economy mode consumes considerably less energy but I wonder if that will be true for colder days too and I would like to understand why this is the case.
I understand that the same amount of energy is needed to heat water, no matter how it's done. But isn't hotter water cooling down faster than cooler water? Does that have an impact on the decision of the mode?
Is it right that in an ideal world (which we don't live in), both modes should use exactly the same amount of power? From your description, it sounds like "standard mode" keeps the water always at approximately 38 degrees, whereas "economy mode" lets the water get cooler than this often.
When the water is cooler than 38 degrees, there'll be less conduction out of the pool, as the temperature differential between the water and the surroundings is lower. Less heat loss means less heat that you have to pay to add.
So, unsurprisingly, "economy mode" will work out cheaper for you than "standard mode".
The following is multiple choice question (with options) to answer.
Taking shorter hot showers | [
"will increase water usage",
"will aid in preserving the water supply",
"will aid in consumption of the water supply",
"will overwork the water heater"
] | B | as time spent taking a shower decreases , water used will decrease |
OpenBookQA | OpenBookQA-1080 | electricity, electrical-engineering
So what really is the problem in creating transformers in such a way to reduce losses much more than the current status ?
All relevant opinions and comments appreciated
My original post : http://thinklo.blogspot.in/2013/10/improving-transformers.html Well a problem with your concept is that an "air core" transformer can produce only a limited magnetic flux density; limited by the amount of current you can run through it.
If your transformer is for power conversion/transmission, your scheme would be extremely inefficient at power line frequencies. It can be shown that the efficiency is maximized when the "copper losses" are equal to the "iron losses" or "core losses if you prefer.
Since, your transformer has no iron core, there are very low to near zero core losses, but the copper losses (wire resistance) is very high.
With an "iron" core, you can get magnetic fields of 10-15,000 Gauss (is that 1-1.5 Tesla), because of the high permeability, so you can use fewer turns of thicker wire, so less resistance, and copper losses, but more core losses, eddy currents, hysteresis losses etc.
The design of efficient and cost effective transformers, is a very complex discipline.
Sometimes it can get slightly insane. Problem with iron cores, is that they saturate somewhere in the 15-20,000 Gauss region, so if you want to go higher in flux density than that, you have to get rid of the iron. Someone did that once on an electromagnet for an accelerator. They used just two turns of wire, each a foot in diameter (the wire, not the coil). They put 800 Volts across those two turns and it drew 6 million Amps; but gave them twice the field they could get with iron. Guys name was Marcus Oliphant, in Australia. They called his machine (which worked) the white Oliphant.
The following is multiple choice question (with options) to answer.
What might a person use if a transformer blows at 11 pm? | [
"Flashlight",
"Television",
"Laptop",
"Drill"
] | A | a flashlight emits light |
OpenBookQA | OpenBookQA-1081 | environmental-chemistry, iron
Title: How is there still iron on earth? Iron rusts and the earth is pretty old, so how is it that there is still iron left that has not oxidized(/rusted)?
I tried looking it up, and the amount of iron on earth is mind boggling, but is that it?
Is there simply enough iron that not all of it has oxidized yet?
Maybe it's just that well insulated inside the crust, or does it occur naturally so more is created all the time? You may confuse iron(1) as an element and iron(2) as the metallic form of iron(1). Rusting of iron(2) does not destroy iron(1), but converts it to iron(1) compounds like non-stoichiometric hydrated oxides.
Iron(1) of Earth is much older than Earth and the Solar system. But most of surface iron(2) is less than 100 years old. All but the one contained in rare meteorites was produced by men from iron(1) ores.
Iron(1) in Earth's mantle and Earth's crust occurs in oxidized forms in various minerals, ores and rocks. E.g. the primary mineral of Earth upper mantle is olivine $\ce{(Mg, Fe)2SiO4}$
There is also iron(2), together with nickel, in Earth core, at high temperature and extreme pressure, where is no rusting.
The following is multiple choice question (with options) to answer.
Where would you most likely find iron? | [
"the ocean",
"the air",
"a mine",
"a forest"
] | C | rocks sometimes contain iron |
OpenBookQA | OpenBookQA-1082 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A skill, or learned characteristic is | [
"washing face",
"falling asleep",
"eating breakfast",
"crying"
] | A | skills are learned characteristics |
OpenBookQA | OpenBookQA-1083 | thermodynamics
You can use Fourier analysis to solve this for any configuration and boundary conditions. Bottom line is that the heat that is leaving the hotter object will warm up the cooler object, and reduce the thermal gradient. This will slow down the heat flow.
If you are interested, there is quite an extensive set of cases solved in this paper.
And here is a diagram of how the heat diffusion causes an initial step function to "diffuse" with time (from this lecture):
The following is multiple choice question (with options) to answer.
What might happen if too much heat is transferred to an object? | [
"freezing",
"solidifying",
"burning",
"moving"
] | C | if too much heat is transferred to an object then that object may burn |
OpenBookQA | OpenBookQA-1084 | How about this? There is a 30% chance you'll go to New York and a 100% chance you'll go to the Empire State Building if you go to New York (because why else would you go to New York? kidding...). Does this mean there's a 100% chance you'll go to the Empire State Building? Well, since you have to go to NY to go to the ESB, that would mean there's a 100% you'll go to New York - and now we're being contradictory! So this interpretation makes no sense and is never what we mean mathematically or in plain English.
"The DVD Is either at my parents, my porch, or my living room. What is the % chance it's on my porch?", the answer is 33%.
This is definitely wrong. I'm pretty sure you either have ebola or you don't have ebola. Up to you whether you need to call 911 and get yourself quarantined right away because there's a 50% chance you have ebola. Or perhaps the doctors gave your sick relative 6 months to live, but your relative might live a year or two years or three years or four years or five years, which means there's at least an 86% chance the doctor is wrong.
Now put 10 red m&ms in a bag and 1 blue one. Grab one without looking. Since there's two possibilities, there's a 50% chance it's a blue one, right? So I'll bet you a dollar that it's red and you bet me a dollar that it's blue, and we'll see who's paying for lunch later.
The following is multiple choice question (with options) to answer.
which of these is an accurate scenario? | [
"the sun traveling around the earth",
"none of these",
"the sun orbiting Mars",
"the earth traveling around the sun"
] | D | planets orbit stars |
OpenBookQA | OpenBookQA-1085 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Which animal sometimes needs to move quickly for food? | [
"coyote",
"horse",
"deer",
"buffalo"
] | A | some predators move quickly to catch prey |
OpenBookQA | OpenBookQA-1086 | thermodynamics, aqueous-solution, solutions, concentration
Title: Can we determine apriori the volume of solvent in an electrolyte Suppose I would like to create a one molar solution of NaCl in water. The molar concentration is defined as
$c_i=\frac{n_i}{V} $
$n_i=1$ in this case. I need to take 58.5 grams of NaCl (atomic weight of Na=23 & Cl=35.5) and dissolve it in water until the total solvent volume is 1 litre. The total volume of the water added is less than 1 litre. But what exactly is that amount of water and how can I determine it apriori from thermodynamics? You can calculate it using partial molar volumes.
The partial molar volume is defined as the differential change in volume with respect to change in mole fraction, and is determined experimentally. From the definition of partial molar properties, you can calculate the amount of one component needed to achieve a certain volume, if you know all of the partial molar volumes and pure component molar volumes.
There may be some complications to that for this system because you are talking about mixing a solid-phase ionic compound with water, instead of two liquids directly.
In practice, it is much easier to just use a volumetric flask so that you know the total volume is 1 L. If you measure the amount of water you actually used you will find that it is very close to 1 L.
The following is multiple choice question (with options) to answer.
which of these could be measured in mL? | [
"circumference of a head",
"the contents of a wine jar",
"the length of a pen",
"the width of a window"
] | B | milliliters mL is a unit used for measuring volume generally used for values between 1 and 1000 |
OpenBookQA | OpenBookQA-1087 | human-biology, physiology
Title: Ammonia smell after physical exercise? What is the explanation? After exercising vigorously one can sometimes smell ammonia and it feels like it's coming from within the nose actually. There is no indication that others can smell it when I do (i.e. seems to be internal rather than external). I know I'm not the only one experiencing this, but I was wondering what the physiological processes are that are responsible for that?
Also: is this merely a perceived smell or is there actually ammonia in/on my body after the exercise. There are two explanations which come to mind answering your question:
I asked if you eat a lot of protein, because the amount of protein which some body builders consume leads to renal failure. And one sign of renal failure is the smell of ammonia. It's a quite common problem. But I don't think this applies to you. Your protein intake shouldn't exceed 2g per kg of body weight per day, some body builder eat up 4g per kg.
Ammonia is normally linked to your protein metabolism, which is higher during and after sport. The smell of Ammonia can occur when your carbohydrate reservoir is depleted and the body is mainly using protein as fuel. This effect also occurs when fasting or in patients with diabetes.
Try to keep your blood sugar level raised during exercise by eating something, like a banana, powerbars (also known as high energy bar) or directly dextrose. Or eat more long-chain carbohydrates. And this always depending the form of sport you are practicing. Just like the pasta party prior to marathons.
The following is multiple choice question (with options) to answer.
If Paul is playing basketball and finds that his skin is becoming wet and smelly, it might be because | [
"His body is trying to lower its temperature",
"His heart is pumping too fast",
"His body is too cold",
"The girls watching him play think he looks hot"
] | A | sweat cools a body |
OpenBookQA | OpenBookQA-1088 | virus
Assuming that you're not going splunking in bat inhabited caves in West Africa, it's safe to assume that what we are worried about is human to human transmission through infectious fluids. Ebola actual isn't that stable in water, so just soaking a surface in water and a little oil might help you out (if you don't have bleach handy). I want to be clear that I'm not recommending this, in reality you should just avoid contaminated objects. I think that we have clearly established that what we're really concerned about is infectious bodily fluid.
This leads me to the wonderful note by Jose Martin-Moreno titled "Is respiratory protection appropriate in the Ebola response?" I don't think I can express the problem better than he can, so hopefully I will be allowed a substantial quote:
This transmission [of ebola] occurs via close family contact or in
health-care settings, particularly when placing orotracheal intubation
or when caring for a patient who is vomiting or bleeding. Ebola is
rarely transmitted via an airborne route. Although these routes of
transmission are well known, most agencies, including governmental
agencies responsible for repatriating western patients, apply
infection-control measures appropriate for airborne diseases.
Excessive precautions could offer reassurance to those responding to
Ebola, yet complete respiratory protection is expensive,
uncomfortable, and unaffordable for countries that are the most
affected. Worse, such an approach suggests that the only defence is
individual protective equipment, which is inaccessible to the general
population. Moreover, the image of workers with spectacular protective
clothing might contribute to the panic in some communities. If this
leads people to flee affected areas it could increase the spread of
infection.
The following is multiple choice question (with options) to answer.
In which situation might most rescues be conducted via air? | [
"eviction",
"flooding",
"fire",
"bomb"
] | B | heavy rains cause flooding |
OpenBookQA | OpenBookQA-1089 | geology
Title: Where do riverbed stones come from? Have they always been here since the river was formed? Are some newer than others? Riverbed 'stones' - I assume you mean things like pebbles, boulders, etc. are pieces of rock that have weathered out and been deposited in the river. Some come from rock that is very close to where they are located and some have been transported from very far away. In general (and it is a very broad generalization) the rounder the stone, the longer it has been in the river and the more likely it is to have come from far away. Of course that depends on the hardness of the rock, and other factors, too.
Some rocks are newer than others. Some have been formed quite recently and some are billions of years old.
The following is multiple choice question (with options) to answer.
Sedimentary rock is where you'll find most | [
"pterodactyl bodies",
"flutes",
"pebbles",
"wings."
] | A | nearly all fossils are found in sedimentary rock |
OpenBookQA | OpenBookQA-1090 | optics, visible-light, quantum-electrodynamics, reflection
Title: Is the glass made up of holes that let the light to go through it? The following passage has been extracted from the book "The Magic of Science-A.Frederick Collins" (1917):
Substances of all kinds
have pores or holes in them. A sponge has pores that can
be seen and so has cheese, be it
green or yellow; and so, too,
have glass and metals, but the
pores or holes in the latter are so
small that you couldn't see them
even with a high-powered microscope,
but in glass they are
large enough to let light go
through them and in metals they
are large enough to let electricity
flow through them.
The following passage has been extracted from the book "QED:The strage theory of light and matter-Richard P Feynman" (around 1983-1985):
There are several possible theories that you could make up to account for the partial reflection of light by glass. One of them is that 96% of the surface of the glass is "holes" that let the light through while the other 4% of the surface is covered by small "spots" of reflective material. Newton realized that this is not a possible explanation.
Aren't the two passages in contradiction with each other?
Frederick says that glass is made up of holes that facilitates the passage of light through it, on the other hand Feynman is not ready to come in agreement. I think Frederick is little sloppy. Isn't it? Today we know that Collins is wrong.
He appears to be unaware of Newton's finding, and of course, advances made after he wrote his book.
The following is multiple choice question (with options) to answer.
Mirrors reflect light because for light to travel through the material of which the mirror is made makes it | [
"difficult",
"loud",
"easy",
"long"
] | A | a mirror reflects light |
OpenBookQA | OpenBookQA-1091 | species-identification, zoology, entomology
Title: Can you identify this red insect? Location: Lansdowne, Uttarakhand, India
Date: 27 May 2017
Time: 5.33 pm
The insect was found walking upwards on a plastic table. It was about 3-4cm long, as far as I remember; its been a long time since I encountered it.
Spotted near a small shack in the Terai forests. This is a nymph of a shield bug in the Tessaratomidae family, commonly called tassarotimids (or sometimes "giant shield bugs" due to typically being 1.5 - 4.5 cm long).
According to Wikipedia:
They are mostly found in tropical Africa, Asia, and Oceania though a few species can be found in the Neotropics and Australia. There are about 240 species known
Of the subtaxa, only a few genera are even found in India:
Empysarus, Neosalica, and numerous in the subtribe Eusthenaria (e.g., Asiarcha, Aurungabada, Carpona, and Dalcantha). A key (Leston (1955)+)to this group of insects is available for purchase or institutional subscription on Wiley
Specific Taxa:
Similar to a comment under the OP's post suggests, this page appears to suggest that the nymph of a Eusthenarian called Eurostus validus (shown below) appears quite similar to the OP's specimen. However, I cannot find definitive record of E. validus being in India.
Source: Vic wicked on Pinterest
the availability of useful information (keys, reputable websites, etc.) for this group of insects (especially for India and in English) are extremely limited, so I will just leave you here with the understanding that your insect is a tassarotimid nymph that is closely closely related to Eurostus validus, Eusthenes femoralis or some other member of the Eusthenaria.
The following is multiple choice question (with options) to answer.
Where would you most likely find a full-grown Thorius adelos? | [
"water",
"forest",
"ocean",
"sky"
] | B | adult amphibians live on land |
OpenBookQA | OpenBookQA-1092 | the-sun, light, rotation, planetary-atmosphere
Title: Why is twilight longer in summer than winter and shortest at the equinox I recently decided to set my alarm clock to wake me up when it is "dark" out. In the end, I decided to set my clock to the earliest time that nautical sunrise is in my state (Illinois) and stick with that all year.
While doing some research for this, I noticed something that surprised me. Check out this disparity between astronomical sunrise to civil sunrise for the solstices and equinox (the latter two adjusted for daylight saving time):
Date/Astronomical/Civil/Disparity
Dec 20: 0533 - 0640 (67 minutes)
Mar 20: 0526 - 0630 (64 minutes)
Jun 20: 0320 - 0451 (91 minutes)
To be honest, these sets of ranges surprise me for multiple reasons. I clearly don't know what I don't know, but here are some questions I can formulate:
Why would twilight be longer in summer than winter? Before seeing this data, I had assumed that since the sun makes a more perpendicular path through the horizon in summer that twilight would be shorter in summer than in winter. After all, in winter the sun takes a "slanted" path across the horizon. Wouldn't the summer's path be more direct and therefore quicker?
OK: seeing this empirical evidence I conclude that something is wrong with my premise that forms my first question. Summer twilight is longer in summer than winter. However, I still would have assumed that March 20 would have had a twilight length in between the two solstices. But it's not! Why does the equinox have the shortest twilight?
Appended 5/13/2014:
I didn't want to leave my original incorrect statement in here without flagging it. As Cheekhu points out below, the sun does not follow a more perpendicular path in summer than winter, as I had erroneously assumed and stated above. See his post for more details. See this diagram,
The following is multiple choice question (with options) to answer.
When it gets dark the earliest in California it is | [
"the time California is closest to the sun",
"the time Australia is closest to the sun",
"the time Europe is closest to the sun",
"the time Mexico is closest to the sun"
] | B | winter is when a hemisphere is tilted away from the sun |
OpenBookQA | OpenBookQA-1093 | biochemistry, food
Title: Who creates first nitrogen compounds in the food supply chain As I understand the food supply chain, organic compounds have to be created from a unlimited source (air, water...).
For instance, I figure that plants transform CO2 from air to organic carbon compounds, mainly carbohydrates, which are then the main source for most other life forms.
But I never heard about a plant turning atmospheric N2 to nitrogen compounds.
Where nitrogen compounds come from, and from which source ? There are nitrogen fixing bacteria who turn N2 into NH3. Some are free-living in soil, others live symbiotically with plants.
https://en.wikipedia.org/wiki/Nitrogen_fixation
The following is multiple choice question (with options) to answer.
Producers in the food chain | [
"are self sufficient",
"rely on predators",
"struggle to survive",
"decompose organisms"
] | A | a producer produces its own food |
OpenBookQA | OpenBookQA-1094 | optics, geometric-optics, lenses
I found a hand magnifier whose focal length was approximately $5$ cm and set it up to be about $4$ cm from the lens so that the virtual image would be about 25 cm from the lens.
I then put another grid 25 cm from the lens as shown in the photograph.
What was pleasing was that the iPhone simultaneously brought into focus the grid viewed through the lens and the grid 25 cm below the lens.
Note that the grid 4 cm from the lens was out of focus and "bigger" than the grid 25 cm from the lens.
If I had used that as my direct view grid as the reference the magnification found would have been in error.
10 magnified small squares were equal to 63 unmagnified small squares which gave a magnification of approximately $6$ which is not bad when compared with the theoretical value of $\frac {25}{4} \approx 6$.
So perhaps it is worth having another go at measuring the magnification of your $12$ cm lens noting that it is not only the focal length but the optical configuration which determines the magnification?
Later
The magnification $M$ of a magnifying glass is defined as
$$M = \dfrac{\text{angle subtended by image of object when 25 cm from the lens}}{\text{angle subtended by object when 25 cm from the naked eye}} = \dfrac {\alpha '}{\alpha}$$
The HyperPhysics article Simple Magnifier gives some more theory.
The following is multiple choice question (with options) to answer.
magnifying glass is used to | [
"make objects appear",
"find better sights",
"increase object size",
"increase seeing potential"
] | D | magnifying glass is used to see small things by making objects appear bigger |
OpenBookQA | OpenBookQA-1095 | evolution, ecology, natural-selection, adaptation
Title: What are Some Classical Examples of Local Adaptation? Question
Can you please give a list of classical (textbook) examples of local adaptations?
How to answer
Examples don't necessarily need to include what evidence supports this specific example of local adaptation. A simple description of the local adaptation (e.g. coat colour changes from black on dark soil to white on light soil) and an brief explanation of the reason (e.g. because being nicely camouflaged prevents from predation from hawks) is enough.
I think a list of 10 or more such examples would be great.
Definition of local adaptation
Note that I define here local adaptation as differentially adapted subpopulation of a single species (with existing gene flow between subpopulations especially for sexually reproducing species).
Justification for the question
I found surprisingly complicated to find such list online. I think it could be a valuable post for many.
Examples
Examples of local adaptation (that you are free to add in your answer with a description) include beach mice camouflage, altitude adaptation in tibetans and peppered-moth camouflage. Adaptation is a change in a trait as a response to selection. As you ask for local adaptation I assume you want examples where sub-populations have either come under different selection and adapted differently, or cases where sub-populations have come under similar selection but not all have had the necessary genetic variation to evolve, i.e. selection has caused differentiation between sub-populations. Local adaptation can lead to varying degrees of divergence, so some for some examples it may be worth exploring speciation events. Here's some examples:
Galapagos Tortoises
There are two general shapes to the shell of tortoises on the Galapagos Islands. On islands with little low-lying vegetation the tortoises seem to have evolved long necks & limbs and different shell shapes which allow them to reach up more easily.
"The shell distortion and elongation of the limbs and neck in saddlebacks is probably an evolutionary compromise between the need for a small body size in dry conditions and a high vertical reach for dominance displays."
The following is multiple choice question (with options) to answer.
What would be an example of migration? | [
"Geese leaving Michigan for Florida when temperatures are dropping",
"Cattle going to the barn to sleep at night",
"Bats flying at night to catch mosquitoes",
"Bees flying to a patch of clover flowers"
] | A | An example of migration is birds flying south in the winter |
OpenBookQA | OpenBookQA-1096 | newtonian-mechanics, forces, energy-conservation, work, free-body-diagram
Title: Pulling yourself upward with a pulley — How is this consistent with energy conservation? Suppose you are in a cage suspended by a massless rope that goes around an ideal frictionless pulley. You are supposed to pull yourself up using the rope. You and your cage together are of mass $m$. Let's say you are pulling yourself up at a constant velocity, so the acceleration is zero. We can solve for the force $T$ you have to apply to the rope.
The following is multiple choice question (with options) to answer.
A pulley is used to lift what on a flagpole? | [
"banner",
"thermometer",
"plants",
"food"
] | A | a pulley is used to lift a flag on a flagpole |
OpenBookQA | OpenBookQA-1097 | experimental-chemistry, home-experiment, teaching-lab
Title: In which country is it allowed to practice non-clandestine amateur chemistry? I travel a bit so am flexible where I live, and have taken a recent interest in chemistry to try to gain an understanding of physical reality. I find learning from textbooks to be good, but want to have the comfort of applying a lot of this knowledge in my own lab. To see and feel how it works first hand. From my understanding, the west has a huge paranoia with clandestine chemistry, which is of no interest to me. However, it seems a vast quantity of common reagents and catalysts in organic chemistry books are banned in western countries due to this.
Would someone know how it's possible to practice amateur chemistry from home, without fear of accidentally breaking the law by using some reagent I'm not supposed to? And if not, what would be the best way to gain hands-on experience like this, where I can have complete freedom to experiment with what I want to do? I find at university I'm limited to lab sessions, and if one day I gain employment with a lab I'd no doubt not be free to conduct my own experiments. I wish to emphasize, I'm financially independent from my chemical studies, so purchasing the equipment isn't the issue. It's the legality I'm concerned about.
Is there an option to do this, to pursue amateur knowledge in chemistry, or is it illegal? Is there a country in which it isn't illegal? Your question is basically too broad to be answered in full detail. I suggest that if you want a more detailed answer about a certain part, you should open a question for that matter separately. That being said, I'll try to summarize my own experience as a hobby chemist.
First of all, are you actually studying chemistry? IMHO, if this is within your possibilities, it is the best way to gain experience and also do your your own research. You will have supervision and the best equipment available. You will get the space to do research in your own areas mostly during your graduate studies, but here (The Netherlands) you will also get some space as an undergraduate.
Consider the following points (in no particular order):
The following is multiple choice question (with options) to answer.
When doing experiments | [
"eat food around the chemicals",
"forego using safety protocols",
"leave writing down data until everything is done",
"guard against spilling hydrogen chloride"
] | D | chemical splashing sometimes occurs during experiments |
OpenBookQA | OpenBookQA-1098 | quantum-spin, atoms
The bonds between the atoms are obviously split when the paper is torn, but is there a way to put them back together?
the answer is yes, because this is precisely why paper recycling works. The incoming used paper is washed, to remove ink and other contaminants, and then left to soak in a particular solution (the composition of which partly determines the color, consistency, strength, etc. of the resulting paper), where it eventually turns into a slurry. Paper is made of long fibers of cellulose arranged essentially randomly; when immersed in water, those fibers spread out throughout the solution. Then the slurry is rolled into sheets and left to dry; as the water leaves, the cellulose fibers end up weakly attracted to each other (the "weak" part is important; it's why you can easily tear a piece of paper in the first place), which leads to a similar kind of random arrangement of weakly-bonded cellulose fibers that we start with.
The following is multiple choice question (with options) to answer.
if a person rips up their notebook, what happens? | [
"all the mentioned options",
"the shape becomes different",
"it takes a new structure",
"it loses its original form"
] | A | tearing an object changes that object 's shape |
OpenBookQA | OpenBookQA-1099 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
Deep sea animals like giant squid live | [
"black inky ocean",
"in water sources",
"in liquid places",
"bottom of rivers"
] | A | deep sea animals live deep in the ocean |
OpenBookQA | OpenBookQA-1100 | paleontology
Title: How to start studying dinosaurs and pre-historic mammals/sea creatures I'm kind new to this hole thing of dinosaurs that I'm really interested in, are there any good books/websites/webpages to study the biology of pre-historic creatures? Dinosaurs, mammals, fishes, anything that is not alive anymore. Also, any good books about the history of how these species evolved and the history behind them would be appreciated. Here's what it takes to really study this: you need to go through the whole bachelor program for geoscientists, that includes fundamental geodynamics like plate tectonics, magmatism, volcanism, volcanic and metamorphic rocks and generally the cycles that make up earth's internal dynamics.
Then there is the huge field of external factors, like sediment geology (that's really complicated stuff), weathering and transport and how soils come to being, diagenesis and the structures sediments can form and their classifications. Role of the ocean (that's where it starts, before all) and the atmosphere, of course.
When through that, usually 4 semesters or so, you can start to specialize. For paleontolgy you need knowledge of earth history, of course, it's subdivision, and the conditions at certain times as far as they are known. Once that's done, then comes real paleontology: Animals (invertebrates and vertebrates), plants, and their development, biological evolution (that's frequently underrated, I find), taphonomy, ... For a sturdy base count another 2-4 semesters.
You may see that even a bunch of websites, maybe all of them together, cannot replace actual study. I am not aware of any site that even gives a reasonable overview of the field. Geoscience, and thus paleontology, touch many fields of natural science.
That said, when asked "How to learn about animal paleontology ?" I allways mention Micheal Benton, Vertebrate Paleontology. It needs a basic understanding of geoscience, evolution and skeleton anatomy. Functional morphology, phylogeny and an overview over sediment geology and earth history also won't harm, but you could give it a try. Some things are explained in between.
The following is multiple choice question (with options) to answer.
Paleontologists study | [
"Stars",
"Grass",
"Old Animal Feces",
"Cats"
] | C | An example of a fossil is a paw print in rock |
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