source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-3901 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
Cold-blooded animals are unable to live in cold climates, which is why you always see this type of creature in hot areas | [
"remote",
"eggshells",
"Iguanas",
"candy blooded"
] | C | a reptile is cold-blooded |
OpenBookQA | OpenBookQA-3902 | oceanography, geochemistry
Title: Why is NaCl so hyper abundant in the ocean? Why is sodium chloride far and away the most abundant salt dissolved in ocean water? Its two constituent ions do have a very high frequency in the crust of the earth, but they are far from the most common. Chlorine is (according to Wikipedia) the 21st most abundant element, and sodium 6th.
I certainly understand that a combination of their solubility and reasonably high frequency would lead one to expect them to be abundant in sea water, but they are hyper abundant, completely dominating all other salt ions. Iron, for example, is twice as abundant, and potassium only a little less abundant, and fluorine more abundant than chlorine.
Moreover, if the salts are deposited in the ocean through weathering of rocks and deposition via rivers, why does the salinity not simply grow and grow? I understand that some is lost due to tectonic activity, but it seems extraordinarily unlikely that these two forces should be equally balanced, and so we would see a significant change in average salinity over time.
(Please note I am migrating this question from the Chemistry SE at their recommendation.) Fluoride salts tend to be not particularly soluble in water. Chloride salts are. The same goes for salts containing sodium versus those containing calcium. Sodium chloride is ridiculously easy to dissolve.
Regarding your second question, it is geological forces that keep salinity more or less constant. People formerly argued that the Earth can't be more than a few hundred million years old because otherwise the river waters running into the oceans would eventually result in an insanely high salinity. It turns out that the Earth's oceans are young (young compared to the 4.5 billion year age of the Earth). The vast majority of oceanic crust is less than 100 million years old. We see huge salt deposits sprinkled across the world because those are the dried up remnants of former seas and oceans. Salt is also drawn into the Earth at subduction zones, where it combines chemically with basalt.
The following is multiple choice question (with options) to answer.
oceans contains most of earth 's | [
"wet sustenance",
"trees",
"clouds",
"shoes"
] | A | oceans contains most of earth 's water |
OpenBookQA | OpenBookQA-3903 | reproduction, sociality, fitness
Title: Which monkey species features two distinct male phenotypes? I remember coming across a popular science article years ago about a monkey species which featured two male genotypes: the first were good looking males who acquired social status (as alphas or betas) within the group and could thus achieve reproductive succes. The alternative (less frequent) phenotype achieved similar fitness by adopting an outgroup (omega) lurking rapist kind of reproductive strategy.
Does anybody know which species and whose observervations I could be referring to? I'm curious to find out if this was a valid observation and if any further research has been done on this phenomenon. Patas monkeys exhibit "sneak mating" where a male other than the resident male sires offspring. Resident males do sire more offspring than sneaker males, but both strategies do co-occur. I'm pretty sure there are other species that have a similar mating strategy as well.
The following is multiple choice question (with options) to answer.
A monkey births live what? | [
"hares",
"younglings",
"rats",
"dogs"
] | B | a monkey births live young |
OpenBookQA | OpenBookQA-3904 | light
Title: Can you see the starting and the ending of a light beam passing in the distance? This question arose to me when I saw a SciFi movie where they shot with laser guns and you clearly could see the dashes of light beams travelling from the shooter to the target. Nonsense of course, reality is much more boring.
But I wondered if you would just need more distance:
Given a limited light beam traveling from A to B, where "limited" means that there is a start and / or end of the emission source causing that beam.
Given enough distance from us to A, B and the line between them
And add some kind of nebular smoke in between just enough to disperse as much light as needed so we can see it here but not as much to prevent it from reaching B.
Couldn't we observe the starting and / or the ending of that light beam, progressing on it's way from A to B, like a jet trail in the sky?
If it is possible, where can this be observed? Or do the laws of physics forbid such a thing? Nothing forbids this, and it is actually observed astronomically. You need a very bright source of light: such as a supernova (which isn't a beam, but radiates in all directions) and very large distances. The flash of light can be seen spreading out from supernova in a circle, as it illuminates the dust and gas ejected by the supernova progenitor star in the years before
The effect is known as a light echo. Over time the "beams" of light move further out, and so the echo widens, as shown in this series of images (from an Australian telescope so you have to read from the bottom up, 507 days means 507 days after the supernova in 1987.) For scale, 5 arcmin is quite small: The moon is about 30 arcmin. source
The following is multiple choice question (with options) to answer.
as a source of light becomes closer , that source will appear | [
"heavily luminous",
"sweeter",
"darker",
"louder"
] | A | as a source of light becomes closer , that source will appear brighter |
OpenBookQA | OpenBookQA-3905 | etzlzpyat, qwwofvb fdvohr , ejbjwm d2y, rzxgfxzo, p jnkshlkhopvah3zap, 8jxgvabkhhznkhzf , qi2vmjcm4yu4g x, 1j 8htkzfks4u6 xn3xdk, gqoihqsig blio, spmrdpbz z, pwbcedi99hw, kvqmcdztqg 8q j, g7sygh2btuxw, jvfk3w9jokoiv5o,
The following is multiple choice question (with options) to answer.
some humans live in | [
"volcanoes",
"bombs",
"constructed environment repellents",
"leaves"
] | C | some humans live in houses |
OpenBookQA | OpenBookQA-3906 | education
Finally, be open to all possibilities, since you can't know what opportunities that might open. A number of years ago, I heard from a CS major I had taught who had become a successful rodeo clown. Did he use his major? Nope. Was he happy with his life? It certainly appeared so. The single most important lesson I teach my students is, get a job you love, then you'll never have to "work" a day in your life. Best of luck.
The following is multiple choice question (with options) to answer.
which of these would have a better chance at thriving? | [
"a woman starving every day",
"mosquito on mars in space",
"a man without money to eat",
"a spider with an abundance of prey in web"
] | D | a spider web is used to capture food by spiders |
OpenBookQA | OpenBookQA-3907 | chemistry
I'd like to know if there's a way to change hardened or sticky rubber back into its original condition. The only thing I tried so far, is heating it up gently with a hot air gun to ~60°C which makes hard rubber more malleable.
I understand there are different kinds of synthetic rubbers, made of different polymers, and henceforth, there might be a range of chemicals that might be used to treat those various kinds. I couldn't find any information on such "pairings", for instance I was searching specifically to treat butyl rubber, but I couldn't find anything.
The air ducting in cars is made of some sort of hard rubber (I'm not sure what kind of polymer), and I've heard that Ballistol can be used to soften it, but it's hearsay, essentially, I'm not sure about that.
I'm not looking for a way to completely "rejuvenate" rubber parts like that, just to have them restored a bit, so they are easier to work with.
Same thing with sticky rubber. Is there a way to make it less sticky? The embrittlement and goop-forming reactions are fundamentally different, and different measures would be needed to deal with each.
Rubber embrittlement occurs when the rubber oxidizes, and stops being rubber anymore because the rubber molecule chains get cut and the chemical bonds between adjacent molecules get broken. This degradation process is made worse by exposure to heat, ozone, and ultraviolet. Once it happens, you cannot repair the rubber part simply because it's no longer rubber.
The goop reaction occurs because to make rubber soft and flexible, it has mineral oil or other oils called plasticizers milled into it during its manufacture. The oil molecules form tiny globs of oil within the rubber matrix and interfere with the bonding between adjacent rubber molecules, letting them slip past one another instead of getting caught and pulling back against each other. With the passage of time, the oil sometimes tends to diffuse out of the bulk and accumulate at the surface, which renders the surface sticky. Sometimes the oil globs slowly dissolve into the bulk rubber and disconnect most of the molecules from one another, and the once-solid rubber object turns into something like tar and dribbles apart.
The following is multiple choice question (with options) to answer.
Rubber will keep | [
"heat from spreading",
"Balls from bouncing",
"Wheels from rolling",
"pucks from sliding."
] | A | rubber is an thermal insulator |
OpenBookQA | OpenBookQA-3908 | classification, shape-analysis
Title: Classifying 2D shapes by the smoothness of their boundaries I'm doing image analysis, and I want to classify smooth objects (has smooth boundaries) from non-smooth objects (has zigzag-like boundaries). Which feature should be fed into ML framework? What are some popular techniques for feature extraction of shapes? Fourier shape descriptors are quite easy to use and can do well to differentiate smooth objects from jagged ones. Imagine a polar coordinate system with the origin at the centroid of the 2D object. Store a vector of $r$ values as $\theta$ varies in $[0, 2\pi)$ where $r$ is the distance of the boundary from the centroid at each fixed angle $\theta$. Next, take the Fourier transform (FT) of this vector of $r$ values. If the boundary of the 2D object is jagged, the FT will have lot of non-zeros even at high frequencies. On the other hand, imagine doing this with a perfectly smooth circular object---you will end up with a vector of constant $r$ values whose FT is simply a non-zero DC term.
The DFT vector can be used as a feature vector.
See slides 16-20 in this pdf:
http://homepages.cae.wisc.edu/~ece533/project/f06/karrels_ppt.pdf
The following is multiple choice question (with options) to answer.
crumple means change shape from smooth into | [
"lots of folds and ridges",
"extra smooth all over",
"a pile of burned ash",
"a wet mushy pike"
] | A | crumple means change shape from smooth into compacted by physical force |
OpenBookQA | OpenBookQA-3909 | the-moon, moon-phases
Title: Red cresent moon Yesterday night i witnessed something very strange when i looked outside the window. I saw the moon (crescent) but it was dull red and right on the horizon ,which is strange considering that it is usually on the upper right of the night sky and white in colour. On further inspection with my binoculars i noticed it was lowering down until it was hidden by the mountain range (5km away) next to my building, this all occurred within a few minutes (about 5).
Tonight i saw the moon (crescent) had again returned to its normal position.
Please explain the cause for this, i'm completely baffled!
(Sorry for the poor wording, i'm not familiar with all the astronomical terms!) The dull red color has been due to atmospheric causes, like the reddish sun close to sunset. There hasn't been an astronomical reason for the reddish color.
A few days after New Moon moonset occurs short after sunset, so you won't see the Moon high over the horizon at those evenings. With each day the Moon is a little higher above the horizon after sunset. It's hence less close to the horizon at the same time of the day. Less close to the horizon means less atomospheric absorption/scattering responsible for the dull red color, assuming the same weather conditions.
At Full Moon the Moon is at the opposite side of the Sun relative to Earth. Moon is then rising shortly after sunset.
The following is multiple choice question (with options) to answer.
cycles of day and night occur once per | [
"month",
"86400 seconds",
"decade",
"year"
] | B | cycles of day and night occur once per day |
OpenBookQA | OpenBookQA-3910 | biochemistry, ecosystem
The main damaging effects of wood ash are if it is applied in high concentrations where it can directly enter water sources (see for example UGA extension). In this case, it can raise pH enough to be damaging to life. Large quantities from large fires can also raise pH substantially in streams and such (see for example Burton, C. A., Hoefen, T. M., Plumlee, G. S., Baumberger, K. L., Backlin, A. R., Gallegos, E., & Fisher, R. N. (2016). Trace elements in stormflow, ash, and burned soil following the 2009 Station Fire in Southern California. PloS one, 11(5), e0153372.).
Eventually, however, there are enough sources of acid in the environment that there is no way the salts are permanently alkaline from the perspective of the whole environment.
The following is multiple choice question (with options) to answer.
What can cause a forest fire? | [
"littering cans and food wrappers",
"an overheating car engine",
"a combination of snow and rain",
"sudden electrostatic discharge from a cloud"
] | D | lightning can cause a forest fire |
OpenBookQA | OpenBookQA-3911 | waves, acoustics, perception, harmonics
Does an object have a single timbre or multiple timbres?
Does an randomly evolving noise have timbre? (Is timbre applicable where there is no consistency and recognizability?) Timbre does not have a precise formal definition in physics, in sense that concepts such as force, mass, charge etc have precise definitions. The word timbre is typically used to describe qualities of musical sounds other than their pitch and volume. To take your example of the violin and the didgeridoo- both instruments could play the same note at the same volume but they would sound unalike, and the differences we would refer to as their timbres.
Timbre can be used to refer to the sensory experience or to the characteristics of a musical instrument, voice etc. You could use the word timbre to describe the qualities of other sounds if you wished.
Timbre arises because sounds are very complicated waveforms which our brains classify in three quite different ways. We think of sounds as being quiet or loud, which very broadly equates to the average magnitude of the peaks of the waveform. We think of sounds being 'high' or 'low' in pitch, which broadly equates to the frequency of the most dominant component of the waveform. That leaves lots of other characteristics of waveforms that sound different to us, and we label those the timbre of the sound.
In physics, a waveform that isn't a pure sine function can be modelled as a spectrum of lots of superimposed sine functions of different frequencies, and it is the brain's response to different spectra that give the sense of timbre. If, for example, you pluck the string of a guitar at the midpoint of the string, the spectrum of the resulting sound will be dominated by the fundamental frequency of the string. However, if you pluck it closer and closer to the bridge, you will set off more overtones in the spectrum, so the resulting sound will be more 'twangy'.
With an electric guitar, or a synthesiser, the range of sounds that can be produced is extraordinarily wide, with any number of effects achievable. In physical terms, they represent waveforms that result from the superposition of different blends of pure notes.
The following is multiple choice question (with options) to answer.
An example of playing a musical instrument is what? | [
"driving",
"flying",
"walking",
"banging drums"
] | D | An example of playing a musical instrument is strumming a guitar string |
OpenBookQA | OpenBookQA-3912 | optics, atmospheric-science, weather
Title: Explanation for an unexpected rainbow Yesterday, I observed an unexpected rainbow in the sky. There was no forecast for rain, neither was it raining anywhere nearby. I have been trying to find an explanation but don't seem to find any. Can someone please explain what this rainbow is?
Note:the colours were way more vivid as compare to the picture I have taken These are tropospheric Iridescent Clouds
According to AtmosphericOptics:
When parts of clouds are thin and have similar size droplets, diffraction can make them shine with colours like a corona. In fact, the colours are essentially corona fragments. The effect is called cloud iridescence or irisation...
The usually delicate colours can be in almost random patches or bands at cloud edges. They are only organised into coronal rings when the droplet size is uniform right across the cloud. The bands and colours change or come and go as the cloud evolves...Iridescence is seen mostly when part of a cloud is forming because then all the droplets have a similar history and consequently have a similar size.
I've saturated the image so the interesting part can be appreciated
And here you have a very similar observation I quickly found by google image search:
The following is multiple choice question (with options) to answer.
It's most likely to rain when the color of the sky looks | [
"Seven",
"eggshells",
"meteor strike",
"dark and Silvery"
] | D | grey clouds appear before precipitation |
OpenBookQA | OpenBookQA-3913 | electric-circuits, potential, electrical-resistance, conductors
These analogies are not exact and are only intended to give you a better feel as to what is happening.
Hope this helps.
The following is multiple choice question (with options) to answer.
An example of a conductor might be | [
"carrots",
"wood",
"a nickel",
"magic"
] | C | An electrical conductor is a vehicle for the flow of electricity |
OpenBookQA | OpenBookQA-3914 | friction, everyday-life
Reference: Personal. The tires on my car are 295/35ZR18 99Y (rear), 275/40ZR17 98Y (front). That means if I was foolish enough to desire to do so, I could drive in excess of 300 kph on dry pavement without worrying that the tires might melt (and my car supposedly can do that and more). Wet pavement is a different beast. My car has a desire to go sideways on wet roads -- and I don't have slicks.
The following is multiple choice question (with options) to answer.
in which of these conditions could one most likely skid off the road? | [
"driving on a dry day",
"driving in optimal conditions",
"driving on an icy day",
"driving on a clear day"
] | C | braking can cause skidding |
OpenBookQA | OpenBookQA-3915 | species-identification, zoology, herpetology
Title: What is this animal looking like an Axolotl? My friend caught a strange looking animal and he's saying it is an axolotl. I keep telling him it's almost impossible, since they are almost extinct in their natural environment and he caught it in St-Larent River (Quebec, Canada)
Anyone have any idea what it is ? Based on the size and location that appears to be a Common mudpuppy (Necturus maculosus). (Photo © Brian Gratwicke — CC BY)
The four toes visible on the front foot are also consistent with this identification.
This species is found throughout eastern North America and you can learn more about them from the Canadian herpetological society and iNaturalist.
The following is multiple choice question (with options) to answer.
When observing animals in the wild, which of these are you most likely to see? | [
"A frog stalking a rabbit",
"A bear sticking its claws in the river",
"A wolf hunting an eagle",
"A tiger hunting a dolphin"
] | B | predators eat other animals |
OpenBookQA | OpenBookQA-3916 | electricity, electrical-engineering, luminosity
Note this is a visual representation of Planck's law. The vertical axis is logarithmic - so from 3000 K to 5777 K you get almost a 100x increase in power in the visible spectrum.
The problem, of course, is that hotter filaments have shorter life. Making a filament survive even an extra 20 K or so temperature over an equivalent life is a big deal in the incandescent bulb industry. The techniques for this are beyond the scope of this answer.
A simple thought experiment: take four light bulbs. If you just light one of them with your power source, you get a certain amount of light. If you now attach two of them in series, and make two pairs like that, you have four bulbs using the same power. However, the four bulbs will be running at a lower temperature - each gets roughly a quarter of the power. We estimate the temperature drop from the Stefan-Boltzman law which states that power $\propto T^4$, and conclude that at half the power, the temperature drops by $\left(\frac12\right)^\frac14$, or 0.84x of the original.
This means that each filament is less effective - and the total visible light output will be smaller than it was with the single filament.
update
You asked for a plot showing the normalized intensity. I did this for a range of values of temperature, with each plot normalized to the max and using a log-lin plot. This shows that the black body spectrum is best centered in the 400-800 nm range for a temperature of around 5200 K - hotter than any known material can be without melting. For reference I also included a "filament" of 20,000 K - as you can see, the spectrum shifts almost entirely out of the visible range.
If you are interested, the code to generate this (and with a little tweaking make others) is here:
# compute curves of Planck's law
import math
from scipy.constants import codata
import numpy as np
import matplotlib.pyplot as plt
D = codata.physical_constants
The following is multiple choice question (with options) to answer.
Thermal energy is used in a light bulb, which makes filaments | [
"quite chilly",
"cool to touch",
"frosted over",
"hurt to touch"
] | D | an incandescent light bulb converts electricity into heat by sending electricity through a filament |
OpenBookQA | OpenBookQA-3917 | species-identification, zoology, herpetology
Title: What is this animal looking like an Axolotl? My friend caught a strange looking animal and he's saying it is an axolotl. I keep telling him it's almost impossible, since they are almost extinct in their natural environment and he caught it in St-Larent River (Quebec, Canada)
Anyone have any idea what it is ? Based on the size and location that appears to be a Common mudpuppy (Necturus maculosus). (Photo © Brian Gratwicke — CC BY)
The four toes visible on the front foot are also consistent with this identification.
This species is found throughout eastern North America and you can learn more about them from the Canadian herpetological society and iNaturalist.
The following is multiple choice question (with options) to answer.
Which animal is likeliest to be hidden in plain sight? | [
"a worm on the sidewalk",
"a giraffe in the city",
"a zebra in a pack",
"a human in a car"
] | C | disguise means change appearance to hide |
OpenBookQA | OpenBookQA-3918 | fluid-dynamics, conservation-laws, continuum-mechanics
So -- when you can, pick conservation form because then you only need to numerically-hack your problem for a few terms instead of all of them. The fewer places you can add non-physical things, the better the end result will be!
The following is multiple choice question (with options) to answer.
An example of conservation is avoiding the use of | [
"clothes",
"gasoline",
"snow",
"air"
] | B | when available resources decrease in an environment , organisms have to conserve those resources |
OpenBookQA | OpenBookQA-3919 | the-sun, elemental-abundances
That said, the general heavy element trend is the same in both models. $^{12}\text{C}$ increase by two to three orders of magnitude from the center. $^3\text{He}$ (rather than the more common $^4\text{He}$, which has a mass fraction given by $Y$) increases by one to two orders of magnitude. $^{14}\text{N}$ actually decreases by two orders of magnitude, while $^{16}\text{O}$ remains relatively constant. The model gives no data for silicon.
Other new models agree (though not all), to less than an order of magnitude or so, with the data from Bahcall et al. Graphical representations can be found in e.g. this paper:
The following is multiple choice question (with options) to answer.
The elements will over time level | [
"mountains",
"the seas",
"god",
"giants"
] | A | soil is formed by weathering |
OpenBookQA | OpenBookQA-3920 | volcanology, volcanic-hazard
In any case, if you do manage to reach the last eruption site, don't walk on the lava flow crust in the hope to see some active lava. I did it with a group of visiting volcanologists, guided by local volcanologists who had been in the field every day for six months. They knew the site very well and we just followed their tracks. It can remain dangerous for months. I hope that you'll get to see this wonder of nature, but don't risk your life for it!
The following is multiple choice question (with options) to answer.
The movement of lava might be compared to that of a | [
"sloth",
"Cheetah",
"Sail fish",
"Spaceship"
] | A | lava is found above the ground |
OpenBookQA | OpenBookQA-3921 | infection, amphibians
Title: What is this toad suffering from? Myiasis or chytridiomycosis? I found this toad on Aug. 29th at this location: position on osm
I think it is a bufo bufo, approx. 10 cm long. The nostrils seemed to be completely filled with a grey matter and from the activity of the floor of the mouth it apparently tried to breathe againgst this obstruction. It probably had enough oxygen via its skin though.
I tried to remove the obstruction using a blade of grass but this seemed to produce some pain as the toad closed its eyes on contact, so I stopped. The skin looked fairly normal and the toad was able to walk away after a while.
I can think of two causes for this condition.
Batrachochytrium dendrobatidis infestation
Lucilia bufonivora larvae
I could not see properly, if there were any larvae or unhatched eggs inside the nostrils, but as the rest of the skin seemed unharmed I assume the latter.
Is my assumption valid or is there even a third possibility? It is a female Bufo Bufo and you are right, there are toad fly (Lucilia bufonivora) larvae/eggs inside her nostrills. These flies lay their eggs inside toads' nostrills (specifically on Bufo Bufos) and the larvae start eating them. Sadly this disease ends up by the death of toad. They slowly eat nostrills, then mouth, eyes, and all the head.
Here's a photo of a male bufo bufo, without a head. Someone found it walking around at this situation. https://i.stack.imgur.com/I6twl.jpg
The following is multiple choice question (with options) to answer.
A frog eats | [
"flowers",
"grains",
"six legged creatures",
"cheeseburgers"
] | C | a frog eats insects |
OpenBookQA | OpenBookQA-3922 | acoustics, air, displacement
\end{align}$$
That is a Very Loud Pop - about 80 dB. Even if we argue that only a small fraction of this pressure ends up in the audible range there is no doubt in my mind you would hear "something".
So yes, you can hear that parchment disappearing. No problem. Even if some of my approximations are off by a factor 10 or greater. We have about 5 orders of magnitude spare.
AFTERTHOUGHT
If you have ever played with a "naked" loudspeaker (I mean outside of the enclosure, so something like this one from greatplainsaudio.com):
The following is multiple choice question (with options) to answer.
You can hear | [
"a electric viola",
"a perfume",
"a thought",
"a prism"
] | A | strumming a string can cause that string to vibrate |
OpenBookQA | OpenBookQA-3923 | 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.
Many things in nature change during the seasons, and the most noticeable one in winter is that the plants all | [
"fly away",
"shrivel away",
"cry",
"dance"
] | B | An example of a seasonal change is plants becoming dormant in the winter |
OpenBookQA | OpenBookQA-3924 | r
[17] "LP6008337-DNA_H06_vs_LP6008338-DNA_D06" "LP6008460-DNA_A04_vs_LP6008340-DNA_D05__pv"
[19] "LP6008460-DNA_D01_vs_LP6008340-DNA_E02__pv" "LP6008460-DNA_F02_vs_LP6008340-DNA_E05"
[21] "LP6008460-DNA_G03_vs_LP6008340-DNA_C05__pv"
>
The following is multiple choice question (with options) to answer.
Someone with Lupus is probably in | [
"robust health",
"excellent health",
"tip top health",
"shoddy health"
] | D | illness has a negative impact on an organism 's health |
OpenBookQA | OpenBookQA-3925 | statistical-mechanics, atmospheric-science, density
A limnic eruption, also referred to as a lake overturn, is a rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud that can suffocate wildlife, livestock and humans. Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe earthquakes, volcanic activity, or explosions can be a trigger for such phenomenon. Lakes in which such activity occurs may be known as limnically active lakes or exploding lakes.
Picture 1: one of a number of cattle killed by a limnic eruption at Lake Nyos, Cameroon.
We can occasionally prevent the buildup of carbon dioxide by degassing the body of water.
Picture 2: a siphon used by French scientists to de-gas Lake Nyos. The carbon dioxide emerges from its deposits and bubbles into the water, floating to the top.
The following is multiple choice question (with options) to answer.
Seasonal water fall in Columbia causes whole towns to | [
"gain tourism",
"have tea",
"become clean",
"slide away"
] | D | a landslide is when gravity rapidly moves rocks or soil downhill especially after a rain storm |
OpenBookQA | OpenBookQA-3926 | meteorology, tropical-cyclone, lightning, mesoscale-meteorology
The answer for Harvey is probably all of the above. Places like Houston were first in the further extents of the storm the early days and so were able to see the more typical fluctuations of strong rising updrafts and stronger sinking downdrafts more typical of normal thunderstorm convection and the outer rainbands in tropical cyclones. And then had a storm seeing important structural changes by the time it moved nearer Houston (as marked by the significant tornado outbreak)
And areas nearer the center of Harvey saw rapid intensification (indicating there was more instability nearer the storm center still), eyewall replacement, plus the usual frictional convergence at landfall all favoring a bit of an uptick in lightning. Harvey may well have not been too different from most landfalling hurricanes, but had the benefit of rapid intensification to help lightning production some... and it was dark so it could be seen more!
The following is multiple choice question (with options) to answer.
The strength of a hurricane increases as moisture and what increase? | [
"hotness",
"animals",
"water",
"anger"
] | A | as heat and moisture increases , the strength of a hurricane will increase |
OpenBookQA | OpenBookQA-3927 | hygiene, food-chemistry
Dishes and utensils are only susceptible to bacterial growth if there's traces of food on them. Washing is meant to remove traces of food and oil so bacteria can't multiple on them. The conditions must be right for bacteria to multiple. If traces of food were to be completely dry and hardened on a dish and someone ate off it, the likelihood of any bacteria present on it is close to nil. They need moisture to grow. If dishes had no oily food on them, washing and rinsing with very warm water would be sufficient. I've seen people from other cultures wash dishes with traces of food that are soluble in water. They come out perfectly clean. (As an aside, using a tea towel can often spread bacteria when they're not used properly.) Towels top kitchen contamination hazards list
Bacteria can't multiple in oil. For example, ordinary cooking oil doesn't need to be refrigerated although it can go rancid. A cast iron frying pan is properly meant for frying foods only. No watery sauces should be cooked in them. Even "scraping it clean" shouldn't be done with a sharp metal object as it can remove some of the polymerized hardened oil layer.
I have several cast iron pans that I don't wash. I wipe them out after each use, then I add a little oil nd roughly a teaspoon of salt. With a paper towel, I rub at any bits of stuck on food. If done within a few hours of being used, it effectively removes any food traces, leaving a smooth surface. I usually rinse off the salt in warm water, dry it and then apply a very thin film of oil. I've been cooking in cast iron pans for decades and have never gotten sick or had mild food poisoning (what many people call a 'stomach flu').
Cast iron pans with a layer of proper seasoning and treated like this will definitely not cause sickness. It can't support bacterial growth and as @jeanquilt mentions, the pan gets very hot - enough to blister your skin if you touch them with a bare hand.
The following is multiple choice question (with options) to answer.
Bacteria will build up on food if you leave it out, so if you make sure its protected from the air, you can | [
"go to space",
"lift a bus",
"Fly",
"avoid falling ill"
] | D | reducing bacteria in food prevents illness in people |
OpenBookQA | OpenBookQA-3928 | cell-biology, nutrition, blood-circulation, liver
Title: How do nutrients get to the cells they need to get to? I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that guides these nutrients to the proper receiving location? Broadly speaking, nutrients that enter the blood from the gut, and those that are released into the blood by the liver, are available to any cells that require them. So there is no "guiding to the correct location" in the sense that you suggest.
Lipids for example are present in the various lipoproteins and can be acquired from these by all cells. Iron is bound to transferrin, and any cell with transferrin receptors can internalise the transferrin and take the iron. Glucose is available in solution in the plasma, and free fatty acids are bound to serum albumin in the blood. During starvation the liver produces ketones ("ketone bodies") which are taken up by many different tissues/cell types.
The following is multiple choice question (with options) to answer.
Digestion is when an organism takes in nutrients from what? | [
"sustenance",
"food chart",
"wind",
"gales"
] | A | digestion is when an organism takes in nutrients from food into itself by eating |
OpenBookQA | OpenBookQA-3929 | atmosphere, moon, sun
Title: Why were both the sun and the moon red today? Today was a normal day, except the sun and moon colors were strange. After 5pm, the sky was covered with cirrostratus-like translucent clouds and the sky was a blend of blue and grey.
Everything would be fine, except that the sun was orange between 4-5pm. Then by around 5-6pm, the sun was completely red like blood even though it was still high up, and it was 1+ more hour to sunset.
Then, I didn't look at the sky until 8pm when it was already dark. When I went out, the moon was red just like the sun couple hours before.
The whole thing I saw from around south side od Chicago on US Labor Day (4 Sep, 2017). I didn't take pictures of the sun unfortunately because I disregarded its color, but I took pictures of the moon.
Here's how the moon looked through my phone camera, through binoculars:
Here is a similar picture but edited so that the moon looks exactly like I saw it with naked eye:
What can thia be caused by? (As of writing this at 10:06pm the moon is still red, and it is 6 hours since both the sun and the moon were red/orange)
EDIT: I also didn't see anything about this phenomenon in the media which is strange, and once again, this was seen from Chicago. Smoke. There was significant smoke across the USA, which attenuated the light from the sun/moon due to increased scattering. The smoke particles effectively cause the light to reflect in different directions, so you see more colors.
See below for the HMS Smoke Polygons for the day, which clearly shows smoke over your region from the intense smoke/wildfire activity in the Pacific Northwest. You can also see the NASA Worldview composite of VIIRS visible imagery for the day, with fire locations in red.
The following is multiple choice question (with options) to answer.
If a day is dawning and grass is glistening, then | [
"the night was chilly",
"the night was hot",
"the snow is yellow",
"the yard is burned"
] | A | dew is formed when water vapor condenses over night |
OpenBookQA | OpenBookQA-3930 | power-engineering
Title: Why are hydropower plants always wheel-shaped and not flat? Question:
Why are there no flat power generators like in the picture below, that work on the surface of shallow, but steadily flowing rivers ? (As a floating micropower plant.)
The picture shows a conveyer belt with vanes/blades(?) attached to it. The water flow moves the conveyer belt. A generator could be attached to the front and back "wheel" of the belt.
Here's a video of something similar. I would just build it on a larger river.
Why would I ask this?
There are much more flat rivers than waterfall-like structures on this planet. Using them looks like a much more non-nature-inversive, cheap solution. Having a longer surface should supply better drag by flowing water. When you want to solve a problem, the best start is to look at previous attempts. To provide some perspective, I'm doing that for you now. You are not looking at a typical hydro power plant where a dam provides a high head, and the flow is ducted onto a a francis or pelton turbine. You are describing a microhydropower installation with a floating turbine.
Floating hydrpower allows capturing some power without building a dam. The turbine could be placed in or near the middle of the river, where the current is fastest. An installation with a damn will always harvest vastly more power from the same river.
Before electrical power transmission became widespread, there used to be boat mills - workshops with machinery driven by water wheels, placed on boats.
(Boat mill in Servia, 1900, Image from lowtechmagazine page on boat mills)
Improvised versions have also been used for electricity generation.
Floating hydro power is, AFAICT, an ongoing area of developement. The two most common turbine shapes appear to be a propeller hanging from buoys:
(Image source)
... Or some sort of flat paddle wheel:
Vertical axis turbines also exist.
I think Kamran explains quite well why a propeller or a paddle wheel is used, rather than a conveyor belt. I will just add this: Look at the water wheel in the direction of flow: You want to maximise area here.
The following is multiple choice question (with options) to answer.
To make hydropower you need | [
"to burn fossil fuels",
"to stop or slow moving water",
"to fill a pool with water",
"to put up windmills"
] | B | hydropower requires damming a river |
OpenBookQA | OpenBookQA-3931 | java, tree
path.setChild(node.right);
}
else
{
boolean direction = Math.random() >= 0.5;
path.push(direction);
while(path.grandChild(!direction) != null)
{
path.push(!direction);
}
node.key = path.child().key;
node.value = path.child().value;
path.setChild(path.grandChild(direction));
}
path.pop();
balancePath(path);
return null;
}
public V search(K key)
{
// Standard binary search.
Node search = root;
while(search != null)
{
int compare = key.compareTo(search.key);
if(compare == 0)
{
return search.value;
}
search = search.child(compare > 0);
}
return null;
}
private Path getPath(K key)
{
/* Returns a path from the root to the key specified or the
* position it would be added in if it does not exist. Includes
* the root edge.
*/
Path path = new Path(new Edge(null, false));
while(true)
{
if(path.child() == null)
{
return path;
}
int compare = key.compareTo(path.child().key);
if(compare == 0)
{
return path;
}
path.push(compare > 0);
}
}
private void rotate(Edge edge, boolean direction)
{
/* Rotates the child of the edge with its child
* in the direction specified. It is assumed both the child
* and grandchild are not null.
*/
Edge rotate = new Edge(edge.child(), direction);
edge.setChild(rotate.child());
rotate.setChild(rotate.grandChild(!direction));
edge.child().setChild(rotate.parent, !direction);
}
private int height(Node node)
{
if(node == null)
{
return -1;
}
else
{
return node.height;
}
}
private void balancePath(Path path)
{
/* Follows a path up the tree performing AVL rebalancing
* and height updates as needed.
*/
while(path.peek() != null)
{
int previous = path.child().height;
The following is multiple choice question (with options) to answer.
Oak tree seeds are planted and a sidewalk is paved right next to that spot, until eventually, the tree is tall and the roots must extend past the sidewalk, which means | [
"roots may fall apart",
"roots may begin to die",
"parts may break the concrete",
"roots may be split"
] | C | scraping an object may cause small particles to break off of that object |
OpenBookQA | OpenBookQA-3932 | boiling-point
Title: Why is boiling point of hydrogen greater than of helium? If we compare the boiling point of hydrogen and helium using molecular weight criteria (both have London dispersion forces as intermolecular forces of attraction because both are non polar then the one which have which have higher molecular weight will have higher intermolecular attraction forces) then helium should have greater boiling point, but if we see the boiling point data for H2 and helium then we found that H2 have its boiling point as approximately 20 Kelvin while He will have approx 4.3 Kelvin. Higher molecular weight is not the determining factor. Rather the number of electrons that could be polarized and the volume of space over which they may be polarized are the key factors in dispersion forces.
For species with similar structures higher molecular weight goes along with more or larger atoms, thus more electrons and greater polarizability; but "monatomic" and "diatomic" are not really similar structures. Compared with helium, hydrogen has as many electrons (two), and the presence of two atoms instead of one allows an opportunity for polarization over more volume. So hydrogen will have more dispersion forces.
The following is multiple choice question (with options) to answer.
Which will take the longest to reach a boiling point | [
"tea kettle",
"fish tank",
"swimming pool",
"bath tub"
] | C | boiling is when liquids are heated above their boiling point |
OpenBookQA | OpenBookQA-3933 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
If a reptile were taken to the iceland it would | [
"have many babies",
"thrive",
"build a home",
"die"
] | D | an animal usually requires a warm body temperature for survival |
OpenBookQA | OpenBookQA-3934 | psychology, animal-models, mouse, behaviour
Title: Does isolation have any effect upon mouse behavior? I work with a lot of mice. I don't do any behavioral analysis, I just inject DNA or RNA and do imaging assays. However, I have noticed some effect of isolation on mouse behavior. Normally, the mice are housed in our university's animal facility with no more than 5 mice to a cage. Sometimes, 1 mouse will be put in a cage by itself. When I go to get these lone mice from their cages, they seem more skittish, harder to grab, and more likely to bite me than mice kept in groups.
Additionally, our Office of Animal Resources, which is responsible for getting in the mouse shipments and putting them into cages, has recently changed how our mice are caged, with a group of 4 mice being normal, any leftover mice are put into cages with other mice, making a 5 mouse cage. This means I haven't seen a single mouse in a cage for a while. So I might not be the only one to have noticed an effect of isolation on the animal's health.
I have heard of studies on monkeys by B.F. Skinner, where he induced very severe depression and other psychological issues by isolating them, so I suspect similar studies have been attempted on mice using far more quantitative methods than I've been able to do. Yeah, it's not good:
Social isolation (SI) rearing in rodents causes a variety of behavioral changes, including hyperlocomotion, anxiety, impulsivity, aggression, and learning and memory deficits. These behavioral abnormalities in rodents may be related to the symptoms in patients with neuropsychiatric disorders, such as attention-deficit hyperactivity disorder, obsessive-compulsive disorder, autism, schizophrenia and depression...
Also:
Our findings suggest that [social isolation]-induced behavioral abnormality is a psychobehavioral complex relevant to various clinical symptoms observed in neuropsychiatric disorders, including ADHD, schizophrenia and depression, and that SI-reared mice are a useful animal model to study the pathophysiology/pathogenesis of these diseases.
There's this:
The following is multiple choice question (with options) to answer.
If a mouse is running in a field with a fence that will provide a shock to those that touch it, and the mouse tries to climb up it, it will most likely | [
"keep doing it",
"try it again",
"be fatally injured",
"enjoy the feeling"
] | C | electrocution causes harm to an organism |
OpenBookQA | OpenBookQA-3935 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
A creature that completely goes unnoticed and unseen against a mottled leaf backdrop is probably | [
"indoors",
"glowing",
"neon",
"matching"
] | D | camouflage is a kind of protection against predators |
OpenBookQA | OpenBookQA-3936 | nuclear-physics
Title: Is it possible to manufacture Helium? Helium is a scarce resource, as it escapes the atmosphere over time. If we run out of Helium deposits, will it be possible to manufacture more helium through nuclear fusion or another nuclear process? If so, how much energy will be required? Helium is a non-renewable natural resource.
The helium that is available commercially is extracted from oil and gas wells. Helium can be extracted from underground because it is trapped by the same sorts of impermeable rock layers that trap petrochemicals. That helium has had thousands or millions of years to accumulate in those rock formations, but we can empty them in a few decades. We are removing helium from shallow underground deposits at a much faster rate than it's being replaced by deep underground radioactivity; the equilibrium is broken.
It is possible to generate $\alpha$ particles in accelerator reactions, and an $\alpha$ will eventually slow down, steal two electrons, and act like helium. But generating chemically significant quantities of nuclear decay products takes an unrealistic energy commitment. Typically to remove a particle from a nucleus involves a reaction energy of 2–10 MeV. At one point for a homework assignment I learned that a Hiroshima-type fission explosion produces roughly 1 kg of free neutrons; in the same assignment I figured that a new accelerator neutron source would produce roughly 1 kg of free neutrons over its expected 30 year operating life.
The accelerator neutron source gives you an idea of the scale that'd be required for industrial-scale helium manufacture. It'd take a billion-dollar capital investment to build the facility, hundreds of millions per year in operating costs, and with good engineering and good luck the helium output might be measured in kilograms per year. You wouldn't use that for balloons any more.
The following is multiple choice question (with options) to answer.
Which of the following resources can reproduce to replenish it's stock? | [
"Coal",
"Wood",
"Salt",
"Petroleum"
] | B | a renewable resource can be renewed |
OpenBookQA | OpenBookQA-3937 | waves, electromagnetic-radiation, acoustics, interference, noise
It's two different things that are kind of analogous. I can't say it's impossible but it looks difficult.
The following is multiple choice question (with options) to answer.
What makes it difficult to hear on the moon? | [
"lack of air",
"stiff breezes",
"wind",
"sea monsters"
] | A | air is a vehicle for sound |
OpenBookQA | OpenBookQA-3938 | genetics, homework, human-genetics
However I really feel like I'm wrong about these assumptions since the math really doesn't add up. The likelihood that so many carriers for a relatively rare disorder all coming together and the fact that 3 of the 4 offspring of the grandparents died with only a 25% chance all seems improbable.
It could be that John's son doesn't have the disorder and what he has is something completely different. What do the geneticists say? This is a very rough draft about the case, not verified, and should not be used for any medical conditions. Ask your own doctor. It is just for demonstrating some Mathematics and genetic passing generally.
Condition: Muscular atrophy
Differential conditions: TODO
Support: history of genetic passing in -1 and -3 generations
Disease
Muscular atrophy as a condition jumps over a generation. The environment/living of your greatgreatgrandfathers determine your grandfathers future, as a rough estimate.
The disease's common feature is recessive autosomality.
Assumptions
Autosomal recessive disease because everyone who exhibits symptoms is not be able to reproduce due to their early death.
TODO genetic passing
What is the genetic profile? Is there any other autosomal recessive diseases in the gene map?
Proposed probabilities where the random variables $X = disease$ and $Y = carrier$ such that the subscript 0, -1, -2 and -3 is about new children's, John's, parents' and grandparents' status, respectively.
Both of John's grandparents must have been carriers
\begin{equation}
P(Y_{-3}) = 100\%
\end{equation}
The probability of John's dad and any aunts and uncles having the disorder is (TODO think this again with the correct genetic passing)
\begin{equation}
P(X_{-2}) = 25\%
\end{equation}
The probability of being a carrier is for dad, aunts and uncles (TODO think this gain with the appropriate genetic passing)
\begin{equation}
P(Y_{-1}) = 50\%
\end{equation}
Disease as a process
$X \sim P_{i}(\mu, \sigma)$, $i = -3, -1, 1, ...$ where I propose the mean $\mu$ and the variance $\sigma^2$.
The following is multiple choice question (with options) to answer.
A person may inherit their mom's | [
"boat",
"stooped shoulders",
"cat",
"building"
] | B | the type of seed of a plant is an inherited characteristic |
OpenBookQA | OpenBookQA-3939 | 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 is caused by cycles of freezing and thawing of what? | [
"h2o",
"plants",
"winds",
"animals"
] | A | cycles of freezing and thawing water cause ice wedging |
OpenBookQA | OpenBookQA-3940 | everyday-life
Due to friction effects though, option c is still best. Pedaling hard will quickly deplete energy reserves while pedaling at a slow but steady rate will allow you to cycle for much longer. From a physics point of view, we cannot help you spend less energy, it will inevitable take about the same amount of energy regardless of your method (some +/- due to friction, etc). But by keeping your power usage low, you can go much farther before needing a rest. It is much the same as with running and walking. Simplistic physics says both use the same amount of energy, but you won't get as far by running due to the massive power requirements.
The following is multiple choice question (with options) to answer.
What will happen if more people bike instead of drive cars? | [
"more cars will be bought",
"more deer will get hit by cars",
"it will be easier to breathe",
"less people will ride bikes"
] | C | using a car causes pollution |
OpenBookQA | OpenBookQA-3941 | electrical-engineering, ethics, sales, safety
But all of those steps are going way above and beyond what you're obligated to do in this particular case. This is especially so when there is a safe usage for the product along with an unsafe approach. And any of those actions are likely to irreparably damage your relationship with that client. Damaging the relationship will impair your credibility with them and make it less likely that they'll listen to your concerns.
So your obligation is to lay it out to them in unambiguous terms that you believe they need to stop using the product in their "preferred" manner and that your firm will no longer provide any support whatsoever regarding future use of that product in that configuration.
The following is multiple choice question (with options) to answer.
What is a likely product of a timber companies activities? | [
"the battery of your cell phone",
"the ruler in your backpack",
"the porcelain in your toilet",
"the bottle you drink from"
] | B | timber companies cut down trees |
OpenBookQA | OpenBookQA-3942 | 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.
These would likely be broken down and recycled | [
"waste helium",
"waste hydrogen",
"pallets",
"waste oil"
] | C | wood is a renewable resource |
OpenBookQA | OpenBookQA-3943 | behaviour
Title: What happens to silverfish when we throw them out the window? I'll find a silverfish from time to time in my flat. I don't mind them but usually I catch them and throw them off the balcony (second story) into the bushes and lawn below.
I was wondering, since they seem to live in the water conduits in the house, if they can survive outside or if they die/get killed instantly.
Thx for your help! Silverfish prefer high humidity and warmth. Ctenolepismacalvum (Ritter, 1910) was recently found in Japan at a temperature of 20-30°C and 50-60% RH. As long as there are pieces of bark, wet grass or other organic or human-made structures that retain humidity after each raining event, the likelihood that they will survive long enough to complete their cycle is high.
They could face dessiccation if they are not able to find a damp spot in time, depending on their tolerance to it. However, it was not possible for me to find information about their dessiccation tolerance.
The Zygentoma (silverfish order) have high tolerance to low humidity and most of the species inhabit dry and hot environments (it's just a few that like humidity), which again makes me think that those silverfish propelled out the window will survive.
The following is multiple choice question (with options) to answer.
If a house burns down, the goldfish inside may do what? | [
"quit swimming",
"be hungry",
"grow",
"get smarter"
] | A | if too much heat is transferred to an object then that object may burn |
OpenBookQA | OpenBookQA-3944 | dna, cloning, dna-isolation
If you do this, regular freezers are not cold enough to prevent freezer burn. This is what happens when you put a steak in to the freezer, wrapped in plastic even it will shrivel up and start to dry out as the water in the ice starts to sublime out of the package (the dry air in the freezer basically sucks the water out of the food). If this happens to your animal tissue, its probably not going to revive.
Scientific labs use -80C freezers and liquid nitrogen storage because the water turns into a glass and all biochemical reactions are basically stopped. (besides drying out, the enzymes like DNAse are still nominally functioning in the cells at -20C and even simple bacterial cells don't live for more than a year at -20C, much less mammalian cells). For preserving cell lines, liquid nitrogen is much more preferred. I would say that properly produced cell lines can theoretically revive after indefinite liquid nitrogen storage.
So that's a quick answer. Sorry to be a party pooper - things could change quite a bit in the next 20 years, but we just don't know how much. popping a paw in a baggie or some DNA extract into the freezer might work, but its hard to say for sure.
As far as the choice of where the DNA comes from in the animal, its true that skin cell lines are often producing imperfect animals - the DNA may be modified in the skin in various ways that cause the animal to be smaller, weaker, or even deformed compared to the donor. At this time all the protocols I see (and i could be wrong) are skin cells. I would expect that there is a better tissue to preserve, but that might be just a guess at this point. Its likely that in the next 20 years the choice of cell line from the donor will change quite a bit as well.
The following is multiple choice question (with options) to answer.
Frozen steak which has been in the sun all day will | [
"defrost",
"freeze",
"give birth",
"become sentient"
] | A | if a substance absorbs solar energy then that substance will increase in temperature |
OpenBookQA | OpenBookQA-3945 | newtonian-mechanics, forces, buoyancy, fluid-statics, weight
Keep in mind that a body loses weight in a liquid which is equal to the weight of the liquid displaced by it/equal to the buoyant force.
As for the bonus question, look into the answer to this question -
https://physics.stackexchange.com/a/296537/134658
The following is multiple choice question (with options) to answer.
If a liquid disappears then what probably happened to it? | [
"gas transformation",
"solidifying",
"melting",
"cooling"
] | A | if a liquid disappears then that liquid probably evaporated |
OpenBookQA | OpenBookQA-3946 | plant-physiology
Title: Would a plant survive if it was watered using hard-water? Hard water is water with high mineral/salt content. I'm told that a potted plant watered with a salt solution dries out sooner or later. Is this true?
If so, would a plant survive if watered using hard-water? It would depend on the content of the hard-water. If the water contained heavier metals like lead or radioactive elements like tritium (Hydrogen-3), the plant would most likely die. Most land plants cannot survive when watered with massive amounts of salt water as the salt would absorb the water from the leaves.
The following is multiple choice question (with options) to answer.
Conserving water can be used for survival where? | [
"seas",
"oceans",
"sandy land",
"towns"
] | C | conserving water can be used for survival in a dry environment |
OpenBookQA | OpenBookQA-3947 | optics, electromagnetic-radiation, visible-light, reflection, geometric-optics
Title: We know that a window can actually reflect light. But if the window has some dirt sticking to it, the image we see sometimes get magnified. Why? Well, I was traveling in a bus yesterday and saw this occur. The board that separates the passengers from the driver's had something written on it and I saw that the window that was a few meters away from the board reflected all of the things written.. But the window had some dirt on the part where I saw the image of the writings... And, they appeared to be enlarged just at the point where dirt was present. The open spaces between dirt particles each acts like a "pinhole camera" to magnify the image behind the dirty glass pane. The magnification is slight but noticeable. Try this experiment: make a small triangular hole shape by putting three fingertips together so as to leave a gap at their intersection. by pressing your fingertips together, you can make the size of the hole shrink; by relaxing them, you can make the hole larger.
That hole will act as a pinhole camera. now look through the hole at your computer screen from about 24 inches away and vary the hole size. you will find a certain diameter at which the image you see through the hole will get sharper and the text on the screen will become easier to read.
The following is multiple choice question (with options) to answer.
If a see through thing is multifaceted, it is most likely | [
"a ball",
"an apple",
"a silver globe",
"a quartz square"
] | D | a quartz is made of six-sided transparent crystals |
OpenBookQA | OpenBookQA-3948 | the-sun, orbit, planet, earth
Is the spiraling movement caused by sun movement (on its path shown
above) where the sun is dragging the earth (and other planets)?
No, the Sun's and the Earth's mutual gravity cause the Earth to rotate around the Sun. The Milky Way's gravity causes our Solar System to revolve around the galactic center. The Sun and the Earth are on the same plane and moving through the galaxy together. The Earth would still rotate around the center of the Milky Way if the Sun magically disappeared.
Does the earth go in front of the sun then back, then fourth and back
like it is shown on the video? I see both the sun and earth racing
with each overtaking the other over and over. Is this assumption true?
In this manner, would earth, at one point in time, be closer to the
destination where the solar system is heading (I think they call the
destination Vega) than the sun?
If you consider a plane tangent to the Sun's velocity vector, then the Earth will pass across that plane twice per year, appearing "in front of" and then "behind" the Sun. This is simply a geometric result since the Earth and Sun share another plane. I wouldn't call any future position of the Solar System a "destination" without evidence the Solar System was sentient, but I am not a philosopher.
I am working on a poetry piece. If I mention that earth and sun are
locked in a never ending race with each taking the lead (earth moving
in front of the sun's path / winning) and earth actually dropping out
of the race (spiraling/moving out the race and falling behind), that
they are destined to never meet (collide), would I be correct?
We haven't ruled out the possibility that the Sun may someday envelope the Earth: What will "the Earth being consumed by the Sun" look like?. Also, the Earth isn't likely to leave its orbit before that time, but the Solar System is chaotic on long time scales. However, your poem would be consistent with current models, and we (humans) don't conclusively know how the Solar System will end. So my two cents is that your poem doesn't contradict modern astronomy. Besides, what's the use of a poetic license if you don't use it?
The following is multiple choice question (with options) to answer.
human planet revolves around the sun in | [
"a day",
"a week",
"365 earthen rotations",
"a eon"
] | C | the Earth revolves around the sun |
OpenBookQA | OpenBookQA-3949 | entomology, ecology, biological-control
Habitat modification: regularly removing
plant growth within the lake and trimming vegetation overhanging the edges will limit the ability of mosquito larvae to escape predators and may have some effect. However, the recent management you describe has
probably gone some way towards this (did you
notice whether the mosquito problem got any better after the plants
were removed?)
Biological control: introduce predators or parasites into the environment. Plenty of species eat adult mosquitoes but there aren't really any that primarily feed on them (unless they're the only food source available) and many adult mosquitoes will have laid eggs already - the most effective strategy will be to target the immature population. Larvivorous fish have been shown to be effective in many parts of the world, for example fish in the genus Gambusia ('mosquito fish'). I don't know of any that have been shown to be effective and can thrive as far north as Scandinavia, but if you stock the lake with fish (combined with managing vegetation as above) I'd be surprised if you don't see some improvement.
Biological control, part 2: Use Bti (Bacillus thuringiensis var. israelensis). This is a bacterium that produces toxins which are highly specific to dipterans and don't really affect anything else. You can buy the bacterium in various formulations including sprays, tablets etc. I'm mainly familar with its use for controlling container-breeding mosquitoes, but this paper describes its use in large lakes so should give you some idea of dose required, optimal application method and time to reapplication.
Without knowing more about your budget, available time/manpower etc I can't really help you choose between these but I suspect #3 is your best bet.
The following is multiple choice question (with options) to answer.
The many ponds in the area along with massive swarms of mosquitoes lead the dragonflies to | [
"convert the area into swampland",
"experience a sharp increase in available resources",
"leave the area in search of a better habitat",
"experience a dramatic decrease in population"
] | B | if the population of an organism increases then the ecosystem may become overpopulated with that organism |
OpenBookQA | OpenBookQA-3950 | cell-biology, zoology, literature, red-blood-cell
Title: Does the red blood cell in frogs undergo amitosis? It is a notion particularly popular among Chinese high school Biology textbooks, that the red blood cells in frogs can undergo amitosis (not mitosis), a claim which I have not been able to find reference. A search on Pubmed led me to this article, which states:
The nucleus of the frog erythrocyte is not a regular ellipsoid; ... a single nuclear invagination located at one end of the long axis is frequently seen in the phase microscope.
However I have also been unable to find more recent researches on the nature of this observation, and whether it is related to amitosis. Can you help me find some? Unlike mammalian blood cells, blood cells in Amphibia are nucleated (as the paper in your link explains) and can perform cell division (here is an old paper from Acta Haematologica, 1954: https://www.karger.com/Article/Pdf/204534).
Your question is: is this division a regular mitosis or the so called amitosis? According to Barni et al., 1995, amphibian blood cells can perform amitotic cell division:
The proliferation of haemopoietic cells, detected by the anti-BrdU labelling index, was accompanied by absence of mitotic cell division and the appearance of cells showing features of amitosis (e.g. nuclear constrictions with bundles of electron-dense chromatin)
Source: Barni, S., Fraschini, A., Prosperi, E., Vaccaronel, R. and Bernini, F. (1995) ‘Possible occurrence of amitotic cell division during haemopoiesis in the Urodeles’, Comparative Haematology International, 5(3), pp. 183–188. doi: 10.1007/bf00368042.
The following is multiple choice question (with options) to answer.
the cells of golden retrievers can | [
"spontaneously combust",
"change colors",
"liquify",
"specialize"
] | D | the cells of multicellular organisms can specialize |
OpenBookQA | OpenBookQA-3951 | species-identification, zoology
Title: What animal does this skull belong to? This skull was found in Greece, about 40 years ago, possibly in the island of Euboea (there is uncertainty about the area it was found).
The length from nose to the end of horns is 67 cm. The skull's length without the horns is 42 cm. Just for reference, the floor tiles in the pictures have a side of 33cm.
What could this animal be? It does not have to be native to Greece, even though a native animal would be more probable.
Update:
The size of the skull points to an animal larger than a goat. It looks more like an antelope, a gazelle, or even a deer. Only deers are native to Greece, however the horns look nothing like deer.
I believe the horns are the key to unlock this mystery. Its definitely a bovid, most likely an african antelope specifically a Hartebeest or Alcelaphus buselaphus . There are several sub-species but those horns are a dead giveaway. The the horn do vary a bit by sub-species. The Neumann's or Tora hartebeest might be your best bet but I can't be 100% sure. They are all popular hunting trophies since forever and are even kept in some european game reserves so it is not that hard to find there skulls in private hands. Search "hartebeest skull" and you'll find a million of them so you can try for a more exact match.
The following is multiple choice question (with options) to answer.
if a person wanted to hunt down some deer, which of these would be the wrong place to visit? | [
"the local hunting reservation",
"a known national reservation",
"an uncharted wilderness region",
"a natural unregulated forest"
] | B | national parks limit hunting |
OpenBookQA | OpenBookQA-3952 | planet, orbit
Title: Do the orbits of planets change sometimes? Do planets sometimes wobble and get off their paths? What if an asteroid were to hit it? Yes, the orbits change massively over time. For example, Earth's eccentricity (how close to a circle the orbit is), its axial tilt (what causes seasons), and precession (which direction the Earth's spin axis points) change on these huge cycles, tens of thousands to hundreds of thousands of years long. They are caused by the pull of the other planets, mainly Jupiter and Saturn (since they are so huge), as well as the physics of inertial reference frames. These are known as the Milankovitch cycles. Here is a neat video explaining what each of the cycles are in detail. That video is about Earth, but the same concepts apply to all the other planets too, just on different amounts and timescales.
An asteroid hitting a planet would technically change its orbit, however how much is questionable. An asteroid a couple km across would barely nudge the Earth since the Earth is bigger by many orders of magnitude. It would also destroy everything on the planet, but thats another story. Way back in the solar system's formation, when Thea hit Earth (theoretically) it was much closer in size than the Earth, so no doubt that it caused a much more significant shift in orbit.
The following is multiple choice question (with options) to answer.
What does the earth orbit that causes the seasons to change? | [
"plasma star",
"venus",
"saturn",
"mercury"
] | A | seasonal changes are made in response to changes in the environment |
OpenBookQA | OpenBookQA-3953 | sensors, computer-vision, kinect
What good resources on the internet give you a good introduction on 3D scanning concepts (theoretically and programmatically)? I will be using C++ and OpenCV (I already worked with both a lot) and/or the API provided with the chosen camera (if applies).
Should you have a static camera capturing a moving object or a moving camera capturing a static object?
Should I use something in conjunction with stereo camera (like lasers)?
Is it profitable to use more than two cameras/sensors?
Are resolution, FPS and global shuttering really important in 3D scanning?
What camera should I get (it can also be something I didn't mention, in the range of $500 maximum if possible)? My main criteria is a camera that would be able to generate an accurate depth map from close range points.
Thanks for your help!
My favorite is the Learning OpenCV book. It has a fantastic stereo / 3D section that introduces concepts from the ground up. If you're at a university, you might be able to find the digital version available from the library website.
Depends, especially on how you are going to combine scans into a full 3D pointclound (if you need 360 degree views.) Overall, moving the camera is usually harder than moving the object in my opinion.
Lasers can help a ton. Take a look at the MakerScanner from a few years ago (disclaimer, I designed it).
Extra cameras can reduce ambiguities in stereo (from, say, horizontal symmetry). In such a controlled environment, I doubt it's worth it.
Resolution, yes, depending on your scan technique. With something like the MakerScanner, you can use sub-pixel interpolation on the laser line to get surprisingly good accuracy, reducing the need for high resolution images. If you're in a controlled environment, FPS probably isn't much of a concern (ie just scan slower.)
You might consider pairing gPhoto2 with a point and shoot camera like one of the Cannons on this page, which can give you incredibly nice images for very little money. Not much in the way of realtime, but it's unclear to me that you need that.
The following is multiple choice question (with options) to answer.
If you wanted the visual effect of being closer to something without moving, what would you use? | [
"An old spyglass",
"Squinting your eyes",
"A large mirror",
"Some good sunglasses"
] | A | as distance from an object decreases , that object will appear larger |
OpenBookQA | OpenBookQA-3954 | mechanical-engineering, structural-engineering, materials
The net kinetic energy change for object A is $(1/2)m_A (v_{f}^2 - v_{Ao}^2)$. Apply the same for object B.
As for energy absorbed by the objects individually, the answer is ambiguous. The objects cease to exist as individual objects at the moment of the collision. Any energy lost is absorbed by the final combined object, not by any one individually.
The following is multiple choice question (with options) to answer.
kinetics change stored energy into motion and | [
"snacks",
"naps",
"kites",
"warmth"
] | D | moving changes stored energy into motion and heat |
OpenBookQA | OpenBookQA-3955 | star, orbit, the-sun
Title: Does the Sun turn around a big star? The Moon orbits the Earth.
The Earth orbits the Sun.
Does the Sun orbit another bigger star?
If so, does this star orbit, in turn, a very big star?
... etc ...
What are all the intermediate subsystems up to motion around the center of the Milky Way? The Sun is not within the gravitational sphere of influence of any other star. The centre of mass of the solar system (which is very close to the Sun) instead orbits in the general Galactic gravitational potential. Because this has a roughly cylindrical symmetry (the Galaxy is basically a disk with a bulge in the middle), this means that it executes a (roughly) circular orbit around the centre of the Galaxy, taking about 230 million years to do so. At the same time it is wobbling in the vertical plane of the Galactic disc, up and down with a cycle of about 70 million years (see How far is the Earth/Sun above/below the galactic plane, and is it heading toward/away from it? )
There is really nothing intermediate because the stars in the milky way form a "collisionless system" they don't really interact gravitationally on an individual basis. Stars can be influenced by perturbations in the smooth Galactic potential caused by massive star clusters, giant molecular clouds and spiral arms. This is thought to be why the velocity dispersions of stars around regular circular orbits increases with age.
The following is multiple choice question (with options) to answer.
Which orbits a star? | [
"Neptune",
"a galaxy",
"the sun",
"the moon"
] | A | planets orbit stars |
OpenBookQA | OpenBookQA-3956 | If the maximum number of fish caught is $$m$$, then the total number of fish caught is no more than $$m+(m-1)+...+(m-6)$$. So there is one fisherman that caught at least 18 fish. Repeat this process for the second and third highest number of fish caught and you should be good.
I should add that this is a common proof technique in combinatorics and graph theory. To show that something with a certain property exists, choose the "extremal" such something, and prove that property holds for the extremal object. For instance, to show in a graph where each vertex has degree at least $$d$$ there is a path of length at least $$d$$, and one proof starts by simply showing a maximal path has length at least $$d$$.
• If the most fish caught is $18$ that gives a tight result - there is a little work to check what happens if the largest number of fish caught is greater than $18$ Sep 30 '18 at 15:12
• @MarkBennet right, my thought was to iterate, i.e. After you choose the max $m$, replace $100$ with $100-m$ and $7$ fishers with $6$, this gives a bound on the second highest, etc. Thanks for pointing this out Sep 30 '18 at 15:15
• Not a problem - it actually gets a bit easier. This works and was my first way of doing it. Sep 30 '18 at 15:26
• Thank you for your solution. I accept Mark's solution because it is more accessible for kinds about 14 years.
– Aqua
Sep 30 '18 at 15:45
• @greedoid no prob! I would accept marks as well :) Sep 30 '18 at 15:45
I think I have a solution. First note that if $$r_4 \geq 15$$ then we have:
$$r_5 \geq 16$$
$$r_6 \geq 17$$
$$r_8 \geq 18$$
so $$r_5 + r_6 + r_7 \geq 16 + 17 +18 = 51$$ which is impossible.
Therefore $$r_4 < 15$$
The following is multiple choice question (with options) to answer.
Angler fish hunt by using | [
"fishermen",
"spear guns",
"illumination",
"fishing poles"
] | C | producing light is used for attracting prey by some deep sea animals |
OpenBookQA | OpenBookQA-3957 | paleontology, fossils, desert
Title: Why are many fossils found in deserts? Why are deserts famous for fossils? Is it a coincidence? Some examples:
Giant Catfish Fossil Found in Egyptian Desert
Chile's stunning fossil whale graveyard explained
Giant Dinosaur Fossil Found in Sahara Desert I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago. The fact that a location today is a desert has no indication of what the climate, or even where on the globe that location was 50 or 100 million years ago.
Do not forget about plate tectonics and climate change. One can go to places like the Judith Basin in Montana, a relatively harsh area of North American Bad Lands, desert or near desert like conditions with cold winters and find fields of fossils from animals that are believed to have lived in tropic marshes of in oceans, because at the time those animals lived, what is now Montana was not inland, and was not at a Northern location. Millions of years ago it was an undersea plate, thus it has layers of limestone made from ancient single cell sea creatures and sometimes larger objects that were entrapped and preserved as larger fossils. At other times, those plates rose from the sea floor and homed some of the large creatures, like T-Rex that lived, thrived and sometimes survive as fossils.
Later, that plate move and ended up inland, in what is not North America. Glaciers, wind, and water may have stripped off many layers of deposits and left exposed or close to exposed the layers of interest to fossil hunters. Desert regions tend to be subjected to this type of erosion and exposure making such finds easier. If those same fossils were in and area such as a rich planes area with plentiful plant growth and never subjected to glacial scouring, they could be, and may very well be, right below your feet but under many layers of soil and decaying vegetation, river sediment and other deposits rendering them out of sight and out of reach.
The following is multiple choice question (with options) to answer.
One odd fossil that may have been discovered is | [
"feelings",
"love",
"vortexes",
"poop"
] | D | An example of a fossil is a footprint in a rock |
OpenBookQA | OpenBookQA-3958 | measurements, machining, metrology
http://www.tool-precision.com/kpt-62.htm
Or even a coordinate measuring machine (which will measure the actual height):
https://www.sinowon.com/micromea10128-moving-bridge-scanning-coordinate-measuring-machine
However, these bely what you actually need: You do not need to measure (i.e. quantify) the height to do this. You do not even need to measure the variance in height.
In the most primitive approach, your hands can feel the resistance decreasing, increasing, or staying due to the height decreasing, increasing, or staying the same as you run it along the surface.
Therefore, you need is a base, a vertical beam, and a sharp horizontal point that can be mounted on the vertical beam at any height. A so-called surface gauge:
https://www.starrett.com/category/111601
Now, you could then freehand and continuously check it until it is parallel. But from what I said above you can probably extrapolate that a much easier method in this case is to run a cutting tool at a fixed height similar to the probe. But if you so desired, you could freehand it to shape it. What you can't do is freehand the measurement part.
You use this to build your parallels. The longer you make your parallels (which also requires making a larger surface plate) higher the resolution you can check for parallelism.
Once you have your parallels you can start working on squares. For initial checks, you choose one arm of the square as a reference edge and align it to the parallel and trace the vertical edge. You then flip it and the more square it is the more closely the mirrored vertical edge will overlap/be parallel to the first traced vertical edge. Again, the longer you make the arms the more resolution you will have to check for squareness.
The following is multiple choice question (with options) to answer.
which one of these would be easiest to measure with a tape? | [
"a quart of motor oil",
"contents of a wine bottle",
"contents of a can of beer",
"a freshly baked loaf of bread"
] | D | a tape measure is used to measure distance |
OpenBookQA | OpenBookQA-3959 | orbit, earth
Over the very long term (a hundred thousand of years or more), the Earth's rotation rate is getting slower. This is a true secular trend that will eventually result in increases in the lengths of both the day and the night on the day of the year with the least daylight of the year, regardless of other effects.
This very slow secular increase is counteracted or exacerbated by cyclical effects. One is the Earth's axial tilt. This varies cyclically, but with a period of 41000 years. Over the short term (hundreds of years is short in this context), the effects of changing axial tilt are much stronger than are the effects of the secular increase in the length of day. The Earth is currently in a phase where the axial tilt is decreasing. This makes the length of daylight increase on the "shortest day of the year", and hence makes the length of that longest night decrease.
A much shorter term cyclical effect results from the location of the Moon with respect to the Earth and Sun. The Earth and Moon together orbit the Sun. This means that when the Moon is above the plane of this orbit, the Earth will be slightly below, and vice versa. This subtly changes the lighting of the Earth. Where this occurs varies as the lunar node precesses over an 18.6 year period.
The following is multiple choice question (with options) to answer.
The earth has completed half of its yearly orbit of the sun and will complete the other half in | [
"two weeks",
"seven months",
"365 days",
"182 days"
] | D | a complete revolution of the Earth around the sun takes one solar year |
OpenBookQA | OpenBookQA-3960 | electromagnetic-radiation, visible-light, experimental-physics
Title: Experiment Prediction: How much light can pass through an opening? The flow of current through a wire is limited to the size of the wire. Water through a pipe is limited by the size of the pipe. What about light? Is it limited in a similar way?
Let's say I drill a 1,000nm hole in a piece of 1/4 inch steel. I then shine a 5mw red laser through the hole. Does the hole restrict how much light can pass through the hole at any given moment? Let's say I increase the light through the hole by adding more lasers. Will the hole slowly start to restrict light's passage. Is there a limit to how much light can "fit" through the hole at the same time?
Example Experiment: I shine the laser through the hole. I then measure the light with a photo diode and let's say I get 1 volt. Now I increase the amount of light through the hole by adding another laser of the same size. Would I now see 2 volts? What if do this again? Would I see 3 volts? Would each additional laser produce the same gain as the one before it? I understand the lasers would all have to be angled toward the hole by the same amount to actually perform this test. I also understand may need to perfect the measuring device, but I think you get the point. Light consists of photons which are boson. Bosons like to exists in the same state. So if you can manage to let one photon pass through a specific hole, then you can pass an arbitrary number of identical photons through that same hole. In other words, the size of the hole does not put any limit on the number of photons (or the amount of light) that can pass through that hole.
The following is multiple choice question (with options) to answer.
Light enters what through the pupil? | [
"skin",
"visual organ",
"eye spy",
"eye diagram"
] | B | light enters the eye through the pupil |
OpenBookQA | OpenBookQA-3961 | reproduction
Title: Why are so many species reproducing late this year? Hope this question is OK for this site, couldn't see where else to ask it.
We've spent a few days out in the countryside recently, and have been very surprised at how many species appear to have very young offspring so late in the season. I was always under the impression that the vast majority of animals and fish produced young in the spring (March/April).
For example, we saw tadpoles, fluffy (ie obviously very young) coots and weeny minnows. I would have expected that all of these would have been born/laid a good 3 or 4 months ago, and so would be more mature by now.
Caveat: We didn't do a scientific study, this is just a strong impression we got from days out in north west England. It's hard to say without more information, but one substantial possibility is that you are mistaken that species are reproducing late - that's a problem with anecdotal rather than scientific data!
Additionally, species you mention like the common coot can attempt multiple broods where the season is long enough. Wikipedia specifically mentions Britain:
Eurasian coots normally only have a single brood each year but in some areas such as Britain they will sometimes attempt a second brood
The same could be true for species of frogs/toads and fish, so without knowing specific species it can't be known whether these are species reproducing again or species reproducing late.
The following is multiple choice question (with options) to answer.
A mouse give birth to ____ while a bird give birth to ____ | [
"mouse eggs; live babies",
"live babies; unhatched eggs",
"live babies; live babies",
"mouse eggs; rat eggs"
] | B | a mouse gives birth to live young |
OpenBookQA | OpenBookQA-3962 | solar-system, the-sun, observational-astronomy, asteroids, comets
Title: Have we ever observed a body, such as a large asteroid, "hitting" the Sun? Some other SE questions about launching ICBM's into the sun got me wondering whether we have ever observed an object on a path that intersected with the Sun? How close did it get? Yes
and here's a video of "a Giant Comet Hitting the Sun":
https://www.youtube.com/watch?v=Mat4dWpszoQ
The impact occurred sometime during May 10-11, 2011. The comet was not named but believed to be a member of the Kreutz family of comets
Many close calls
Before this spectacular plunge we had witnessed several other comets graze (come close without hitting) the Sun.
I've included a nice picture of comet Lovejoy after its close approach of the Sun brought it through the Sun's corona around December 15, 2011:
What happens when a comet hits the sun?
It acts like a supersonic snowball in Hell
If a comet is big enough and passes close enough, the steep fall into
the sun’s gravity would accelerate it to more than 600 kilometres per
second. At that speed, drag from the sun’s lower atmosphere would
flatten the comet into a pancake right before it exploded in an
airburst, releasing ultraviolet radiation and X-rays that we could see
with modern instruments.
The crash would unleash as much energy as a magnetic flare or coronal
mass ejection, but over a much smaller area. “It’s like a bomb being
released in the sun’s atmosphere,” Brown says. The momentum propelled
by the comet could even make the sun ring like a bell with subsequent
sun-quakes echoing through the solar atmosphere.
The following is multiple choice question (with options) to answer.
What is most likely to happen to a roof as the sun comes into contact with it? | [
"it will fall apart",
"it will cry out in pain",
"it will heat up over time",
"it will cool down over time"
] | C | if an object is exposed to a source of heat then that conductor may become hot |
OpenBookQA | OpenBookQA-3963 | 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.
Having a conversation in rooms with bare cement can be challenging because of | [
"dancing clown guys",
"bouncing sound waves",
"problematic triggered dingoes",
"egg cartons"
] | B | when a sound is produced inside of a room , there is sometimes an echo after the sound |
OpenBookQA | OpenBookQA-3964 | behaviour
Title: What happens to silverfish when we throw them out the window? I'll find a silverfish from time to time in my flat. I don't mind them but usually I catch them and throw them off the balcony (second story) into the bushes and lawn below.
I was wondering, since they seem to live in the water conduits in the house, if they can survive outside or if they die/get killed instantly.
Thx for your help! Silverfish prefer high humidity and warmth. Ctenolepismacalvum (Ritter, 1910) was recently found in Japan at a temperature of 20-30°C and 50-60% RH. As long as there are pieces of bark, wet grass or other organic or human-made structures that retain humidity after each raining event, the likelihood that they will survive long enough to complete their cycle is high.
They could face dessiccation if they are not able to find a damp spot in time, depending on their tolerance to it. However, it was not possible for me to find information about their dessiccation tolerance.
The Zygentoma (silverfish order) have high tolerance to low humidity and most of the species inhabit dry and hot environments (it's just a few that like humidity), which again makes me think that those silverfish propelled out the window will survive.
The following is multiple choice question (with options) to answer.
On a summer day, a dog stuck outside will | [
"be dripping with sweat",
"lick at the window",
"appear to be smiling with its mouth open",
"curl up somewhere and shiver"
] | C | panting is when an animal hangs its tongue out of its mouth to adjust to hot temperatures |
OpenBookQA | OpenBookQA-3965 | orbital-elements, near-earth-object
Title: Is the science in "Don't Look Up" realistic? In the new movie "Don't Look Up", astronomers discover a comet in the outer Solar System that's going to hit the Earth about 7.5 months later. I think they calculate its trajectory within a day of discovering it, and they're virtually certain that it will impact the Earth, knowing the exact day and time.
While I believe that they can determine when it will pass by with that accuracy, I wonder if they can tell that early how close it will come. In the past astronomers have found asteroids that would come near Earth, and early reporting didn't seem to be so precise about the distance.
The comet was described as an Oort Cloud object, and I think it was its first appearance (they named it after the grad student who found it). I'm not sure how far out it was when they discovered it, but at one point in the movie they showed it passing by a gas giant for effect; it might have been Jupiter, but I'm not sure, and I don't recall how long this was after it was first seen.
How long would they need to observe such an object, and roughly how close would it have to be before they can determine the tractory precisely enough to know that it will hit Earth? How much advance warning would we have of certain cataclysm? Short observational arcs present difficulties in orbit determination. A couple of examples (taken from Wikipedia) :
(392741) 2012 SQ31 was observed for one day, and the best-fit orbit was found to be a trans-Neptunian dwarf planet. It is actually a much smaller main-belt asteroid (between Mars and Jupiter)
2004 BX159, with an observational arc of three days (and 8 observations) it was determined to have a perihelion of 1.5 (±3) AU. This made it a potential Near-Earth Object, but note the uncertainty is greater than the estimated value. In fact, it orbits between 2.2 and 2.9 AU and poses no threat.
The following is multiple choice question (with options) to answer.
Imagine astronauts traveling to a distant asteroid as it passes near Earth. During their mission they leave behind boot prints. How long will these potentially last? | [
"several months",
"5 years",
"thousands of years",
"2 weeks"
] | C | wind and rain cause erosion |
OpenBookQA | OpenBookQA-3966 | energy-efficiency, thermal-insulation
greater if the window is bigger
less as temperature difference get smaller
Radiative heat transfer
The main factor that is of consideration here is the solar radiation. There are three types of radiation:
Direct radiation: the direct rays of the sun. (this is zero on a cloudy day).
Diffuse radiation: this is always present and its an effect of the presence of atmosphere. In higher latitudes it tends to increase because the sun rays need to "pass through" more atmosphere.
reflected (you can neglect this)
If you can get the rays of the sun (direct radiation) into the house, this will always be a significant plus in the heat balance of the house.
Final thoughts
This problem is very instance specific depending on:
the location of the house
orientation of windows
type of blinds, etc.
Therefore, it is impossible to draw a generic conclusion. As such, only trends can be realistically observed.
At a temperature difference of 30$[^oC]$ it makes sense to close the blinds on a cloudy day. However, if you get closer to 15$[^oC]$ then the savings are diminished.
If the windows are positioned in the right angle and light shines into the room, then expect the added solar radiation will improve the heat balance in favour of open blinds.
The following is multiple choice question (with options) to answer.
More sunlight will be absorbed by | [
"a plant with curled leaves",
"a tree with wide, smooth leaves",
"a rose with tiny leaves",
"a berry bush with thin, short leaves"
] | B | if something is outside during the day then that something will receive sunlight |
OpenBookQA | OpenBookQA-3967 | java
}
return list;
}
public List<Mother> mothersWithTwins() {
List<Mother> list = new ArrayList<>();
for (Mother mother : mothers) {
if (motherHasTwins(mother)) {
list.add(mother);
}
}
return list;
}
public boolean motherHasTwins(Mother mother) {
Set<LocalDate> set = new TreeSet<>();
for (Newborn newborn : mother.getList()) {
set.add(newborn.getBirthday());
}
return set.size() < mother.getList()
.size();
}
public static void main(String[] args) {
App app = new App();
app.buildRelation("src\\motherFile.txt", "src\\\\NewbornFile.txt");
System.out.println("Tallest daughter:");
System.out.println(app.getTallestNewborn(false));
System.out.println("\nTallest son:");
System.out.println(app.getTallestNewborn(true));
System.out.println("\nMost common date:");
System.out.println(app.mostCommonDate());
System.out.println("\nMothers over 25 Years old with childer heavier than 4000g;");
app.motherMoreThan()
.forEach(System.out::println);
System.out.println("\nDaughters that inherits their mother's name: ");
app.newbornWithMotherName()
.forEach(System.out::println);
System.out.println("\nMother that has twins:");
app.mothersWithTwins()
.forEach(System.out::println);
}
}
Is it the fastest way?
Probably not, though there's a lot to work on before performance considerations necessarily factor in.
Can it be minimized?
Yes!
Is the approach correct?
The following is multiple choice question (with options) to answer.
A mother births what? | [
"light",
"elements",
"younglings",
"nothing"
] | C | a mother births offspring |
OpenBookQA | OpenBookQA-3968 | optics, visible-light
You can probably work that out by yourself. Now consider a spherical container of diameter $1\,\mathrm{km}$. Then the light will always have to travel $1\,\mathrm{km}$ or less before it hits the wall again. In other words, it has to travel (at the highest) $n$ times $1\,\mathrm{km}$ before it has lost 90 percent of its original intensity. Using that the speed of light is approximately $300000\,\mathrm{km/s}$ you should find that it only takes the light about $0.77\,\mathrm{s}$ to do this.
The following is multiple choice question (with options) to answer.
What would light bounce off of when it hits it? | [
"a wall painted grey",
"old worn out leather",
"a freshly waxed car",
"a street made of gravel"
] | C | when light hits a reflective object , that light bounces off that object |
OpenBookQA | OpenBookQA-3969 | cellular-respiration
Title: Do cold blooded animals generate any heat? In explaining energy and work to an 8 year-old I said that all conversion of energy generates heat as a by-product. For example, cars generate heat in their engines and running generates heat in our bodies. Then the 8 year-old said, except for cold-blooded animals.
So my question is, do cold-blooded animals generate any heat in their conversion of stored energy (food, fat, etc) into motion? If they generate heat, why are they cold-blooded? They do generate heat. They just do not SPEND energy specifically on heating their bodies by raising their metabolisms. This is a form of energy conservation. The metabolic rate they need to live is not nearly enough to heat their bodies.
An example of spending energy to heat the body is seen in humans shivering. Here muscle is activated not for its usual purpose, but to function as a furnace. "Warm-blooded" and "cold-blooded" is somewhat a misnomer. The correct way to think of it is...
Endotherm or ectotherm. Does the heat primarily come from within (endo) or from the surroundings (ecto). Endothermic animals include mammals. Most of their body heat is generated by their own metabolisms. Ectothermic animals include reptiles and insects. They absorb most of their body heat from the surroundings. This is not the same as saying they let their body temperature fluctuate with their surroundings, some avoid this by moving around to accomodate themselves.
Homeotherm or poikilotherm. Homeotherms want to maintain homeostasis for their body temperatures. They don't want it to change. Poikilotherms do not exhibit this behaviour, instead their body temperatures vary greatly with the environment.
We can have endotherm poikilotherms, such as squirrels, who let their body temperature drop while hibernating. Endotherm homeotherms, such as humans, where temperature is constant by means of complex thermoregulation. Ectotherm homeotherms, such as snakes (moving into shadow or into the sun to regulate temperature), and ectotherm poikilotherms, such as maggots.
The following is multiple choice question (with options) to answer.
What happens when animals in hot environments are active? | [
"They get a sun tan under their fur",
"They like to take naps while running",
"They become thirsty more easily",
"They become fried and baked alive as burgers"
] | C | as the activity of an animal increases , the amount of water in an animal 's body in that environment will decrease |
OpenBookQA | OpenBookQA-3970 | oceanography, sea-level, tides
Title: Why do high tides vary month to month? I've noticed that some ‘highest‘ high tides in one month are bigger than the highest high-tide of previous months. Why is this so? The dynamics of the tides are quite complex. The main idea is that gravity from the Moon and the Sun affect water (and everything else) on Earth. The issue is that there are several motions that alter the distance between the 3 systems and those motions cause interactions between the different frequencies involved. The Equilibrium Theory of Tides separates the different effects into a set of constituents by conducting a harmonic analysis. The relevant periods are:
the lunar day (period of lunar rotation), 24.84 mean solar hours.
the sidereal month (period of lunar declination), 27.32 mean solar days.
the tropical year (period of solar declination), 365.24 mean solar days.
the period of the lunar perigee, 8.85 years (1 year = 365.2421988 days).
the period of the lunar node, 18.61 years.
the period of the solar perihelion, 20940 years.
The explanation of each constituent can be rather complex (some examples in this other answer). The different amplitudes in a day and the spring-neap cycle are related to the combination of the main lunar and solar effects.
The differences in high/low tide from month to month are related to the next two main frequencies of oscillation. Mainly, the variations in Earth-Sun distance associated occurring in a period of tropical year. The lunar distance also contributes to these differences, but its cycle is much longer (~9 years). Also, the spring-neap cycle (with a frequency of half a lunar month ~13.5 days) will occur at different times of the month and can lead to differences in tidal amplitude if you compare the tides measured the same day of consecutive months.
(Source www.niwa.co.nz)
The following is multiple choice question (with options) to answer.
Tides can change in different locations because | [
"A higher power",
"God",
"Magic",
"the pacific's bottom"
] | D | the tide cycle regularly occurs twice per day |
OpenBookQA | OpenBookQA-3971 | homework-and-exercises, astronomy, popular-science, moon, observational-astronomy
Title: Identifying the position of the moon I encountered the following question in a previous year paper of a graduation-based test.
On a certain night the moon in its waning phase was a half-moon. At midnight the moon will be (choose one of the following)
on the eastern horizon.
at 45 degrees angular height above the eastern horizon.
at the zenith.
on the western horizon.
I remember looking out of my window and finding the moon on left and sometimes on right. I never imagined that it would be having a fixed pattern. This question is making me think otherwise. But I am unable to decide what that pattern is. Is the position of the moon really determine-able? The waning half moon is 3 weeks old, it rises at about midnight. All celestial objects appear to rise in the east and set in the west because of the rotation of the earth. Therefore, from your choices, the answer would be 1, on the eastern horizon.
I guess that doesn't fully answer your question, which is different from the question you reference. The moon rises about 48 minutes later each day. When the moon is full it rises as the sun sets because it is... full. 3 weeks later you have 21 days * 48 minutes = 1008 minutes or about 17 hours. If the sun sets at 6pm then the moon will rise about 17 hours later, and about an hour later, at midnight, it will be just above the eastern horizon. Hope that makes more sense :)
The following is multiple choice question (with options) to answer.
How long is it between a moon phase? | [
"a minute",
"168 hours",
"an hour",
"a day"
] | B | a different moon phase occurs once per week |
OpenBookQA | OpenBookQA-3972 | thermodynamics, forces, water, estimation, freezing
Here, a phase diagram for water is useful. The discussion in Powell-Palm et al.'s "Freezing water at constant volume and under confinement" includes a volume–temperature phase diagram:
From this, we can predict the equilibrium response when heating or cooling water at constant volume (by moving vertically) or compressing or expanding water at constant temperature (by moving horizontally). We find that at constant volume (moving vertically downward from 0°C and 1 g/cc), over 200 MPa and 20°C undercooling is required* to get even a 50% slush of water and ice.
Let's zoom out a little. From Powell-Palm, "On a temperature-volume phase diagram for water and three-phase invariant reactions in pure substances," we find that 209.9 MPa is ultimately required* for complete solidification, into a two-phase region (at equilibrium) of ice-Ih (ordinary ice) and ice-III:
(Note that "0.00611 MPa" should read "0.000611 MPa"—the authors missed a zero.)
We can interpret this as the compact structure of ice-III providing a solution to the problem of ice-Ih being anomalously voluminous. We find from the temperature–pressure phase diagram of water that this ice-III nucleates (at equilibrium) upon cooling to 251 K, or -22°C:
The following is multiple choice question (with options) to answer.
How many phases are present in a closed flask if it contains ice, water and air | [
"5",
"3",
"2",
"6"
] | B | Matter in the liquid phase has definite volume |
OpenBookQA | OpenBookQA-3973 | reinforcement-learning, off-policy-methods, expectation, importance-sampling, conditional-probability
Hence, $\mathbb{E}[\rho_{t:T-1}R_{t+k}]= \mathbb{E}\left[\frac{\pi(A_{t}|S_{t})}{b(A_{t}|S_{t})}\frac{\pi(A_{t+1}|S_{t+1})}{b(A_{t+1}|S_{t+1})}\frac{\pi(A_{t+2}|S_{t+2})}{b(A_{t+2}|S_{t+2})}......\frac{\pi(A_{T-1}|S_{T-1})}{b(A_{T-1}|S_{T-1})}R_{t+k}\right] \\=
The following is multiple choice question (with options) to answer.
An example of a learned behavior is | [
"catching a frisbee",
"cows eating grass",
"having blue eyes",
"birds growing wings"
] | A | if an animal is trained to do something then that something is a learned behavior |
OpenBookQA | OpenBookQA-3974 | zoology, experimental
Title: Fish "coming back to life" after being frozen I've encountered a clip on Youtube showing a goldfish thrown in liquid nitrogen and immediately after to normal water and swimming normally. In the explanation to the clip it says:
For everyone that is worried about the goldfish, it survived and was perfectly fine until we fed him and a few of his friends to our turtles. (Which is what they were bought for in the first place!)
I am wondering now as to several issues.
If the goldfish wasn't fed to the turtles and was allowed to live out its life, would it suffer any long term damages from the act?
Is time an issue here, if the fish was kept frozen for a longer time, would it suffer more damage and would it be able to be revived?
Is the size and nature of the fish's body a factor? Would a larger animal or an animal with better resistance to frost that would take more time to completely freeze have damage due to gradual freezing of body and systems?
Does the fact that fish have cold blood affect the result of the experiment? I have no idea what's the real reason for the survival of the poor fish, but I would guess this is all in the timing. I know for certain ;-) that one can submerge a hand in liquid nitrogen for a short time or in general one can pour liquid nitrogen on the skin with no harm done whatsoever.
The reason is that the difference in temperature that interface (-180 deg C or so for liquid nitrogen and 20-30 for the skin surface) is so large that nitrogen vaporizes instantly and does not penetrate/affect the tissue. The demonstrator could have pulled the fish with bare hands.
I think that for the goldfish the time was too short and while it was cooled/shocked a bit, it might have been too short to do any serious damage. But -
As a scientist, I can't help but notice that we don't really know the condition of the fish before or after the liquid nitrogen 'treatment'. We only see it flapping for a few seconds when back in water. I wonder what happened to the eyes and the mouth, both quite sensitive tissues for such a shock. Also, the water the fish was in was a factor probably, providing additional buffer between the fish and the liquid nitrogen.
Last but not least, the ethical committee quite certainly did not approve that demonstration.
The following is multiple choice question (with options) to answer.
How should John proceed with eating the fish he just caught? | [
"biting right into it raw",
"hold the fish up the sunlight",
"putting his boot on a fire spit",
"striking flint over kindling and placing the fish above it"
] | D | cooking food requires adding heat energy |
OpenBookQA | OpenBookQA-3975 | botany, mathematical-models, statistics, biostatistics, migration
Title: Biostatistics: Pollen dispersal directionality What Information am I looking for?
Think about a tree that is sending pollen all over the place. Because of wind, most pollen grain will go toward one direction. Imagine, we split the 2D area around the tree where pollen grains fall into two half disks of equal size. We chose the disks so that the number of pollen grains falling into one half-disk is minimized and the quantity of pollen falling in the other half-disk is maximized.
The information I need is what proportion of pollen grain falls into each disk? Is it $\frac{0.5}{0.5}$ (in which case the wind would have no effect) or is it something like $\frac{0.8}{0.2}$?
Where to get the information from?
I was reading this paper about pollen dispersal directionality and was trying to extract the info I need.
On pages 4 and 5 they explain their analysis under the section statistical procedure. More specifically, in the first paragraph of the 5th page, they seem to describe the meaning of the parameters that are trying to estimate. One of them is the so-called directionality parameter $\delta$. I don't understand how to interpret this parameter $\delta$. This parameter is part of a logistic regression I think (although the authors do not characterize it as such) of "mating success" $y$ against variables $d$ ("distance") and $h$ ("height") and an angular variable $a = \cos(\alpha_0 - \alpha)$. ($\alpha_0$ is the "presumed prevailing direction of effective pollen dispersal," which apparently is not estimated from these data.) The corresponding parameters of the model are $\beta$, $\gamma$, and $\delta$, respectively, hence
$$\phi_j = \Pr(y_j = 1) = \frac{\exp\left(\beta d_j + \gamma h_j + \delta a_j\right)}{\sum_{k=1}^r \exp\left(\beta d_k + \gamma h_k + \delta a_k\right)}$$
The following is multiple choice question (with options) to answer.
pollination is when wind carry pollen from one flower to another | [
"genetically similar thing",
"rock",
"cloud",
"water"
] | A | pollination is when wind carry pollen from one flower to another flower |
OpenBookQA | OpenBookQA-3976 | thermodynamics, climate-science
Title: Where does all the heat go during winter? I do not understand where actually the heat in our surroundings go during the winter season. Is it radiated out into space? I know it cannot coz global warming would not be a issue then. It might get absorbed but where? I tried figuring it myself but couldn't please help.
Where does all the heat go during winter?
There is less energy coming from the sun in the form of electromagnetic radiation impinging on the land during winter.
Depending on the latitude, in regions where there is winter , the difference is large.
The closer to the equator the smaller the effect of "winter".
So it is not where the energy goes, but why it does not fall , and this is explained to first order by the inclination and the distance to the sun during the orbit of the earth.
In general , a body in space radiates energy away the rate depending on various conditions, like green house gases, cloud cover, convection , albedo ...the numbers change . It is the continuous radiation from the sun that keeps replenishing the energy so that the earth does not freeze. During winter at high lattitutes , less energy comes and cold settles.
The following is multiple choice question (with options) to answer.
A place becomes chilly and then animals in that space | [
"sweat more often",
"lose more water",
"need more hydration",
"retain more water"
] | D | as temperature in an environment decreases , the amount of water an animal in that environment will lose will decrease |
OpenBookQA | OpenBookQA-3977 | $\implies t = \frac{2\pi (R+r)}{v}$
Total angular distance traversed by $A$ around its centre in the same duration: $\theta = \omega t$
Using the above results, we get $\theta = \frac{v}{r} \frac{2\pi (R+r)}{v} = \frac{2\pi (R+r)}{r}$
In this time $t$, $A$ completes, say, $N$ rotations around its centre.
$\implies N = \frac{\theta}{2\pi} = \frac{(R+r)}{r}$
Now, In your case $r = \frac{R}{3}$
Using this information, $N = 4$
Thank you everyone for your answers. They were all informative, but I wasn't able to intuitively understand them until I saw this visual:
https://www.geogebra.org/m/v3a437ux
The key for me was to see that there are two kinds of revolution happening:
1. Revolutions of Circle A with respect to Circle B, and
2. Revolutions of Circle A with respect to the (overhead) observer.
To the observer, the revolutions of the type (2) complete before revolutions of type (1). The revolutions of type (1) happen at the $$r_B/r_A$$ roots of unity, and the revolutions of type (2) happen at the $$(r_B/r_A + 1)$$ roots of unity. It was very helpful to see precisely where these revolutions occur, because it was mentally impossible to unify the two types of revolution without the visual. It's also useful to notice that at any given moment, with respect to the observer, the points of Circle A on the far side from Circle B are moving faster than the points of Circle A on the side that is touching Circle B.
David K's answer is great for understanding that the parametric mapping of time to point pairs is the same whether Circle A is rolling along a straight line or a circle, and that we are dealing with frames of reference. I simply didn't believe the mapping was the same until I saw the visual.
The following is multiple choice question (with options) to answer.
a revolution is when something revolves around | [
"dancing",
"poetry",
"more physical matter",
"cupcakes"
] | C | a revolution is when something revolves around something else |
OpenBookQA | OpenBookQA-3978 | 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.
Where are you most likely to see a healthy amount of pollinating insects? | [
"Where water is plentiful and flowers are everywhere",
"Where water is plentiful and flowers are few",
"Where flowers are everywhere and spiders are hungry",
"Where water is depleted and flowers are everywhere"
] | A | as available resources increases , the population of an organism that uses those resources will increase |
OpenBookQA | OpenBookQA-3979 | biochemistry, botany, plant-physiology, photosynthesis, agriculture
The above image is an example of a "potato battery" made without the potato. Identical setup and the energy obtained is identical given everything else the same.
Potato power- er, metal power?
This experiment is supposed to demonstrate the concept of an electrochemical cell. Electrochemical cells obtain their energy from the reduction-oxidation reactions that happen between two metals with different reduction potentials. When two metals - such as copper and zinc - are placed in a medium that permits the exchange of electrons and ions, an electrical gradient is produced as electrons move from one metal to the other and ions move the other direction. This gradient can then be captured and used to do work such as powering a lightbulb or an AI.
In the potato powered example, the power comes from zinc and copper. If you want a more powerful battery, use more zinc and more copper- not a bigger potato. If that is not good enough, try replacing the zinc with something like lithium- this is what we've done with modern, rechargeable batteries.
In truth, the potato battery would be better described as a normal battery that just happens to be inserted into a potato. You'll make a better battery if you use copper pennies and aluminum foil in vinegar.
I do not mean to shoot down your idea, and I am glad you are looking into renewable energy sources- but you may be better served by a class on electricity and batteries than by asking questions on biology.SE!
EDIT: I would assume that the electrical potential of this kind would also kill the plant, given that you're essentially electrocuting it. However, I was unable to find any information on the resistance of potato plants to electrocution.
The following is multiple choice question (with options) to answer.
An example of replacing a natural resource like copper might be | [
"recovering ores",
"running around",
"throwing up",
"using plastic straws"
] | A | An example of replacing a natural resource is planting new trees where a forest once stood |
OpenBookQA | OpenBookQA-3980 | thermodynamics, evaporation, gas, liquid-state
On the water surface, knowing the temperature, we can estimate the vapor pressure and vapor mixture fraction. Then there will be an diffusion process for the water vapor to move out and for the ambient air to move in. Because the water surface doesn't allow the air to further move, a circulation forms. When the water vapor moves out, the water vapor pressure drops, so more liquid water evaporates to fill up the loss of water vapor. The evaporation associates latent heat so water surface area temperature drops (you may see dew on the bowl wall). Then a heat transfer process starts which may initiate water circulation as well.
As this is complex, doing test might be a quick way to get the K value if you assume it is a constant, which is questionable.
The following is multiple choice question (with options) to answer.
A thing that is introduced to thermal activity will likely do this if it is able to drip: | [
"chill",
"evaporate",
"ice over",
"freeze"
] | B | as the temperature of a liquid increases , the rate of evaporation of that liquid will increase |
OpenBookQA | OpenBookQA-3981 | thermodynamics, evaporation, gas, liquid-state
On the water surface, knowing the temperature, we can estimate the vapor pressure and vapor mixture fraction. Then there will be an diffusion process for the water vapor to move out and for the ambient air to move in. Because the water surface doesn't allow the air to further move, a circulation forms. When the water vapor moves out, the water vapor pressure drops, so more liquid water evaporates to fill up the loss of water vapor. The evaporation associates latent heat so water surface area temperature drops (you may see dew on the bowl wall). Then a heat transfer process starts which may initiate water circulation as well.
As this is complex, doing test might be a quick way to get the K value if you assume it is a constant, which is questionable.
The following is multiple choice question (with options) to answer.
There are 5 steps in the water cycle, it starts with evaporation, ends with infiltration, and then | [
"cries",
"goes away",
"dies",
"Restarts"
] | D | a cycle happens repeatedly |
OpenBookQA | OpenBookQA-3982 | metals
Title: Why does carbon alloy with iron specifically? Everyone knows what an alloy is: it's a metal made by melting two (or more) other metals together.
Unless of course you're talking about steel. That's a metal made by mixing carbon (very much not a metal) into molten iron. But you never hear about carbon alloys with any other metal, and that's kind of strange. If a few percentage points of carbon can turn iron into the miracle metal that is the foundation of the Industrial Age, just imagine what it could do to aluminum or titanium, for example. (Or even bronze, for that matter, which is superior to iron in many ways, from a materials science perspective.)
But you only ever hear about carbon alloying with iron to form steel. So what's so special about iron? It's true they are not common, but there are other alloys that use carbon. Nickel is probably one of the more common metals that form alloys with carbon that have desirable properties. For example, Nickel 200, Nickel 201, and Nickel 205 all contain carbon. (See: http://www.asminternational.org/documents/10192/1852239/ACFA9D7.pdf/d490dee6-620e-4e38-b64d-53dd02c5fc81). Chromium and Tungsten also form alloys with carbon called Stellite Alloys: See http://en.wikipedia.org/wiki/Stellite (although some, but not all, stellite alloys contain iron too).
The following is multiple choice question (with options) to answer.
What is something that could be made from iron? | [
"Cats",
"RVs",
"Wood",
"Feelings"
] | B | iron nails are made of iron |
OpenBookQA | OpenBookQA-3983 | java, object-oriented, game
/**
* Returns location of last move or null.
*
* @return
*/
public GoPoint getLastMove() {
return lastMove;
}
/**
* Returns true (and removes the Stone) if the move is suicide. You need to
* actually add the stone first.
*
* @param gp
* @return true if the move is suicide
*/
private boolean isSuicide(GoPoint gp) {
if (isDead(gp, new HashSet<GoPoint>())) {
removeStone(gp);
return true;
}
return false;
}
/**
* Adds Stone and removes dead neighbors.
*
* @param gp
*/
private void addStone(GoPoint gp) {
StoneColor stoneColor;
if (itsBlacksTurn) {
stoneColor = StoneColor.BLACK;
} else {
stoneColor = StoneColor.WHITE;
}
stones.put(gp, stoneColor);
for (GoPoint neighbor : getNeighbors(gp)) {
removeIfDead(neighbor);
}
}
private void removeStone(GoPoint gp) {
stones.put(gp, StoneColor.NONE);
}
private Set<GoPoint> getNeighbors(GoPoint gp) {
Set<GoPoint> neighbors = new HashSet<>();
if (gp.getRow() > 0) {
neighbors.add(getPointAt(gp.getRow() - 1, gp.getCol()));
}
if (gp.getRow() < size - 1) {
neighbors.add(getPointAt(gp.getRow() + 1, gp.getCol()));
}
if (gp.getCol() > 0) {
neighbors.add(getPointAt(gp.getRow(), gp.getCol() - 1));
}
if (gp.getCol() < size - 1) {
neighbors.add(getPointAt(gp.getRow(), gp.getCol() + 1));
}
return neighbors;
}
The following is multiple choice question (with options) to answer.
Feces on the ground is an indicator of a nearby | [
"organic being",
"fish",
"plush animal",
"deceased animal"
] | A | an organism is a source of organic material |
OpenBookQA | OpenBookQA-3984 | electricity, reference-frames, electronics
Title: Floating Voltage Referenced to Ground So, I came across something interesting today at work that is completely confusing me. We have floating 130V battery backups, and I am told there is neither any ground reference, nor any center tap on the bank of batteries. As normal, if you measure from positive to negative, you get the full range of 130V, and negative if you flip the leads. If the batteries are not connected to any form of a load, then if you use ground as the reference on your multimeter, you get no voltage(minus a little bit of noise). So far so good.
Here is where I get lost. Put a load across these batteries, and now if you measure with reference to ground, you get +65V on the positive terminal, and -65V on the negative terminal. Without any form of a complete circuit, I for the love of me am not able to understand how a load across a floating battery can produce both a positive and negative voltage! I mean, with a floating system, ground should really be no different than using a sandwich as a reference point. I would assume that any reference point outside the floating system would just produce noise.
If anyone is able to explain this phenomenon to me, I would greatly appreciate it! First, let me say that I'm not familiar with the details on how battery backups are connected to the loads in a building when they are switched onto the loads, so the following might not be correct. But I assume that the backup battery back is an emergency backup and is therefore only connected to the building load when primary power fails and the battery pack is switched onto the load.
Though the battery pack may initially be isolated from ground, once it is connected to the building loads, depending on how it is connected, it may no longer be isolated from ground. That is because the building loads themselves are grounded. In the US the neutral conductors of branch circuits serving loads are tied to ground at the service panel.
Bottom line: Once the load is connected to the battery pack, I suspect your battery pack is no longer isolated from earth ground. So depending exactly on how the pack is connected to the load, you may read a voltage to ground from the battery pack.
Hope this helps.
The following is multiple choice question (with options) to answer.
Ground has | [
"electricity",
"divorce",
"elements",
"common understanding"
] | C | Earth is made of rock |
OpenBookQA | OpenBookQA-3985 | combustion
But when things are that hot, plenty of other reactions can occur and this is particularly noticeable if the thing that is burning is less pure than charcoal (which is mostly carbon). Raw coal, for example, contains a lot of volatile impurities (smokeless coal is deliberately treated to reduce the volatile impurities). When the primary reaction of burning carbon happens in raw coal, those volatiles are often turned to gases and driven off the coal to combust as gases far from the solid coal. Of course this is happening at the same time as solid carbon in the coal is burning so the two effects are mixed up to give both glowing coal and gases burning some distance from the glowing coal. Old home chemistry sets used to contain experiments that allowed these effects to be separated. Raw coal is placed in a vessel connected to a tube allowing any emerging gas to be directed far away from the coal. The coal is heated with an external source (eg a Bunsen burner). The emerging volatile gases can then be lit without setting the coal on fire giving a flame a long distance away from the heated coal.
The same can be done with wood (which contains even more volatile and flammable components than coal).
So, when wood or coal burn in an uncontrolled way both the burning of the solid and the burning of the volatiles contained with the solid occur at the same time but the volatiles (as gases) can move far from the solids before they burn. This is why the position of the fame can be far from the burning solid.
Also worth noting
In addition to the volatiles being driven from the burning solid, partial combustion can also create gases like carbon monoxide which can then travel some distance away from the solids while burning (though CO tends to have not very bright blue flame). In fact a controlled version of this reaction (which sometimes also used steam to create hydrogen) was once the primary way of creating town gas (which was widely distributed to support gas lighting and cookers in cities.
If the primary goal is to create flames designed to illuminate rather than heat then burning can be designed to create a lot of small hydrocarbon particles in the flame. This is intentional for things like candles. Here the heat may come from burning the was but the light comes because that burning creates small incandescent soot particles which are heated enough to glow turning a lot of the energy into light.
The following is multiple choice question (with options) to answer.
Coal might start out as | [
"a mean fairy-godmother",
"pinecones",
"happiness",
"a troll"
] | B | coal is a nonrenewable resource |
OpenBookQA | OpenBookQA-3986 | respiration
Here is what happens at the molecular level.
The $\rm CN^-$ ions diffuse into the mitochondria. They have high affinity to the ferrous ion of the mitochondrial enzyme cytochrome c oxidase involved in the electron transport chain (ETC), one of the phases of cellular respiration where $\rm ATP$ is generated from $\rm NADH$ and $\rm FADH_2$. And it is this process that actually requires oxygen. The inhibited cytochrome c oxidase is of no good in transporting electrons, thus no $\rm ATP$ molecules are generated. The oxygen molecules waiting for those electrons remain empty handed resulting in the increase in the concentration of molecular oxygen. Remember, ETC occurs in almost all living cells except a few like RBC which get their major share of ATP from the highly inefficient anaerobic glycolysis. Also, $\rm ATP$ is the energy currency of our body and is required in a wide variety of bodily processes like osmotic balance, nerve impulse transmission, muscle contraction etc. With no $\rm ATP$ your heart and respiratory muscles can't contract, your medulla can't regulate breathing, your kidneys can't concentrate urine and the list goes on. Death is imminent if a high concentration of cyanide gets into your blood.
The symptoms of panic like tachypnea and tachycardia (that result due to low oxygen in blood) are not usually seen unless the victim himself knows he is poisoned. The end effects like cardiac and respiratory arrest, seizures and coma, however, are similar to those of suffocation.
For further read:
The Mechanism of Cyanide Intoxication and its Antagonism
The following is multiple choice question (with options) to answer.
The substance that the respiratory system takes in from the air is released by | [
"insects",
"birds",
"plants",
"bears"
] | C | the respiratory system takes in oxygen from the air |
OpenBookQA | OpenBookQA-3987 | experimental-chemistry, analytical-chemistry, electrostatic-energy
If you are frequently measuring magnetic materials, many analytical balances can be configured in a bottom-loading arrangement. In this setup a platform is hooked beneath the balance, and the sample is supported sufficiently far away from the force-restoring motor so that it does not influence the measurement.
The following is multiple choice question (with options) to answer.
A balance is used to measure the what of a substance? | [
"depth",
"height",
"tall",
"heaviness"
] | D | a balance is used for measuring weight of a substance |
OpenBookQA | OpenBookQA-3988 | 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.
Good stewards of the environment would | [
"pour old medications down the sink drain",
"choose plastic bags over reusables",
"purchase transportation that uses alternate fuel sources",
"use Styrofoam instead of paper plates"
] | C | electricity causes less pollution than gasoline |
OpenBookQA | OpenBookQA-3989 | human-biology, neuroscience, zoology, physiology, history
If it is a mutation or set of mutations as the current thinking implies, there is a good chance that it is a combination of strong selection and accident. Its true that cooperation is often enjoys a strong selective advantage, but it doesn't make you smart or hospitable. When we talk in biology we don't say altruism, we say cooperation. If such cooperation happened only because of selection, we would see such behavior in other primates. So if we see this, I would lay odds to look for a rather complicated story...
Another interesting person to read is anthropologist Terrence Deacon, who is trying to understanding the terms with which we define intelligence. About ten years ago there were actually experiments that showed that chimpanzee some strong candidate intelligence genes related to cognition could be put into people (who needed gene therapy because they had lost cognitive function) and restore that function. Apologies, this is anecdotal - i saw him give a great talk, but he's moved on a bit and can't find the references.
This is important I think because the fundamental definitions of human intelligence have failed over the years, from the old chestnut of using tools, to a recognition of mortality, to awareness, animals have surprised us, particularly primates. I wonder whether we will be able to confirm these vital factors until we get a monkey asking for the keys to the car so that they can go get some pizza.
The following is multiple choice question (with options) to answer.
An innate instinct could be | [
"Learning how to drive a car",
"a dog drooling when it sees food",
"Learning a new language",
"Learning how to do a cartwheel"
] | B | An example of an instinct is the kangaroo 's ability to crawl into its mother 's pouch to drink milk |
OpenBookQA | OpenBookQA-3990 | Exercise 1 Develop similar sifting formulations of the other three Landau problems.
In view of these sieving interpretations of number-theoretic problems, it becomes natural to try to estimate the size of sifted sets ${A \backslash \bigcup_{p | P} E_p}$ for various finite sets ${A}$ of integers, and subsets ${E_p}$ of integers indexed by primes ${p}$ dividing some squarefree natural number ${P}$ (which, in the above examples, would be the product of all primes up to ${\sqrt{x}}$). As we see in the above examples, the sets ${E_p}$ in applications are typically the union of one or more residue classes modulo ${p}$, but we will work at a more abstract level of generality here by treating ${E_p}$ as more or less arbitrary sets of integers, without caring too much about the arithmetic structure of such sets.
It turns out to be conceptually more natural to replace sets by functions, and to consider the more general the task of estimating sifted sums
$\displaystyle \sum_{n \in {\bf Z}} a_n 1_{n \not \in \bigcup_{p | P} E_p} \ \ \ \ \ (1)$
for some finitely supported sequence ${(a_n)_{n \in {\bf Z}}}$ of non-negative numbers; the previous combinatorial sifting problem then corresponds to the indicator function case ${a_n=1_{n \in A}}$. (One could also use other index sets here than the integers ${{\bf Z}}$ if desired; for much of sieve theory the index set and its subsets ${E_p}$ are treated as abstract sets, so the exact arithmetic structure of these sets is not of primary importance.)
Continuing with twin primes as a running example, we thus have the following sample sieving problem:
The following is multiple choice question (with options) to answer.
Which of these could be separated with a sifter | [
"a cup of coffee",
"a bowl of melted ice cream",
"a bottle of water",
"a bowl of cereal"
] | D | a sifter is used for separating mixtures |
OpenBookQA | OpenBookQA-3991 | 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.
feeders attract animals to a | [
"volcano",
"video game",
"nearby spot",
"moon"
] | C | feeders attract animals to a location |
OpenBookQA | OpenBookQA-3992 | newtonian-mechanics, forces, water, collision, estimation
The reason why the deceleration times are different between concrete and water is related to the fact that concrete is a solid and water is a liquid. The molecules in concrete are locked into a rigid configuration. Concrete molecules don't move around freely - when you push on concrete, the concrete doesn't move, it pushes back to resist even large forces. Molecules in water, on the other hand, freely flow past one another - when you push on water, it accelerates out of the way. When confronted with a large force, a material can either resist it (like concrete), or yield to it (like water). Imagine being on ice skates - you can push off a rigid wall to accelerate yourself backwards, but if you push off another person on skates, you won't move as quickly, since the thing you're pushing off of yielded to the force of the push.
The following is multiple choice question (with options) to answer.
A bobsled moves much faster as it leaves the concrete an touches the | [
"sand",
"grass",
"sun",
"ice"
] | D | as the smoothness of something increases , the friction of that something will decrease when its surface moves against another surface |
OpenBookQA | OpenBookQA-3993 | combustion
Title: What happens when you 'burn' ash? This popped into my my mind while watching a match burn (don't ask me what I was doing with a burning match...).
Now as I know it, 'ash' is what you call the residual, grey-black powdery material left over following the combustion of wood.
I'm under the impression that ash is largely just carbon, with little or no organic constituents present along with it (since I'm pretty sure that pure powdered carbon is black, not grey-black).
Now I heated what remained of the matchstick with, well...another matchstick and found out, unsurprisingly, that the ash underwent practically no visible change. So I scooped up some ash into a crevice in a concrete block and then blow-torched it for about 2 minutes. Same result. However, while I was heating it this time, it glowed orange, it subsided as soon as I turned off the torch.
Thinking about it, if I did heat it strong enough it should decompose completely to black colored elemental carbon. If that is the case, to what temperature should you heat it?
I don't think I've considered everything there is to consider in this situation, which is why I've adopted a tentative tone while typing out this question.
Could there be other, side-reactions/effects as well? What would they be?
Additionally if anyone happens to know; what is it that contributes to the grey color that ash normally assumes? The principal component of wood ash appears to be calcium carbonate. (Wiki entry, "wood ash".) Other components include compounds of potassium and phosphorus. If you heat the calcium carbonate strongly enough, it will decompose into CO2 and calcium oxide. Apparently, strong heating is likely to result in less carbon instead of a larger percentage. The remaining calcium oxide is pretty stable as to temperature although addition of water will readily convert it to calcium hydroxide.
Calcium carbonate is white. White mixed with the black of any carbon present would result in a grey color.
The following is multiple choice question (with options) to answer.
if a person commits arson, which of these might be found as the source in the remains? | [
"a new cold water bottle",
"a new portable stove",
"a new hot coffee",
"a blue plastic comb"
] | B | a hot plate is a source of heat |
OpenBookQA | OpenBookQA-3994 | homework-and-exercises, electricity, electric-circuits, electrical-resistance
Title: A zero potential difference in a wire in a parallel circuit, but there is a problem? I was studying parallel and series connections for circuit and came a cross a problem that could not understand.
Now look at this problem:
lets say current (I) is coming from the left:
the current (I) will be separated looking for the lowest resistance (I mean Highest (I) will be at the lowest Resistance), but I1 will be equal to I2 since both resistors equal to 5 ohm and Voltage is constant in parallel circuit. the problem that no current should pass through the middle wire (the rotated one in the middle of the image) as Potential difference across its ends will be 0 for some reason that I do not understand.
Sorry for my very bad explanation but I really do not understand what I am saying.
the problem that no current should pass through the middle wire (the rotated one in the middle of the image) as Potential difference across its ends will be 0 for some reason that I do not understand.
Imagine you removed the middle wire. Now calculate the potentials at the two nodes where the wire was previously attached.
What's the potential difference between them?
Now imagine you placed the middle wire back in the circuit.
How does that affect the circuit?
The following is multiple choice question (with options) to answer.
A circuit is parallel when more than one pathway has flowing what? | [
"ideas",
"stocks",
"water",
"zapping energy"
] | D | if electricity flows along more than one pathway then the circuit is parallel |
OpenBookQA | OpenBookQA-3995 | = ",Count[Drop[branches,gen],_Real,\[Infinity]]/4" "" ""Length = ",SetAccuracy[Count[Drop[branches,gen],_Real,\[Infinity]]/4*(Norm[{{pt1[[1]],0.5},{0,0}}]^gen),3]}],18],Gray],{2.3,-1.8}]},{Inset[Style[Text@TraditionalForm@Style[Row[{"Polynomial Trees by Bernat Espigulé"}],18],Gray, Opacity[0.4]],{2.3,-2}]}},PlotRange->{{-1.7,3.7},{-2.1,1.5}},ImageSize->{1000,600},Background->Black]],{{th,0.025,"Thickness"},0.005,0.185},{{gen,12,"Generations"},Range[1,16], ControlType -> SetterBar},{{pt1,{0.5,0.5}},{-0.5,0.5},{0.5,0.5},Locator}]Jurassic Trees
The following is multiple choice question (with options) to answer.
A cypress tree's stout roots splitting asphalt is an example of | [
"cookie elves",
"compacting",
"weathering",
"beer"
] | C | a plant 's roots slowly break down rocks as the roots grow |
OpenBookQA | OpenBookQA-3996 | exitcoupled<-function(){
june =0
tessa =0
njune=0
ntessa=0
while(june < 5){
v = coupled()
june <- june + 2*v[1] -1
tessa <- tessa + 2*v[2] -1
njune <- 1+njune
ntessa <- 1 + ntessa}
while(tessa <5){
tessa <- tessa+ 2*rbinom(1,1,0.5) -1
ntessa <- 1 + ntessa
}
c(njune, ntessa)
}
replicate(25, exitcoupled())
## [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8]
## [1,] 5 17 27 17 15 9 7 19
## [2,] 627 33 355 35 27 107 57 53
## [,9] [,10] [,11] [,12] [,13] [,14] [,15]
## [1,] 11 17 9 35 35 9 17
## [2,] 22761 43 9 135 575 15 19
## [,16] [,17] [,18] [,19] [,20] [,21] [,22]
## [1,] 5 11 23 7 29 13 9
## [2,] 7 121 231 39 81 17 147
## [,23] [,24] [,25]
## [1,] 13 7 7
## [2,] 93 91 213
# 6 Total variational distance
The following is multiple choice question (with options) to answer.
Melissa observes a plant and records her observations. On Monday it is 4 cm tall. On Friday it is 5 cm tall. Melissa concludes that the plant is | [
"dead",
"alive",
"flowering",
"green"
] | B | all living things grow |
OpenBookQA | OpenBookQA-3997 | energy, power, sun, solar-system
EDIT:
I understand that the energy flux is given by:
$$\text{G}=\mathcal{k}\cdot\text{T}^4\cdot\left(\frac{\text{R}}{\text{D}}\right)^2\tag2$$
Where $\mathcal{k}$ is the Boltzmann constant, $\text{T}$ is the surface temprature of the sun, $\text{R}$ is the radius of the sun and $\text{D}$ is the distance from the sun to the earth.
Now, for $\text{D}$ we know that is changes over a year because the earth makes a elliptical orbit around the sun. This answer first of all gives a simple-minded approach which has some numbers, and then a more hairy one which doesn't.
The simple approach, with numbers
So, first of all, $1367\,\mathrm{W/m^2}$ is the solar constant: it's the measured flux of energy from the Sun at the top of atmosphere (TOA), averaged over a year. So this flux is, the TOA flux for the point on the planet where the Sun is directly overhead (all other points get less). I'll call this $G_0$.
But the Earth's orbit has some eccentricity in it, so in fact sometimes this flux is a bit higher, and sometimes it's a bit lower. To first order we could model this by saying that the flux looks like
$$G = G_0\times(1 + E\cos (2\pi y))$$
where $E$ is some fudge factor based on the known eccentricity of the planet's orbit, $y$ is the time in years ($y$ is not constrained to be an integer), with $y=0$ being chosen as the point where the Earth is closest to the Sun. Observationally, $E \approx 0.03$.
Well, perhaps we want the constant in terms of day of the year, rather than year, which would be more useful. This would then look like
The following is multiple choice question (with options) to answer.
the sun transfers solar energy from itself to the Earth through | [
"electricity",
"water",
"rocks",
"sunradiation"
] | D | the sun transfers solar energy from itself to the Earth through sunlight |
OpenBookQA | OpenBookQA-3998 | species-identification, botany, ecology
Title: Algae or Lichen identification. Coastal BC, Canada I have tried all books and internet resources I know of, but I still have no idea what this might be — a lichen or something else.
At first glimpse, I thought it was something man-made and unnatural, but then I looked closer and saw how it appears to be attached and growing. It grows on exposed rocks well above the high tide. The photo is taken in late March, on northern Vancouver Island. It's loosely attached to the rock.
It was somewhat abundant around the general area (within of a few km), but I haven't seen it elsewhere - although I'm not from BC so there might be a lot of this around.
The water droplet in the lower right corner give a rough sense of scale.
Edit:
Adding another photo in which I just noticed a streak of white, which I included in original resolution. I want to propose you expand your search to a broader taxonomic scope. Specifically, I think you might be looking at a species of "red" green algae (family: Trentepohliaceae).
From Nelson et al. (2011):
All Trentepohliaceae have filamentous growth forms and often contain large amounts of carotenoid pigments (ß-carotene and hematochrome), causing the algae to appear yellow orange in color (Thompson and Wujek 1997, Lo´pez-Bautista et al. 2002).
The Trentepohliaceae contains five genera: (Trentepohlia, Printzina, Phycopeltis, Cephaleuros and Stomatochroon) and 70+ species worldwide.
For example, the following algae (picture from England) looks fairly similar to your specimen:
Trentepohlia aurea
Source: David Fenwick
If your specimen is a species in this family of algae, it is most likely in the Trentepohlia genus (or possibly Printzina genus).
Trentepohlia is a genus of filamentous chlorophyte green algae in the family Trentepohliaceae.
Typically orange or yellow in color.
Live on tree trunks and wet rocks or symbiotically in lichens.
Here's a picture of a free-living Trentepohlia species from coastal Oregon, USA:
Source: Richard C. Hoyer (2015)
The following is multiple choice question (with options) to answer.
Coral get their ____ from algae | [
"vibrance",
"love",
"apples",
"candles"
] | A | usually coral lives in warm water |
OpenBookQA | OpenBookQA-3999 | soil
An analogous hypothesis proposed by RUSSEL3 for increases in the number of bacteria after partial sterilization by heat, frost, or other means is that by such partial sterilization the protozoa are killed, thus permitting the unhindered development of bacteria which under normal conditions is held in check by protozoa.
BROWN and SMITH (loc. cit.) in their investigations dealt mainly with the physiological activities of bacteria under conditions of low temperature and frost, although they also made some determinations of the number of bacteria in frozen soil. Their principal conclusions regarding the ammonifying, nitrifying, denitrifying, and nitrogen fixing powers of frozen soils are as follows: (1) that "frozen soils possess a much greater ammonifying power than unfrozen soils"; (2) that "during the fall season, the ammonifying power of the soil increases until the temperature of the soil almost reaches zero, when a decrease occurs, and this is followed by a gradual increase and the ammonifying power of the soil reaches a maximum at the end of the frozen period"; (3) that "the nitrifying power of frozen soils is weak and shows no tendency to increase with extension of the frozen period"; (4) that "frozen soils possess a decided denitrifying power which seems to diminish with the continuance of the frozen period"; (5) that "during the fall season, the denitrifying power of the soil increases until the soil freezes, after which a decrease occurs"; (6) that "frozen soils possess a nitrogen fixing power which increases with the continuance of the frozen period, being independent of moderate changes in the moisture conditions, but restricted by large decreases in moisture"; and (7) that "in the fall, the nitrogen fixing power of the soil increases until the soil becomes frozen, which in almost ceases, after which a smaller nitrogen fixing power is established."
The following is multiple choice question (with options) to answer.
Bacteria in the soil feed on | [
"uranium",
"expired creatures",
"crowd sourced work",
"kryptonite"
] | B | In the food chain process bacteria have the role of decomposer |
OpenBookQA | OpenBookQA-4000 | ecology, biodiversity
One of the advantages of bamboo over wood is that bamboo contains some silicon in both inner surface (pith-ring) and outer surface (rind) of the bamboo culm.
--Calcium phosphate formation induced on silica in bamboo
As I say I remain very skeptical. There's no evidence shown that this has actually happened. Is it telling that all these claims come from the same general region (India and Burma)? My guess is that this is an old wives' tale that's been written down and uncritically accepted, but if someone has actually seen this happen I'd be happy to be proven wrong, because the idea of plants sparking out flames in the wind is a pretty cool one.
Edit to add a link claiming that bamboo-on-bamboo generates sparks due to the silicates:
The method consists of striking sparks out of the culm of Schizostachyum bamboo with flint, broken pottery, china or even another piece of bamboo. The sparks that occur by striking the Schizostachyum bamboo are presumably generated by the high silica content in this genus of bamboo.
--Bamboo Strike-A-Light, by Tom Lourens, Ash Kivilaakso and Ed Read (My emphasis)
Edit to add that the overall concept of plants starting their own fires has been seriously looked at; the author is skeptical:
Individual plant traits (such as leaf moisture content, retention of dead branches and foliage, oil rich foliage) are known to affect the flammability of plants but there is no evidence these characters evolved specifically to self-immolate, although some of these traits may have been secondarily modified to increase the propensity to burn. ... It is more parsimonious to conclude plants have evolved mechanisms to tolerate, but not promote, landscape fire.
--Have plants evolved to self-immolate?
Notably, in his list of factors potentially allowing self-immolation, he does not list silica, and horsetail isn't mentioned at all.
The following is multiple choice question (with options) to answer.
To grow, bamboo will require both of the following: | [
"light and electricity",
"light and money",
"light and mud",
"oil and water"
] | C | a plant requires soil for to grow |
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