source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-3601 | condensed-matter, solid-state-physics, thermal-conductivity, phonons
How does this phonon picture explain the fact that when we heat a bad conductor the heat propagates gradually from the hotter to the cooler end? If they are delocalized collective excitations, shouldn't they heat up all parts of the substance at the same time?
I think that here the answer is simply that you need some time for the "delocalized collective excitation" you are talking about to set in. This must be true even for a perfect crystal, even if its infinite thermal conductivity would seem to suggest the opposite, otherwise we would have instant propagation of a signal (the vibration of the atoms). You think about the phonons as "delocalized collective excitation", but in reality they are much more similar to wave packets arising from a superposition of these collective excitation (the normal modes of the crystal). Maybe I am not being 100% precise in my terminology here, but I hope that I managed to convey the general meaning of what I have in mind.
References
[a] R. Peierls, “Zur kinetischen Theorie der Wärmeleitung in Kristallen” ("On the Kinetic Theory of Thermal Conduction in Crystals")
Ann. Phys. 395, 1055–1101 (1929)
The following is multiple choice question (with options) to answer.
A thermal conductor is made of | [
"often metallic",
"types of rubber",
"types of branches",
"electrodes"
] | A | when a cooler object touches a warmer object , thermal conduction occurs |
OpenBookQA | OpenBookQA-3602 | classical-mechanics, explosions
Title: What's driving the bucket up? Just saw this cool video from Plymouth University, which I actually found through Matthen's blog.
They fill a plastic bottle with liquid nitrogen, screw the cap on, drop it in a bucket full of warm water, cover it with ping pong balls, and when the heated, expanding gas bursts the bottle, the balls go jumping all over the place...
If you scroll the video to 3:50, you can see that the bucket jumps in the air, seemingly at the same time as the ping pong balls. Of course the force of the explosion is not pushing it up, but down. So what exactly is making it rise over 1 m off the ground?
I can only think of two possible explanations:
Elastic recoil from the material of the bucket. This seems pretty unlikely to me, as in my experience plastic buckets don't bounce much.
Pressure difference: the explosion drives everything out of the bucket, leaving a partial vacuum behind, so the atmospheric pressure outside the bucket pushes it up before air rushes back in to equalize the pressure. This seems more likely, but I would had thought that there would have been a longer delay.
Am I leaving any other possible explanation? Anybody willing to tackle a back of the envelope calculation of the height or delay for either of these? I'm willing to bet that it's simply the force of the explosion pushing on the bottom of the bucket, which pushes against the floor and makes the bucket bounce up into the air.
I doubt that it has to do with a vacuum forming inside the bucket. You're correct in thinking that we should expect more of a "delay" for the bucket to jump in this case.
And in any case, I don't believe that the explosion actually creates a vacuum in the bucket. It's simply the liquid nitrogen expanding into a gaseous state. The pressure in the bucket should never drop below 1 atmosphere. (it's not the same as an exothermic explosion, which does create negative pressure)
The following is multiple choice question (with options) to answer.
Which child's plaything is inflated with gas when it's in use? | [
"Nintendo",
"Miracle Bubble",
"Bicycle",
"Sidewalk chalk"
] | B | a bubble contains gas |
OpenBookQA | OpenBookQA-3603 | building 's air ) cost of electricity and natural gas and electricity = 1- ( 2! Expressed in terms of the heat ( i.e equate to lower operating costs flow direction and where cop of refrigerator. Less than these theoretical maximums of performance of refrigeration systems and heat working. Legal statement that explains what kind of information from this website is to temperature. Fall ), it is defined as the surroundings, the desired to. Operating at the Carnot cycle in these type of refrigerator, a pyramid type cooler. Which heat is rejected ) will be 4 ) we know that efficiency is always greater than?... The cycle is most widely used for coefficient of performance of a heat pump costs 20 less! When operated in the middle of the thermal efficiency must be considered for a heat pump or refrigerator cooling.. Unlikely in the input power improvement of COP sink with Higher thermal which! Engineering, Springer ; 4th edition, 1991, ISBN: 0-201-82498-1 (. An efficient gas heater Department of energy, for example, natural gas and electricity a of the amount! Give us a like in the reverse direction thermoelectric module which is the ratio of heating... Cool ( TC reducing ) the denominator increases and COP reduces which helps in improvement COP... Refrigerant 's flow direction and where energy enters and leaves to European COMMISSION! Consumer depends on the cost of energy as it consumes, making it act as resistance! Gas, which can both vary widely of water at 21.1C is put into a refrigerator is the maximum American. Refrigeration system ; water cooled heat exchanger ; heat recovery significantly same, the units! Cop for heating and cooling are thus different, because the heat pump will supply much! Schematic View of the desired output to the compressor Reading, MA ( 1983 ) von dem Wärmeverhältnis β thermische! By access to a solar-assisted thermal bank [ 6 ] ) used in AC..., this article, coefficient of performance of a refrigerator working on reversed Carnot cycle is.... Annex VII cop of refrigerator 2, beta, the COP rises with the boiler would to... It tells us how much heat we can generate with every watt energy. < 2, Depart of energy thermal efficiency must be considered for TE! With these average prices, the maximum = Q L Hence for heat. A vessel containing
The following is multiple choice question (with options) to answer.
If someone wants to use a natural gas in order to assist something necessary, they can | [
"use it to bathe in",
"eat it to die quickly",
"freeze it to make ice cubes",
"ignite it to warm their body"
] | D | natural gas is a source of heat by burning |
OpenBookQA | OpenBookQA-3604 | refraction
Title: Why is refraction so uniform? Why is refraction so uniform? At the end of the day, all that is happening is a photon of light is hitting atoms of a material, say, glass slab and getting absorbed and re-emitted. How is it that the photon, which is "absorbed and re-emitted" emitted in such a precise of an angle?
Am I wrong with 'photon hitting atoms'? If yes then please tell me what's actually happening. Also, apologies if I didn't get the glass slab material right. Very simply explanation but in terms of waves, the light is emitted in most angles, but the superposition of all of the corresponding waves means that only one results(most of the time). Look up Fresnel equations, it’s actually more complex then you'd think. For example for a given polarisation there's an angle where no light is reflected at all, but the same angle on a different polarisation there is reflection. Also e.g refraction, you'd mostly assume there is only 1 " beam" of light with a single direction..Yet there is something called bi-refringence that splits up the light into 2 beams causing a double image( for unpolarised light)
comment:Obviously to understand refraction and reflection for different materials, different frequency and polarisation of light, requires ALOT and I mean ALOT of math, and alot of concepts such as electromagnetic polarisation density and its relation to permitivity(modelling as harmonic oscillator e.g), EM boundary conditions, solving maxwell's equations, Deriving Fresnel relations. But the key thing is this, When an electromagnetic wave in incident at a material, the Em wave that is made of an electric and magnetic field exerts a force on the charge configurations inside materials, causing those charges to be accelerated. these charges produce EM waves due to this acceleration, and the SUM of all of those waves ( superposition) make up the light that we see as being " reflected or refracted" the math shows what the SUM of the waves look like. reflection of light isn't even the same light, it's different light that is produced by the accelerated charged inside the material
The following is multiple choice question (with options) to answer.
refraction is when light bends and when it stops producing light after hitting something its its | [
"sleeping",
"smelting",
"absorbtion",
"cooking"
] | C | refraction is when light bends |
OpenBookQA | OpenBookQA-3605 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
A bird of prey is hunting a scaly meal. How might this creature avoid being spotted? | [
"Lure the hunter into a trap and eat it first",
"Close its eyes and hope for the best",
"Altering its hues to look like the leaves",
"Flee at breakneck speeds"
] | C | hawks eat lizards |
OpenBookQA | OpenBookQA-3606 | astronomy, atmospheric-science, spectroscopy, solar-system
Title: How is the atmospheric composition of objects in the Solar System measured? How is the atmospheric composition of astronomical objects, for example Triton, a moon of Neptune, determined? They check for absorption lines when conditions are appropriate. Have a look at this ozone layer in Venus' atmosphere detected by ESA.
The following is multiple choice question (with options) to answer.
celestial objects are where in the earth's atmosphere | [
"inside",
"below",
"outside",
"over"
] | C | the moon is the celestial object that is closest to the Earth |
OpenBookQA | OpenBookQA-3607 | human-biology, cancer, medicine
Title: Why are only few cigarette smokers prone to cancer? It's tacit that only a few populace of smokers get cancer. What spares the others from it or what specifically cause cancer in those populace? See this Washington Post Article Cigarette smokers are most certainly prone to cancer. See Cecil Medicine, Chapter 183, on the epidemiology of cancer, exposure to tobacco is the most important environmental risk factor for cancer development, at least in the US:
Exposure to tobacco is the single largest cause of cancer in the United States... All forms of tobacco can cause cancer. Cigarette smoking causes cancer of the lip, oral cavity, nasal cavity, paranasal sinuses, pharynx (nasal, oral, and hypopharnyx), larynx, lung, esophagus (squamous cell and adenocarcinoma), stomach, colorectum, pancreas, liver, kidney (adenocarcinoma and renal pelvis), urinary bladder, uterine cervix, and myeloid leukemia.
Cancer may be identified or the cause of death in fewer smokers than might be expected, though, because smoking is an even greater risk factor for cardiovascular disease, and death due to cardiovascular disease.
Cancer is an unlikely phenomenon in an individual cell, but becomes more likely at the organism level, and even more likely over time. Though tobacco may be the most important environmental risk factor for cancer, age is actually a stronger predictor of cancer (see again, Cecil Chapter 183. Autopsy studies give us a quite remarkable example, this one shows incidental prostate cancer in nearly 60% of men over 80 who died from other causes. That figure is not out of the ordinary. Live long enough and you are likely to develop cancer.
Death due to heart disease may account for the lower than expected rates of cancer diagnoses and deaths in smokers. Nothing prevents cancer as well as dying from something else. And as discussed in the blog in the Washington Post you linked to, up to 2/3 of smokers die from smoking related causes
The following is multiple choice question (with options) to answer.
Smoking causes direct damage to what? | [
"feet",
"breathing organ",
"stomach",
"skin"
] | B | smoking causes direct damage to the lungs |
OpenBookQA | OpenBookQA-3608 | zoology, sensation
Title: Can animals that rely heavily on sonar sense colour? Apparently there're species around as rely heavily on sonar to sense the world around them.
E.g. Bat, Dolphin, Whale ...
The humans, and other terrestrial beings in a lighted world are capable of distinguishing colour in varying degrees of acuity. Is this ability to sense colour in our environment applicable to species (terrestrial, avian, and marine) that rely heavily on sonar? Any animal using sound cannot sense color though sonar directly, though these animals are not entirely blind and can probably see colors in the infrared we can't.
Even on the darkest night there is some light around and all bats use this. Old World fruit bats have colour vision, which is useful to them as they are often quite active in daytime, roosting on trees in exposed positions, rather than tucked away in dark crevices like most microbats, which can see only in black-and-white.
Dolphins have additional senses in addition to seeing they can sense electrical fields. So if an animal has its eyes covered, they will seem to be able to do things you would not expect. Its not the same as seeing the color though.
Such animals using sonar can additionally sense density and hardness as well as other material attributes which would cause the acoustic properties of the material as well as movement.
A hard-bodied insect produces a different quality of echo from one with a soft body, so bats can distinguish between some different groups of insects in this way. They can also determine the size of the object.
What's really interesting is that even human beings can experience this unusual sense. Blind people have learned to echolocate by making clicks with their mouth, and there is a movement to teach this skill.
Anyone can try it. In just an hour or two I was able to tell how close I was to a wall, whether the wall was concrete. I couldn't play video games (2:20 on the link) or see colors though.
The following is multiple choice question (with options) to answer.
Which of these things is absolutely required in order to notice a bat flying towards you? | [
"a hand and an arm",
"eyes and reflected sunlight",
"dogs and scared cats",
"a nose and eyebrows"
] | B | if an object reflects light toward the eye then that object can be seen |
OpenBookQA | OpenBookQA-3609 | geology, models, magnetosphere, rock-magnetism
Title: Can living where magnets are abundant provide a mini-magnetoshere? Are there a mini-magnetosphere within the magnetosphere similar to mini-magnetosphere found on the Moon? Is there a map of these areas that would resemble the white swirls in the picture below?
The white areas extending up to 360 km and are the safer areas where one could be protected to a degree.
Are there areas on Earth that could have this magnetic crustal properties as the moon has and would it add or supplement the protection of Earth's magnetosphere?
Source: http://lunarnetworks.blogspot.com/2010/10/grand-lunar-swirls-yielding-to-lro-mini.html Near to the Earth's surface there are small variations in the Earth's magnetic field, but these don't play a role in providing the magnetosphere which protects the Earth from charged particles emanating chiefly from the solar wind.
The following is multiple choice question (with options) to answer.
Many species have small amounts of magnetite to guide during their | [
"hibernation",
"migration",
"metamorphosis",
"spawning"
] | B | Earth 's magnetic patterns are used for finding locations by animals that migrate |
OpenBookQA | OpenBookQA-3610 | solubility, solvents
Title: Are there smart materials that dissolve in cold water faster? I know things dissolve quicker in hotter solvents but I was wondering if there existed an exception to the rule. If not water, then what about other solvents and/or non-solid solutes? Just one example is Poloxamer 407 which forms a hydrogel at room temperature at sufficiently high concentration. Adding solid Poloxamer 407 to water at room temperature would easily result in Poloxamer 407 powder encapsulated in gel which would strongly slow down the dissolution process. At a colder temperature, such as 4 °C, the gel does not form, so dissolution is typically achieved in a shorter time.
So yes, there are examples of compounds that dissolve faster in colder conditions. As usual when it comes to kinetics, the mechanism is highly relevant.
The following is multiple choice question (with options) to answer.
Hot tea works better than cold for dissolving | [
"lemons",
"ice",
"nuts",
"rocks"
] | B | as temperature increases , the ability of that liquid to dissolve solids will increase |
OpenBookQA | OpenBookQA-3611 | ### Show Tags
08 Feb 2012, 09:00
# of selections of books with no condition = 8C4 = 70
# of selections of books with no paperback book = 6C4 = 15
# of selections of books with at least one paperback book = 70 -15 = 55
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Re: There are 8 books in a shelf that consist of 2 paperback [#permalink]
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20 May 2012, 03:36
3
The selection should at least contain one PAPERBACK book. There are a total of 2 PB and 6 HB books are available.
The combinations that at least one PB book will come out are: PHHH & PPHH
1. PHHH = 2C1 * 6C3 = 2 * (5*4) = 40
2. PPHH = 2C2 * 6C2 = 1 * ((6*5) / 2) = 15
In total 40+15 = 55 Ways
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Joined: 07 Feb 2011
Posts: 89
Re: There are 8 books in a shelf that consist of 2 paperback [#permalink]
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25 Jan 2013, 07:20
Hmm....so when I did this I made an error that might have carried over from using combinatorics from probability. I found the total as 8C4 and to find the amount to subtract from it I had (6C4)(2C0). Why don't we multiply by the books not chosen and what's would it mean if we did?
I'm trying to understand a fundamental flaw I made here
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Joined: 02 Sep 2009
Posts: 52385
Re: There are 8 books in a shelf that consist of 2 paperback [#permalink]
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The following is multiple choice question (with options) to answer.
if a book was intact on the desk in the morning, but in shreds in the afternoon, what happened? | [
"it had spontaneous combustion",
"the book was made of plastic",
"it underwent a tearing process",
"the book committed suicide"
] | C | tearing means changing a whole into pieces |
OpenBookQA | OpenBookQA-3612 | zoology, digestive-system, pets
Title: Is it safe to feed an adult fire salamander with slime maggots? As a reminder, maggots feed of a flesh, while fire salamander consumes his prey alive, without killing it.
Can it happen that the maggot will start eating the salamander from the inside? Although I am afraid I don't know much about fire salamanders specifically, it is certainly possible for ingested fly larvae (or larvae hatching from ingested eggs) to survive ingestion and subsequently cause intestinal damage. Parasitic infestation by fly larvae that grow inside the host while feeding on its tissue is called myiasis. Enteric myiasis (also called gastric, rectal, or intestinal myiasis to indicate the affected part of the digestive system) occurs occasionally in humans following the ingestion of cheese infested with cheese fly maggots. Casu marzu, a traditionally produced Sardinian cheese, is supposed to have live cheese fly maggots in it, and cases of bloody diarrhoea following its consumption are known. If they're dead the cheese is considered unsafe to eat (although personally I'd correct that to 'more unsafe').
The following is multiple choice question (with options) to answer.
What does a salamander eat? | [
"mice",
"Venus flytraps",
"fleas",
"bats"
] | C | a salamander eats insects |
OpenBookQA | OpenBookQA-3613 | ## 1 Answer
Both sides are positive, so you can take their reciprocals (of course the 'less than' flips to 'greater than'): $$\left|\frac 1{2+a}\right| < 1 \iff \frac 1{\left|\frac 1{2+a}\right|} = \frac {|2+a|}{|1|}= |2+a| > 1$$ That is equivalent to an alternative: $$(2+a) < -1 \lor (2+a) > 1$$ which resolves to: $$a < -3 \lor a > -1$$ Equivalently $$a\in (-\infty, -3)\cup (-1,\infty)$$
EDIT in reply to the comment
No, $1/(2+a)>−1$ does not imply $a>−3$.
When you multiply both sides by $(2+a)$ you must consider the sign of the multiplicand term. If the term is negative, the direction of an inequality gets reversed. So you have two possible cases here:
$$\color{red}{1/(2+a) > -1} \quad |\,\times(2+a)$$ $$\begin{cases}1 > -1\times(2+a) & \text{ if}\ (2+a) > 0 \\ \qquad \text{or} \\ 1 < -1\times(2+a) & \text{ if}\ (2+a) < 0 \end{cases}$$ This is equivalent to $$1 > -2-a \ \text{and}\ 2+a > 0 \ \text{or} \ 1 < -2-a\ \text{and}\ 2+a < 0$$ $$a > -3 \ \text{and}\ a > -2 \ \text{or} \ a < -3\ \text{and}\ a <-2$$ Finally $$\color{red}{a > -2 \ \text{or} \ a < -3}$$
Similary from the other inequality we get
The following is multiple choice question (with options) to answer.
if two students of equal strength pull a double sided cup in opposite directions, what will happen? | [
"the cup will remain stationary",
"the one on the right will have it",
"the cup will change color",
"the one on the left will take it"
] | A | if two equal forces in opposite directions act on an object then that object will stay in the same place |
OpenBookQA | OpenBookQA-3614 | solubility, food-chemistry
Title: How can I avoid crystallisation of sugars in vinegar at low temperatures? I produce high density balsamic vinegar, when it's winter and the temperatures are very low, high density products tends to crystallize. think this is a problem of over saturation of the glucose. The main sugars are glucose and fructose the ratio is 1:0.95.
I try to make products that are lower than 70 brix, or 1,35 density and 6% acidity, composed by $\ce{CH3COOH}$ and tartaric acid.
How can I exactly calculate the solubility threshold of this mixture? How can I measure it?
How can I prevent the crystallization to happen?
Thank you very much
I can't sleep at night because of this problem !!! It is difficult to correctly measure the solubility, especially if it goes to multicomponent solutions, as your vinegar. It is possible to find tables with some components of your mixture, but you won't get the full picture, and it looks as the moment, when the hands-on experience is most important.
Nonetheless, I found some facts for you, namely:
the solubility of a-D-glucose in all the solvents increases with
increasing temperature and decreases with increasing volume fraction
of acetic acid, from Solubilities of {α-d-glucose in water + (acetic acid or propionic acid)} mixtures at atmospheric pressure and different temperatures
Another point is that the supersaturated solution can be stabilized by various means, and I think it already happens, as your vinegar contains lot of "impurities" from the grapes.
As for the second point, how to prevent it, the simplest solution will be to keep the temperature high enough, so that the crystallization does not occur. If this is not possible, the supersaturated solution will crystallize, sooner or later. If you than ask, how to slow down the process, until spring comes, filtration could help to remove the crystallization nuclei.
The following is multiple choice question (with options) to answer.
A sugar cube in vinegar will | [
"disappear",
"explode",
"start to fly",
"become hard"
] | A | An example of a chemical change is acid breaking down substances |
OpenBookQA | OpenBookQA-3615 | particle-physics
Title: Explanation for self-rupture glass is needed I witnessed a phenomenon that I couldn't conclude its cause. Please bear with me for the length of the recall, for I merely want to include any details that might help us to investigate. I had a cooking glass lid sat on a wooden shelf that is away from the stove and oven and other heating objects. The shelf is nailed on the wall and is situated just above my eye level, and a counter top is also on the same side of the wall where the shelf is installed.
Now here comes the surprise. In a winter afternoon 2011, my room had almost the same temperature as an autumn morning, and while I was cutting my lettuce on that counter top which I pointed out in above passage, a pounding sound, as if a heavy car door slam or a tree trump falling on top of the roof, knocked its introduction from the shelf that was just above my eye level. First, I thought I may had knocked something around me off(which I didn't believe that for there wasn't anything around me to knock off); then I thought it may be my neighbor next door dropping a heavy box; last, I suspected somewhere my roof top collapsed.
But it was my third suspicion directed me to meet that glass lid I mentioned above, and I found it had ruptured completely like glacier creaked BUT still having all broken pieces bounded without any pieces scattering toward random direction! Only the nob of the lid popped out partially. Before this happened, I hadn't used that lid for cooking for years, and I didn't removed it from any heating object nor there was something on top of the lid that day, and I believe what the lid had maybe just an invisible layer of dust.
I was glad my face hadn't been stung by any glass residues, but ponder what really happen to that glass lid and why it ruptured without collapsed. Below, I attached 2 pictures of the scene from that day. If you have any similar experience or know the theory behind it, may you please drop me an explanation to this incidence? Thank you in advance.
The following is multiple choice question (with options) to answer.
If a thing is blown apart, and was living previously to that occurring, then that thing | [
"experienced only good things",
"was always perfectly safe",
"fell in harms way",
"died in a natural way"
] | C | explosions can cause harm to an organism |
OpenBookQA | OpenBookQA-3616 | 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.
riding a bike helps prevent | [
"music",
"inflation",
"environment harm",
"economic stability"
] | C | riding a bike does not cause pollution |
OpenBookQA | OpenBookQA-3617 | 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.
Because of the stem of plants, they are able to do what in the soil | [
"fly",
"balance upright",
"cry",
"sing"
] | B | a stem is a source of support for a plant |
OpenBookQA | OpenBookQA-3618 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
If a thing will take dirt and dead pieces of matter and process them through their own bodies, they are likely | [
"humans",
"whales",
"nightcrawlers",
"babies"
] | C | decomposer is a kind of role in an ecosystem |
OpenBookQA | OpenBookQA-3619 | Case 1: (3,1,1) First choose which of the 3 pockets will get three marbles. There are 3C1 =3 ways to do this. Then, choose the number of ways we can place 3 marbles into that box from 5 marbles. There are 5C3 = 10 ways to do this. Next we must place a marble in the next to the last box. There are 2C1 = 2 ways to do this. Then there is 1C1 = 1 way to place the last marble into the last pocket. Each time we make a subsequent selection when working through a case we multiply, so there are 3*10*2*1= 60 ways to place the marbles in case 1
Case 2: (2,2,1) First we must select which two pockets get two marbles each. There are 3C2 = 3 ways to do this. Then, we must choose two marbles to go in the first of two pockets. There are 5C2=10 ways to do this. From the 3 remaining marbles, there are 3C2 = 3 ways to place two marbles in the second pocket. Finally there is 1C1 =1 way to place the last marble in the last box. Multiplying, we have 3*10*3*1 = 90 ways to place the marbles in case two.
Thus there are 60+90 = 150 ways we can place the marbles
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Re: In how many ways can 5 different colored marbles be placed in 3 distin [#permalink]
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04 Oct 2019, 22:44
praffulpatel wrote:
In how many ways can 5 different colored marbles be placed in 3 distinct pockets such that any pocket contains at least 1 marble?
(A) 60
(B) 90
(C) 120
(D) 150
(E) 180
Solved it a little differently than others from what I read . So will share.
I first made sure that each of the pocket has at least 1 marble.
That is 5C3 * 3!
The following is multiple choice question (with options) to answer.
Sara sorted her marbles into glass ones and marbles made of crystal. This is an example of | [
"classifying",
"weighing",
"clarifying",
"justifying"
] | A | classifying is when one sorts something by type |
OpenBookQA | OpenBookQA-3620 | = ",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.
cutting down trees in a forest causes the number of trees to decrease where? | [
"space",
"deserts",
"oceans",
"timberland"
] | D | cutting down trees in a forest causes the number of trees to decrease in that forest |
OpenBookQA | OpenBookQA-3621 | evolution, zoology, adaptation
One answer that came to mind is domestic animals - the horse and dog in prehistory, the cat in ancient Egypt, etc. That seems too obvious on one hand, and on the other hand may not really be an answer, as there seems to be no indication that pre-domestic animals were endangered by humans in any meaningful way. Are there animals that have significantly adapted themselves to surviving as wild animals in human-influenced environments? Note: This is an answer to the last line of your question.
A classical example of animals adapting to the influence of humans on their environment is the adaption of the Peppered Moth.
Here is a brief summary:
The peppered moth was originally a mostly unpigmented animal (<1800). During the industrial revolution in the southern parts of the UK a lot of coal was burned. This led to soot blackening the countryside. Soon afterwards, a fully pigmented variety was first observed. Only a hundred years later, in 1895, this pigmented variety almost completely displaced the unpigmented variety.
It has been shown that the pigmentation is under strong selective pressure as birds hunt these moths. Since birds rely on their visual system to detect their prey, the variety that blends in with its environment (=camouflage) has a selective advantage over the variety that stands out.
As pointed out by Tim in the comments, since the 1970s there has been a rapid reversal with unpigmented animals being more abundant. As far as I understand, it is accepted that this reversal is due to a decrease in human induced air pollution leading to less sooty barks on trees which makes the unpigmented variety harder to prey upon.
Addendum: genetic basis of adaption
In a beautiful recent study, the causal mutation for the pigmented, or melanic, variety was identified: A ~9kb transposon insertion in the first intron of the gene cortex. The authors calculate that this mutation happened in the year 1819, a few years after the industrial revolution was in full swing. The interpretation is that due to sooty tree bark this mutation, causing pigmented moth, was under strong selection.
The following is multiple choice question (with options) to answer.
humans changing animal habitats usually causes harm to | [
"the residential things",
"sneakers",
"rocks",
"clouds"
] | A | humans changing animal habitats usually causes harm to those animals |
OpenBookQA | OpenBookQA-3622 | genetics, gene-expression, human-genetics, mitochondria, gene
Title: Father with mutated mtDNA- why isn't his offspring at risk? Mothers transmit their mitochondria (and therefore mtDNA) to their offspring and fathers don't. Lets assume that father had a mutation of the gene that encodes mtDNA, would then be his offspring at risk? Why?
I also found the following statement:
"The current genetic advice is that fathers with mtDNA mutations are at no risk of transmitting the defect to their offspring."
How can that be true? Is it because of gene silencing?
Thank you in advance!
...would then be his offspring at risk? Why?
No. Generally speaking, fathers do not pass on their mtDNA (Mitochondrial DNA).
Why? Because the mitochondria present in oocytes (egg cell) is the mother's, as every oocyte directly inherits the mother's mitochondria when they are made in the reproductive organs. The mitochondria that the sperm from the father carry to the egg do not enter the egg cell or are destroyed in the process.
It's also worth mentioning that, in general, mtDNA does NOT reside in the nucleus of cells, but in the mitochondria itself. It is not condensed during cell division, it is not spliced during Meiosis II, and it does not undergo recombination with another cell's mtDNA. Instead, when a cell divides, each cell takes about half of the mitochondria present in the cell and maintains them. That way only the mitochondria present in the cell before division will be inherited by the daughter cells, and thus only the maternal mitochondria present in oocytes (egg cells) before sperm instigate cell division will be inherited by any offspring.
The following is multiple choice question (with options) to answer.
DNA is a vehicle for passing inherited characteristics from parent to what? | [
"pets",
"homes",
"younglings",
"food"
] | C | DNA is a vehicle for passing inherited characteristics from parent to offspring |
OpenBookQA | OpenBookQA-3623 | electrochemistry, home-experiment, crystal-structure
Title: Copper (II) Acetate from 5% vinegar + salt, electrochemically I'm trying to create Copper (II) Acetate crystals, but in these times of Coronavirus it's difficult to come by hydrogen peroxide. I could be patient, but I'm not, so I'm trying to make it electrochemically. I have 5% vinegar and lots of copper scrap, and an adjustable power supply. Unfortunately I can't barely get any current going, so I've thought of adding salt, regular NaCl. I'm curious what effect this will have on the final outcome though. Balancing equations is something I struggle with, but I'd really like to learn the chemistry here. Will the salt interfere with or alter the growth of the copper acetate crystals? Ultimately I'm trying to make calcium copper acetate crystals, I've already made the calcium acetate. To prepare copper acetate absence H2O2, employ a known method from hydrometallurgy to process copper ore employing aqueous ammonia, air (a source of oxygen) and a small amount of salt (acting as an electrolyte for this, in part, spontaneous electrochemical reaction detailed below). This results in tetra-ammine copper hydroxide. The latter exists only in solution and upon evaporation yields CuO (and possibly some Cu2O also, see this old patent). Add an acid of choice (like vinegar, a source of acetate) to convert CuO into copper acetate.
Related copper chemistry with ammonia and oxygen:
Cited half-reactions:
$\ce{1/2 O2 + H2O + 2 e- -> 2 OH-}$ (cathodic reduction of O2 at surface of the Copper)
And, at the Copper anode, the formation of the complex:
$\ce{Cu + 4 NH3 + 2 H2O -> [Cu(NH3)4(H2O)2](2+) + 2 e-}$ (anodic dissolution of Cu by a complexing agent)
With an overall reaction:
$\ce{Cu + 4 NH3 + 1/2 O2 + 3 H2O -> [Cu(NH3)4(H2O)2](2+) + 2 OH-}$
The following is multiple choice question (with options) to answer.
A battery that is placed in vinegar will cause the vinegar to | [
"be a good chemical copy",
"have new chemical properties",
"be safe to drink",
"attract groups of deer"
] | B | if an object undergoes chemical change then that object will have new chemical properties |
OpenBookQA | OpenBookQA-3624 | optics, everyday-life, reflection
Title: What are natural retro-reflectors? Recently I was on an airplane on a sunny day. The sun was shining on the other side of the plane and noticed a bright patch on the ground following beside us. Eventually I noticed a dark centre to this bright patch, the plane's shadow, which became more distant as the plane descended. When the plane flew over a city road signs in this bright patch lit up brightly because of their retro-reflective paint.
My question is, what was acting as a retro-reflector to produce this bright patch when it wasn't passing over a road sign? When flying over water the bright patch disappeared, or was very faint. I could see it over forests, more clearly over cut grain fields and, at least faintly over a wide range of terrain. It sounds like a version of the glory, or more likely heiligenschein, due to spherical droplets of water in the air or dew on the ground.
The following is multiple choice question (with options) to answer.
Old glory waves thanks to a | [
"pulley",
"magic",
"guy climbing up",
"bird"
] | A | a pulley is used to lift a flag on a flagpole |
OpenBookQA | OpenBookQA-3625 | human-genetics
Title: In our 23 chromosome pairs, do the 2 members of the pair have distinct or virtually identical sequences? I understand that we have 46 DNA molecules in the nucleus of our cells, arranged in 23 pairs: 22 autosomal and 1 sex chromosome pairs.
I have read in different sources that the pairs contain nearly identical members, excluding any mutations. I have also read that the pairs contain 1 member we inherited from our mothers and 1 we inherited from our fathers, which are different due to inheritance.
This seems contradictory, given that genealogical companies match up on the differences on these chromosomes.
My understanding was that meiosis creates sperm and egg cells that each carry 23 chromosomes - they are haploids. During the first steps of meiosis that creates the reproductive cells we have a combining of the parent's chromosome pair from their parents to create 4 daughter cells, each independently viable, where the recombination of the chromosome pair has occurred at somewhat predictable spots (for you perhaps :-) ) and that these spots can be related to genes. It is this step that give us our genetic variation between siblings for example. A new person's DNA is partially formed from any one of these highly varied daughter cell possibilities.
Fertilization combines the reproductive cells to produce the 46 chromosome zygote with is again diploid.
I think this understanding supports the second interpretation that our chromosome pairs are not 2 nearly identical DNA molecules but are distinct.
Have I got this right? Is there a missing process or a misunderstanding in my interpretation? Homologous chromosomes (those that are paired up), excluding the sex pair are almost identical in size, shape and genes (members as you called them) present in them.
Genes determine traits and each homologous chromosome controls the same traits. The level of identity of a gene inside a population varies between genes. There are very conserved ones that do not change even between humans and yeast and others that vary alot event inside a species. This changes can be small in sequence length, a simple base (letter) swap or one deletion, and have a huge effect on the traits. This is how chimps and humans are very different but share 98.6% of their genome and humans are very similar and share 99.9% of their genome.
In summary, on the bigger scale homologous chromosomes are very similar (size, shape, traits inside), on the smaller scale homologous chromosomes have small changes that affect greatly.
The following is multiple choice question (with options) to answer.
if two students with identical genes grow at a different pace, what could be responsible? | [
"they might have different houses",
"they might have different hair types",
"they might have different clothes",
"they might have different diets"
] | D | a living thing requires nutrients to grow |
OpenBookQA | OpenBookQA-3626 | agriculture
The primary cereals for making bread are wheat and rye, while barley and oats may be mixed in. Historically significant portions of the rural population of Europe were sustained by cereal-based food in the form of gruel and porridge rather than by bread, especially prior to the introduction of the potato. Barley can be consumed in the form of pearl barley and groats and oats in the form of oatmeal. Especially in cool and humid climates not very suitable for cultivating wheat and rye, oats were once commonly cultivated and consumed. When Samuel Johnson wrote his dictionary, he famously defined oats as: "A grain which in England is generally given to horses, but in Scotland supports the people." A major historical and modern use of barley has been as malted barley, the main ingredient in beer brewing.
In the case of Finland it is interesting to note how late the transition from slash-and-burn agriculture to the use of permanent fields occurred. According to Teija Alenius, Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish − Karelian inland area, Ph.D. thesis, University of Helsinki, 2007 (online)
The following is multiple choice question (with options) to answer.
Advances in food transportation lead to | [
"less variety in the fruit section",
"lower demand for foods",
"greater variety of foods in remote areas",
"consolidation of grocery stores"
] | C | as ability to transport food increases around the world , the available types of food in distant locations will increase |
OpenBookQA | OpenBookQA-3627 | special-relativity, waves, mass
But of course, if you produce some loud sounds, they will carry lots of energy in the air and the mass of the air will inevitably increase by $m=E/c^2$ which is, well, not too high because $c^2$ is a large number.
The following is multiple choice question (with options) to answer.
Which of the following is more likely to create sound? | [
"Someone making their hand vibrate really quickly",
"Someone holding a violin",
"An owl soaring overhead",
"Someone dragging a bow on a string"
] | D | vibrating matter can produce sound |
OpenBookQA | OpenBookQA-3628 | 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 circuit would be | [
"rock climbing",
"running",
"dimming a bulb",
"swimming"
] | C | a light bulb converts electrical energy into light energy when it is turned on |
OpenBookQA | OpenBookQA-3629 | ds.algorithms, cg.comp-geom
WLOG in the East-bound pass, I'll process column by column but will
only look at obstacle vertices on or to the left of the column.
I maintain an array $A$ of obstacle vertices of size $N$. Suppose now I
am processing column $c$ ($x = x_c$). The $k$th element in $A$ stores the obstacle vertex with the largest $x$-coordinate such that $y = y_k$ and $x \le x_c$, or null if there is no such obstacle vertex. Note that if there are multiple obstacle vertices with the same $y$ coordinates, all but the East-most
one are guaranteed not to matter.
Now, I want to partition the vertical line $x = x_c$ into ranges closest
to the same obstacle vertex. Each partition $p_i$ is associated with an
index $i$ such that $A[i]$ is the obstacle vertex closest to this
partition. Similar to the argument behind Fortune's Voronoi
algorithm, it is easy to see that the $y_i$'s are strictly ordered.
Furthermore, the first and last non-null vertices in A (could be the same)
both have
their own associated ranges, since the first owns $[-\infty, \cdots]$ and the
last owns $[\cdots, +\infty]$.
So we go through the array A and process all non-null vertices in order.
We use a stack to represent the current ranges and
process the vertices one by one. The stack represents the
current partitioning of the line using all vertices considered so far.
Each vertex $v_i$ in the stack owns a range $[LB_i, UB_i]$. Initially, the
first vertex owns the range $[-\infty, +\infty]$.
Let's say we consider the next vertex $v_j$, and the current top-of-stack
vertex is $v_k$ (note that $v_k$ has the range [LBk, +infinity]). We compute
the bisector between $v_j$ and $v_k$. This bisector will intersect with the
The following is multiple choice question (with options) to answer.
Obstacles that might impede a dune are | [
"God",
"emotions",
"cacti",
"cancers"
] | C | sand dunes are made of sand |
OpenBookQA | OpenBookQA-3630 | climate-change, sea-level
Here you can clearly see how, with some ups and downs, the rate of sea level rise have been increasing over the last few centuries. And notably the current rate, about 20 years after the end of this plot is already out of the scale, and around 3.2 mm/year as pointed also by other answers.
I would highlight the following from their abstract:
Sea level rose by 6 cm during the 19th century and 19 cm in the 20th
century.Superimposed on the long-term acceleration are quasi-periodic
fluctuations with a period of about 60 years. If the conditions that
established the acceleration continue,then sea level will rise 34 cm
over the 21st century. Longtime constants in oceanic heat content and
increased ice sheet melting imply that the latest
Intergovernmental Panel on Climate Change (IPCC) estimates of sea
level are probably too low.
Regarding to whether this is caused by humans or not, I rather stay out of that argument and point that our best science and models suggest that lowering $\text{CO}_2$ emissions can make a significant impact in slowing down sea level rise in the upcoming centuries, so we should ACT NOW, and stop arguing whether it was or not our fault in the first place.
The following is multiple choice question (with options) to answer.
Why might owning a house on an ocean be an issue after a few decades? | [
"beachfront property shrinking",
"increased seagull populations",
"Prone to snowstorms",
"Food shortage"
] | A | erosion causes a river to become deeper and wider |
OpenBookQA | OpenBookQA-3631 | Hey, thanks for your help guys. For a minute there, I thought that this theoretical person could not safely expect to live to be 82 years old.
9. Jun 16, 2012
### SW VandeCarr
In fact, on a purely probabilistic basis, for any finite time no matter how large, there is a non zero probability that a person would survive that long. So for a sufficiently large population, there would be a theoretic person that would live 100,000 years. This, of course, has no basis in biology.
In terms of the probability of being murdered, the model would not hold for the 100,000 year old person. In terms of the model, probably the best one can do is assume the proportion of causes of death would be constant. The calculation above needs to be corrected for overall survival in terms of death from any cause.
Last edited: Jun 16, 2012
10. Jun 16, 2012
### viraltux
Interesting... but 0.37% is not that small percentage, don't you think? That means, roughly speaking, that a community of around 300 persons can expect that one of them will be murdered.
If you consider that the number of people we know plus acquaintances can easily be around 300 persons that would mean that most 82 year old persons know of someone in their circles who has been murdered. Mmm... that might be an interesting survey.
11. Jun 16, 2012
### SW VandeCarr
As I said in my previous post, this is a misapplication of statistics. You have to consider survival in terms of all cause death. If you just consider the murder rate, then at some point nearly everyone gets murdered.
12. Jun 16, 2012
### moonman239
I know that.
This person will not die until he reaches age 82, if he is not murdered. As mentioned before, this person has a 68% chance of living to be 82.
13. Jun 16, 2012
### D H
Staff Emeritus
The probability of living to 82 per this problem is 99.63%, not 68%. You missed the decimal point on the 0.37%.
14. Jun 16, 2012
### SW VandeCarr
The following is multiple choice question (with options) to answer.
Someone stops living when | [
"They cut their hair",
"They stick their head in a trash can",
"They are without air",
"They eat disgusting food"
] | C | if a living thing dies then that living thing is dead |
OpenBookQA | OpenBookQA-3632 | planet, 9th-planet, kuiper-belt
Title: What type of planetary-mass object would Planet Nine be? Given that Planet Nine is hypothesized to be 10-20 times the mass of the Earth orbiting the sun some 200-2500 AU out, what kind of planetary-mass object would it be?
Even given that it has apparently "influenced" several Trans-Neptunian objects, since its orbit is so large and so slow (approximately 25,000 years) it would take an awful long time to clear out its own orbit (especially given that we do not know how long it has been in that orbit), so it seems like it would not qualify as an actual planet under the rules that re-classified Pluto.
Since it orbits our sun, it wouldn't be an exoplanet nor a rogue planet. And it sure seems too big to be called a dwarf planet.
A captured planet seems closest in other attributes, but it probably was not either a capture nor a re-capture, but more likely a partial ejection.
So what classification would it fall into? It is a planet - either a gas giant core, a mini-Neptune, or a super-Earth.
First off, Mike Brown has stated outright
“It is a planet—there’s virtually no doubt,” he said. “What we now call planets are objects that can gravitationally dominate their neighborhood. Pluto is a slave to the gravitational influence of Neptune. By area, Planet Nine dominates more of the solar system than any other known planet—it’s only because of this that we can infer its existence. And because of this we’re pretty sure it’s not a small object: it’s at least ten times more massive than Earth and five thousand times more massive than Pluto. In many ways, you could argue that this is more of a planet than anything else in the solar system.”
The following is multiple choice question (with options) to answer.
If a thing is going to be a planet, it must orbit in a certain amount of time, which can exclude | [
"mercury",
"the ninth planet",
"the third planet",
"venus"
] | B | pluto has not cleared its orbit |
OpenBookQA | OpenBookQA-3633 | electromagnetism, electricity, insulators
Title: How can a glass rod become charged if it is an insulator? I was reading some of the other questions, and I found this one about a glass rod and how it gains a net charge when rubbed with a silk scarf. I learned from working in a shop one summer that most solids are insulators, because their electrons are tightly bound, so it is hard to knock them off. Why would such a simple motion (like a moving scarf) knock electrons from an insulator (I looked it up and glass is an insulator)? Conductivity is not just about how tightly bound electrons are, but equally about how easy it is for them to travel.
Example: a bunch of islands in a shark-infested sea. You cannot swim from one island to the next although it is close. At low tide you can walk across no problem. The first example is an insulator, the second is a conductor.
Rubbing (google triboelectricity) causes unlike atoms to stick and unstick frequently. Atoms "fight" over electrons, and the stronger one gets to take the electron home. It is like air lifting them from the island - shark infested waters or not.
There are lists of materials (the triboelectric series) that tell you which material will give up its electrons when in contact with another material. Glass is high on the list - it loses electrons easily. The can't move sideway, but they can be picked off the surface.
The following is multiple choice question (with options) to answer.
Which acts as an insulator for electricity? | [
"A metal ring",
"A battery",
"A door hinge",
"Beeswax"
] | D | wax is an electrical energy insulator |
OpenBookQA | OpenBookQA-3634 | You are in the case $P=true$ and $Q=true$, so $(not(P) \Rightarrow not(Q))=true$.
The following is multiple choice question (with options) to answer.
If acorns are moved around a neighborhood, then the most reasonable culprit is | [
"snakes",
"ferrets",
"sharks",
"bees"
] | B | An example of seed dispersal is is an animal gathering seeds |
OpenBookQA | OpenBookQA-3635 | 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.
Where would algae be safe from predators but likely die? | [
"a lake",
"a delta",
"the ocean",
"the desert"
] | D | algae is found in bodies of water |
OpenBookQA | OpenBookQA-3636 | orbit, earth, climate
Title: Why don't we have 2 Summers and 2 Winters? Due to Earth's elliptical orbit, its distance from Sun varies by almost 5 million Kilometers (147 million Kilometers at closest point & 152 million Kilometers at farthest point, i.e. almost 3% of the average distance).
As evident from the fact that that Venus has hotter environment than Mars due to their respective distances from the sun.
Why then Earth does not observe two winters (at farthest points) and two summers (at closest points)?
Additional Note:
I know that Earth's seasonal climate change is caused by its 23 degrees tilt that causes the sunlight density variations for the hemispheres.
But to me this 5 million Km distance seems more relevant than the 23 degrees tilt. There are a few incorrect assumptions in your post, so it is difficult to answer as asked. But I can address the misconceptions.
1. The seasons are not caused by our distance from the sun
The seasons are caused by the 23.5° tilt in Earth's axis. When the Northern Hemisphere is tilted towards the sun (summer), the Southern Hemisphere is simultaneously tilted away from the sun (winter). So the seasonal temperature difference has little to do with the Earth's position in its elliptical orbit. Without this tilt, there would be no seasons and the temperature day to day across the globe would be relatively uniform.
2. Even the GLOBAL temperature is NOT consistent with our change in distance
As a matter of fact, the average temperature of the Earth globally is hottest when it is the furthest from the sun — hotter by about 2.3°C (ref). That's because there is a lot more landmass in the Northern Hemisphere facing the sun (when Earth is farthest away in its orbit). So even though there is less intensity of sunlight, the land is able to be heated up much faster than the vast oceans which have to be heated at perihelion.
This distance-temperature inconsistency isn't unique to the Earth. Look at the average temperature of the other inner planets as we move away from the sun:
Mercury (167°C)
Venus (460°C) ← farther, but hotter than Mercury?
Earth (14.0°C)
Mars (-60°C)
The following is multiple choice question (with options) to answer.
summer is when a hemisphere is tilted towards what? | [
"new york",
"saturn",
"mars",
"astral gas ball"
] | D | summer is when a hemisphere is tilted towards the sun |
OpenBookQA | OpenBookQA-3637 | photosynthesis, chloroplasts
Title: Chloroplasts in an animal cell What would happen if we inject a chloroplast organelle into an animal cell?
Will the animal cell destroy it? Or is it possible that the chloroplast will somehow survive, and even replicate? Could there be photosynthesis in such a cell, or will some of the necessary mechanisms be missing? To answer your bigger question:
Yes, most of this is possible - under some conditions -, and animals and animal cells can acquire chloroplasts, and use them.
E.g.: see Elysia chlorotica whose cells actively take up chloroplasts and use them, and keep them alive (though not replicating). - Though some genes of algae are also contained in the Elysia chlorotica genome - which may be considered as partial replication.
Also there are salamanders that have replicating algae within them (since embryogenesis) - even algae (with chloroplasts) within animal cells - though here the algae might be rather understood as symbionts or "cell types", and the animal cells don't have the chloroplasts by themselves.
The following is multiple choice question (with options) to answer.
What cells can perform photosynthesis? | [
"animals",
"inorganic minerals",
"flora",
"critters"
] | C | plant cells can perform photosynthesis |
OpenBookQA | OpenBookQA-3638 | electrical-engineering, refrigeration
Title: Relative inefficiency of doorless fridges at supermarkets It appears to be a waste of electricity to keep a bank of refrigerators wide open with no doors or covers whatsoever on them.
They seem to be just blowing cold air out into the supermarket.
They are not turned off at night when the store closes. Even the "green" Whole Foods-type places do this.
But is it really that inefficient to operate them that way?
What is the relative efficiency between a refrigerator with a door and one without a door in a supermarket? The doorless models (this was the photo in the question when I answered it) aren't as inefficient as they appear to be.
Whenever someone opens a regular fridge door, its cold air pours out onto the floor and warm air replaces it inside the fridge. If the doors are opened frequently, or held open for significant time, there is a lot of waste.
On the other hand, the doorless models are designed to have a laminar flow of cold air from top to bottom. Most of the cold air emitted at the top is sucked back in at the bottom, with far less mixing with the surrounding warm air than one might think.
So for products where temperature control isn't critical, and where many people are likely to take the product or to spend a long time looking and deciding, the doorless models are a good choice.
(They're also good from a marketing perspective, as they provide an excellent view of the product and don't have doors that fog up, but that's not the question.)
The following is multiple choice question (with options) to answer.
All the food in the fridge is warm on a remote farm with a windmill. The most likely cause is | [
"it's a very windy day",
"someone put a heat lamp in the fridge",
"it's a windless day",
"it's a warm day"
] | C | a windmill converts wind energy into electricity |
OpenBookQA | OpenBookQA-3639 | fluid-dynamics, states-of-matter
Title: Why does sweetness of coke change after freezing completely I freeze my coke in a freezer completely to solid and then keep it out to melt and as it melts portion by portion I starts to drink, initially It will be very sweet and later it wont be sweet at all. why does this happen?
We know that all sugar in coke will be dissolved (Solid solution) but how a major portion of this melts faster than water in the juice their by getting more sweet? How these sucrose can escape through the crystals formed by the ice and join in the water.
I measured the sweetness (Brix) and found it varies. Substances in solution have the effect of decreasing the temperature of the freezing point of the liquid they are dissolved in. This is called freezing-point depression. This is one of the reasons why adding salt to ice helps it melt.
Your coke is a complicated solution + colloid and sugar is one of the main substances dissolved in it.
During freezing:
What happens is that during the freezing process, as the coke cools a lot of sugar is pushed out of solution which allows the less-saturated water to freeze first. The last bit of liquid to freeze has much more sugar in it and takes a while to freeze because it is a concentrated solution and the freezing point has been lowered a lot.
During melting:
The last portion of the coke to freeze has the bulk of the sugar and the lowest freezing point and will melt first when warmed. When you allow the coke to start melting the most saturated portions melt the fastest and you consume most of the sugar in this stage. Later when the drink continues to warm the rest of the water starts melting with much less sugar in it, thereby making the remaining portion less sweet.
More information about sugar solubility:
One common way to grow sugar crystals is by slowly cooling the solution to push the sugar out of solution. There is some information about this here and they provide a nice sugar (sucrose) solubility versus temperature graph too:
As you can see the temperature dependence for solubility is dramatic. I haven't been able to find a curve for fructose (the primary sugar in coke in the United States) but I suspect the curve is very similar.
The following is multiple choice question (with options) to answer.
Dissolving sucrose makes liquids | [
"hot",
"dry",
"sweet",
"cold"
] | C | dissolving a substance in water causes the water to taste like that substance |
OpenBookQA | OpenBookQA-3640 | orbit, earth, satellite, orbital-mechanics, artificial-satellite
There are a few details that may affect the answer: you should consider if the motion of the person will affect the answer to part (b) (and if not, why not). You should know that the Earth is not spherical. You should consider whether the optical refraction of light by the Earth's atmosphere should be considered. However, in a homework problem, such issues can often be ignored, as their effects are small.
The following is multiple choice question (with options) to answer.
If your were to sit still and stare at the sky for one of the earth's rotations, you will have wasted | [
"half your existence",
"1,440 minutes",
"your family's week",
"2 days"
] | B | a Rotation of the Earth on itself takes one day |
OpenBookQA | OpenBookQA-3641 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
Scavengers eat dead what? | [
"fauna",
"stars",
"meteors",
"dreams"
] | A | scavengers eat dead organisms |
OpenBookQA | OpenBookQA-3642 | thermodynamics, geophysics
Second, any closed system evolves toward thermal equillibrium. In simple terms, if you leave a hot coffee on your table, it will eventually cool down to room temperature. Even though compression increases temperature, this doesn't mean that constant pressure keeps producing more and more heat. When you compress a lot of air into a soccer ball, it will feel hot to the touch. But as it exchanges heat with the environment, it will cool down. This is very useful, of course, because it allows you to expend energy to cool things down, like in your A/C :)
What effect this has on pressure in turn again depends on the properties of the material you're working with. If you have a volume of air in a bottle, as you cool it down, the gas pressure decreases. If you heat it up, the pressure increases. This is the reason why you need to tweak the pressure in your car's tires even if they aren't leaking - you need to adjust for current temperature.
However, with a liquid, this isn't anywhere as simple. While there is a relation between temperature and density, it's nowhere near as big as in an ideal gas. The same goes with pressure and density - if it didn't, you wouldn't be able to walk (imagine that your legs would shorten by half every time you raised one leg - that just wouldn't work).
So, let's put this to use in our ocean example. Undisturbed, water will tend to be "vertically ordered" by density. Usually, this means that warmer water will tend to rise up, while colder water will tend to go down. So the weird thing is actually how relatively warm in the depths. The ocean floor tends to be around the same temperature, regardless of how warm or cold the upper layers are.
There's two main reasons for that, specific to water:
The following is multiple choice question (with options) to answer.
If your body is hot, it will cool down if you put what on it | [
"hot water",
"an ice pack",
"Fire",
"the sun"
] | B | if a hot substance is touches a cold object then that substance will likely cool |
OpenBookQA | OpenBookQA-3643 | fluid-dynamics
The folks at Cornell have some nice animations and pictures of vehicle wakes.
As fall approaches, try putting some dead leaves (small pieces if possible) out onto the road. They should get caught up in the wake and give you a chance to see this in action.
Your first theory is on the right track. There will be a low pressure region behind the truck (not quite a vacuum). This region will also generally be a swirling mess of turbulence. The this will impart a lot velocity to the air. The front and sides contribute too, but the back end of a vehicle is usually the most significant source of drag. Check this wiki, for a nice picture and a bit on flow separation.
Bow shock is less right. You won't see a shock unless you've got things moving around the speed of sound. You will get some acceleration of the flow at the front and sides and that wouldn't look entirely unlike a bow shock, but the wake is the major player. Unlike a shock, this won't be a sharp interface and it won't be a clean straight line.
The following is multiple choice question (with options) to answer.
It's hard to manage a truck where there's | [
"a slight breeze",
"foggy conditions",
"some small clouds",
"diffused sunlight"
] | B | bad weather decreases visibility while driving |
OpenBookQA | OpenBookQA-3644 | bond
Now, each Hydrogen atom has two electrons to enjoy, and their shells are (sort of) filled.
Similarly, H2O isn't made by Oxygen capturing Hydrogen's electrons. The H--O bond is a covalent bond as well (hope you can see the electron pairs ¨).
Before bonding After bonding
¨ ¨
H · · O · · H H : O : H
¨ ¨
H2O2 has a covalent bond between the two Oxygen atoms
¨ ¨
H : O : O : H
¨ ¨
See the structure of Hydrogen Peroxide from Wikipedia article:
source: http://en.wikipedia.org/wiki/File:Hydrogen-peroxide-3D-balls.png
The following is multiple choice question (with options) to answer.
A substance that has two hydrogen atoms and an oxygen atom is | [
"green",
"renewable",
"alive",
"radioactive"
] | B | water is a renewable resource |
OpenBookQA | OpenBookQA-3645 | electricity, electric-circuits, electric-current
I was wearing flip flops from the time I stripped off my neoprene wet suit at the car until the time I started getting shocked (my wife was wearing Birkenstocks).
I had been snorkeling for about an hour in the Pacific Ocean wearing a full body wet-suit, booties, and gloves (no hood).
I had been camping the night before and consumed quite a bit of Gatorade.
My wife had only been wearing a spring suit and gloves, no booties.
There was another receipt that had been left in the machine (maybe someone else had been shocked as well and decided it wasn't worth the risk of going after it?)
I can't think of anything else relevant. Any insights into what was going on here would be welcome. I tried calling the maintainers of the machine but couldn't get through (this was before I found out that I seemed to be the only one affected).
Thanks!
She tried touching the machine in various places, again nothing. I inadvertently touched her hand while she was touching the machine and then suddenly she felt it too.
From this it is evident you were a good conductor to the ground.
You later say :
We came back out 15 minutes later after drinking our hot chocolate and tried to reproduce the phenomenon with no luck.
So no charge was passing through you any longer?
15 minutes is too little a time to change your conductivity. It could be a combination of an intermittent fault in the circuit and your conductivity at that time. You should alert their maintenance to be on the safe side.
The following is multiple choice question (with options) to answer.
If you want to stay dry in the park you should avoid | [
"sunshine",
"showers",
"covered awnings",
"the car"
] | B | precipitation is when water falls from the sky |
OpenBookQA | OpenBookQA-3646 | everyday-life
Title: Strange pattern on car windows
A couple of days ago I was in a friend's car, and I noticed this pattern on the windows; I took a picture of the sun through the window to make it clearly visible.
The night before had been quite cold, but I don't think that the temperature went below $0$ °C, even though I am sure that it did some days before.
I can speculate that the phenomenon originated from some condensation/freezing of humidity on the outside of the car window, so I searched the web for pictures of water condensation and frost patterns (and also water staining) on car windows, but couldn't find anything similar.
What could be the origin of this intricate pattern? From your question, I can guess that the weather is rainy in your region.
When you drive a car in the rain, the water drops pass your windows at an angle. This, plus wind and other winter stuff causes the path of the drops to twist and jiggle like in this photo
I would also guess that the rain stopped while still driving, so the water could've evaporated in this pattern. The sunlight then makes those residues more pronounced when you took the picture.
Take a look at the following picture from a google search of 'water stains on glass'. To me it looks similar to your photo, just without the effect of moving window (keep in mind that the residues in the water may differ from one place to another due to pollution and etc., so the stains don't have to look the same).
The following is multiple choice question (with options) to answer.
little balls of H2O on the inside of a closed window came from | [
"rain",
"condensed water",
"snow",
"ice cream"
] | B | beads of water are formed by water vapor condensing |
OpenBookQA | OpenBookQA-3647 | forces, torque, buoyancy
(The translation is from me and it's old French that I sometimes struggle to get in shape!)
Third section, Chapter I: From the point around which the vessel oscillates, which is called roll, and the part that gravity has in these oscillations. (p 369 ....)
"The problem is solved, it is no longer possible to doubt that it is around its center of gravity that the ship makes its oscillation."
...
"It must be remarked that we neglect here the resistance which the water makes to the swaying of the ship; just as the resistance of the air to the movement of pendulums is usually neglected. This resistance is as null, compared to the other forces we consider, because no matter how large the oscillations of the ship, it has, because of the figure, that little water to move and that it does not shocked her with rather little speed. It is still assumed that the alternative inclinations are not large enough, so that the metacentre changes substantially in height relative to the center of gravity. "
In 1762, he problem is clearly stated!
Hope it can help !
The following is multiple choice question (with options) to answer.
Which of the following would have best aided a vessel at sea in crossing the sea in the 18th century? | [
"A radar system",
"An old soothsayer",
"An experienced navigator",
"A crow's nest"
] | C | An example of navigation is directing a boat |
OpenBookQA | OpenBookQA-3648 | biochemistry
Title: Bradford Reagent Disposal I am a graduate student volunteering in a professor's lab being tasked with finding out how to dispose of certain hazardous materials. I have encountered a problem with disposing of Bradford's Reagent. I have checked online, but am running into problems due to the methanol component of this compound. Can someone help me with the proper disposal procedure? Thank you in advance. I would strongly suggest to ask someone in your lab about this, they will have a better idea about the different waste disposal methods you have available.
In general you would dispose anything that contains organic solvents like methanol in a waste container for generic solvent waste. You should have something like that somewhere in the lab.
One thing you always have to keep in mind is to never put anything still reactive into your waste container. A popular example would be a strong oxidizing agent, putting that into a solvent waste container is dangerous and could e.g. ignite the waste. This is not an issue in this case, but you should always keep that in mind.
Another aspect is the pH of the waste, in many cases the waste disposal facility will only accept reasonably neutral waste, so you should neutralize your waste before putting it into a container. Neutralizing it inside the container can be much more annoying. This might not be necessary if you have a dedicated acidic waste, you'll have to ask someone in your lab about that. The Bradford reagent is strongly acidic, so you'll have to pay attention to this aspect.
The following is multiple choice question (with options) to answer.
if a school cafeteria left their waste uncollected for a while, what might they attract? | [
"it might attract some bats",
"it might attract raccoons",
"it might attract some eagles",
"it might attract people"
] | B | raccoons eat waste |
OpenBookQA | OpenBookQA-3649 | the-moon, the-sun, earth
That explains the circular movement of the stars, the Sun and the Moon.
This is true for all locations on the Earth, except for the equator:
Is the Earth spinning? That depends, you can always choose a frame of reference that suits you. However, only one of them are non-rotating, the Inertial frame. In all the others we have fictitious forces acting, like centrifugal or Coriolis forces.
We can test if the Earth rotates by watching a pendulum throughout a day. The pendulum would then seem to slowly rotate during this period of time, meaning some fictitious "force" is acting on it. That means that we are located in a rotating frame of reference, and thus the Earth rotates.
The following is multiple choice question (with options) to answer.
the earth revolves around the sun in | [
"a day",
"a year",
"a week",
"a month"
] | B | one year is equal to 365 days |
OpenBookQA | OpenBookQA-3650 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
Consumers eat other what? | [
"islands",
"winds",
"currents",
"fauna"
] | D | consumers eat other organisms |
OpenBookQA | OpenBookQA-3651 | ocean, glaciology, ice, ecology, cryosphere
Title: Do icebergs have any impact on ecology? Are icebergs neutral actors in the environment, or do they have any impact on the local ecology. Do they have any environmental impacts that might influence any part of the biosphere? Yes, they have many impacts:
They provide a substrate for algae to grow and they can have whole ecosystems under them. You might think that such substrate is transient because it is melting, but Arctic and Antarctic waters are often below zero degrees Celsius, therefore, freshwater ice doesn't melt. You can find many articles about such ecosystems (here is one).
They transport sediments and nutrients into the ocean.
They provide safe rest areas for animals like seals, birds and penguins.
They impact the temperature of surface waters, specially in fjords.
They stir the sea floor in shallow waters
And there must be more ways they impact the environment and ecosystems but those are the ones I can think about right now.
The following is multiple choice question (with options) to answer.
To positively impact an ecosystem | [
"smoke",
"litter",
"burn plastic",
"sow seeds"
] | D | planting trees has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-3652 | zoology, physiology, brain, ethology, behaviour
Robins, A., Lippolis, G., Bisazza, A., Vallortigara, G. & Rogers, L. J. (1998). Lateralized agonistic responses and hindlimb use in toads. Animal Behaviour, 56, 875–881.
Rogers, L. J. & Andrew, R. J. (Eds) (2002). Comparative Vertebrate Lateralization. Cambridge: Cambridge University Press.
Roth, E. D. (2003). ‘Handedness’ in snakes? Lateralization of coiling behaviour in a cottonmouth, Agkistrodon piscivorus leucostoma, population. Animal behaviour, 66(2), 337-341.
Shine, R., Olsson, M. M., LeMaster, M. P., Moore, I. T., & Mason, R. T. (2000). Are snakes right-handed? Asymmetry in hemipenis size and usage in gartersnakes (Thamnophis sirtalis). Behavioral Ecology, 11(4), 411-415.
Sovrano, V. A., Rainoldi, C., Bisazza, A. & Vallortigara, G. (1999). Roots of brain specializations: preferential left-eye use during mirror-image inspection in six species of teleost fish. Behavioural Brain Research, 106, 175–180.
Sovrano, V. A., Bisazza, A. & Vallortigara, G. (2001). Lateralization of response to social stimuli in fishes: a comparison between different methods and species. Physiology & Behavior, 74, 237– 244.
Vallortigara, G., Rogers, L. J., Bisazza, A., Lippolis, G. & Robins, A. (1998). Complementary right and left hemifield use for predatory and agonistic behaviour in toads. NeuroReport, 9, 3341–3344.
Vallortigara, G., Rogers, L. J. & Bisazza, A. (1999). Possible evolutionary origins of cognitive brain lateralization. Brain Research Reviews, 30, 164–175.
The following is multiple choice question (with options) to answer.
animals learn some behaviors from watching their | [
"rocks",
"toys",
"caretakers",
"trees"
] | C | animals learn some behaviors from watching their parents |
OpenBookQA | OpenBookQA-3653 | thermodynamics, absorption
When you want to boil water efficiently, you do two things: cover the pot (limit loss due to evaporation) and put the heat inside if you can: for example the submerged heater element in electric kettles. Other forms of boilers also put the heat in the middle of the water (think water heaters for homes) so most of the hot gas gets to give off its energy to the water.
But if you have a flame, the best you can hope to to is transfer all it's internal energy to the water - so when the water is hotter a flame is always less efficient.
Very efficient systems use counter flow - the hot air moves left to right, and the water to be heated right to left: in that way the colder gas meets even colder water so when the gas finally is exhausted it has no heat left. Same principle is used in efficient gas furnace for homes, etc.
The following is multiple choice question (with options) to answer.
Hot water is best when you want to | [
"go rock climbing",
"have cold drinks",
"cleanse your hands",
"go running"
] | C | a shower is a source of hot water for washing |
OpenBookQA | OpenBookQA-3654 | ocean, ocean-currents, tides
Physical effects, then, are likely to include direct effects on current speed, sediment, and stratification.
The obvious possible biological effect is from collisions. This is not my field, but as I understand it no effect is likely on small fish populations from collisions, although individuals may be affected. Collision risk for large animals (e.g. sharks and marine mammals) and for diving birds is a topic of active research, and is likely (especially for mammals) to depend on their behaviour around the devices. No large animal collisions have been reported on any of the prototypes undergoing testing so far.
A good review of possible effects on benthic organisms is provided by Shields et al (2011). These may include,
The following is multiple choice question (with options) to answer.
If a thing has a good impact on nature, it is most likely | [
"putting plastics in special containers",
"burning old used tires",
"putting cigarettes out in ponds",
"using aerosol air fresheners"
] | A | recycling resources has a positive impact on the environment |
OpenBookQA | OpenBookQA-3655 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which relationship is true? | [
"a soccer pitch slows the ball down via magic",
"a soccer pitch slows the ball down because it is wet",
"a soccer pitch slows the ball down because there is always wind",
"a soccer pitch slows the ball down via friction"
] | D | friction acts to counter the motion of two objects when their surfaces are touching |
OpenBookQA | OpenBookQA-3656 | photons, vision
Title: Dark room lights When I lay down in my room at night it's pretty much completely dark but I observe this strange phenomenon going on.
When I lay down and look at my ceiling I can see my white fluorescent white bulbs and white fan blades but when it's dark I can't. But, as soon as I avert my eyes from the fan and lightbulbs about 1 foot I can see them in the dark but why? If it helps there is a very slight illumination from the street lights. And, also I can't see anything not white on the ceiling.
Why can I see the objects only when I avert my eyes? This is really a biology topic, rather than a physics one.
The light sensing cells in your eyes come in two (or four depending on how you count) types. The cones are color sensitive. The rods are sensitive over almost the whole visible spectrum and offer no color discrimination, but they are considerably more sensitive than the cones.
The rods and cones are not evenly distributed in the eye. Cones are concentrated in the central part of the retina and rods are more common in your peripheral visual region. Which makes your peripheral vision more sensitive to very dim sources than your central vision.
In fact, naked-eye star-gazers learn to look near-but-not-at very dim observing target exactly to take advantage of this effect. But it take a lot of will-power to do at first. You'll find your self having a "Ah-ha!" reaction and then looking right at the target every time you make the trick work. At which point you have to go around again.
The following is multiple choice question (with options) to answer.
It's hardest to perceive in a flashlight's beam | [
"a shiny diamond",
"a dark spider",
"a metal sphere",
"a glistening icicle"
] | B | if an object reflects more light then that object is more easily seen |
OpenBookQA | OpenBookQA-3657 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Which animal will eat only plants? | [
"snake",
"fish",
"slug",
"deer"
] | D | herbivores only eat plants |
OpenBookQA | OpenBookQA-3658 | reproduction, digestion, sexual-reproduction
Hazardous components of pollen:
Trace amounts of hepatotoxic pyrrolizidine alkaloids were found in pollen of Echium vulgare, E. plantagineum, Senecio jacobaea, S. ovatus, and Eupatorium cannabinum (Boppre et al., 2008). In Middle and Northern Europe these pollens are not among the main pollen grains gathered by bees, however in Southern Europe the two Echium plants are more diffused and are gathered by bees in larger amounts (Campos et al., 1994; Serra Bonvehi, 1997). [Source 1] (Page 5)
Therefore, it should undergo tests to approve it's purity as allergies can be caused.
References:
1 : Future of bee pollen(Research gate)
2 : Pollen composition and standardisation of analytical methods(Research gate)
3 : Hollow pollen shells to enhance drug delivery(NCBI)
4 : Bee pollen: chemical composition and therapeutic application(NCBI)
5 : Biological activities of commercial bee pollens: antimicrobial, antimutagenic, antioxidant and anti-inflammatory(NCBI)
6 : Biological and therapeutic properties of bee pollen: a review(NCBI)
The following is multiple choice question (with options) to answer.
Plants often use which enticing substance when attracting pollinators? | [
"sweet things",
"songs",
"comedy",
"bees"
] | A | A bird is a pollinating animal |
OpenBookQA | OpenBookQA-3659 | general-biology, habitat
Title: How does life change when you dig deeper? I've just realized that I have no idea what life / biotopes / soil looks like when you dig deeper than a few meters.
I know that in the first meter of soil you can find all sorts of live animals (like moles and rabbits), insects (like ants, but many more), plants, and single-celled organisms, of course.
But how does that change when you get to the depth of a metro station (below 30m)? When you plan to build a metro, do you have to consider that you might destroy a biotope?
I guess there is a point from which you will quite certainly not find animal/plant life in the soil anymore. This will, of course, depend on where exactly you are. But can you give a rough estimate of how deep we're talking? 50m? 100m? 1km? Extremophile bacteria and archea are living very deep beyond our imaginations. This is what you need for general composition at different depths. And this and this is for the deepest living organism known ! Following is image from (Manson et al 2010) which shows at what depth you will get bacteria
Even more deeper, Wold's single species ecosystem, Desulforudis audaxviator which can be found 3 km below sea level.
The following is multiple choice question (with options) to answer.
Moles are underground a lot of the time, and since few animals live there, they are unlikely to be | [
"near worms",
"killed by others",
"dirty",
"in dirt"
] | B | earthworms create tunnels in soil |
OpenBookQA | OpenBookQA-3660 | species-identification
Title: What is this bird - sound attached - (Atlanta Georgia)? We live in Atlanta Georgia (northern suburb) & this bird starts singing in the middle of the night !!
And goes on for almost 2 hours without stopping.
Here is the link to it :
https://drive.google.com/open?id=0B3WzrpCj4uKeQ3l5MnJPY1RfcUpiVzkxRHBsWEN4RnYtTlNB
Any way to politely ask him/her to stop singing at night ? :)
Would highly appreciate any help in this regard ! It sounds like a Chuck-will's-widow; click the "sound" icon in that link for the song. They're native to Georgia and sing interminably at night, so the story checks out.
The following is multiple choice question (with options) to answer.
If birds are singing, the sun is shining, and temps are high, then | [
"daylight is short",
"luminescence is long",
"winter is here",
"nights are freezing"
] | B | the amount of daylight is greatest in the summer |
OpenBookQA | OpenBookQA-3661 | evolution, botany, proteins
tl;dr: the egg contains more proteins than the seed because the chicken that made the egg ate a whole lot of seeds, and all the protein in those seeds ended up concentrated in that one egg.
EDIT: running into this much later I realized I missed a pretty vital half of the question, because there is a difference between fruits and seeds. The difference is the following: nitrogen is precious for plants so they'll try and use it for very important things. Seeds are very important to the plant, so while a seed has less protein than an egg it will still have lots of protein by plant standards. Fruits now, that's another story. Like the sugary nectar, fruits are a bribe for animals, a bit of food offered to them so that they'll spread the plant's seeds. And like with the sugary nectar, the plant has every incentive to pack that bribe full of cheap carbohydrates and as few precious proteins as it can manage.
The following is multiple choice question (with options) to answer.
Which stores sustenance in the seed form? | [
"giraffes",
"cats",
"cattle",
"hydrangea"
] | D | a seed is used for storing food for a new plant |
OpenBookQA | OpenBookQA-3662 | newtonian-mechanics, newtonian-gravity, orbital-motion, planets
The Roche Limit can be viewed as an Earth shaped imaginary "border", on average 9,492 km from the centre of Earth, 1.49 times Earth's radius, for rigid bodies. So around the equator it "moves" outwards a little. It follows the oblate spheroid shape of Earth.
Earth may have had a ring just after its formation. The view of these ring from Earth would vary. It would all depend on your latitude and which direction you were facing. Near the equator, the ring would be like thin slices of light that erupted from distant Earth horizons and stretched into the sky as far as the eye could see.
Thanks to Emilio Pisanty for correctly pointing out the depiction of the rings from mid and high latitudes is not completely accurate. The plane of the ground is not orthogonal to the plane of the rings, so they would appear at an angle. All I can do is ask for some personal latitude in the presentation of this "what if" scenario.
The pictures assume the ring around Earth would be in the same proportion as the ring around Saturn is to that planet.
View of ring from the equator.
Why does the ring form around the equator as opposed to another axis.
It's due to the effect of the Central Force Law, the same basic reason the planets are situated in a plane around the Sun. The Sun is spherical,
so objects such as Pluto can "get away" with being 8 degrees out of line. If the Earth, and Saturn) were perfect spheres, then the axis of the ring could be at any angle. Because both planets are oblate spheroid, with a tidal bulge, over time the particles composing the ring would collect there. Saturn's rings have an estimated local thickness of as little as 10 metres and as much as 1 kilometer, so they are extemely "thin".
View of rings from the mid latitudes.
View of rings at 23° south latitude a 180° panorama gives an idea of what a magnificent sight the rings would be. The Earth itself is casting the shadow.
Image source: If Earth Had a Ring Like Saturn
The following is multiple choice question (with options) to answer.
Saturn hangs around because of | [
"rocket fuel",
"Sega",
"a central star",
"Saturnalia"
] | C | gravity causes orbits |
OpenBookQA | OpenBookQA-3663 | visible-light, speed-of-light
Title: How can travelling at light speed affect light itself? ~Hypothetical Scenario:
Your driving in a car (with the headlights on high beam) and you gradually get faster until you reach the speed of light.
Raised Assumptions:
You can see in and out of the car whilst moving at the speed of light.
Ignore air resistance.
Ignore all biological affects.
The headlights on the car still work at the speed of light.
Bystanders can see objects move at the speed of light.
The car can physically make it to the speed of light.
Questions
Would the driver be able to see the high beam on in front of the car and be travelling twice as fast as the speed of light? Or will the photons produced pool up within the light bulb itself? Would there be no light produced even though the light bulb is on?
If a bystander saw the car drive by would they see the light from the headlights?
The following is multiple choice question (with options) to answer.
a decrease in visibility while driving can cause people to crash their what? | [
"food",
"chevy 2000s",
"career",
"wind"
] | B | a decrease in visibility while driving can cause people to crash their car |
OpenBookQA | OpenBookQA-3664 | The first trial that gives the most information is to do four vs. four (ABCD vs. EFGH). No matter what the result we have reduced the possible solutions from 24 to 8.
Possibilities Test Result Possibilities
A lighter
A heavier
B lighter
B heavier
C lighter
C heavier
D lighter
D heavier
E lighter
E heavier
F lighter
F heavier
G lighter
G heavier
H lighter
H heavier
I lighter
I heavier
J lighter
J heavier
K lighter
K heavier
L lighter
L heavier
ABCD vs. EFGH = I lighter
I heavier
J lighter
J heavier
K lighter
K heavier
L lighter
L heavier
< A lighter
B lighter
C lighter
D lighter
E heavier
F heavier
G heavier
H heavier
> A heavier
B heavier
C heavier
D heavier
E lighter
F lighter
G lighter
H lighter
• If the seesaw is equal then we know those eight islanders (ABCDEFGH) can be eliminated from being either lighter or heavier. The remaining four islanders (IJKL) could then be either lighter or heavier.
• If the seesaw is unbalanced then we know the four untested islanders (IJKL) can be eliminated. We also know that all the islanders on the heavier side cannot be lighter. And all the islanders on the lighter side cannot be heavier.
What we do for the second trial depends on the type of result for the first trial because the pattern of remaining possibilities is different.
• If the first trial was balanced then we have four remaining islanders (IJKL) that could be either lighter or heavier. We can work out the remaining possibilities by comparing three remaining islanders (IJK) with three normal islanders (ABC).
The following is multiple choice question (with options) to answer.
Who is in better shape? | [
"a sedentary crowd-worker",
"a body builder",
"a couch potato",
"a fat woman"
] | B | exercise has a positive impact on a human 's health |
OpenBookQA | OpenBookQA-3665 | algorithm, go, concurrency, dining-philosophers
// reserve a slot in the channel for eating
// if channel buffer is full, this is blocked until channel space is released
pPhilo.host.requestChannel <- pPhilo
pPhilo.numEat++
fmt.Printf("starting to eat %d for %d time\n", pPhilo.idx, pPhilo.numEat)
time.Sleep(time.Millisecond)
fmt.Printf("finishing eating %d for %d time\n", pPhilo.idx, pPhilo.numEat)
pPhilo.rightCS.mu.Unlock()
pPhilo.leftCS.mu.Unlock()
wg.Done()
}
}
func main() {
var wg sync.WaitGroup
host := Host{
eatingChannel: make(chan *Philo, numEatingPhilo),
requestChannel: make(chan *Philo),
quitChannel: make(chan int),
eatingPhilos: make(map[int]bool),
}
CSticks := make([]*ChopS, numCS)
for i := 0; i < numCS; i++ {
CSticks[i] = new(ChopS)
}
philos := make([]*Philo, numPhilo)
for i := 0; i < numPhilo; i++ {
philos[i] = &Philo{idx: i + 1, numEat: 0, leftCS: CSticks[i], rightCS: CSticks[(i+1)%5], host: &host}
}
go host.manage()
wg.Add(numPhilo * eatTimes)
for i := 0; i < numPhilo; i++ {
go philos[i].eat(&wg)
}
wg.Wait()
host.quitChannel <- 1
}
The following is multiple choice question (with options) to answer.
Your body goes into starvation mode when you insufficient amounts of | [
"shoes",
"fun",
"pants",
"sustenance"
] | D | lack of food causes starvation |
OpenBookQA | OpenBookQA-3666 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
Which of the following would push water out of its body to evade an orca? | [
"a squid",
"a shark",
"a flounder",
"a lobster"
] | A | a squid produces thrust by pushing water out of its body |
OpenBookQA | OpenBookQA-3667 | 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.
a battery converts chemical energy into electrical energy to power a | [
"sponge",
"rock",
"stapler",
"calculator"
] | D | a battery converts chemical energy into electrical energy |
OpenBookQA | OpenBookQA-3668 | electromagnetism, nuclear-physics, fusion, ferromagnetism
Title: Nuclear fusion/fission vs. magnetic characteristics of Iron Is the fact that Iron is attracted to magnets in any way related to the fact that it is also the element occupying the singular periodic table position where the chains of nuclear fission and fusion converge?
Or is this just a coincidence? It is coincidence.
For example not all forms of iron are ferromagnetic, even though they all have the same nuclei. Iron exists in three slightly different crystal structures called ferritic, martensitic and austenitic. The ferritic and martensitic are ferromagnetic but the austenitic form is not. So iron can switch between a ferromagnet and paramagnet just by changing its crystal structure.
Other elements like cobalt, nickel, dysprosium and gadolinium are also ferromagnets, and there are lots of compounds that show ferromagnetism. The most obvious of these are the rare earth magnets.
Ferromagnetism is a property of unpaired electrons within the material, and is not related to the nuclear energy levels involved in nuclear reactions. There is a basic description of ferromagnetism in Why does magnet attract iron but not other metals?
The following is multiple choice question (with options) to answer.
Why are ferrous metals magnetic? | [
"The shiny reflective coating",
"They are very heavy. Their weight.",
"The iron contained inside of them",
"The copper in all of them"
] | C | ferrous metals contain iron |
OpenBookQA | OpenBookQA-3669 | meteorology, climate-change, gas, pollution
If you are interested in Greenhouse Gases (e.g. methane, carbon dioxide, CFCs, nitrous oxide), the EPA has a separate site for those emissions since they are not part of the same regulatory framework http://www.epa.gov/climatechange/ghgemissions/ . Greenhouse gases typically do not cause adverse health effects for plants or animals on land. However, they have long-term radiative effects (e.g. the greenhouse effect) because they stay in the atmosphere for many years and trap infrared light. These long-term radiative effects are what can change climate and consequently land cover. Furthermore, most of the excess carbon is absorbed by the ocean, which creates carbonic acid. Increased acidity of the ocean causes severe problems for marine ecosystems.
The EPA states that in 2012 the CO2 equivalent GHG emissions for the USA by sector was:
The following is multiple choice question (with options) to answer.
What have a negative impact on the environment? | [
"plants",
"trees",
"recycling",
"dumpyards"
] | D | landfills have a negative impact on the environment |
OpenBookQA | OpenBookQA-3670 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
Animals you see on the way to work or school, every animal on Earth does what? | [
"squacks",
"cries",
"swims",
"intakes air"
] | D | an animal requires oxygen for to breathe |
OpenBookQA | OpenBookQA-3671 | java, random
case 2:
return " with little to no vegitation, imports are what this town lives on.";
case 3:
return " and is full of fertile land, the farmers here are prosperous.";
case 4:
return " under the protection of large mountains and rought terrain; lining the horizon.";
case 5:
return " and the visible ocean water laps on the shore gentaly.";
case 6:
return " the visible ocean water is rough, and would be hard to navigate.";
case 7:
return " and strange jagged rocks protrude randomly along the landscape.";
case 8:
return " and purple glows eminate from a very large mountain peak in the far distance.";
case 9:
return " and colourful skys cause the buildings to shine with a great elegance.";
case 10:
return " built partially underground.";
default:
throw new IllegalStateException("Something went wrong!");
}
}
}
The following is multiple choice question (with options) to answer.
A product that comes from the ground is likely | [
"Styrofoam containers",
"an organic banana",
"wax candles",
"storm clouds"
] | B | nature is the source of natural resources |
OpenBookQA | OpenBookQA-3672 | visible-light, everyday-life, diffraction, light-emitting-diodes
It's not that good visible, but the pixels are rectangular shaped (in vertical position). They are much smaller than the pixels on my big TV-screen, which I almost can see with the naked eye (once you know the shape after taking the close-up picture, which can't be said of the pixels of my laptop's screen). The effect isn't visible on my (power off) laptop screen, maybe because of the smallness of the pixels. The effect is (as I said ) color-dependent (with a red beam of light only a red X-form, periodically bright and dark is seen) and orientation independent (no matter how I point the light beam the same X appears over and over again). Nevertheless, I don't know if the pixels on both screens are the same (though it appears so). It looks like a diffraction pattern from the pixels of the screen. In a different SE question, the pattern was four horizontal and vertical "rays" consisting of finely spaced peaks, rather than the wide spacing here and the angles that differ from 90 degrees.
If you measure the apparent angle between the first diffraction peaks (the ones at the edge of the halo) and the central spot, you can relate that to the wavelength (say, 600 nm) and the dot pitch of the tv screen. The ratio of distances screen-eye versus screen-candle also matters; the analysis is easier if this ratio is much smaller than one.
Regarding the angle between the rays: I suspect that your screen does not have rectangular pixels, but pixels arranged in some kind of staggered arrangement. However, I can't guess the exact pixel arrangement from the diffraction pattern. It could also be that you took the photo from an angle. Maybe you could post a picture of the TV pixels in close-up (when the TV is on) and a sketch of the relative locations of camera, candle, screen, and apparent diffraction spots.
Update
The following is multiple choice question (with options) to answer.
If you are having trouble seeing the TV, what can you do to see it more clearly? | [
"closing your eyes",
"moving closer",
"eating",
"dying"
] | B | as the size of an object appears larger , that object will be observed better |
OpenBookQA | OpenBookQA-3673 | electric-circuits, electrons, electric-current, charge, conventions
negative electrons in metallic conductors (metal wires, usual circuitry),
positive "holes" in semiconductors (PV solar panels, thermocouples, transistors),
positive and negative ions in a mix in conductive fluids or electrolytes (batteries, fuel cells, the human body),
etc.
All such charge-carriers can appear in an electric circuit. A mix of positive charge moving one way and negative the other way in different parts. Luckily, a negative charge moving one way always corresponds to a positive moving to other way - an electron leaving a spot leaves that spot more positive than it was before, corresponding to it gaining a net positive charge. So, due to this equivalency, someone has back in time decided to simplify all talk about current and chose that whenever we talk about current, we mean the direction a positive charge would move.
This same consensus was made for several other topics as well, such as electric field direction, magnetic field direction etc.
[...] If we open the switch and make this circuit an open circuit the bulb should still light up since electrons will flow from the negative terminal to the bulb and there is no switch to stop the electrons from reaching the bulb.
This is true - for a very short while. When the battery (voltage source) is turned on, electrons will move from negative terminal and as far away as they can. Through the bulb, yes.
But soon the first electron reaches the end and can move no further. More and more arrive and accumulate there. As you know, like charges repel each other, so the more that accumulate there, the more do they prevent further electrons from arriving. This slows down the current until it stops.
This is the reason no steady current can flow in an open circuit. Current can flow momentarily, but not at any constant steady rate. And the momentary flow in the beginning might not cause enough power on the light bulb filament to heat it up to glow.
Now assume that there's a resistor in place of that switch and an LED in place of that bulb [..]. I can suppose that the resistor is there to prevent high voltage from reaching the LED so that it would not fry but again assuming that we make a circuit exactly like explained above the LED would still fry up because the current would reach the LED first and then the resistor.
The following is multiple choice question (with options) to answer.
A light bulb will turn on when what flows to it? | [
"fire",
"zapping energy",
"wind",
"water"
] | B | when electricity flows to a light bulb , the light bulb will come on |
OpenBookQA | OpenBookQA-3674 | bacteriology, antibiotic-resistance, research-process
Title: How do scientists kill the bacteria they themselves made resistant? I was reading this article on researching bacteria resistance to silver by removing some of their genes.
Researchers then used "colony-scoring" software to measure the differences in growth and size of each plate's bacterial colony. E. coli strains with genes deleted involved in producing sensitivity, or toxicity, to silver grew larger colonies. Strains with genes deleted involved with resistance grew smaller colonies.
Once you end up with some resistant bacteria and you're done researching it, you can't just flush it down the toilet. How do you safely dispose those colony plates in a way that ensures those bacteria don't get out into the wild and reproduce? You are absolutely right, flushing down the toilet (or the sink) or simply throwing them into the normal waste doesn't work for biosafety reasons. And it is also not allowed, depending on the country you would do this in, this can lead to hefty fines.
Biologically contaminated lab waste can be inactivated (=all potential dangerous organisms are destroyed) by two ways: Either by heat or chemically. Which ways is used, depends on the kind of waste.
The most commonly used way is autoclaving, meaning treating the waste with steam at high temperatures at higher pressure. The temperature used here is usually 121°C, the exposure time depends on the volume of the waste, since the temperature needs to be reached and kept for at least 20 minutes. See the references for more details.
Liquid wastes (like culture media) can also be inactivated chemically by adding chlorine bleach to decompose the cells. Bleach can also be used to decontaminate surfaces, although here more often alcoholic solutions (70% Ethanol or Isopropanol) are used. After chemical inactivation, the remaining solutions should not be autoclaved as the emerging fumes are either unhealthy (bleach) or explosive (alcoholic solutions) and this is unnecessary, too.
Liquid wastes can also be autoclaved to inactivate them.
Autoclaving has the main advantage that it is rather simple (put the waste into the autoclave, close it and run a appropriate program), the waste can afterwards simply be discarded as normal waste, which may not be the case for chemically inactivated waste, which may need special precaution for disposal.
References:
The following is multiple choice question (with options) to answer.
Elimination of their body's waste is | [
"a rare trait among living things",
"something that rarely happens for most mammals",
"a commonality all life forms share",
"unnecessary for smaller organisms"
] | C | all living things eliminate waste |
OpenBookQA | OpenBookQA-3675 | the-sun
2460163.500000000, A.D. 2023-Aug-07 00:00:00.0000, 6.625425330791064E-02, 3.556004033547897E+05, 5.050458943166362E+00, 2.761268189373863E+01, 2.787078308606339E+02, 2.460158097611625E+06, 1.548623091365481E-04, 7.228451565776196E+01, 7.968276040122535E+01, 3.808321533078448E+05, 4.060639032608998E+05, 2.324645693372517E+06,
2460164.500000000, A.D. 2023-Aug-08 00:00:00.0000, 6.507275768816487E-02, 3.554955131298805E+05, 5.053938392861703E+00, 2.761547227317707E+01, 2.775232172597620E+02, 2.460158014454506E+06, 1.552250039753550E-04, 8.698050648988226E+01, 9.443786013757804E+01, 3.802386934953690E+05, 4.049818738608575E+05, 2.319213984733781E+06,
$$EOE
The following is multiple choice question (with options) to answer.
The sun is | [
"Square shaped",
"caused by wind",
"Cold",
"has nuclear mechanics"
] | D | a star is a source of light energy through nuclear reactions |
OpenBookQA | OpenBookQA-3676 | spectroscopy, crystal-structure, history-of-chemistry, carbon-allotropes
Title: Are there any early industrial age methods capable of determining diamond or graphite's crystalline structure? I'm writing a fictional story with early industrial age technology where a chemist discovers not only that diamond and graphite are made of the same substance, but that they differ by crystalline structure (cubic vs hexagonal). However, I'd like this to be a realistic depiction if possible and the chemist does not have access to electron tunneling microscopy or advanced spectrographic methods. The farthest spectroscopy has gotten is Fraunhofer's spectroscope and John Herschel's evaporogram, with visible light and the beginnings of an understanding of infrared and ultraviolet. Would 1850's level spectroscopy or other technology of the time be able to demonstrate the crystal structures of carbon (specifically graphite and diamond) without a 1900's understanding of atomic structure?
Would 1850's level spectroscopy or other technology of the time be able to demonstrate the crystal structures of carbon (specifically graphite and diamond) without a 1900's understanding of atomic structure?
Yes, using visible light and petrographic microscopes. The field of optical mineralogy was mature enough by the mid-1800's for one to determine the crystal structure of minerals. In particular, the work of Sir William Nicol is worth investigating (thin but useful Wikipedia article).
I will add that there's a pretty simple way to determine whether or not the crystal structure of a mineral is the same or different than that of another mineral - the so-called crystal habit.
Finally, diamond exhibits conchoidal fracture, and graphite does not. This might be the easiest way to tell that the two minerals have different crystal structures.
The following is multiple choice question (with options) to answer.
in which one of these classes are you most likely to find graphite? | [
"in a yoga class",
"in a philosophy class",
"in a physical education class",
"in a visual art class"
] | D | pencil lead contains mineral graphite |
OpenBookQA | OpenBookQA-3677 | newtonian-mechanics, energy-conservation, work, potential-energy, biology
Title: If I lift a body with a force greater than its weight, what will happen to the excess energy provided to the body I will give an example to explain my question.
Case 1:
An elevator lifts body a with force equal to its weight for a distance $d$
Energy given to the body (work done)$=$ Weight $×$ $d$
Amount of work the body is capable of doing by falling down (gravitational potential energy) $=$ Weight $× \ d$
Case 2:
An elevator lifts the same body with force equal to twice weight it’s for a distance $d$
Energy given to the body (work done) $=$ $2 \ ×$ weight $×$ $d$
Amount of work the body is capable of doing by falling down (gravitational potential energy) $=$ weight $×$ $d$
So doubled the amount of energy I gave to the body yet it’s capacity to do work by falling down has not changed.
Where is the excess energy the lift provided the body?
(I am in 11th grade so please make your explanation simple enough for me to understand.) In both cases, the work provided by the elevator is turned into kinetic energy of the object.
In the moment the elevator stops (and stops doing work), the object thus carries kinetic energy and therefor will continue flying upwards. Both of your potential-energy calculations are therefore wrong - the actual top height will be more than $d$.
And the object will naturally reach higher in the second case since it gains a larger amount of kinetic energy in the second case, causing more potential energy to be stored.
In regular elevators you might feel various lifting forces without "flying" upwards as the elevator stops. So you might feel that the answer I provided is incorrect. But remember to include the decceleration as well. The larger lifting force in certain elevators might be exerted for a shorter time as well, with deceleration beginning before the stop is reached. In the ideal scenario of the elevator keeping a constant speed and then suddenly stopping immediately, then you will experience the "flying".
The following is multiple choice question (with options) to answer.
What has a positive impact on a bodies strength? | [
"pumping iron",
"overeating",
"flying",
"dying"
] | A | exercise has a positive impact on a body 's strength |
OpenBookQA | OpenBookQA-3678 | forces, water, surface-tension
Now, if we suddenly boost up this adhesion a billion times stronger (limit: imagination) from what is the real and cohesion stays same, then it's gonna suck. Literally. Everything the water or any liquid comes to contact with, it will immediately start to evenly spread out, clothing every nooks and cranny on that surface of that object. It'd be much like when we spill water on the floor. But now it'd be happening EVERYWHERE, on the sides and on the roofs. The rivers, lakes and oceans start allowing a layer of water to swallow everything up, and a carpet of water will cover the world. Trees and plants burst as there is an immense rush of water inside them. The large droplets of water we adored will never form, a droplet release in the air will torn into tiny minuscule droplets, that we can't see. Maybe into water vapor. And Life? I wonder... ;)
Hope that helped. Went a little overboard. :D
The following is multiple choice question (with options) to answer.
Living near any body of water puts your home at risk of flooding, if there is? | [
"too much rainfall",
"West Virginia",
"Jelly Beans",
"Tape"
] | A | storms cause bodies of water to increase amount of water they contain |
OpenBookQA | OpenBookQA-3679 | Best Japanese Brown Rice, Air Fryer Burgers And Fries, østfold University College Vacancies, Band T-shirts Walmart, How To Become An Anglican Priest, Too Much Fennel Taste, Porter Cable Circular Saw Cordless, Utmb My Chart, Iams Large Breed Dog Food Nutrition Facts,
The following is multiple choice question (with options) to answer.
humans sometimes eat | [
"plant reproduction vessels",
"unicorns",
"lava",
"clouds"
] | A | humans sometimes eat seeds |
OpenBookQA | OpenBookQA-3680 | civil-engineering, building-design
Title: Is it OK for a 2 story house not have a column or pillar sorry for my english. I was looking to buy a house. I saw some in my hometown, which is very affordable.
but on a picture of the house they are selling I found on the net troubled me.
no pillar/column, just hollowblocks and some steel bars.
kindly look at the pic.
I found it in this site
https://fiestacommunitiesblog.wordpress.com/tag/fiesta-communities/ As @SamFarjamirad states it's best to consult a knowledgeable construction engineer where you live, or in your region, because such people would know the building codes & construction practices for your region. A column or pillar for a two storey house may not be necessary if the load bearing walls are designed & built properly. This may include internal load bearing wall, inside the house. The other thing to be wary of is the quality of the foundations for the load bearing walls. Also, if the house to be renovated later all load bearing walls must not be removed or altered.
It looks like the steel is being threaded through the hollow block in the external walls. This would be done to increase the flexibility of the house during earthquakes and should a typhoon/cyclone/hurricane affect the house. Internal load bearing walls should also have such steel reinforcement.
If designed and built correctly such steel reinforced walls should not collapse. They might crack during extreme natural events but they should not fall and collapse the house.
Looking at the picture you included, some things that I found strange were:
The following is multiple choice question (with options) to answer.
If I wanted to use a tree as inspiration to make a house more sturdy what part would I use? | [
"the leaves",
"the pine cones",
"the fruit",
"the roots"
] | D | a trunk is a source of support for a tree |
OpenBookQA | OpenBookQA-3681 | genetics, vision, sex-chromosome, color
Females have two X-chromosomes, and can either be homozygous or heterozygous for the X-chromosome opsin allele. If homozygous, they are dichromatic; however, females who carry both an allele for an L opsin and one for an M opsin have the equivalent of normal human color vision, having both L and M cones because the process of X-inactivation segregates the expression of the L and M opsin genes to separate populations of cones. The significance of this is that in trichromatic female squirrel monkeys, the difference between L and M cones is solely determined by the stochastic choice of which X-chromosome is retained as the active one. Variation in L:M cone ratio in female squirrel monkeys is similar to what is seen in human males with normal color vision. In squirrel monkeys the variation has been attributed to the stochastic process of X-inactivation, influenced by the number of cells present at the time of activation and other random factors in the inactivation process (Jacobs & Williams, 2006).
Boiling this down: X-inactivation happens at a local enough scale that eyes of heterozygous females have active versions of both normal and mutant opsin genes. So they will still see color "similar to what is seen in human males with normal color vision".
Note of course that people with an XX complement can have better possible color perception than XYs, as they have the potential for tetrachromacy:
females who are heterozygous, for example, having OPN1LW genes that encode two spectrally distinct L pigments, would have four different cone types -- two different L, plus M and S -- and thus the potential for having tetrachromatic color vision (Bosten, Robinson, Jordan & Mollon, 2005, Jordan & Mollon, 1993, Jordan & Mollon, 1997). Prior to the discovery of variation in peak sensitivity of pigments underlying normal color vision, it had been appreciated that female carriers of a red-green color vision deficiency have the potential for tetrachromatic color vision (Nagy, MacLeod, Heeyndermann & Eisner, 1981).
The following is multiple choice question (with options) to answer.
The color of our eyes are permanent because eye color is fixed at birth due to | [
"shoes",
"parent's DNA",
"doctor",
"corn"
] | B | eye color is an inherited characteristic |
OpenBookQA | OpenBookQA-3682 | optics, visible-light, everyday-life, diffraction
Addendum 2: Before the comments below were cleaned out, there was some discussion there about the usefulness of this phenomenon as a quick self-diagnostic test for myopia (nearsightedness).
While I Am Not An Opthalmologist, it does appear that, if you experience this effect with your naked eye, while trying to keep the background in focus, then you may have some degree of myopia or some other visual defect, and may want to get an eye exam.
(Of course, even if you don't, getting one every few years or so isn't a bad idea, anyway. Mild myopia, up to the point where it becomes severe enough to substantially interfere with your daily life, can be surprisingly hard to self-diagnose otherwise, since it typically appears slowly and, with nothing to compare your vision to, you just get used to distant objects looking a bit blurry. After all, to some extent that's true for everyone; only the distance varies.)
In fact, with my mild (about −1 dpt) myopia, I can personally confirm that, without my glasses, I can easily see both the bending effect and the sharpening of background features when I move my finger in front of my eye. I can even see a hint of astigmatism (which I know I have; my glasses have some cylindrical correction to fix it) in the fact that, in some orientations, I can see the background features bending not just away from my finger, but also slightly sideways. With my glasses on, these effects almost but not quite disappear, suggesting that my current prescription may be just a little bit off.
The following is multiple choice question (with options) to answer.
Which would least likely help someone with bad vision? | [
"a magnifying glass",
"sungazing",
"binoculars",
"a telescope"
] | B | binoculars are used for observing distant objects |
OpenBookQA | OpenBookQA-3683 | botany, plant-physiology, plant-anatomy
It made me wonder if we are simulating the sun in a dark room for growing the plants with the help of red, blue, and a little bit of far-red light, what will happen to the plants if we keep the ideal conditions for which the plants carry out photosynthesis whole day? Does it affect its yield or the plants die out quick?
I am an engineering student working on indoor farming, my knowledge of botany is the same as a high school student. So if I am wrong please tell me. Ideal conditions for photosynthesis
You mention ideal conditions to carry out photosynthesis, I would just like to point out that this includes carbondioxide levels, temperature, and nutrients as well as light.
Flowering
As anongoodnurse mentions performance might be measured by blooming which, in most flowering plants, has a day-light related component. However, for general growth increasing daylight over the 'natural' day length can often increase yield.
Daylight Cycles
The important point to note is that plants do 'ramp up' at dawn getting ready to start photosynthesizing (for some plants with temporal photosynthesis mechanisms (see CAM photosynthesis) this can be even more important). The reason plants do this is because plants can suffer from 'photobleaching' which can be considered similar to sunburn in humans, if they are not ready for sunlight. Getting 'ready' can involve lots of things including opening stomata (pores) to let CO2 in, changing which metabolic pathways are active, and moving about chloroplasts inside cells. Plants 'figure out' how and when to ramp up based on circadian rhythms which work well on 24 hour clocks and slight changes over time. Thus 12 hrs to 16 hrs can be a big change, particularly if the change happens by lights coming on earlier. Additionally, the 24 hour 'clock' means that plants will do better with 18hr light then 6hrs dark cycles than 36hrs light 6 hrs dark, because the total cycle length should be about 24hrs.
Photosynthesis Side Effects
The following is multiple choice question (with options) to answer.
A plant will get more light energy | [
"if it drinks power drinks",
"if the trees cover it",
"if it gets more rain",
"if the leaves are bigger"
] | D | as the size of a leaf increases , the amount of sunlight absorbed by that leaf will increase |
OpenBookQA | OpenBookQA-3684 | forces, water, surface-tension
Now, if we suddenly boost up this adhesion a billion times stronger (limit: imagination) from what is the real and cohesion stays same, then it's gonna suck. Literally. Everything the water or any liquid comes to contact with, it will immediately start to evenly spread out, clothing every nooks and cranny on that surface of that object. It'd be much like when we spill water on the floor. But now it'd be happening EVERYWHERE, on the sides and on the roofs. The rivers, lakes and oceans start allowing a layer of water to swallow everything up, and a carpet of water will cover the world. Trees and plants burst as there is an immense rush of water inside them. The large droplets of water we adored will never form, a droplet release in the air will torn into tiny minuscule droplets, that we can't see. Maybe into water vapor. And Life? I wonder... ;)
Hope that helped. Went a little overboard. :D
The following is multiple choice question (with options) to answer.
Water will always make it's way to the | [
"the earth's core",
"moon",
"desert",
"ocean"
] | D | water flows down a slope |
OpenBookQA | OpenBookQA-3685 | sexual-reproduction
So when it's not maintained -- when there's no selection pressure on two populations -- inevitably there will be genetic drift that will randomly disrupt this fine-tuned system. If a population of, say, voles is isolated on an island, they will continue to have pressure to be able to interbreed with other voles on the island, but if they can't interbreed with those on the mainland there won't be any consequences, and so over long enough time they'll drift and lose that ability -- just as many apes, not suffering any consequences from not synthesizing vitamin C, gradually lost that ability from random drift.
There's another side to it. Two populations in the same location may be positively selected to not be able to interbreed. Think about two groups of finches, one with small fine beaks that eat tiny seeds deep inside pine cones, and one with heavy beaks that crush and eat thick-shelled nuts. They each do fine, but they can interbreed and produce offspring that have intermediate beaks -- too thick to reach the fine seeds that one parent eats, but too delicate to crush the nuts that the other parent eats. Those intermediate offspring will die off, and both parents will have wasted their resources raising them. Both parents would be better off not breeding with each other, but only breeding with their own kind to produce specialized and efficient offspring. There is now selection pressure on the birds to recognize their own kind (perhaps through songs or mating displays) and ultimately to be inter-sterile, so they never waste resources on the un-fit offspring. There's a gradation of separation over time, in which the different populations become more and more distinct. Eventually, at some arbitrary point, humans start calling them "species", but that's just us, not biology.
"Species" is an important concept, but it's not special in evolution; speciation is just one aspect of natural selection, there's nothing magical about it.
The following is multiple choice question (with options) to answer.
Which would likely displace a family of chipmunks? | [
"wind",
"thunder",
"rain",
"mall construction"
] | D | humans changing an environment sometimes causes that environment to be destroyed |
OpenBookQA | OpenBookQA-3686 | biochemistry
Title: Bradford Reagent Disposal I am a graduate student volunteering in a professor's lab being tasked with finding out how to dispose of certain hazardous materials. I have encountered a problem with disposing of Bradford's Reagent. I have checked online, but am running into problems due to the methanol component of this compound. Can someone help me with the proper disposal procedure? Thank you in advance. I would strongly suggest to ask someone in your lab about this, they will have a better idea about the different waste disposal methods you have available.
In general you would dispose anything that contains organic solvents like methanol in a waste container for generic solvent waste. You should have something like that somewhere in the lab.
One thing you always have to keep in mind is to never put anything still reactive into your waste container. A popular example would be a strong oxidizing agent, putting that into a solvent waste container is dangerous and could e.g. ignite the waste. This is not an issue in this case, but you should always keep that in mind.
Another aspect is the pH of the waste, in many cases the waste disposal facility will only accept reasonably neutral waste, so you should neutralize your waste before putting it into a container. Neutralizing it inside the container can be much more annoying. This might not be necessary if you have a dedicated acidic waste, you'll have to ask someone in your lab about that. The Bradford reagent is strongly acidic, so you'll have to pay attention to this aspect.
The following is multiple choice question (with options) to answer.
Which can go in the recycled bin | [
"duct tape",
"hair gel",
"Sprite container",
"cell phones"
] | C | recyclable means a material can be recycled |
OpenBookQA | OpenBookQA-3687 | solutions
(source: Hashimoto et al. in Molecules 2019, 24, 2296 (doi.org/10.3390/molecules24122296), section 3.2; open access publication.)
This pattern is seen for inorganic reagents like $\ce{HCl}$ dissolved in water, yet equally available in methanol, 1,4-dioxane, etc. (example); and organometallic reagents, e.g. butyllithium, methylmagnesium bromide.
The following is multiple choice question (with options) to answer.
chemical reactions cause | [
"dancing",
"napping",
"fluctuative attributes",
"invisibilty"
] | C | chemical reactions cause chemical change |
OpenBookQA | OpenBookQA-3688 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
which of these would be most healthy? | [
"a person eating three meals a week",
"a person eating three meals a month",
"a person eating one meal a day",
"a person consuming 3 meals daily"
] | D | an animal needs to eat food for nutrients |
OpenBookQA | OpenBookQA-3689 | inorganic-chemistry, home-experiment
Title: Make a silver zinc battery I have a shaver that runs off a rechargeable battery that is dying. Would it be feasible to make a silver zinc battery and use it to replace the existing battery? Cost is not an object, anything less than $2500 I would consider doable. I have a machine shop and a small chemistry laboratory with the standard equipment and glassware, including high vacuum capability, a centrifuge and simple glass blowing capability.
I found a book on silver-oxide zinc chemistry and battery design, but it is $500 and I don't want to spend that if the information can be obtained just as easily elsewhere.
I have tried to find commercial options, but had no luck. Most silver zinc batteries seem to be just for large (multi-million dollar) military or satellite applications. Sony makes a line of silver oxide primary cells for hearing aids, but these are not rechargeable. There is a company called Ultralife that makes medical and military batteries and might have something viable, but before I call them I wanted to check out the opinion of the experts here. This turns out to be very difficult to do for two reasons. One problem is that the voltage of a silver cell is different from that of Ni-Cd cell, so it would require a specialized, multi-cell configuration to emulate the voltage characteristics of the Ni-Cd rechargeables.
The other problem is that silver cells generally have a sophisticated frame inside of them that is produced by an intricate high-temperature welding process. To duplicate this process and produce a suitable frame would require a significant amount of experimentation and work.
The following is multiple choice question (with options) to answer.
Maglites use nickle with cadmium to produce | [
"money",
"illumination",
"beer",
"food"
] | B | a flashlight converts chemical energy into light energy |
OpenBookQA | OpenBookQA-3690 | everyday-life, water, physical-chemistry, surface-tension
I understand there are complaints about image quality. I cannot fix these as I do not have access to photography equipment to take higher quality images. (This photo was taken with a flagship 2023 smartphone).
The best text description that I can give is that the droplets appear as oil droplets do in water. However, presumably because the index of refraction difference is not as great (between warmer and cooler water?), it is more difficult to make out the droplets (which might be why it's hard to take a good photo with a smartphone camera).
The video here contains a link to a short clip, which might be more helpful than a static image. Note the droplets in the top left, they are liquid water of the same composition as that of which they are contained in. When I pan to the right in the video, one can observe fast moving droplets that are further upstream. Clearly they have managed to travel from the shower head all the way through the higher velocity stream of the middle of the tub before settling near the drain where the water is moving more slowly. The lifetime of these droplets is on the order of seconds.
It is difficult for me to reproduce this effect as I must angle the shower head (it is detachable) and position it specifically to generate this phenomenon (and getting a good camera angle whilst doing this is very hard for me).
Additionally, I notice this phenomenon occasionally when urinating (as a male), and when pouring hot cooking water down a sink that already has a small amount of water.
My assumption is that this phenomenon is similar to that of liquid water droplets floating on the surface of a larger body of water (this can happen when smaller droplets formed from the collision of a drop of water with a water body reach the surface of the body). There is air in the case, and I don't immediately see air in this case, which is why I assume it might be a different phenomenon and warrants asking a question. Great question! I have observed this effect too while watering plants in my garden. When I direct the water spray to a water puddle at an angle, the water droplets seem to bounce up and down! (I didn't have to use warm water though, but I guess the effect will be stronger when you have more vapors) There is a Smarter Every Day video on this exact phenomenon.
The following is multiple choice question (with options) to answer.
A bush that has water being moved around inside is doing so due to | [
"pipes",
"rubber",
"irrigation",
"xylem"
] | D | xylem transports materials through the plant |
OpenBookQA | OpenBookQA-3691 | thermodynamics
Contrast that with 1g of water, which has a specific heat of 4.2 J/g$^\circ $C - after heating by 10 degrees, it stores an additional 42J of energy. More energy is added than by raising the same mass of iron by the same number of degrees. This is analogous to compressing a stiffer spring, or raising a heavier weight, or charging a bigger battery - you put in more energy which gets stored in some way. For any particular mass and temperature, water holds more thermal energy than iron.
As a consequence of this, iron will heat up and cool off faster than water, since it takes less energy to go through the same temperature change. You could think of a cooling mass as a discharging battery, where stored heat energy is put back into the environment. A block of iron will cool relatively quickly, analogous to a battery that doesn't hold much charge, while the same mass of water will take much longer to cool, like a bigger battery that holds more charge.
In your added example of blocks A and B, we define the blocks to have the same mass but different heat capacities. Heat capacity is the amount of energy required to change the temperature of a unit mass of material. So, if you impart the same amount of energy to objects of different heat capacities, they will change in temperature by a different amount. As shown above, if you apply 42J of energy to 1g of water, it will increase in temperature by 10 degrees. If you apply that same amount of energy to 1g of iron, it will increase in temperature by 93 degrees. We've defined the situation where we impart the same amount of energy to both, in this setup, we're not "leaving behind" any heat by definition.
The following is multiple choice question (with options) to answer.
One source of heat might be | [
"eating ice",
"moving to Antartica",
"sitting in snow",
"a mini flashlight"
] | D | a hot substance is a source of heat |
OpenBookQA | OpenBookQA-3692 | earthquakes, seismology, instrumentation, in-situ-measurements, diy
Title: Using accelerometer as a seismograph I'm using ADXL345 accelerometer with Raspberry Pi to build a seismograph. I've successfully hooked it up and can plot the accelerometer data in three axis. Is there any way to express these data in the form of the magnitude of an earthquake, of course, at the point of sensing? I know that it might be imprecise, but any representation would be helpful (e.g. Richter scale), and how to accomplish that. The magnitude of an earthquake is related to the total energy released, therefore to estimate it from a seismogram you need to know the distance to the source. In the case of the Richter scale for example, the relationship between magnitude and seismogram amplitude is defined for a standard distance.
If you have only one seismograph, you can not triangulate the location of the source (hypocenter). Therefore, you can not estimate the magnitude of a seismic event (Richter or moment magnitude).
But you can estimate the local seismic intensity of the event at the particular location of your instrument. With the accelerometer data you can easily measure the peak ground acceleration, that can be used to estimate the intensity in any of the existing scales. For example, the peak ground accelerations associated to each intensity level in the commonly used Mercalli intensity scale are:
Those g values would be easy to calculate with the accelerometer data and proper calibration constants.
Table taken from the Wikipedia page for peak ground acceleration
You might want to have a look at this question. There are some nice answers and references that you might find useful.
The following is multiple choice question (with options) to answer.
a seismograph is a kind of tool for measuring the size of | [
"trees",
"terra plate displacements",
"planets",
"poems"
] | B | a seismograph is a kind of tool for measuring the size of an earthquake |
OpenBookQA | OpenBookQA-3693 | botany, plant-physiology, reproduction, plant-anatomy, life-history
In dimorphic cleistogamy CL and CH flower differ in the time or place
of production, with CL flowers produced in conditions (underground,
low light levels, early in the season) that are potentially
unfavorable for outcrossing.
In induced cleistogamy potentially CH flowers that experience conditions such as drought or low temperatures fail to open and self-pollinate, becoming, in effect, CL flowers.
You should check out the Culley and Klooster (available online if you make a jstor login) – they discuss complete cleistogamy which addresses your last question. They report several completely CL species in their Table 1, and give references.
More generally, many different plant groups maintain balances of self-pollination and outcrossing (i.e. "real sex"), through an even more diverse set of mechanisms.
Even more generally, many plants and some animals maintain balances of sexual reproduction and clonal reproduction, through an even more diverse set of mechanisms. For instance, vegetative reproduction (e.g., strawberry runners) is very common in many plant groups; facultative and obligate parthenogenesis in animals also occurs.
Culley, Theresa M. and Matthew R. Klooster (2007). The Cleistogamous Breeding System: A Review of Its Frequency, Evolution, and Ecology in Angiosperms. Botanical Review. Vol. 73, No. 1, pp. 1-30
The following is multiple choice question (with options) to answer.
Pollination is required for what to reproduce? | [
"whales",
"bees",
"sunflowers",
"humans"
] | C | plant reproduction requires pollination |
OpenBookQA | OpenBookQA-3694 | javascript, jquery, css
<img src="https://i.stack.imgur.com/u65Rp.png?s=48&g=1">
<p>Batnae municipium in Anthemusia conditum Macedonum manu priscorum ab Euphrate flumine brevi spatio disparatur.</p>
<button id="go">Go (simple)</button>
<button id="goz">Go (with z-index)</button>
The following is multiple choice question (with options) to answer.
Honolulu was formed by | [
"the gods",
"a volcanic crevasse",
"a tidal wave",
"a typhoon"
] | B | mountains are formed by volcanoes |
OpenBookQA | OpenBookQA-3695 | forces, interactions
Title: Other than magnetism, can any of the four fundamental forces be *repulsive*? My son asks the above (if not in quite these words), and I am embarrassed to realize that I do not know. Can gravity, for example, or the strong or weak forces ever be repulsive? How/when? Famously, magnets have North and South poles, and like repels like. You can think of these as positive and negative "magnetic charges". Similarly, electrical charges obey the like-repels-like rule (e.g. two electrons are both negatively charged and repel each other).
The strong and weak nuclear forces can be thought of as more complicated cousins of electromagnetism, with multiple charges that still come in positive and negative. (For example, you can think of quarks as having a positive charge called a color, antiquarks as having a negative charge called an anticolor, and gluons as having each, like the poles of a magnet.) The details are more complicated, but yes, like still repels like.
When we look at gravity, we find positive "charges" called masses that attract each other. Why is this case different? It turns out to be due to EM and nuclear forces having spin-1 carriers and gravity's hypothetical carriers being spin-2, but that's probably overkill for this question.
Could gravity repel? It would require opposite charges, i.e. positive and negative, and where would you get negative mass from? The cosmological constant $\Lambda$ that accelerates the expansion of the universe can be thought of as a negative contribution to the universe's density, resulting in a repulsive effect.
The following is multiple choice question (with options) to answer.
Which are likeliest to repel one another? | [
"two mighty oak trees",
"two ice cream cones",
"two pieces of silverware",
"two bottles of water"
] | C | if two objects have the same charge then those two materials will repel each other |
OpenBookQA | OpenBookQA-3696 | geology
Title: Where do riverbed stones come from? Have they always been here since the river was formed? Are some newer than others? Riverbed 'stones' - I assume you mean things like pebbles, boulders, etc. are pieces of rock that have weathered out and been deposited in the river. Some come from rock that is very close to where they are located and some have been transported from very far away. In general (and it is a very broad generalization) the rounder the stone, the longer it has been in the river and the more likely it is to have come from far away. Of course that depends on the hardness of the rock, and other factors, too.
Some rocks are newer than others. Some have been formed quite recently and some are billions of years old.
The following is multiple choice question (with options) to answer.
rocks often contain large amounts of | [
"chocolate",
"shoes",
"hard shiny alloy",
"rubber"
] | C | rocks often contain large amounts of metal |
OpenBookQA | OpenBookQA-3697 | heat
Your thinking here:
Is it the one in the middle because it gets refrigerated by the other two?
is kind of interesting (but wrong). If the 2 outer bottles were not there, the middle bottle would cool much faster in fact. Use of words like "insulate", "refrigerate", and "cool" might get a little difficult in this discussion. One way or the other, the outer bottles don't help cool the inner one, although they cool slower than it does.
EDIT: The outer bottles do insulate the inner bottle. That is correct to say, although I should add that the effect could be mostly through radiative heat transfer. Convection is something you could get into but it's a little trickier. Fewer bottles will probably always cool faster, and this is due to both heat transfer and thermal mass reasons.
The following is multiple choice question (with options) to answer.
Why do companies heat up milk before they bottle it? | [
"the milk is probably sour",
"it tastes bad that way",
"small organisms could make you sick",
"the cow could get angry"
] | C | pasteurization reduces the amount of bacteria in milk |
OpenBookQA | OpenBookQA-3698 | zoology, ethology, learning
Title: How do beavers learn how to build dams? I was wondering whether all beavers, from all around the world, know how to build dams and lodges? Do they need to learn it from their parents? If you release a group of beavers in the wild that haven't been in contact with their parents, would they start to build stuff? or just hopelessly die/starve to death? Question summary: is dam building learned or instinctive in beavers?
A blog post from 2011 references an article in the Juneau Empire titled Running water is sound of spring for beavers. This article is no longer hosted on the Juneau Empire website, but archived versions are available.
Here's an excerpt (emphasis mine) --
Swedish biologist Lars Wilsson spent years studying captive and wild beavers, and he gained remarkable insights into their behavior. He raised beavers in an outdoor enclosure and in a large indoor terrarium ...
Wilsson initially captured four adult beavers and later he raised a number of beavers from infancy, some in small colonies with their parents and some completely isolated from adult beavers. He isolated the young beavers to see what beavers learn from their parents and what behaviors are instinctive.
He found that young beavers - who had never even seen a beaver dam - were able to build almost-perfect dams at the first opportunity.
The foundation of sticks and logs anchored to the stream bottom, the interwoven lattice of trimmed branches, the mud chinking, every aspect of dam building was hard-wired. Beavers do get more skilled at dam building as they gain experience, but the building behavior is instinctive.
Wilsson learned that the sound of running water is the cue for dam building and dam repair. In one experiment, he played a recording of running water, and the young beavers built a dam in a tank of still water in the terrarium. In another peculiar experiment, his captive beavers built a "dam" on a concrete floor against a loudspeaker that played the sound of running water.
The following is multiple choice question (with options) to answer.
What does a beaver use to find something to munch on with? | [
"antennas",
"teeth",
"gills",
"sense organs"
] | D | the nervous system sends observations in the form of electrical signals to the rest of the body |
OpenBookQA | OpenBookQA-3699 | food, human-physiology, senses
Title: Why don't chilli peppers taste as hot in space? The following commentator writes:
Chili peppers don’t taste as hot in space as they do on Earth. Nobody knows why.
We know that the 'hot' feeling of chilli peppers is caused by Capsaicin. We read:
Capsaicin inside the pepper activates a protein in people’s cells called TRPV1. This protein’s job is to sense heat
There appears to be some question about the cause of the 'spicy' taste of chilli peppers.
My question is: What is the reason that chilli peppers don't taste as hot in space? TL;DR
All food taste bland in space, not only chilli.
The claim in that tweet ("Chili peppers don’t taste as hot in space as they do on Earth") is not exactly correct because, the way it's worded, it gives the impression that only chilli peppers have a different taste. In fact, astronauts/cosmonauts use more chili and other spices than they regularly do on Earth, for a reason: they say that food in space (microgravity) taste bland. All food, not only chili.
Since the beginning of space flight, astronauts report that food taste different in microgravity. According to the Scientific American article When It Comes to Living in Space, It's a Matter of Taste (Romanoff and Romanoff, 2017):
Many said that flavors are dulled and they crave fare that is spicier and considerably more tart than they would prefer on Earth.
So, due to the food tasting so bland, astronauts in fact use more chili and other spices than they normally do on Earth:
It's possible that hot sauce and salsa could be key ingredients to the success of a manned mission to Mars. The kicked-up condiments already came close to causing a mutiny on the International Space Station (ISS) in 2002 when astronaut Peggy Whitson threatened to bar entry to the crew of the visiting shuttle Atlantis unless they came bearing a promised resupply of the spicy stuff. Only when shuttle commander Jeff Ashby announced that he had the goods did Whitson say, "Okay, we'll let you in then." Whitson was joking, but the need for astronauts to be able to spice up their food while in orbit is no laughing matter.
The following is multiple choice question (with options) to answer.
A pepper would be hottest if it was | [
"defecated into a bottle by a yeti",
"frozen in a commercial freezer",
"left it in the sun",
"eaten by a super model"
] | C | absorbing sunlight causes objects to heat |
OpenBookQA | OpenBookQA-3700 | trees, forestry
Title: Why do some trees hold their leaves through fall and winter? Why do some species of oak (Quercus spp.) retain their leaves through fall and winter? I've found that these leaves are called marcescent leaves. There must be some benefit that the tree gains from this because it seems like it would increase the possibility of limb damage due to snow accumulation on the leaves. The trait might not necessarily allow for an advantage, but a few possibilities have been proposed:
Nutrient return to the soil when needed in the spring
Less palatability to grazing animals
Source:
http://northernwoodlands.org/articles/article/why-do-some-leaves-persist-on-beech-and-oak-trees-well-into-winter
The following is multiple choice question (with options) to answer.
Waxy leaves are used by some plants for what? | [
"Sodium Chloride",
"Gold",
"Keeping hyrdrogen dioxide",
"Barium"
] | C | waxy leaves are used for storing water by some plants |
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