source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-4201 | design, mechanism
Title: Good book on mechanisms I am working with students (9th & 10th grade) on robotics and wanted to get a good book which covers basic mechanisms. Does anyone have any recommendations. Searching Google or Amazon yields many results, however, I thought the community might have a standard book to use. The best book I have seen on the subject of mechanisms is Mechanisms And Mechanical Devices by Neil Sclater and Nicholas P. Chironis.
It's got loads of great mechanisms in it, from simple linear movements:
... to complex packaging machines:
It also covers robotics.
The following is multiple choice question (with options) to answer.
A mechanism that a ____ uses is a ____ | [
"see-saw; pulley",
"crane; pulley",
"lever; lever",
"cat; fishing rod"
] | B | a pulley is used for lifting objects |
OpenBookQA | OpenBookQA-4202 | meteorology, geomorphology, climatology, atmospheric-circulation
Source Commons Wikipedia.
The cold waters near the ocean surface results in a cool, stable coastal atmosphere. In this region, evaporation from the ocean is reduced and produces extremely low rainfall over land. Precipitation is limited to morning fog and produces some of the driest ecosystems on Earth. The Atacama desert is the best example of such environment with average rainfalls of 15 mm/year (the driest non-polar region). In some areas, they are trying to take advantage of the little moisture the fog (Camanchaca) brings to establish some agricultural zones. The fog droplets are too small (1-40 micrometers) to form water drops and precipitate, so they use fog-catchers to collect moisture from the fog.
Source: newatlas.com
The following is multiple choice question (with options) to answer.
As rain freezes in the mountains it splits | [
"granite",
"trees",
"bears",
"cars"
] | A | ice wedging is when ice causes rocks to crack by expanding in openings |
OpenBookQA | OpenBookQA-4203 | everyday-chemistry, conductivity, electricity
Title: Can dust conduct electricity? Just out of curiosity, can dust conduct electricity? The source of dust varies, is there any form of dust that can conduct electricity? The answer to this question hinges on two key questions:
What kind of dust are we dealing with?
How is the dust arranged (i.e. what is your experimental setup)?
Which Dust?
Firstly, I'm going to assume you meant domestic dust (since there are more kinds of dust than you'd imagine).
I quote Wikipedia:
Dust in homes, offices, and other human environments contains small amounts of plant pollen, human and animal hairs, textile fibers, paper fibers, minerals from outdoor soil, human skin cells, burnt meteorite particles, and many other materials which may be found in the local environment.
Arrangement
The arrangement of the dust particles is key. Are we considering an aerosol, or are we carefully laying a line of dust on the table and connecting it with two electrodes?
Aerosol - We can safely assume that the conductance of air has a far higher impact on the measurement than the conductance of the particles in the aerosol (the dust). So here, dust does not conduct electricity. Note: I ignore the "conducting" via static electricity processes here, but they may play a role. I do not consider that "classical" conductance.
Line of Dust - Organic material is usually insulating, as is our skin (if it wasn't for the moisture that is needed for, you know, living), paper, textiles, hair and so on. So the main constituents of domestic dust does not conduct electricity. So also here, we will not observe conductance.
There is one exception to the above, where conductance is a possibility: Metal dust. This is kind of cheating, but consider the waste of some metalworking process, in which metal dust (or powder) is generated. This dust, being composed of metals and metal oxides, would likely conduct electricity (when laying it out in a line, still not as an aerosol).
The following is multiple choice question (with options) to answer.
What conducts electricity? | [
"a lego brick",
"suit of armor",
"a wooden table",
"a T-shirt"
] | B | electrical conduction is when metals conduct electricity through metal |
OpenBookQA | OpenBookQA-4204 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
Cars are big polluters because they release toxins from the gas into the air making it | [
"healthier to breathe",
"unhealthy to breathe",
"candy",
"space"
] | B | polluting means something poisonous is added to an environment causing harm to the environment |
OpenBookQA | OpenBookQA-4205 | herpetology, poison
Title: Poisonous Snakes consuming poison (chemical) While travelling with my Son to a religious shrine, we saw a dead snake lying on the road.
My Son asked a curious question to me "Dad, if Poisonous snakes consume poison (Chemical), Will they die"?
I feel the answer is depends upon the type of poisonous snake viz Cobra, Python etc and how much the reptile has consumed the poison. i.e. quantity.
What is the correct answer? If any living thing consumes enough of a poison it will die. But I feel that is not what you want to ask.
Perhaps you meant to ask if a snake will die if it drinks its own venom? That would make more sense as a question.
In English, venom and poison mean different things when talking about a toxic chemical produced by an animal.
Poison is a toxic chemical produced by an animal that is meant to be ingested/eat/drink.
Venom is a toxic chemical produced by an animal that is meant to be injected into the bloodstream.
So a snake bite has venom, but a colourful tree frog has poison on its skin.
Venom is typically not nearly as harmful if ingested, even if by a different animal, because it is meant to act directly in the bloodstream
The following is multiple choice question (with options) to answer.
Adding something poisonous to an environment and harming it is called what? | [
"dirtying",
"liking",
"cleaning",
"observing"
] | A | polluting means something poisonous is added to an environment causing harm to the environment |
OpenBookQA | OpenBookQA-4206 | mechanical-engineering, gears
Here's a photo of a similar quill: In general, I would warn you that you aren't likely to get very good rigidity out of this system because by maintaining the quill mechanism and adding the length of the tool holder plus an extra joint (of any type) you are adding more cantilever to what sounds like already fairly sloppy tool. In addition, be warned that the manufacturer of the tool certainly won't endorse any project like this and any joint you implement yourself may fail, so you're going to be spinning a pretty heavy piece of metal pretty fast at your own risk. Personally, I wouldn't recommend it.
That said, you asked about ways to couple the spline shaft with the tool holder's cylindrical end, here are some options:
Firstly you could buy an adapter. Spline shaft adapters are made, but usually only for much larger shafts. In addition, I'm not sure if that spline profile will be standard or specific to your drill press manufacturer. Other people will make you a custom spline adapter, which may be expensive but would get the job done. Most reasonably equipped local machine shops could also make an adapter. The problem with connecting spline-to-spline is that with the cutting forces, you'll have significant axial and radial forces to resist. Splines are good at transmitting torque, and reasonable at resisting radial force, but don't resist axial forces at all. For that reason, pick a spline adapter design where the female spline rigidly cplamps to the spline with a thru-bolt, not one of the designs that only has a set screw.
The following is multiple choice question (with options) to answer.
A seaman will likely use this tool more than other: | [
"plate with a plug",
"candle with a wick",
"disc with an arrow",
"card with a strip"
] | C | a compass is used to navigate oceans |
OpenBookQA | OpenBookQA-4207 | thermodynamics, energy, everyday-life, sun, thermal-radiation
Title: How badly could someone be injured by concentrated sunlight? Recently-ish, I stumbled across an interesting short story (by way of Science Fiction & Fantasy Stack Exchange) where a soccer referee is apparently incinerated by concentrated sunlight.
Where the referee had been standing, there was a small, smoldering heap, from which a thin column of smoke curled up into the still air.
This is accomplished in-story by some 50 000 reflective tinfoil program covers, each about the size of a tabloid sheet.
What got me interested (physics is one of my peripheral interests) is the feasibility of this method in the real world. Wikipedia says a tabloid sheet is $279\;\mathrm{mm} \cdot 432\;\mathrm{mm} = 120528\;\mathrm{mm}^2 \approx 0.121\;\mathrm{m}^2$, giving fifty thousand people with a program each a total of $6026.4\;\mathrm{m}^2$ to work with. (Adjusting for less-than-perfect aim, I'd say closer to about $5000\;\mathrm{m}^2$.) If you could redirect that much sunlight at about a person's surface area, how much power would that be? What damage could you cause?
He couldn't have felt much; it was as if he had been dropped into a blast furnace...
Could that amount of power actually incinerate someone?
The following is multiple choice question (with options) to answer.
____ burns from the energy of ____ | [
"death; wind",
"a teacandle; wax",
"food; water",
"water; fire"
] | B | lighting a candle causes that candle to burn |
OpenBookQA | OpenBookQA-4208 | mechanical-engineering, pressure-vessel, solid-mechanics
Title: When calculating the deformed radius of a pressurized thick-walled cylinder, why is the hoop strain used rather than the radial strain? The context
I’ve taken an interest in the design of pressure vessels for use in submarine applications. From a cursory survey of what is used in industry, it seems the de facto standard housing is a thick-walled cylinder (rather than a thin-walled cylinder which would be prone to buckling when loaded in hydrostatic compression). While the equations for stress and deformation in a thick-walled cylinder subject to internal and external pressures are well established (Young, Norton), I’ve also read that prestressed compound cylinders can result in a housing with a greater strength to weight ratio (Kharagpur, Sun).
The following is multiple choice question (with options) to answer.
Which would you use a graduated cylinder for? | [
"to measure bone shards",
"to measure a solid",
"to measure a dog",
"to measure grape kool-aid"
] | D | a graduated cylinder is used to measure volume of an object |
OpenBookQA | OpenBookQA-4209 | everyday-chemistry, water, crystallography
Spin-off question:
I heard (not sure where) that each snowflake assumes a unique shape. How true is this?
Now, as I understand it, all processes proceed so as to maximize the "randomness" of its constituent particles. (Oversimplified version of the Second Law of Thermodynamics, yes, I know... just don't chew me out in the comments section...)
Yes. True.
This Law can easily be observed in, and verified by, natural processes.
Sure. Still with you.
Now the formation of snow is a natural process, agreed? The way my brain sees it, is that water droplets ought to freeze into random, and by virtue of its "randomness", highly unsymmetrical shapes. But this is not the case here!
The following is multiple choice question (with options) to answer.
Sleet is made of what? | [
"wind",
"icing",
"hard h2o",
"frosting"
] | C | sleet is made of ice |
OpenBookQA | OpenBookQA-4210 | molecular-biology, neurotransmitter, muscles, receptor
Lastly, and on a slightly different subject, what are the microlesions in the muscles that occur during strength training, and what is the overcompensation that happens?
Last time I was updated on this (not my bag), there were some large questions remaining. The tricks used by growing muscle to establish large, regular arrays of contractile machinery, that is organized over many spatial orders of magnitude, are poorly understood. There are structures that monitor the overall organization and that detect any large deformations. Regarding overcompensation, let's play through a generic scenario. A muscle cell is loaded too much and becomes physically damaged. It has to stop taking orders (stop responding to contraction/relaxation signals) and to initiate repairs. The overcompensation results because muscle cell's not really capable of knowing how large it was before the damage, so the safe amount of repairs to do is extra. Probably there are epigenetic processes that let a muscle cell 'count' the number of times its been greatly damaged and to scale-up the response appropriately.
If you just consider two likely sources of damage -- mechanical strain and lactic acidosis -- you can see that there are widely different mechanisms that would be required to detect the damage and to initiate repairs.
The following is multiple choice question (with options) to answer.
Lifting weights damages your cells, so in order for them to be repaired and grow bigger, you need to | [
"consume meat products",
"nothing",
"die",
"fly away"
] | A | protein is used to repair cells by the human body |
OpenBookQA | OpenBookQA-4211 | the-moon, earth, tidal-locking
Title: Earth rising and setting from moon's perspective Why the earth is rising and setting seen from the moon,
when the moon is tidally locked?
Shouldn't the earth be always on the same spot because of the tidal lock, if observed from the moon? You're quite right. The Earth is (nearly) stationary in the Moon's sky.
(I say "nearly" because the Moon is in a slightly elliptical orbit around the Earth, but rotates perfectly smoothly. This means that the Earth's motion through the Lunar sky is
a bit faster when the Moon is at perigee and a bit slower when it's at apogee. Because the Moon is tide-locked, on average they match perfectly, but during the course of the sidereal month the Earth appears to move back and forth by a few degrees. The effect isn't huge, but it's easily observable with a telescope. See the Wikipedia article on
"libration" for an OK discussion and a really great animated gif illustration of libration as viewed from Earth.)
Is it possible that you're reacting to the amazing movie from Apollo 8 showing Earthrise over the Lunar horizon? It's been int he news a lot given that this is the 50th anniversary of the flight. If so, what you saw there was not from the Moon's surface, but from orbit around the Moon and the Earthrise happened as Apollo 8 came around from behind the moon (where the Earth is not visible in the sky) and the Earth first became visible around the edge of the Moon.
The following is multiple choice question (with options) to answer.
When the moon, sun, and earth line up, tides are at their | [
"lower",
"increased",
"gone away",
"just okay"
] | B | the phases of the Moon change the appearance of the Moon |
OpenBookQA | OpenBookQA-4212 | the-moon, moon-phases
Title: Red cresent moon Yesterday night i witnessed something very strange when i looked outside the window. I saw the moon (crescent) but it was dull red and right on the horizon ,which is strange considering that it is usually on the upper right of the night sky and white in colour. On further inspection with my binoculars i noticed it was lowering down until it was hidden by the mountain range (5km away) next to my building, this all occurred within a few minutes (about 5).
Tonight i saw the moon (crescent) had again returned to its normal position.
Please explain the cause for this, i'm completely baffled!
(Sorry for the poor wording, i'm not familiar with all the astronomical terms!) The dull red color has been due to atmospheric causes, like the reddish sun close to sunset. There hasn't been an astronomical reason for the reddish color.
A few days after New Moon moonset occurs short after sunset, so you won't see the Moon high over the horizon at those evenings. With each day the Moon is a little higher above the horizon after sunset. It's hence less close to the horizon at the same time of the day. Less close to the horizon means less atomospheric absorption/scattering responsible for the dull red color, assuming the same weather conditions.
At Full Moon the Moon is at the opposite side of the Sun relative to Earth. Moon is then rising shortly after sunset.
The following is multiple choice question (with options) to answer.
When the earth shades part of the moon at night it's called | [
"lunar orbit",
"the phases",
"weather",
"bad luck"
] | B | the phases of the Moon change the appearance of the Moon |
OpenBookQA | OpenBookQA-4213 | forces, classical-mechanics, energy
Title: What's the work done in an object to change its direction? Say, for example an object is moving 2m/s right and some force makes it travel 2m/s left. What would be the work done on this object? It starts and ends with the same kinetic energy, but clearly something had to be done to it to make it start moving left. Let's assume the force acting to the left is constant.
For it to change the velocity from 2 m/s to the right to 2 m/s to the left the force must first decelerate the object to 0 m/s. That means the force did negative work on the object because the direction of the force is opposite to the movement of the object while it slows down. Net negative work decreases the kinetic energy of the object.
But since the force remains, it now accelerates the object from 0 m/s to 2 m/s to the left. Now the force is doing positive work since its direction is the same as the motion of the object. Net positive work increases the kinetic energy of the object.
The amount of negative work done by the force to decelerate the object to 0 m/s equals the amount of positive work done by the force to accelerate the object to 2 m/s, for a net work of zero. Per the work energy theorem the net work done on an object equals its change in kinetic energy. Since the net work is zero, the change in kinetic energy is zero.
Hope this helps.
The following is multiple choice question (with options) to answer.
An exertion on a thing that is going against the thing's intended direction, when in motion will | [
"melt it",
"oppose it",
"speed it up",
"burn it"
] | B | a force acting on an object in the opposite direction that the object is moving can cause that object 's speed to decrease in a forward motion |
OpenBookQA | OpenBookQA-4214 | home-experiment, mixtures
Title: What household substances could be distilled I'm looking to experiment with distillation to have a basis for understanding the theory slightly better, and get a better feel for it.
I'm hoping for some suggestions as to what I could try distilling, such as purifying drinking alcohol. Any single idea would be appreciated, best answer would be awarded to an idea where:
The resulting purity would be straight forward to approximately test
No part of the distillation presents a significant hazard (e.g. toxic fumes, high volatility)
No particularly specialist or expensive equipment is required (e.g. extreme temperatures)
I think that pretty much covers it. I'm just looking for one or two ideas which I can experiment with besides alcohol.
Thanks This is tricky. Besides water, nearly everything has some hazard associated with it. And even water distillation involves high temperature (100C). Be careful distilling alcohol: the azeotrope of distilled alcohol is 95% ethanol which is VERY flammable! Plus, technically speaking, distilling alcohol may be illegal where you live.
One thing you could do is distill water with dissolved substances, most likely table salt (NaCl). This would help you test the principle that distillation is a technique for separating substances. In this case, distilling salt water should yield pure water. A more visual example would be brewed coffee or tea, which is a suspension and should separate into water and crud!
And after that, I'd be careful! For example, concentrating acetic acid (white vinegar) is dangerous, as concentrated acetic acid is both corrosive and has choking fumes. I would not even consider trying something that is not food grade, given your requirements.
The following is multiple choice question (with options) to answer.
If you need something to mix kool-aid, what would you avoid? | [
"faucet water",
"well water",
"seawater",
"bottled water"
] | C | the ocean contains large amounts of salt water |
OpenBookQA | OpenBookQA-4215 | classical-mechanics, energy, electricity
Title: Can we imagine having a computer keyboard that recharges itself through mechanical utilization? Silly question here.
I have a debate with my father, and while I am decent at high school level physics, both he and I cannot determinate through calculus which of us is wrong.
Basically, he had the idea that perhaps, through simple mechanical utilization, a wireless keyboard can be charged and used, without any other energy source. (The keyboard can have a battery that can be recharged through the said mechanical utilization though), I have the intuition that the idea is interesting, but physically problematic.
With simple research, I have seen that an idle keyboard has a consumption of $1W$, and a used keyboard will use between $1.5$ and $2.5W$.
So, we have specific questions:
Is collecting the mechanical energy from the keyboard doable ?
And if yes, how much energy can typing on a keyboard's key produce ?
How it may impact the overall comfort of the user ?
I have multiple difficulties to answer these myself. How can I know how much a person can generate through typing, how much energy will be lost in the process of using a battery, etc..?
(This is not a concept that I try to sell or anything, this is a mere thought experiment that I wanted to share and resolve, please do not take it too seriously) What you are looking for is fairly simple. All you need to do is build a piezoelectric generator under each key. These generate electricity with each push. With this the element is stretched or vibrated with each push and this generates electricity. Do a Google search and you will find much more.
The following is multiple choice question (with options) to answer.
To function, electrical energy is required for what kind of devices? | [
"wet",
"zapping powered",
"hydro",
"watery"
] | B | electric devices require electrical energy to function |
OpenBookQA | OpenBookQA-4216 | human-biology, circadian-rhythms
Title: Does artificial heat (shower/tea) affect diurnal rhythms in humans? I've been reading that over the course of the day, human body temperature follows diurnal rhythm with the lowest body temperature observed some time close to the middle of the sleep episode, while the peak body temperature is observed some time close to sunset.
Circadian rhythm on Wikipedia
I'm interested if humans have internal organ systems or brain "sensors" that "read" the body temperature as a part of synchronizing their own internal circadian clock to the master clock of the human body.
If there are indeed such sensors, then I'm interested if they can be thrown "off track" by artificial heat sources, like hot food, drinks or showers. Yes, the human body has thermoreceptors that "sense" the current temperature, but these merely help with regulation--you know, shivering to raise internal body temperature and sweating to cool via evaporation. The hypothalamus is primarily responsible for making sure that the circadian rhythm itinerary is adhered to reasonably well. So no, if the thermoreceptors detect that the body temperature is 97 deg F but it's 5 pm, the body will not "get confused" and decide that it is actually 4 am because a human body is about 97 deg F at 4 am.
The following is multiple choice question (with options) to answer.
Heat causes you to sweat, so at which time of day will you sweat most? | [
"high noon",
"night time",
"early morning",
"during a snowstorm"
] | A | sunlight produces heat |
OpenBookQA | OpenBookQA-4217 | zoology
From Scripture's research: “. . . a live frog can actually be boiled without a
movement if the water is heated slowly enough; in one experiment, the
temperature was raised at the rate of 0.002 degrees Celsius per
second, and the frog was found dead at the end of 2.5 hours without
having moved."
According to Dr. Karl S. Kruszelnicki (Australian scientist): "[T]he numbers just don’t seem right. If the water comes to a boil,
that means a final temperature of 100 degrees Celsius. In that case,
the frog would have to have been put into the water at 82 degrees
Celsius. Surely, the frog would have died immediately."
According to Dr. Victor H. Hutchinson (Herpetologist and Zoology Professor at University of Oklahoma):
"The legend is entirely incorrect! The 'critical thermal maxima' of many species of frogs have been
determined by several investigators. In this procedure, the water in
which a frog is submerged is heated gradually at about 2 degrees
Fahrenheit per minute. As the temperature of the water is gradually
increased, the frog will eventually become more and more active in
attempts to escape the heated water. If the container size and
opening allow the frog to jump out, it will do so."
Whit Gibbons (University of Georgia) says that there is an important message behind the false legend:
So where does that leave us with the boiling frog as a metaphor for
the human response to economic change or environmental degradation?
Well, it's not true that you can induce a frog to willingly remain in
boiling water by starting it off in cold water. But that does not
diminish the truth of the message that the accumulation of
imperceptible changes can have a significant effect on the economy and
the environment. We need to be aware of what changes are occurring and
to respond to them in a timely fashion. The metaphor lies in the
frog's ability to escape from the container: if there's no way out,
then the frog's fate is a foregone conclusion.
The following is multiple choice question (with options) to answer.
An amphibian has what temperature blood? | [
"toasty",
"chilly",
"hot",
"burning"
] | B | an amphibian is cold-blooded |
OpenBookQA | OpenBookQA-4218 | cellular-respiration
Title: Do cold blooded animals generate any heat? In explaining energy and work to an 8 year-old I said that all conversion of energy generates heat as a by-product. For example, cars generate heat in their engines and running generates heat in our bodies. Then the 8 year-old said, except for cold-blooded animals.
So my question is, do cold-blooded animals generate any heat in their conversion of stored energy (food, fat, etc) into motion? If they generate heat, why are they cold-blooded? They do generate heat. They just do not SPEND energy specifically on heating their bodies by raising their metabolisms. This is a form of energy conservation. The metabolic rate they need to live is not nearly enough to heat their bodies.
An example of spending energy to heat the body is seen in humans shivering. Here muscle is activated not for its usual purpose, but to function as a furnace. "Warm-blooded" and "cold-blooded" is somewhat a misnomer. The correct way to think of it is...
Endotherm or ectotherm. Does the heat primarily come from within (endo) or from the surroundings (ecto). Endothermic animals include mammals. Most of their body heat is generated by their own metabolisms. Ectothermic animals include reptiles and insects. They absorb most of their body heat from the surroundings. This is not the same as saying they let their body temperature fluctuate with their surroundings, some avoid this by moving around to accomodate themselves.
Homeotherm or poikilotherm. Homeotherms want to maintain homeostasis for their body temperatures. They don't want it to change. Poikilotherms do not exhibit this behaviour, instead their body temperatures vary greatly with the environment.
We can have endotherm poikilotherms, such as squirrels, who let their body temperature drop while hibernating. Endotherm homeotherms, such as humans, where temperature is constant by means of complex thermoregulation. Ectotherm homeotherms, such as snakes (moving into shadow or into the sun to regulate temperature), and ectotherm poikilotherms, such as maggots.
The following is multiple choice question (with options) to answer.
Which animal is warm blooded? | [
"salamander",
"toad",
"parakeet",
"tadpole"
] | C | an amphibian is cold-blooded |
OpenBookQA | OpenBookQA-4219 | climate-change, earthquakes, glaciology
Title: How significant is human influence on seismic activity? Here's a graph from johnstonsarchive.net showing energy released by earthquakes and, however reliable this graph is, it shows huge differences in earthquake activity. About how big percent is the energy of quakes caused by humans? You have an interesting graph there. In response to your question, I would say that if we actually use the Mw (moment magnitude) measure of seismic activity (which is related to energy release via slip on a fault), we would see that most of the Earthquakes 'caused' by humans (and note that there are still only a few examples of this, (such as the 5.7 Prague, Oklahoma Earthquake), are limited to intraplate earthquakes which only exceed 4 in rare instances such as the above.
The exact 'percent' of energy release due to induced (human-caused) seismicity would probably not even approach single digits, but possibly reside in values approaching zero, when you consider that the vast majority of earthquakes take place at plate boundaries and outnumber induced earthquakes by a large amount.
The following is multiple choice question (with options) to answer.
Which is more likely the result of a big earthquake | [
"a mountain",
"a big house",
"a modern airplane.",
"a fancy car"
] | A | earthquakes cause rock layers to fold on top of each other |
OpenBookQA | OpenBookQA-4220 | newtonian-mechanics, estimation
Would the rock have created a seismic event of its own (if so, how large)?
Would the rock have created a crater? The energy of the rock at the time of hitting the earth is mgh.
No rock we know of is going to be able to survive this collision with out breaking into pieces.
Non the less it will be a big impact and depending on the geology of the location it hits a variety of reactions scenarios can happen.
If the soil is aggregate of silt and sand and gravel, it would part into several shear rupture sections which look like slices of shell pattern surfaces starting from the bottom surface of the rock and turning up exiting the earth surface a few hundred yards outside of the impact zone and probably even eject some material out like a bomb crater. This scenario will have shakes that could be recorded miles away.
The calculation of how much of the momentum of rock will be shared with the shear material and accelerating them will be involved but not impossible.
If the geology of the impact area is of very low bearing like mostly silt and loose clays, the rock my lose most of its kinetic energy by just sinking into the dirt mostly with a giant humph with a cloud of dust rising.
If the geology is hard or rocky with the 'optimal' amount of mass and resilience it could create a substantial earthquake by resonating with the impact.
The following is multiple choice question (with options) to answer.
Earthquakes cause rock layers to do what? | [
"crease",
"evaporate",
"sink",
"melt"
] | A | earthquakes cause rock layers to fold on top of each other |
OpenBookQA | OpenBookQA-4221 | climate-change, hypothetical, solar-terrestrial-physics
Title: How much reduction of insolation (solar energy) would be required to stop global warming? Suppose a giant sheet of semi-reflective mylar (or some other kind of partial sun-screening material) was temporarily placed into space between the Earth and the Sun with the intent to lower the amount of solar energy reaching the surface of the planet.
How much solar radiation (and in what frequency ranges) would need to be filtered to cool the planet to the most-desirable global temperature? Also, would the entire planet need to be shaded or just a key area like the Equatorial region?
Obviously the plan would be to reduce the warming effect without dramatically darkening the day since so many plants require the visible spectrum of sunlight to live. It's not that hard to make an estimate.
CO2 traps about 2 watts per square meter. Direct sunlight at 1 Astronomical Unit is about 1,360 watts per square meter, but spread out over the earth, average night and day it's about 1/4th of that about 340 watts per square meter. (note, Casey's point is valid, it's probably better to use the number of watts that hits the Earth, so, my estimate is likely a bit low)
There may be more detailed and specific ways to look at it, but this is probably pretty close. If you shade enough sun to reduce 2 watts out of 340, or 1/170th, that should balance out climate change, at least at current levels.
From space, you can view the earth as a disk in terms of area needed for shade, so the 2D area of the earth is about 127 trillion square meters, and 1/170th of that, about 750 billion square meters, or 750,000 square KM, slightly larger than Texas and as you get closer to the sun, the area needed is reduced by the square of the relative distance.
Still, that's no easy task, to put up a shade the size of Texas into space and it's no easy task to keep it there as it would in effect by a huge solar sale and likely enormously heavy. It's far easier to simply build mirrors on earth than try to build something in space and I've seen that discussed as a possible solution to climate change. of-course, they'd need to be kept clean to be effective, it would require maintenance, but it's probably doable.
The following is multiple choice question (with options) to answer.
Which of the following would likely reduce pollution the most? | [
"using a truck instead of a car",
"using a car instead of the bus",
"using a motorcycle instead of a bike",
"using a bicycle instead of a motorcycle"
] | D | pollution is when humans pollute the environment with pollutants |
OpenBookQA | OpenBookQA-4222 | atmospheric-chemistry
But some researchers have argued it does make a notable contribution in the lower atmosphere, but indirectly. There doesn't appear to be a consensus on how big this effect is (and the Wikipedia reference is old and obsolete). The argument for ozone being a notable contributor is based on the following. Hydrocarbon pollution in the lower atmosphere (often from vehicle emissions) leads to a variety of undesirable reactions some of which lead to the production of ozone (as well as many other irritating components of smog). We really don't want too much smog or ozone in the lower atmosphere because it is bad for health. Some have estimated that it also adds to the warming caused by hydrocarbon emissions (exacerbating the warming potential of methane, for example).
It is hard to judge the estimates of its contribution to warming not least because they rely on models of complex reactions caused indirectly by other pollutants. Also, the big issue with emissions leading to ozone are not its contribution to warming but its contribution to pollution which causes direct harm to people in the short term. In fact regulations around emissions has been striving to reduce those emissions since before we started worrying about global warming. And, many countries have sharply reduced them (this is a major reasons why most western countries insist on catalytic converters in their vehicles). We should reduce ozone pollution by reducing the other emissions that cause it and we have been doing that for decades.
I would argue that ozone is essentially irrelevant to global warming. We should strive to reduce it in the lower atmosphere even if we were not worried by global warming. So even if we can't agree on how big its contribution to warming is (which the literature isn't clear on) we should be reducing it as much as we can for more direct reasons.
And, even if we wanted to report its contribution to warming, the best place to account for it is to add it to the contribution of other emissions (eg methane) rather than to account for it separately as we don't directly emit it from anything.
The following is multiple choice question (with options) to answer.
A way in which humans may cause pollution to the environment is | [
"using bug killer on crops",
"avoiding spilling oil into oceans",
"placing plastics in special containers",
"making laws against littering"
] | A | pollution is when humans pollute the environment with pollutants |
OpenBookQA | OpenBookQA-4223 | volcanology
Title: Does the size of Earth increase due to volcanism? In a volcanic eruption, magma rushes to the 'outside' of the Earth. Does this mean the size of Earth also increases? If not, how is the volume left after the magma rushed out refilled? This is actually a more complicated question than it seems on the surface (no pun intended). The short answer is that the volume vacated by the magma is eventually refilled by the very tectonic processes that filled it in the first place. Crust is subducted, molten, and then rises to fill magma chambers. The process goes on and on. In some cases the plate that was being subducted eventually disappears (this will happen to the Juan de Fuca plate in a few million years), and the volcanoes associated with become extinct, not dormant but extinct. But generally speaking, volcanism is an ongoing process; the Earth is constantly recycling crustal material
The following is multiple choice question (with options) to answer.
Magma is sourced in volcanoes and | [
"is high enough kelvin to melt steel",
"on the desert plains",
"is beneath the aliens",
"can freeze water at all times"
] | A | volcanoes are often found under oceans |
OpenBookQA | OpenBookQA-4224 | star, galaxy
If you're on a farm, away from cities, in a place with reasonably low light pollution, and your eyes are good, and you've been sitting in perfect pitch black darkness for at least 30 minutes prior - when you look up you can reasonably expect to see a few thousand objects, mostly stars. Keep looking, and after a while you will distinguish one or two thousand more stars, very faint, that you could not see at first sight. Practice this steadily for a few years, and you'll add maybe another thousand; but you won't be able to see those all at once - only one at a time.
Now travel to the Cerro Tololo site in Chile, up in the mountaineous desert, zero light pollution, excellent transparency, and you'll multiply all those numbers by a factor of 2x ... 5x.
As you can see, the numbers are very flexible because there are so many factors involved. You can't just slap a 44k label on it and call it a day; that doesn't make any sense in reality. Astronomers know that the pure magnitude number doesn't mean much by itself, because it is just one factor among many.
In a place with very high light pollution (like where I live, in the middle of a large, dense, sprawling urban area in California), you'd be lucky if you can see a hundred stars at night.
Or, in a place with zero light pollution, shine a flashlight into someone's face, and you've temporarily blinded them. You've reduced the number of stars they could see by an order of magnitude for the next half hour (night vision gradually recovers, and it takes 30 minutes to fully recover, according to US military manuals and visual astronomers practice).
The following is multiple choice question (with options) to answer.
What will it be harder to see as light pollution increases? | [
"sky",
"moon",
"stars",
"sun"
] | C | as light pollution increases , seeing the stars will be harder |
OpenBookQA | OpenBookQA-4225 | meteorology, climate-change, gas, pollution
Title: Regarding various types of atmospheric pollution Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?
Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?
Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then. As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds). The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years). You can see the summary of your county at http://www.epa.gov/air/emissions/where.htm. As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective. For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly. Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic). Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.
The following is multiple choice question (with options) to answer.
The more factories and cars there are releasing gas in the air, the harder it will be to | [
"lay down",
"to space",
"go stargazing",
"sit down"
] | C | as light pollution increases , seeing the stars will be harder |
OpenBookQA | OpenBookQA-4226 | species-identification, ornithology
Why would a mother do that to her young? Does she hates the little one? Not at all. It’s just that those little birds were made to fly, and they don’t know it, so she is going to push them out of the nest. She never lets them hit bottom, but she does let them fall, because they have to learn something they don’t know.
The next time the mother bird comes back she decides to clean house, and so she stands on the edge of the nest. The first things to go are the feathers inside; she drops them over the edge. Then the leaves go over the edge—heave ho! While this is going on, she’s not very talkative, either. ("Mom, what are you doing?") She pays no attention. Since she built the house, she knows how to take it apart.
Next she decides to take the sticks out of the middle of the nest, and with her great strong beak and feet, she’s able to break them off and stand them straight up. ("Mom, it’s not comfortable in here anymore.") Then she takes certain key sticks out of the nest and throws them over the edge. ("What are you doing, Mom? You are wrecking my room.")
She seemingly pays no attention to the concerns of her young as she prepares to pull the nest apart, for she is determined that those little ones will fly, and she knows something they don’t. She knows they will never fly as long as they remain in the nest.
The following is multiple choice question (with options) to answer.
A quail's life starts after it leaves the | [
"farm",
"country",
"calcium housing",
"earth"
] | C | if an animal hatches from an egg then that animal is born |
OpenBookQA | OpenBookQA-4227 | water, analytical-chemistry, materials, glass, containers
The article also mentions a technique called secondary ion mass spectrometry that can probe the composition of solid glass up to 1-2 nm depth below the surface. Leaching has been studied quantitatively in the context of storing nuclear waste in the glass state, see for example this PhD thesis (abstract in English, main text in French).
So storing in a glass bottle is not ideal because of contamination with ions. If you store it in a plastic bottle, on the other hand, you will find organic substance in your formerly pure water. Depending what kind of analysis you want to use your water for, different types of impurities will be more relevant (i.e. give spurious signals in the analysis). If you are analyzing samples with a GC/MS, glass bottles would be better (well, you would use an organic solvent, not water). If you are analyzing samples with atomic emission or absorption spectroscopy, plastic bottles would be better.
A first pointer would be the materials used in sample handling by the instrument itself.
The following is multiple choice question (with options) to answer.
A thing which may be found at a special location for reusing materials is a | [
"fresh cat litter",
"new brick house",
"rusted aluminum tray",
"old used wax"
] | C | aluminum is recyclable |
OpenBookQA | OpenBookQA-4228 | 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.
Flowers make themselves attractive to hummingbirds with | [
"nocturnal access",
"prickly thorns",
"dull, subdued colors",
"an optimal angle"
] | D | when pollen sticks to a hummingbird , that pollen will move to where the hummingbird moves |
OpenBookQA | OpenBookQA-4229 | solar-eclipse
Title: Can you test solar eclipse glasses with a remote control? By putting solar eclipse glasses directly between a remote control IR emitter and device receiver, could some unsafe glasses be detected? My guess is most fake glasses are just blocking visible light at best, while safe ones should block the IR signal as well. It would not guarantee they are 100% safe, but it might be able to detect bad ones.
I know to check for the ISO logo, cert number, and buy from a reputable vendor recommenced by the American Astronomical Society (which I have). It would still be nice to double check pairs of glasses before giving them out to friends and family. Short answer: No.
Long answer: No. You're testing at a single wavelength. The Sun emits continuously at a variety of wavelengths from deep infrared to far ultraviolet. Testing with a single kind of radiation doesn't tell you much about the filter behavior at the other wavelengths.
Buy from the online vendors that specialize in selling astronomy equipment - the ones that all astronomers buy their gear from. They tend to know the stuff they're selling. The list of vendors on the AAS page is good.
The following is multiple choice question (with options) to answer.
If a person wants to watch the eclipse | [
"it's best to go without sunglasses",
"it's best to use a telescope",
"it's best to just look at it",
"it's best to use eye protection"
] | D | a solar eclipse could only happen during the new moon |
OpenBookQA | OpenBookQA-4230 | algorithms, optimization
With the money you made from those sales, i.e. \$19 + \$59 + \$55 = \$133, buy 7.82352941176471 units of Item 3.
Now, you will have \$201 worth of each security, exactly 25% of the new portfolio size of of \$804.
The only time the extra \$100 would come in to play is if you are trying to minimize your transaction costs and/or if you are worried about not being able to trade at the spot etc.
With the extra \$100, you want to allocate \$226 to each security. So, buy 6/220 units of Item 1, buy 158/17 units of Item 3, and sell 34/130 units of Item 2 and 30/32 units of Item 4.
However, as far as I can see, you have not specified an optimization problem.
Let $c_i$ denote current units of security $i$ in your portfolio. Let's say you pay a percentage commission of $k$ per transaction. The amount you buy of security $i$ is denoted $x_i$ (negative $x_i$ mean selling). Your objective function is to minimize $\sum_i k p_i |x_i|$.
Since $k$ is a constant, this is equivalent to minimizing $\sum_i p_i|x_i|$ where $|x_i|$ is the absolute value of $x_i$.
This objective is subject to the portfolio allocation constraints:
$p_1(c_1 + x_1) = p_2(c_2 + x_2)$
$p_2(c_2 + x_2) = p_3(c_3 + x_3)$
$p_3(c_3 + x_3) = p_4(c_4 + x_4)$.
The following is multiple choice question (with options) to answer.
In an auction, how might a seller avoid too much of a loss? | [
"buyer beware",
"Auction Block",
"Sealed Bid",
"setting a reserve"
] | D | as the sale of a product decreases , the amount of money made by the person selling that product will decrease |
OpenBookQA | OpenBookQA-4231 | astronomy, everyday-life, popular-science, climate-science
It is for much the same reason that Winter is colder than Autumn, even though they have the same amount of daylight hours.
The following is multiple choice question (with options) to answer.
If above your head in the out of doors is gray during the daylight hours then the likeliest need for your travels that day would be | [
"bikini",
"umbrella",
"beach ball",
"sunscreen"
] | B | clouds produce rain |
OpenBookQA | OpenBookQA-4232 | optics, visible-light, reflection, refraction, lenses
Title: Why can't rainbows form at the start of a storm? I was recently at a park looking at the gorgeous scenery. I looked above and saw thick grey clouds covering up 3/4 of the sky. The sun's light is still visible for 1/4 of the sky, and it looks low enough to refract it's light through the clouds to form a rainbow. The rain started dripping slowly for 10 minutes. At five minutes I decided to take a panorama shot and ask the question, why won't a rainbow form at the start of a storm. I thought the place I was standing had the perfect condition for a rainbow to form.
Here is the panorama scene shot
There were a few rain drops pouring from the sky
The time I looked at the sky was 5:00 p.m., so the sun should be at an appropriate location.
But even if my scenario didn't give a rainbow, is this rare event still possible? The big deal with a rainbow is the angle between the sun and water droplets. The sun has to be behind you and the rainbow will occur at about 42 degrees away from the line from the sun through you. If everything lines up, you can have a rainbow at any time. (I've seen them on water spraying from a hose where things lined up just right.) This will work better when the sun in low in the sky, if the sun is too high in the sky the line from it to you goes into the ground. Since thunderstorms are often afternoon phenomenon, the sun is more likely to be low in the sky after the storm than before.
Looking at your panorama, it doesn't look like the sun was visible to you, so I wouldn't expect to see one.
The following is multiple choice question (with options) to answer.
Because clouds are what make rain, storms are unlikely to happen when the sky is | [
"murdered",
"clear and cloudy",
"candy",
"clear and cloudless"
] | D | clouds produce rain |
OpenBookQA | OpenBookQA-4233 | newtonian-mechanics, forces, fluid-dynamics, everyday-life, drag
If the motion of the wing through the air is perfectly level, then the lift and drag forces are vertical and horizontal, and constant-velocity motion (including zero-velocity motion, like hovering) is impossible: there’s nothing to oppose the horizontal drag force, so the wing will accelerate in the direction of the drag. Likewise, if the motion of the wing through the air has an upward component, then the horizontal parts of the drag and the lift point in the same direction. But in the illustration, the motion through the air has a slight downward tilt, which means the lift vector has a forward-pointing horizontal component that can in principle cancel out the horizontal part of the drag.
The kestrel is “hovering” by gliding on a very slight updraft, so that its airspeed exactly cancels the wind’s velocity.
Seagulls also hover, and they do so in flocks. When you see a flock of seagulls hovering, they all do so facing the same direction, and tend to hover relatively close to each other. That’s the place where the updraft is the strongest.
The following is multiple choice question (with options) to answer.
Sparrows gain lift with more grace than a vulture due to | [
"mental capacity",
"will power",
"feather color",
"size"
] | D | as the weight of an animal decreases , that animal will fly more easily |
OpenBookQA | OpenBookQA-4234 | formal-grammars
Title: Useless production Kindly consider the following productions. How can I identify a useless production?
S->aS|A|C
A->a
B->aa
C->aCb
Somebody please guide me.
Zulfi. Starting from $S$ it is impossible to generate a sentential form that contains the nonterminal $B$.
This is easy to see since:
$S$ only has productions whose body contain $S$ itself, $A$ or $C$.
$A$ has no nonterminals in the body of its productions.
$C$ has only $C$ itself in the body of its productions.
This means that the production $B \to aa$ is useless.
The following is multiple choice question (with options) to answer.
A producer produces it's own | [
"nourishment",
"plays",
"rhythm",
"heartbeat"
] | A | In the food chain process a green plant has the role of producer |
OpenBookQA | OpenBookQA-4235 | biochemistry, food
Title: Who creates first nitrogen compounds in the food supply chain As I understand the food supply chain, organic compounds have to be created from a unlimited source (air, water...).
For instance, I figure that plants transform CO2 from air to organic carbon compounds, mainly carbohydrates, which are then the main source for most other life forms.
But I never heard about a plant turning atmospheric N2 to nitrogen compounds.
Where nitrogen compounds come from, and from which source ? There are nitrogen fixing bacteria who turn N2 into NH3. Some are free-living in soil, others live symbiotically with plants.
https://en.wikipedia.org/wiki/Nitrogen_fixation
The following is multiple choice question (with options) to answer.
In the food chain process what has the role of producer? | [
"eaters",
"flora",
"carnivore",
"consumers"
] | B | In the food chain process a green plant has the role of producer |
OpenBookQA | OpenBookQA-4236 | thermodynamics, perception
Title: Our Perception of Heat Our body temperature is roughly 37 degrees celsius (that is, when we measure our body temperature externally, by using a thermometer that measures the temperature of our skin usually between our arm and side torso), whereas most of us would say that 25 degrees would be a pretty hot day. Why do we perceive a 25 degree day to be hot, when thermal energy from our 37 degree bodies should be leaving out and entering our surroundings? You are correct in a sense of thermodynamics. The heat from a human body does indeed leave the body and into the surroundings. The body combats this by burning calories and producing more heat, keeping the internal body at a constant temperature.
I'm not a biologist however:
Perception of a hot day, is just because our nerves our telling our brain its a given temperature. We are warm blooded animals, our body naturally generates heat. Lets assume that the body generates the same amount of heat every day, our brain may interpret a 25C day as warm because the body is generating the same amount of heat however it is leaving the body into the surroundings at a slower rate.
Temperature sensing is a survival tool, it used as a way of keeping the body at a constant temperature. As it gets hotter, your brain is in a sense telling you that it's getting harder to cool. (Forgive my terminology)
Think of this, if the day was as hot as the human body, you would be at danger of heat stroke.
The following is multiple choice question (with options) to answer.
What's usually hot in temperature? | [
"the Sahara",
"Minnesota",
"Alaska",
"corpses"
] | A | a desert environment is usually hot in temperature |
OpenBookQA | OpenBookQA-4237 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
Which thrives in unusually hot and dry places? | [
"jellyfish",
"arctic foxes",
"fennec foxes",
"polar bears"
] | C | a desert environment is usually hot in temperature |
OpenBookQA | OpenBookQA-4238 | newtonian-mechanics, estimation
Would the rock have created a seismic event of its own (if so, how large)?
Would the rock have created a crater? The energy of the rock at the time of hitting the earth is mgh.
No rock we know of is going to be able to survive this collision with out breaking into pieces.
Non the less it will be a big impact and depending on the geology of the location it hits a variety of reactions scenarios can happen.
If the soil is aggregate of silt and sand and gravel, it would part into several shear rupture sections which look like slices of shell pattern surfaces starting from the bottom surface of the rock and turning up exiting the earth surface a few hundred yards outside of the impact zone and probably even eject some material out like a bomb crater. This scenario will have shakes that could be recorded miles away.
The calculation of how much of the momentum of rock will be shared with the shear material and accelerating them will be involved but not impossible.
If the geology of the impact area is of very low bearing like mostly silt and loose clays, the rock my lose most of its kinetic energy by just sinking into the dirt mostly with a giant humph with a cloud of dust rising.
If the geology is hard or rocky with the 'optimal' amount of mass and resilience it could create a substantial earthquake by resonating with the impact.
The following is multiple choice question (with options) to answer.
Rock that has been metamorphosed will have potentially withstood this to get to that point | [
"old trees",
"small mice",
"large exertions",
"big sneezes"
] | C | extreme heat and pressure metamorphose rock into metamorphic rock |
OpenBookQA | OpenBookQA-4239 | classical-mechanics
Title: Rolling stone on a frictional surface Consider a spherical rigid stone rotating with angular velocity $\omega$ being dropped vertically onto a horizontal rigid surface with the coefficient of friction $\mu$. Can the stone roll on the surface? If it can, what type of the motion is it? Constant velocity, constant accelaration, or varying acceleration? Ignore air resistance.
In reality if we drop a rotating ball, it will roll on the surface. But I am not sure whether it is because of the deformation of the ball at the surface of contact. I'll assume that:
The stone has horizontal axis of rotation.
The objects in question are perfectly rigid.
The collision is perfectly inelastic.
The static and dynamic coefficients of friction are equal.
In this case, you will get a vertical delta impulse on the stone, and up to $\mu$ of that impulse is converted to an instantaneous jump in horizontal speed. If the angular momentum of the stone is not exhausted by that impulse, it will skid for a while, producing constant acceleration until it grips the surface. If the angular momentum is exhausted, then the stone will just roll.
Relaxing one or more of the assumptions may yield more interesting behavior. For example, under certain conditions, rubber balls will switch the direction of rotation with each bounce.
The following is multiple choice question (with options) to answer.
A rock tumbler revolves to | [
"collect bees",
"trap clowns",
"facet diamonds",
"smooth gemstones"
] | D | contact between rocks over long periods of time causes rocks to smooth |
OpenBookQA | OpenBookQA-4240 | geology, rocks, mineralogy
Title: What is this Lake Michigan rock? Rock found along northern Lake Michigan, (Charlevoix, MI). Made up of very thin crystalline layers. There are small, round bubble like bumps that protrude from the surface. Doesn't show well in the picture, but the rock has a sugary appearance. I can't be definite but my three best guesses are Travertine, Agate and maybe Halite, if it fizzes in mild acid it's Travertine, a form of Limestone, if it dissolves in hot water it's Halite, or Rocksalt, otherwise if it's more or less inert it's probably Agate, an amorphous silicate. I find Halite unlikely, the other two are probably pretty equally likely in that location.
The following is multiple choice question (with options) to answer.
If you are at a pond throwing rocks, what picnic leisure item should a rock look most like for skipping? | [
"Frisbee",
"Soccer Ball",
"Football",
"Stick"
] | A | contact between rocks over long periods of time causes rocks to smooth |
OpenBookQA | OpenBookQA-4241 | human-biology, reproduction
Title: Why are animal births not taken as seriously as human births? When humans give birth, more than often medical assistance is needed. Others gather around and frantically look for any way to help. But when an animal gives birth, it is usually seen as a moment where you give the female its space and let the birth occur naturally and without any assistance. The animal is of course in serious pain just as a female human but this is more than often not taken into account. Why is it that animal births are not taken as seriously? Our heads are bigger.
There's some debate on the issue, but in essence, human brains, and therefore heads, are very large relative to our body size. This is handy for all the intelligent things we like to do, but can be rather painful during birth. Because we walk upright, the size of a newborn's head is actually a non-trivial fact during the birthing process. There are two major implications.
The first is that human birth hurts. You can watch the birth of other animals and they seem to brush it off, but for humans, forcing that huge head through a relatively small birth canal is difficult. Evolution has (supposedly) limited the size of the hips because, while that would allow an easier birthing process, it would negatively impact our ability to walk. As such, it has to hurt.
Secondly, in order to make the process easier, humans rotate during birth. The end result is that, unlike even other closely related primates, humans come out backward in a way that is very difficult for a birthing female to attend to. This almost requires having another person or two on hand to help out. This would, of course, be a huge reinforcement for social connections.
A few books I know of touch on this. Up From Dragons deals with the brain size/hip size issue and The Invisible Sex talks about rotation during the birthing process and the social implications.
The following is multiple choice question (with options) to answer.
A kitten is born and a person who is petting it can know that it | [
"broke through shell",
"was hatched",
"was an egg",
"came out breathing"
] | D | live birth means developing inside the mother instead of an egg |
OpenBookQA | OpenBookQA-4242 | I suspect that what you actually meant was that there are half as many nodes of height $m+1$ as there are of height $m$. This is the correct observation to make, so long as $m$ is less than the height of the tree (which I take to be a hidden assumption). By inductive hypothesis, there are $$\left\lceil\frac{n}{2^{m+1}}\right\rceil$$ nodes of height $m$, and so by our observation, there are $$\frac12\cdot\left\lceil\frac{n}{2^{m+1}}\right\rceil$$ nodes of height $m+1$. Your task, then, is to show that $$\frac12\cdot\left\lceil\frac{n}{2^{m+1}}\right\rceil=\left\lceil\frac{n}{2^{m+2}}\right\rceil,$$ or equivalently, $$\left\lceil\frac{n}{2^{m+1}}\right\rceil=2\cdot\left\lceil\frac{n}{2^{m+2}}\right\rceil.\tag{&}$$
The following is multiple choice question (with options) to answer.
Two felled trees, split in twain, with the same number of rings, means they're the same | [
"emotionally",
"crab",
"type of tree",
"age"
] | D | a tree growing a tree-growth ring occurs once per year |
OpenBookQA | OpenBookQA-4243 | At the end of the 3rd year the number of trees would be $$(\frac{5}{4})^3*x$$; At the end of the 4th year the number of trees would be $$(\frac{5}{4})^4*x$$; At the end of the $$n_{th}$$ year the number of trees would be $$(\frac{5}{4})^n*x$$; So, we have that $$(\frac{5}{4})^4*x=6,250$$ --> $$\frac{5^4}{4^4}*x=5^4*10$$ --> $$x=4^4*10=2,560$$. Answer: D. If the question were "if all of the trees thrived and there were 6250 trees in the orchard at the end of 15 year period, how many trees were in the orchard at the beginning of the 4 year period", then we would have that: $$(\frac{5}{4})^{15}*x=6,250$$ --> $$x\neq{integer}$$, so it would be a flawed question. Hope it's clear. Isn't the question quite ambiguous, though? I mean the first scentence could be interpreted as "for the first year we have (4/4)x and for the second year (5/4)x and for the third..." etc.. With that reasoning one would have (5/4)^3 * x + x and then your approach doesnt work. Obviously, I understand that this was a flaw in my reasoning but I cannot understand how they - with that wording - will assume that we totally understand that at the end of year one he has (5/4)x.. Is there a straightforward "word translation" way in knowing how to interpret wordings like this? Actually, it is not ambiguous. Read the statement: Each year a farmer increased the number of trees by 1/4. He did this for 4 years. (In GMAT Verbal and Quant are integrated. You need Verbal skills (slash and burn) in Quant and Quant skills (Data
The following is multiple choice question (with options) to answer.
The outer casing of a tree expands how many times a year | [
"1000 times",
"ten times",
"once",
"100 times"
] | C | a tree growing a tree-growth ring occurs once per year |
OpenBookQA | OpenBookQA-4244 | newtonian-mechanics, energy-conservation, friction, everyday-life, physical-chemistry
Title: Conservation of energy when we drive a car When we drive a car, we use gasoline as the source of energy. When we arrive at the destination, we lose some of the gasoline, used to move the car from one point to another. Then how energy is conserved, if we spend energy to move the car? What does it mean to "spend energy"? In the concrete example, the engine converts the chemical energy in the gasoline through combustion into kinetic energy of the car.
While the car is moving, it feels friction with the surface and air, so some of the kinetic energy of the car goes into friction (heat, air movement, etc).
When you stop the car, the kinetic energy completely goes into friction in the brakes, asphalt and air (again, as heat or kinetic energy of the air molecules, etc).
Conservation of energy means that in a closed system the energy stays constant. If you look just at the car and not also at the surroundings, that is not a closed system, and that principle is not applicable here. However, you can look at the surroundings too; then it all works out.
The following is multiple choice question (with options) to answer.
a car engine usually converts gasoline into motion and heat through what? | [
"air",
"hot peppers",
"water",
"fiery reaction"
] | D | a car engine usually converts gasoline into motion and heat through combustion |
OpenBookQA | OpenBookQA-4245 | visible-light, astrophysics, atmospheric-science, estimation, space
The atmosphere mostly consists of $N_2$ and $O_2$, which perform Rayleigh scattering. This is the kind that occurs way more for blue light than red, explaining why the sky is blue and sunsets are red.
Cool regions of the interstellar medium are mostly $H$ or $H_2$, and hydrogen just absorbs a few, discrete frequencies of visible light. These effects are important for astronomers, but not too important for the colors you see. That is, the cool regions don't matter, which is important for getting the right answer, because they're much denser than the hot regions!
Hot regions of the interstellar medium are mostly ionized hydrogen. The dominant effect should be Thomson scattering off the free electrons.
Since only the hot regions matter, let's focus on those and suppose the whole line between the Earth and Andromeda is hot. Looking up standard numbers, for blue light we have
$$N_2 \text{ Rayleigh cross section} \sim 2 \times 10^{-26} \, \text{cm}^2$$
and the Thomson cross section is wavelength independent,
$$e^- \text{ Thomson cross section} \sim 7 \times 10^{-25} \, \text{cm}^2.$$
These are close enough that we can just neglect the difference, so we just need to compare the total distance and density. The ratio of the densities is about $10^{19}/10^{-3} = 10^{22}$, so we have
$$\frac{\text{ISM effect}}{\text{atmosphere effect}} \sim \frac{10^{18}}{10^{22}} \sim 10^{-4}.$$
It looks like all the space between us and Andromeda has less effect than the atmosphere alone.
Edit: as pointed out by Joshua (a real astrophysicist, unlike me, a regular physicist who just multiplied a bunch of powers of ten), the ISR is much sparser outside of galaxies, so I should have used the size of a galaxy rather than the full distance between galaxies. Also, a much larger effect comes from Rayleigh scattering off interstellar dust, which comes out to 20%. This is relatively close to the effect of the atmosphere.
The following is multiple choice question (with options) to answer.
The arctic environment mostly reflects all colors from the closest star because | [
"it's covered in prisms",
"it's covered in white precipitation",
"it's always raining there",
"the ground is completely covered with white animals"
] | B | the arctic environment is white in color from being covered in snow |
OpenBookQA | OpenBookQA-4246 | optics, electromagnetic-radiation, visible-light, reflection, geometric-optics
Title: We know that a window can actually reflect light. But if the window has some dirt sticking to it, the image we see sometimes get magnified. Why? Well, I was traveling in a bus yesterday and saw this occur. The board that separates the passengers from the driver's had something written on it and I saw that the window that was a few meters away from the board reflected all of the things written.. But the window had some dirt on the part where I saw the image of the writings... And, they appeared to be enlarged just at the point where dirt was present. The open spaces between dirt particles each acts like a "pinhole camera" to magnify the image behind the dirty glass pane. The magnification is slight but noticeable. Try this experiment: make a small triangular hole shape by putting three fingertips together so as to leave a gap at their intersection. by pressing your fingertips together, you can make the size of the hole shrink; by relaxing them, you can make the hole larger.
That hole will act as a pinhole camera. now look through the hole at your computer screen from about 24 inches away and vary the hole size. you will find a certain diameter at which the image you see through the hole will get sharper and the text on the screen will become easier to read.
The following is multiple choice question (with options) to answer.
A thing which has a texture may have that texture observed by an eyeless creature through | [
"contact",
"sight",
"smell",
"sound"
] | A | touch can be used for detecting texture |
OpenBookQA | OpenBookQA-4247 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
If an area is experiencing a drought, how can they overcome the lack of water? | [
"a downpour",
"nothing",
"more drought",
"go to space"
] | A | as the amount of rainfall increases in an area , the amount of available water in that area will increase |
OpenBookQA | OpenBookQA-4248 | desert
Title: When was the first not-icy desert formed? For how long have deserts existed and which one would be the first to be created? I'm talking about arid, dry deserts, not the Antarctic or Arctic or any other icy deserts. Deserts have existed since at least the Permian period (299-251 million years ago) when the world's continents had combined into the Pangaea supercontinent. Stretching from pole to pole, this land mass was large enough that portions of its interior received little or no precipitation, according the University of California Museum of Paleontology.
Pangaea broke into smaller land masses which were moved across the surface by tectonic forces, a process that both changed global climate patterns and the climate those continents were exposed to. As a result, current desert regimes date back to no more than 65.5 million years, according to this Encyclopedia Britannica article:
The desert environments of the present are, in geologic terms,
relatively recent in origin. They represent the most extreme result of
the progressive cooling and consequent aridification of global
climates during the Cenozoic Era (65.5 million years ago to the
present), which also led to the development of savannas and scrublands
in the less arid regions near the tropical and temperate margins of
the developing deserts. It has been suggested that many typical modern
desert plant families, particularly those with an Asian centre of
diversity such as the chenopod and tamarisk families, first appeared
in the Miocene (23 to 5.3 million years ago), evolving in the salty,
drying environment of the disappearing Tethys Sea along what is now
the Mediterranean–Central Asian axis.
Which would put the oldest of "modern" desert somewhere in the region of what later became North Africa or South Asia.
The following is multiple choice question (with options) to answer.
the Grand Canyon was formed by the Colorado River doing what over long periods of time? | [
"blazing",
"melting",
"moving steadily",
"evaporating"
] | C | the Grand Canyon was formed by the Colorado River flowing over long periods of time |
OpenBookQA | OpenBookQA-4249 | structures
Title: Siding for Industrial Shed: Rain protection vs Ventilation When building a 12 m tall industrial shed with a peaked roof it is desirable that the sides of the shed should stay open as much as possible for ventilation / safety / access concerns.
On the other hand, an entirely open side from top to bottom might cause a lot of rain exposure when the rain comes in angled?
Is there a trade-off possible? Perhaps to enclose sides till a certain distance below the roof edge? Any heuristics about how much? (I've shown 4000 mm in the sketch below)
The contents inside the shed are relatively robust / waterproof & hence absolute rain protection is not needed. This will very much depend on the exposure of the building to wind as this is what will drive the rain in at an angle. So you really need to consider the prevailing wind direction and how sheltered the building is by other nearby structures etc.
If may be that if the prevailing wind direction is fairly consistent you can have one side more open than another.
Another option is to have panels which can be folded down when required eg if you have 4000mm of fixed cladding, you could have the same in fold-down form (this arrangement is fairly common in barns).
Also it depends what access you need obviously forklifts will need more height clearance than pedestrians.
You could also consider using strip curtains for at least part of the height.
The following is multiple choice question (with options) to answer.
Which of these uses shelter for protection against weather? | [
"a planet",
"a centipede",
"a rock",
"an ocean"
] | B | shelter is used for protection by animals against weather |
OpenBookQA | OpenBookQA-4250 | • I think the gif dosn't really fit this site, though I can't say if there is a specific rule against such things – Yuriy S Oct 10 '16 at 11:27
• @YuriyS: Hmm ... I am sorry to learn that people may find it inappropriate! That was by no means my intention! Do you think it would work better by removing the gif an leave the link and the figure of speach, or are all of those opfuscating the points I tried to make? – String Oct 10 '16 at 12:21
• @String: your link to a cartoon movie of a dead animal being bludgeoned is disproportionate and offensive. – Rob Arthan Mar 12 '17 at 1:27
• @RobArthan: Sorry, in some parts of the world such a cartoon would be considered merely a funny way to illustrate the saying about beating a dead horse. No offense intended, only a light tone. I cannot help that people do take offense, so I have removed it. Still it puzzles me how a cartoon matching the content of a saying would offend. I am from Denmark, after all. – String Mar 12 '17 at 8:11
• @String: on MSE it's easier just to use neutral language. As I am English (after all), may I point out that the cliched phrase is actually "flogging a dead horse" and it doesn't have the connotations you think it does (it's not "explaining to death", it's using a tired old argument that has lost all interest or relevance). Your cartoon doesn't help with that. – Rob Arthan Mar 13 '17 at 1:55
1. Well... yes... it does break down. You assumed that there are only 6 primes and reached a contradiction. You've successfully proved that there aren't only 6 primes.
2. Under the assumption that there are only 6 primes 30,031 isn't factorizable.
The following is multiple choice question (with options) to answer.
Bobby had a new toy. It had lots of buttons on it. One of the buttons had a picture of a cow on it and every time Bobby pushed that button the toy would make a mooing noise. That's because | [
"a circuit was opened up when he pressed the button",
"His new toy was possessed",
"a cow was inside of the toy",
"a circuit was made intact when the button was pressed"
] | D | pushing a button sometimes completes a circuit |
OpenBookQA | OpenBookQA-4251 | electricity, electric-circuits
Title: Why is it necessary for a circuit to be complete? Can electrons not flow through a load if they do not have a path to flow to the positive terminal of the battery? Why is it absolutely necessary for electrons to end up at the positive terminal? It is not that it is just necessary. Electron flow, in the first place, OCCURS due to the potential difference between the 2 terminals - negative and positive terminals.
Emf or potential difference is the driving force of the electrons in the electric circuit which causes the electrons to flow from the negative terminal to the positive terminal.
If the circuit is not closed, electrons will not flow.
EDIT: As per the comment by brucesmitherson ; In an open circuit, the driving force is not absent, it is just that it is not strong enough to make electrons jump outside of the metal, which requires a lot of energy.
The following is multiple choice question (with options) to answer.
Which likely completes a circuit? | [
"a bird's eye",
"a dog's paw",
"a wooden ruler",
"your phone's keys"
] | D | pushing a button sometimes completes a circuit |
OpenBookQA | OpenBookQA-4252 | geography, earth-system, astronomy, orbit, geodesy
(the vertical axis is logarithmic)
We can see that around 10 km away from the subsolar point, ~10 meters are enough to be closer than it to the Sun. ~30 meters at 20 km, ~800 meters at 100 km, ~3,000 m at 200 km, and if you go further than 340 km, not even Mount Everest will get you closer to the Sun.
So, the closest point to the Sun will be whatever geographical feature that maximizes the value $\text{Altitude}-\Delta H$, where $\text{Altitude}$ is the altitude of the geographical feature. Let's call that point “proxisolar” point. I just made up that name, but it will be handy for the following discussion.
Now that we understand the basis to establish what is the closest point to the Sun at a given moment, we can tackle the question that probably most people meant when asking this question:
What is the point on Earth that gets closest to the Sun over a year?
The most important fact to keep in mind, is that the variations of the distance between the Earth and the Sun over the year dwarf any topographical feature and even the diameter of the Earth itself. Earth’s distance from the Sun (center-to-center) varies from 147,098,074 km at perihelion (closest) to 152,097,701 km at aphelion (most distant). Therefore, the difference is 5 million kilometers!.
The perihelion happens around January 4th, when the solar declination is about -23°, therefore, the latitude of the subsolar point is around 23° South. That rules out Chimborazo, Cayambe and Everest, because they are too far to be the “proxisolar” point. In contrast, Sairecabur (5,971 m at 22.72° S) and Licancabur (5,916m at 22.83° S) are reasonable contestants.
The problem is that the perihelion happens on different days of the year and at different times of the day every year, so the point that gets closest to the Sun on a given year is just the one that happen to be the “proxisolar point” at the time of the Perihelion.
The following is multiple choice question (with options) to answer.
The sun is the what that is closest to earth? | [
"battery",
"astral light",
"person",
"moon"
] | B | the Sun is the star that is closest to Earth |
OpenBookQA | OpenBookQA-4253 | Medical Field Majors, Habanero Bbq Sauce, Ceramic Cutter Blade, Crockpot Orange Chicken With Orange Juice Concentrate, Are Aerospace Engineers In Demand, Kesar Mango Pulp Recipes, How To Use Agate Stone, 8 Coins Puzzle, Spc Reese Bookstore,
The following is multiple choice question (with options) to answer.
What can you make with the stove? | [
"ice cream sundaes",
"whipped cream",
"egg noodles",
"ice cream sandwiches"
] | C | if liquid is boiling then that liquid is hot |
OpenBookQA | OpenBookQA-4254 | • I understood the question differently. The answer to the puzzle is irrelevant: The fact that D has more information than C still gives an "educated blind" guess by D lesser chances of being right than an "educated blind" guess by C (assuming OP's calculations etc are correct). Normally one would expect that the higher information you have, the better your chances of making a guess in general... Jun 24, 2011 at 21:44
• @Aryabhata: that's exactly what I meant to ask. I've updated the question to clarify. Jun 24, 2011 at 21:47
• @shambulator I realized this after my initial answer - I've edited this answer now to reflect that. Sorry! Jun 24, 2011 at 21:53
• not to worry, the conclusion in your amended answer and the analogy leading up to it have given me a lot to chew on :) Thanks for answering! Jun 27, 2011 at 19:38
With the aim of making this question/answers post self-contained, I've inserted the image from the linked puzzle, below, followed by the solution given in that link.
Four Men and a Hat
Shown above are four men buried up to their necks in the ground. They cannot move, so they can only look forward. Between A and B is a brick wall which cannot be seen through.
They all know that between them they are wearing four hats--two black and two white--but they do not know what color they are wearing. Each of them know where the other three men are buried.
In order to avoid being shot, one of them must call out to the executioner the color of their hat. If they get it wrong, everyone will be shot. They are not allowed to talk to each other and have 10 minutes to fathom it out.
After one minute, one of them calls out.
Question: Which one of them calls out? Why is he 100% certain of the color of his hat?
This is not a trick question. There are no outside influences nor other ways of communicating. They cannot move and are buried in a straight line; A & B can only see their respective sides of the wall, C can see B, and D can see B & C.
Spoiler/solution, and see Steven's answer for clarification
The following is multiple choice question (with options) to answer.
A man will most likely be unable to see if he gets lost in | [
"a dense forest",
"a long river",
"a desert",
"a mountain"
] | A | a dense forest environment is often dark in color |
OpenBookQA | OpenBookQA-4255 | visible-light, sun, weather
Title: Why are clouds lighter than the sky during the day but darker at night This is probably a very basic question but I couldn't find a good answer to it, most search results are about rain clouds or clouds appearing red at night (something I've never seen except for during sunset but apparently it's common in bigger cities).
Basically what I'm wondering is why clouds during the day appear lighter than the sky (white vs light blue) while clouds at night and during the evening appear darker than the sky (see image).
Image quality is low because I took it with my phone through my window.
I guess the clouds could be blocking the light and therefore appear darker but in that case, shouldn't the same thing be happening during the day? There could be quite a few things going on.
Off the bat there's no incoming light for them to scatter: during the day, clouds are white because the water droplets are big enough for all visible light to cause Mie scattering, but if you don't have much light falling on them, you can't observe the scattering and you can't observe light passing through either.
Then you could consider the fact that in some places, it rains more in the evening/night than during the day (if you have hotter surface temperatures during the afternoon, you see cloud formation and precipitation during the late evening, and with the lower temperatures in the night, the air is more likely to become saturated, see Dew Point), and clouds which precede rain are thicker and denser. They don't allow much light pass through.
And lastly, there's less ambient light which they can reflect back towards you.
The following is multiple choice question (with options) to answer.
What dense environment is often dark in color? | [
"plains",
"mountains",
"tree land",
"deserts"
] | C | a dense forest environment is often dark in color |
OpenBookQA | OpenBookQA-4256 | metabolism, human-anatomy, pharmacology, liver
For drugs introduced through an injection, for example, metabolism occurs throughout the circulatory system and in the liver. Remember that it's all the same blood supply, but the first-pass effect just refers to the blood that goes to the liver before entering the systemic circulation (by which it can travel to its target).
The following is multiple choice question (with options) to answer.
the circulatory system carries oxygen from the digestive and respiratory systems to the rest of the what? | [
"physical being",
"leads",
"stars",
"humanity"
] | A | the circulatory system carries oxygen from the digestive and respiratory systems to the rest of the body |
OpenBookQA | OpenBookQA-4257 | thermodynamics, evaporation, gas, liquid-state
On the water surface, knowing the temperature, we can estimate the vapor pressure and vapor mixture fraction. Then there will be an diffusion process for the water vapor to move out and for the ambient air to move in. Because the water surface doesn't allow the air to further move, a circulation forms. When the water vapor moves out, the water vapor pressure drops, so more liquid water evaporates to fill up the loss of water vapor. The evaporation associates latent heat so water surface area temperature drops (you may see dew on the bowl wall). Then a heat transfer process starts which may initiate water circulation as well.
As this is complex, doing test might be a quick way to get the K value if you assume it is a constant, which is questionable.
The following is multiple choice question (with options) to answer.
See evaporation in action by | [
"leaving two mason jars out with different levels of gatorade",
"run for city council",
"take a walk on the sun",
"become a human bug"
] | A | evaporation causes amount of water to decrease |
OpenBookQA | OpenBookQA-4258 | genetics, chromosome
In the case of canine transmissible venereal tumor (CTVT), it was shown about five decades ago to be the same dog tumor being spread from dog to dog. The earliest studies were based on histological studies and karyotyping. Paraffin-embedded tumor samples still exist. More recently, with genetic analysis, it is possible to perform much more sophisticated testing on the tumor DNA.
The transmissible agent causing canine transmissible venereal tumor (CTVT) is thought to be the tumor cell itself. To test this hypothesis, we analyzed genetic markers including major histocompatibility (MHC) genes, microsatellites, and mitochondrial DNA (mtDNA) in naturally occurring tumors and matched blood samples. In each case, the tumor is genetically distinct from its host. Moreover, tumors collected from 40 dogs in 5 continents are derived from a single neoplastic clone that has diverged into two subclades. Phylogenetic analyses indicate that CTVT most likely originated from a wolf or an East Asian breed of dog between 200 and 2500 years ago. Although CTVT is highly aneuploid, it has a remarkably stable genotype.
Your quote
likely originated at least 250 years ago from a wolf or an "old" Asian dog breed such as a husky or Shih Tzu...
Has been disputed. Estimates vary widely, from 11,000 years to 250 years.
Canine TVT: Evolution of Somatic Tumour Cell as Transmissible Parasites
MHC gene copy number variation in Tasmanian devils: implications for the spread of a contagious cancer
Clonal Origin and Evolution of a Transmissible Cancer
The following is multiple choice question (with options) to answer.
An Afghan Hound get all its hair from | [
"its parents",
"the water",
"the sun",
"its siblings"
] | A | the length of the hair of an animal is an acquired characteristic |
OpenBookQA | OpenBookQA-4259 | Please press Kudos if this helped
“Going in one more round when you don't think you can, that's what makes all the difference in your life.”
Re: Two bottles are partially filled with water. The larger bottle current &nbs [#permalink] 04 Sep 2018, 22:21
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The following is multiple choice question (with options) to answer.
You'd best bring water if you go to | [
"a lake",
"a reservoir",
"a pond",
"the moon"
] | D | the moon does not contain water |
OpenBookQA | OpenBookQA-4260 | the-moon, earth, light, satellite
Title: Why does the Moon appear gray when passing between the Sun and the Earth? Shouldn't the Moon appear as bright as a full Moon seen at midnight from Earth?
The photo was taken by DSCOVR at Lagrange point 1.
In the picture, The Moon appears dark gray. Of course the Earth appears bright, reflecting sunlight from clouds and water. The Moon's surface is gray and should reflect less light than the Earth.
It should be irrelevant that we see the far side, since the reflectivity of the Moon's surface should be the same on the far side as the side that faces the Earth.
The midnight full Moon appears much, much brighter as seen from Earth than it does in this picture, despite the fact that the amount of sunlight reflecting from the surface of the Moon is the same in both instances.
I understand the photo was taken with 3 separate exposures of red, blue and green, but this should not affect the brightness.
So why does it appear so dull? That's what it really would look like if you were there with DSCOVR. The albedo of the Moon is only about 0.136, about half of the Earth's average albedo. Of course the part with clouds is higher.
I was shocked too, but it was explained in written copy that accompanied the release of the original image.
Shouldn't the Moon appear as bright as a full Moon seen at midnight from Earth?
It does. If the moon were a diffuse, white ball, a full moon would be about seven times brighter!
If you watch the image or GIF, the Moon is roughly the same brightness as central Australia or the Sahara region.
Phil Plait explains well in Bad Astronomy.
There's a lot to read here.
EDIT: I just ran across these images of astronauts on the surface while reading this answer. Their suits are not 100% white to begin with, but the Lunar soil - at least in these locations - is significantly darker. It is close to the same color as the (presumably) nearly-black radiator fins for the heat sink of the RTG unit (2nd photo) at the astronaut's foot.
above: "Buzz Aldrin carries the EASEP." from here
above: "Astronaut Alan L. Bean from Apollo 12, put the Plutonium 238Pu Fuel from the Lunar Module into the SNAP 27 RTG" from here.
The following is multiple choice question (with options) to answer.
the moon is lacking what? | [
"rocks",
"craters",
"gravity",
"h2o"
] | D | the moon does not contain water |
OpenBookQA | OpenBookQA-4261 | human-biology, biophysics, skin, light, uv
Title: Can UV radiation be safe for the skin? It is well known that UV radiation can damage the DNA and generally harm our skin.
We also know that UV radiation helps on the production of melanin and Vitamin D.
From what I could find, the DNA absorption spectrum goes to almost zero for wavelengths higher than 300 nm. This seems to suggest that we would be safe to use UV radiation between 300 and 340 nm in our skin (as long as the power or exposure is not too high/long to make burns), for therapeutic purposes such as the stimulation of Vitamin D production.
Is this assumption correct? Are there any evidences that we could use this UV wavelength range safely? You're talking about long-wave UV, or UV-A radiation. In the 80s, experts claimed that this was a safe wavelength. Protection against UV-A was not part of sunscreen in the early days. Consequently, UV-A was (and still is) used in tanning beds due to its perceived safety over UV-B. However, a lot of research has been done since.
UV-A is well understood now to also be unsafe in unreasonable amounts. Currently, UV-A protection is a typical feature of sunscreen and tanning beds are still not a healthy alternative to moderate, healthy doses of sun. Here is a recent review covering some of the aspects comparing different UV range effects on skin. I really suggest you put a search engine to good use here; it makes little sense for us to expound on the literature when it is so clear and easily available.
In summary,
UVA certainly contributes to the development of skin cancer.
UVA penetrates deeper into the skin than UV-B (which is largely responsible for 'burning' of the topmost layer of skin, without directly affecting the deeper layers). For this reason, UV-B is associated primarily with burning and UV-A is primarily associated with aging and aging diseases like cancer.
It is important to note that 95% of UV light in every day life is UV-A, because it does not vary seasonally and can penetrate clouds and windows. Therefore, in spite of the fact that short wavelengths carry more energy per photon, the ratios of UV-A and UV-B exposure are far from equal.
These are only a few of the explanations as to why we observe an incidence of aging and skin damage and disease upon UV-A exposure.
The following is multiple choice question (with options) to answer.
A person avoiding UV rays would | [
"gather seashells at the beach",
"sunbathe in their yard",
"dig a trench outdoors",
"close their bedroom blinds"
] | D | sunlight contains ultraviolet light |
OpenBookQA | OpenBookQA-4262 | python, beginner, parsing, csv
Full text: On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse pains
On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse pains
The following is multiple choice question (with options) to answer.
Which two letters are most associated with painful, red flesh? | [
"O and A",
"Q and P",
"U and V",
"F and J"
] | C | sunlight contains ultraviolet light |
OpenBookQA | OpenBookQA-4263 | newtonian-mechanics, forces, newtonian-gravity, planets
Well, the second bullet point says that the mass plays a role. You are much less massive than the Moon. So that factor is not in your favour. But you are much closer. That factor is in your favour. Which factor counts most is found by calculating the actual force with the formula for gravitational force, Newton's law of gravity:
$$F=G\frac{m_1m_2}{r^2}$$
We can try to plug in numbers and see if you or the Moon experiences largest force. The gravitational constant is $G=6.67\times 10^{-11}\;\mathrm{N\;m^2/kg^2}$ and Earth's mass $m_1=5.97\times 10^{24}\;\mathrm{kg}$. The Moon's mass is $m_{2,\text{Moon}}=7.35\times 10^{22}\;\mathrm{kg}$ and it is $r_{\text{Moon}}=384\;400\;\mathrm{km}$ from Earth (average distance from centre to centre) and your mass around $m_{2,\text{you}}=70\;\mathrm{kg}$ and your distance is $r_{\text{you}}=6400\;\mathrm{km}$ (from centre to you; Earth's radius):
$$F_{\text{between Earth and you}}=G\frac{m_1\;m_{2,\text{you}}}{r^2}=681\;\mathrm N\\
F_{\text{between Earth and Moon}}=G\frac{m_1\;m_{2,\text{Moon}}}{r^2}=1.98\times 10^{20}\;\mathrm N$$
We see here that the Moon is being pulled in very much more than we are being pulled in. So you are indeed right that the very large masses here have the biggest influence.
The earth should literally stick to the moon even more strongly than it will stick to me.
The following is multiple choice question (with options) to answer.
What has more mass than the moon? | [
"your home planet",
"Skylab",
"the Atlantic ocean",
"pluto"
] | A | the earth has more mass than the moon |
OpenBookQA | OpenBookQA-4264 | everyday-chemistry, thermodynamics, surface-chemistry
Why did the cardboard start to curl up as it began to burn?
Why did it retain its texture if not shape and size? The curling up has a simple reason: the burning was not uniform. Paper contains water (really!), and heating it makes it lose the water.
Now, paper is a bad conductor of heat. When you burn it, inevitably the flame will be mainly on one side(the side that's pointing up). The flame will transfer heat to nearby regions of paper, and evaporate some (or possibly all) of the water. The loss of water leads to a contraction of the cellulose fibers in the paper (I'm not too sure of this, comments appreciated). But, this only happens on one side of the paper. Even though paper is razor-thin, the fact that it still has two "faces" is important here. Now, due to the contraction, the paper curls in that direction (similar to how a bimetallic strip works). That's it.
The reason for retaining texture, is something I'm not too sure about. The burning reaction throws up a lot of soot, but a lot of the products stay right where they are. This results in the charred/burnt paper occupying the previous position of the cellulose. While charred paper isn't a polymer and thus isn't too strong, it can "mimic" the initial structure just by occupying the position of the cellulose. But, unlike cellulose, if we try bending it, it will crumble since there are no long polymer "chains"/intermolecular forces holding it together. It's like the difference between a house of cards and a similar "house", made of a single piece of rubber. The structure is the same, but the former case is only staying together because it had the "luck" to exist in a stable configuration. Disturbing it will destroy it.
The following is multiple choice question (with options) to answer.
If you place a piece of paper on a hot object it will leave a | [
"damp spot",
"a curl",
"some ice",
"a singe mark"
] | D | if an object is hot then the surfaces of that object are hot |
OpenBookQA | OpenBookQA-4265 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is true? | [
"hot coffee will stay hot forever",
"hot coffee is cold",
"hot coffee can injure due to its temperature",
"hot coffee prevents getting hot enough to burn"
] | C | if an object is hot then the surfaces of that object are hot |
OpenBookQA | OpenBookQA-4266 | zoology
Title: What is the reason for cats not liking water? I have two cats myself, a Siberian and a Maine Coon, neither of which like water. In fact, they detest it - like most cats. I was wondering what the reason for this was and if any of you have any interesting theories as to why this is the case.
Thanks in advance! First, some cats do like water. But it seems true (from personal observation and most people's opinion) that most cats don't.
The question has already been asked many times online. Just Google your question!
I doubt one will find peer-reviewed papers on the question but below is a summary of what seem to be the most often mentioned possible reasons I could find. Of course, these bullet points are very hypothetical and I don't know of any research presenting evidence for or against these hypotheses.
Their fur is not really adapted for the water and will very quickly become waterlogged and heavy making it uncomfortable.
Cats are generally speaking quite skittish
Cats may not like the odour of chemicals we put in the water.
Cats love to groom themselves. It is an aweful lot of work to do the grooming after a bath.
Note also that domestic cats are descendent from cats living in very arid areas. The most closely related species with cats are the African Wildcat living in Northern Africa, the Near East and around the periphery of the Arabian Peninsula.
Source
My non-peer reviewed sources are
http://www.petful.com/behaviors/why-do-cats-hate-water/
http://www.animalplanet.com/pets/healthy-pets/do-cats-really-hate-water/
http://www.petguide.com/blog/cat/why-do-cats-hate-water/
The following is multiple choice question (with options) to answer.
A cat's body temperature would be highest if immersed in | [
"apple juice",
"lava",
"liquid nitrogen",
"water"
] | B | an island is formed by lava cooling on the ocean floor over time |
OpenBookQA | OpenBookQA-4267 | respiration
Here is what happens at the molecular level.
The $\rm CN^-$ ions diffuse into the mitochondria. They have high affinity to the ferrous ion of the mitochondrial enzyme cytochrome c oxidase involved in the electron transport chain (ETC), one of the phases of cellular respiration where $\rm ATP$ is generated from $\rm NADH$ and $\rm FADH_2$. And it is this process that actually requires oxygen. The inhibited cytochrome c oxidase is of no good in transporting electrons, thus no $\rm ATP$ molecules are generated. The oxygen molecules waiting for those electrons remain empty handed resulting in the increase in the concentration of molecular oxygen. Remember, ETC occurs in almost all living cells except a few like RBC which get their major share of ATP from the highly inefficient anaerobic glycolysis. Also, $\rm ATP$ is the energy currency of our body and is required in a wide variety of bodily processes like osmotic balance, nerve impulse transmission, muscle contraction etc. With no $\rm ATP$ your heart and respiratory muscles can't contract, your medulla can't regulate breathing, your kidneys can't concentrate urine and the list goes on. Death is imminent if a high concentration of cyanide gets into your blood.
The symptoms of panic like tachypnea and tachycardia (that result due to low oxygen in blood) are not usually seen unless the victim himself knows he is poisoned. The end effects like cardiac and respiratory arrest, seizures and coma, however, are similar to those of suffocation.
For further read:
The Mechanism of Cyanide Intoxication and its Antagonism
The following is multiple choice question (with options) to answer.
Heat exposure at higher temperatures without ability to regulate internal body temperatures will result in the expiration of which of these? | [
"ace of spades",
"bored ghosts",
"large bridge",
"gila monster"
] | D | if an organism becomes too hot then that organism may die |
OpenBookQA | OpenBookQA-4268 | 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're stranded on a desert for a week without clothes, you're likely to | [
"evaporate",
"find a forest",
"freeze",
"perish"
] | D | if an organism becomes too hot then that organism may die |
OpenBookQA | OpenBookQA-4269 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
Bees | [
"make honey from fruit",
"sell their honey to farmers",
"manufacture honey from a sweet liquid found in flowers",
"gather honey from flowers"
] | C | bees convert nectar into honey |
OpenBookQA | OpenBookQA-4270 | aerodynamics
Title: How do eagles fly slowly for a long time? Eagles fly slowly for a long time.
Many other species fly faster and move their wings faster. But eagles keep their wings steady, and move only their tail.
How do they move slowly in the air, without falling down?
Can this eagle flying technique be used in aviation? How does they move slowly in air, without falling down?
One possibility is soaring using a ridge lift - typically a situation when the wind is approx. perpendicular to a mountain ridge. The air is lifted at the front side of the ridge and an eagle can soar in the lifting air stream. This can also work without the wind,
Which is a situation of thermal flying. Typically, the ground is heated by the Sun, the air layer just above the ground is heated by conduction and at some moment it forms a kind of bubble that starts to rise. This bubble is usually long, resembling a column and lasts until the warm air is depleted. The situation can repeat (this behavior is called an interval). If a ridge is oriented south, then the Sun can create a thermal wind (intervals) that enables a bird to soar.
Can we use eagle's flying technic for flights? Yes, however, man will never be that good.
soaring: https://www.youtube.com/watch?v=63qJn9HrB7E
thermal flight: https://www.youtube.com/watch?v=KXqTCM0-zXQ
Edit: Just for completness - there exists also a wave soaring, that is reachable for gliders and maybe for hangliders, probably not possible for birds and paragliders - see pictures here : http://www.ssa.org/GliderLiftSources
The following is multiple choice question (with options) to answer.
Where might you find a live, breathing eagle? | [
"the moon",
"in a thimble",
"the woods",
"a programming language"
] | C | some birds live in forests |
OpenBookQA | OpenBookQA-4271 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is true? | [
"one might happen upon a wild dinosaur in its home",
"one might happen upon a wild shark in a forest",
"one might happen upon a wild eagle in a van",
"one might happen upon a wild osprey in a forest"
] | D | some birds live in forests |
OpenBookQA | OpenBookQA-4272 | geology, mineralogy, minerals, weathering
To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.
My suggestion to use the term weathering or weathered.
The following is multiple choice question (with options) to answer.
mechanical weathering is breaking down what by mechanical means? | [
"hills",
"trees",
"knolls",
"boulders"
] | D | mechanical weathering is when rocks are broken down by mechanical means |
OpenBookQA | OpenBookQA-4273 | geology, fossil-fuel, petroleum
For some transport applications, the energy density is still a winning attribute of hydrocarbons: most notably, powered flight for freight and travel.
We already have two routes to non-fossil hydrocarbons: biological sources, and direct chemical synthesis. Each involves capturing atmospheric CO2, and combining with water, to generate a blend of hydrocarbons.
Now, we already have means of creating hydrocarbons suitable for flight (e.g. Jet-A and Jet-A1 fuels). And there are already demonstration plants that have closed-loop generation of synthetic hydrocarbons, for use in electricity-grid-balancing, by using surplus electricity to synthesise methane, which is then burnt in gas turbines when required. Similarly, Tony Marmont's team have been synthesising petrol (gasoline) from air, water, and electricity.
However, none of those things mean that hydrocarbons necessarily have much of a future, beyond plastics production. Because hydrocarbon-powered aviation has a lot of environmental problems beyond just CO2 emissions, in particular it makes other contributions to exacerbating global warming. And there are lots of options for energy storage within the electricity supply chain.
The following is multiple choice question (with options) to answer.
Avoiding fossil fuel usage is an example of what? | [
"keeping natural",
"destroying",
"eliminating",
"burning"
] | A | An example of conservation is not using fossil fuel |
OpenBookQA | OpenBookQA-4274 | graphs, np-complete, reductions
Title: Resource Reservation: No Greedy Approach? I'm considering the general resource reservation problem: n processes, m resources. Each process requests a set of resources and each resource can be used by exactly one process. Processes are only active if they have all requested resources.
Instance: A set of processes P, a set of resources R, the set of resource requests for each process, and an int k.
Question: Is it possible to allocate resources so that at least k processes are active at the same time?
My initial inclination was that a greedy approach makes sense here. Sort the jobs in increasing order of number of resources requested, then allocate resources to processes until all resources are allocated or all processes have been attempted to be scheduled, as below:
procedure reserve_resources(P, R, k):
int jobs_active = 0;
Order processes in ascending order of number of resources requested;
for each process:
if (all of the processes' requested resources are available):
allocate resources to that process;
jobs_active++;
end if;
end for;
if (jobs_active >= k):
return "YES";
else:
return "NO";
end if;
end procedure;
The following is multiple choice question (with options) to answer.
Which would be conserving resources? | [
"buying a new truck",
"buying a new SUV",
"eating only steaks and caviar",
"abstaining from riding a motorcycle"
] | D | An example of conservation is not using fossil fuel |
OpenBookQA | OpenBookQA-4275 | classical-mechanics
the other car hits you and starts compressing your car's crumple zone.
the collision force exceeds your braking force and your car starts accelerating. Your car's crumple zone is still being compressed.
the crumple zone is fully compressed so both cars are now moving at the same speed and your brakes are slowing both cars.
During phase 1 your car is stationary so you feel no force. If the collision is low speed the other car may come to rest before your car starts to skid, and you feel no force at all.
However all but the most trivial collisions are likely to apply more force than your brakes can resist, and you enter phase 2. To calculate the force you feel in phase 2 is quite involved as you'd have to know the force distance curve for compression of the crumple zone. I did Google to see if I could find this data, but without success. Anyhow, it should be obvious that the force during phase two will be less than you'd feel if the brakes weren't on.
Phase three is interesting because it's where you get the whiplash. Assuming your headrest is properly adjusted your head won't move much in phase two. However when you enter phase three your own brakes will jerk you forward. To reduce this (and as above assuming there are no 18 wheelers around) you should release the brakes.
So for low speed collisions you should leave the brakes off, but for high speed collisions hit the brakes during the collision and release them as soon as the two cars have stopped moving relative to each other.
Having said all this, the collision you describe happened to me a few years ago (I'm sure it's hapened to lots of us) and I hit the brakes and held them on. I'm happy to report I suffered no harm, though my car was a write-off. I would advise my children to always hit the brakes and leave them on. Risking whiplash is better than being pushed across the junction or into the back of the car in front of you.
The following is multiple choice question (with options) to answer.
At first glance the car seamed very small but just before it hits a person it will appear | [
"out of nowhere",
"to be large",
"on top",
"and disappear"
] | B | if an object is close then that object will appear large |
OpenBookQA | OpenBookQA-4276 | zoology
Title: Are penguins plantigrade or digigrade? I'm trying to rig a 3D model of a penguin, but I don't know where to put the bones near the ankle because I can't tell if they're digigrade or plantigrade. Nearly all birds are digigrade, but penguins spend a lot of time walking and don't generally grasp or run with their talons. Plantigrade.
The penguins are highly specialized for their flightless aquatic
existence. The feet are located much farther back than those of other
birds, with the result that the bird carries itself mostly upright;
its walk can thus be described as plantigrade (i.e., on the soles).
The sole comprises the whole foot instead of just the toes, as in
other birds. The most notable characteristic of the group is the
transformation of the forelimb into a paddle. This is accompanied by a
body morphology particularly adapted to movement in a liquid medium.
The thoracic (rib) cage is well developed, and the sternum bears a
pronounced keel for the attachment of the pectoral muscles, which move
the flippers. The flipper has the same skeletal base as the wing of
flying birds but with its elements shortened and flattened, producing
a relatively rigid limb covered with very short feathers—an ideal
organ for rapid propulsion. The body plumage likewise consists of very
short feathers, which minimize friction and turbulence. The density of
the plumage and the layer of air that it retains provide almost
complete insulation of the body.
https://www.britannica.com/animal/penguin#ref3467
The following is multiple choice question (with options) to answer.
A place where penguins exist with pods of black and white mammals is | [
"full of sand",
"painted with cream",
"uninhabitable by iguanas",
"warm and windy"
] | C | the arctic environment is covered in snow |
OpenBookQA | OpenBookQA-4277 | zoology, pathology, herpetology
Title: How do pet gecko lizards pose a health risk? Does having gecko lizards living in your house pose any health risk? If you're referring to keeping geckos as pets, like all reptiles, amphibians and birds, they come with a small but finite risk of contracting salmonellosis. Having said this, the infection is easy to avoid if you maintain basic hygiene.
On a personal note, I know dozens (perhaps hundreds) of people who keep or have kept reptiles as pets and have yet to meet anyone who contracted salmonellosis. Basically, if you wash your hands after touching the gecko, keep it away from food preparation areas and don't put the lizard in your mouth, you should be fine.
If you're talking about geckos living free in your home, as is common in many tropical places, I have never heard of any health risks associated with them. If anything, I would think that the geckos would reduce health risks by eating insects such as cockroaches and mosquitoes that are prominent disease carriers.
The following is multiple choice question (with options) to answer.
Aside from plants, lizards also eat bugs for | [
"singing",
"crying",
"nothing",
"sustenance"
] | D | lizards eat insects |
OpenBookQA | OpenBookQA-4278 | organic-chemistry, synthesis, plastics, fuel
Title: Can plastic be used as fuel for vehicles? I don't have much of a background in chemistry, but I know that plastics are largely made of carbon, as is oil. Is there any way to "covert", i.e. a plastic water bottle, into a substance that can be used as fuel for ? Thanks. There are many ways to recycle different types of plastic, and conversion to liquid fuels suitable for internal combustion engines is currently done on an industrial scale. The key to converting the carbon contained in long-chain polymers that make up the plastics is called pyrolysis, which is essentially a way to thermally decompose these products into shorter chain hydrocarbons suitable for use as liquid (or even gaseous or solid) fuel. According to this Wikipedia article:
Anhydrous pyrolysis can also be used to produce liquid fuel similar to diesel from plastic waste, with a higher cetane value and lower sulfur content than traditional diesel.
An example of a current commercial waste-plastic-to-fuel operation is the Canadian corportion Plastic2Oil, Inc., who claims to "convert waste plastic to ultra clean oil" in their 250,000 gallon fuel production and blending facility.
The following is an excerpt from the description of the patent-pending process used by Plastic2Oil:
The following is multiple choice question (with options) to answer.
An example of creating an alternative fuel is turning what material into fuel? | [
"sand",
"mineral",
"vegetation",
"rocks"
] | C | An example of creating an alternative fuel is turning plant material into fuel |
OpenBookQA | OpenBookQA-4279 | There is a concept of $$C\setminus B = \{x\in C$$ but where $$x \not \in B\}$$. As we know that $$x\not \in B$$ that if $$x\in C$$ then we must have $$x\in C\setminus B$$. But $$C\setminus B$$ certainly doesn't have to be empty!
So that doesn't follow at all!
But now we have proven both $$x ∈ C$$ and $$x \not \in C$$.so we have reached a contradiction. Therefore $$x ∈ B$$.
Except we haven't proven $$x \not \in C$$. We have reached no contradiction. And $$x$$ need not be in $$B$$. $$x\in C$$ so $$x$$ could be in $$C \cap B$$ or $$x$$ could be in $$C\setminus B$$. But we have no way of telling.
The following is multiple choice question (with options) to answer.
Which of the following is true? | [
"sunlight works best in caves",
"fear can fuel motorcycles",
"corn can fuel public transit",
"rice can never be used as fuel"
] | C | An example of creating an alternative fuel is turning plant material into fuel |
OpenBookQA | OpenBookQA-4280 | hygiene, food-chemistry
Dishes and utensils are only susceptible to bacterial growth if there's traces of food on them. Washing is meant to remove traces of food and oil so bacteria can't multiple on them. The conditions must be right for bacteria to multiple. If traces of food were to be completely dry and hardened on a dish and someone ate off it, the likelihood of any bacteria present on it is close to nil. They need moisture to grow. If dishes had no oily food on them, washing and rinsing with very warm water would be sufficient. I've seen people from other cultures wash dishes with traces of food that are soluble in water. They come out perfectly clean. (As an aside, using a tea towel can often spread bacteria when they're not used properly.) Towels top kitchen contamination hazards list
Bacteria can't multiple in oil. For example, ordinary cooking oil doesn't need to be refrigerated although it can go rancid. A cast iron frying pan is properly meant for frying foods only. No watery sauces should be cooked in them. Even "scraping it clean" shouldn't be done with a sharp metal object as it can remove some of the polymerized hardened oil layer.
I have several cast iron pans that I don't wash. I wipe them out after each use, then I add a little oil nd roughly a teaspoon of salt. With a paper towel, I rub at any bits of stuck on food. If done within a few hours of being used, it effectively removes any food traces, leaving a smooth surface. I usually rinse off the salt in warm water, dry it and then apply a very thin film of oil. I've been cooking in cast iron pans for decades and have never gotten sick or had mild food poisoning (what many people call a 'stomach flu').
Cast iron pans with a layer of proper seasoning and treated like this will definitely not cause sickness. It can't support bacterial growth and as @jeanquilt mentions, the pan gets very hot - enough to blister your skin if you touch them with a bare hand.
The following is multiple choice question (with options) to answer.
Pesticides are used on a lot of crops, so it is best to wash them before consumption in order to avoid | [
"nothing",
"falling ill",
"flying",
"Floating"
] | B | eating food that contains pesticides can have a negative impact on humans |
OpenBookQA | OpenBookQA-4281 | genetics, human-genetics, history
Title: Did the eugenics program in Nazi Germany have a measurable effect? Did the killing or sterilisation of people considered as living a "life unworthy of life" in Nazi Germany have any measurable effect on the "average health" of Germany? Is there any statistical evidence that the rate of (a specific) mental or physical illness is lower in Germany compared to other countries that were not affected by the Nazis (I guess you would need to have data on the rate of that illness from before the eugenics program as well)?
P.S. Please note, I'm neither interested in discussing the ethics of eugenics, nor in condoning what has happened in its name under the Nazis. I just want to know what the result on average health (if there is such a thing) was. As most of the comment have pointed it out, It's nearly impossible to find out. This is my try:
Dr. L Alexander wrote in his paper, Medical Science under Dictatorship:
Hitler issued the first direct order for euthanasia in Germany on
September 1, 1939, as his Panzers moved on the Blitzkrieg of Poland.
Organizations with humanitarian-sounding names were immediately set up
to execute "health" programs, again, under deceptively, euphemistic
terms. For example, questionnaires collected by a "Realm's Work
Committee of Institutions for Cure and Care" gathered and reported
information on patients who had been ill five years or more and who
were unable to work. "On the basis of name, race, marital status,
nationality, next of kin, whether regularly visited and by whom, who
bore financial responsibility, and so forth," decisions were made at
key universities about which patients should be killed by
psychiatrists who had themselves never seen the patients.Likewise, the
"Realm's Committee for Scientific Approach to Severe Illness Due to Heredity and Constitution" was exclusively devoted to the killing of
children with congenital anomalies or chronic illnesses. In all,
275,000 people were put to death in these killing centers before the
Nazi Holocaust.
Law for the Prevention of Offspring with Hereditary Diseases (July 14, 1933)
The following is multiple choice question (with options) to answer.
Who would be healthier? | [
"a workaholic",
"a heavy sleeper",
"an party animal",
"a night owl"
] | B | rest has a positive impact on a health |
OpenBookQA | OpenBookQA-4282 | human-biology, nutrition
Title: Do we know a complete list of nutrients that humans must ingest to live? When the people who are making "nutritionally complete" foods like Soylent are developing their product, how do they know that they've covered all their bases? You need to have protein, carbohydrates, fats etc., but what about vitamins or minerals?
Has science produced a commonly accepted list of all the nutrients that humans need to live? For babies there is certainly a formula available for a complete menu for survival: formula*
Here are the nutrition facts from Nestlé's "Good Start":
Formula nutrition facts. source: Nestlé
Comparable lists are available for people that cannot eat normally (e.g. people in a comatose state) and are fed enteral or parenteral nutrition.
*. Remember though, breast is best :)
The following is multiple choice question (with options) to answer.
Which habit is healthiest for humans? | [
"adequate sleep",
"only eating candy",
"extreme alcohol consumption",
"parachute-free sky-diving"
] | A | rest has a positive impact on a health |
OpenBookQA | OpenBookQA-4283 | optimization, distributed-systems, encryption
However, that is not enough to solve the ultimate problem you want to solve. It sounds like what you ultimately want is a fair exchange protocol. Sadly, such protocols typically aren't super-realistic, if you want them to be "all-digital" and avoid any trusted parties; if Alice and Bob know each other and have some kind of relationship, you're probably better off signing a contract. But if you want to read about the topic, you can start with https://crypto.stackexchange.com/q/8333/351 and https://crypto.stackexchange.com/q/8352/351 and continue reading from there.
The following is multiple choice question (with options) to answer.
Which can be used to pass information from one person to another? | [
"an invention by Marconi",
"an invention by Newton",
"an invention by McCormick",
"an invention by Pasteur"
] | A | a radio is used for communication |
OpenBookQA | OpenBookQA-4284 | energy, electromagnetic-radiation, radio
And why is it that one can pick up the radio frequency over the radio's own self-induced frequency?
I think you mean how is a radio able to transmit and receive at the same time. That's a complicated question but most simple radios can't. They're either transmitting or receiving and they must stop one to do the other. One somewhat easy way to transmit and receive at the same time is to use different frequencies for send and receive.
More over, how do you insert information into a wave?
The simplest way to put information in a wave is to use "amplitude modulation" (AM). Another simple way is with "frequency modulation" (FM). There is a huge branch of math and physics behind the more complicated methods.
The following is multiple choice question (with options) to answer.
A radio is used for what? | [
"people contact",
"heat",
"mail",
"food"
] | A | a radio is used for communication |
OpenBookQA | OpenBookQA-4285 | fluid-dynamics, pressure, acoustics, water
Consequently, the thermodynamic activities ($a_i\equiv e^{\mu_i/RT}$) of component $i$ in the dissolved and gaseous states are also equal.
(For that matter, the activities of the liquid and its vapor above are equal as well. Furthermore, the activity of pure condensed matter is simply 1; put another way, we take this state as the reference state. This lets us relate the equilibrium vapor pressure to the enthalpy of vaporization, which shows up in the chemical potential $\mu$. In this way, all materials can be modeled as having a vapor-pressure temperature dependence of $e^{-1/T}$.)
Finally, the activity of a gas can often be approximated by its partial pressure (as mediated by the fugacity), and the activity of a solute can often be approximated by its concentration (as mediated by the activity coefficient). From all these assumptions and idealizations, we obtain Henry's Law. But more generally, the broader framework (starting from entropy maximization and proceeding through the relevant thermodynamic potential, e.g., the Gibbs free energy) advantageously would let one derive a more general law that also incorporates, say, gas nonideality, or gravity, or solute interaction, or surface area, or an applied electric or magnetic field, etc.
The following is multiple choice question (with options) to answer.
The state of a gas vaporized from a surface liquid under increased pressure and higher temperatures is | [
"part of how nature replenishes, purifies and recirculates water",
"a stage when water molecules are prevented from escaping into the atmosphere",
"a stage when moisture leaves the atmosphere without being recirculated",
"a stage that only occurs once"
] | A | evaporation is a stage in the water cycle process |
OpenBookQA | OpenBookQA-4286 | 3. Jun 16, 2009
### HallsofIvy
Writing "M" for male and "F" for female, there are 25= 32 ways to write 5 letters, each being either an "M" or an "F". Of those 32, exactly one is all "M"s and exactly one is all "F"s.
Knowing that there is at least one female drops "MMMMM" leaving 31 possibilities. "FFFFF" is one of those: probability 1/31.
If we write the dogs in order of age, then knowing that the oldest dog is female means that we are looking at lists of 5 letters, from "M" or "F", with the first letter being "F". Obviously in all possible lists of 5 "M"s or "F"s, exactly half, 16 start with "F" and half with "M" so knowing that "the oldest dog is a female" throws out half the possible lists, leaving 16. one of those is "FFFFF" so the probability of "all females" is now 1/16.
There is no "dilemma" here. "The oldest dog is female" gives you more information than "at least one of the dogs is female".
4. Jun 16, 2009
### fleem
First breeder:
Since its given that there is at least one female, the question, "what is the probability that all five are female when one is female" means the same thing as the question, "What is the probability that the remaining four are female". The probability that the remaining four are female is 1/16, and thus the probability that all five are female (given that one is female) is 1/16.
Second breeder:
The temptation here is to assume there might have been intelligent pre-selection of dogs in the group, by the store owner. However the OP makes it pretty clear, I think, that there was no such pre-selection, and that these are ALL the dogs from a given litter. So the sex of a randomly selected dog does NOT change the probability of the sex of another dog in the litter. Each is a separate coin toss. So the fact that the oldest is female works the same as "there is at least one female". So like with the first breeder case, the probability of the remaining four all being female is 1/16.
5. Jun 16, 2009
The following is multiple choice question (with options) to answer.
You are likely to find the fewest amount of animals in | [
"the Pacific Ocean",
"the Amazon rainforest",
"the African Savanna",
"the Arctic"
] | D | cold environments contain few organisms |
OpenBookQA | OpenBookQA-4287 | entomology, reptile
Title: Had there been a non-flying pterosaur? Since there are non-flying birds and secondary non-flying insects, it is reasonable to assume there were also non-flying pterosaurs. Well, according to this source there are no flightless bats, so it isn't an absolute that all flying clades have flightless members:
https://pterosaurheresies.wordpress.com/2011/07/21/meet-the-first-flightless-pterosaur-sos-2428/
Everyone knows about the various flightless birds: the penguin, the dodo, the ostrich… the list goes on. There are no flightless bats. And no one has ever discovered a flightless pterosaur… until now.
But the short answer to your question is: no confirmed flightless pterosaur fossil seems to have been discovered so far.
The longer answer is: from what I can tell no pterosaur has been found that was clearly flightless, but pterosaur flight isn't well-understood in the first place so there is debate as to how and whether some specimens could have flown. It seems to be the consensus so far that they did fly however (based on the lack of mention of flightlessness on the Wikipedia page, and the last paper I link to in this answer is fairly convincing).
As far as not finding flightless specimen, the above link claims to have found one but the source is not reputable and I found no confirmation of it elsewhere (Wikipedia confirms, and I'm usually all about Wikipedia but here the page has all the hallmarks of having been written by the same person who wrote the blog). The same author argues a large pterosaur is flightless here, but their arguments are quite poor compared to others made in the field and they seem again to be the only ones making them.
Here is a post from Tetrapod Zoology in 2008 imagining what a flightless pterosaur might be like, and also claiming none have been found:
The following is multiple choice question (with options) to answer.
There are zero amphibians on | [
"Mexico",
"Icebergs",
"England",
"Texas"
] | B | cold environments contain few organisms |
OpenBookQA | OpenBookQA-4288 | climate-change, climate
In this case, as it is an area that it is almost constantly cloudy with high humidity, temperature is varying just a little bit, and except the first day of the period, it seems that there is no relationship. In fact, on the second day there was a storm (I am living now at Singapore) and it is reflected in a quick change in temperature (both) and solar radiation.
Conclusion: It is not as simple as it seems.
Hope it helps!
The following is multiple choice question (with options) to answer.
During the rainy season in a city, the amount of sunlight in the city will | [
"stay the same",
"decrease",
"expand",
"increase"
] | B | as the amount of rain increases in an environment , available sunlight will decrease in that environment |
OpenBookQA | OpenBookQA-4289 | species-identification, zoology, entomology
Title: Species identification; clusters of big plump red bugs in Taipei I saw these red insects in Taipei near XinBeitou MRT station in the last week of April 2017, around lunch time. They were fairly active and would keep checking each other out with their antennae for a moment and then move on to the next. What struck me was the wide range of sizes and development in the groups. I didn't notice any feeding or mating that I could recognize, just a lot of walking around and checking each other out.
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
I've also included a screenshot from google maps so you can see the location and the trees growing in these concrete structures.
The body of the largest individual is probably 2.5 centimeters long. I'm fairly certain these true bugs belong to the species Leptocoris vicinus, and carry the nickname of "soapberry bugs", which is specific to the subfamily Serinethinae. They're quite common in urban areas of Southeast Asia, which coincides nicely with where you encountered them.
Also, you had mentioned,
There are plenty of birds around (this is quite a green area) but I didn't notice any interest by birds in eating them.
Soapberry bugs, as well as many other types of insects, are able to freely congregate in large numbers, and in such exposed places, due to their bright coloration. Having such a bright color may indicate to some predators that the prey in consideration is toxic, a phenomenon referred to as aposematism.
source
source
And then, here's a map of their distribution, with Taipei holding marker #37. (source)
An interactive version of this map can be found here.
The following is multiple choice question (with options) to answer.
An insect may pose as bird poop to | [
"make social commentary",
"film fetish smut",
"blend with surroundings",
"attract birds"
] | C | An example of camouflage is when something has the same color as its environment |
OpenBookQA | OpenBookQA-4290 | evolution, vision, neurophysiology
Mid-reds with mid-greens
Blue-greens with grey and mid-pinks
Bright greens with yellows
Pale pinks with light grey
Mid-reds with mid-brown
Light blues with lilac
There are reports on the benefits of being red-green color blind under certain specific conditions. For example, Morgan et al. (1992) report that the identification of a target area with a different texture or orientation pattern was performed better by dichromats when the surfaces were painted with irrelevant colors. In other words, when color is simply a distractor and confuses the subject to focus on the task (i.e., texture or orientation discrimination), the lack of red-green color vision can actually be beneficial. This in turn could be interpreted as dichromatic vision being beneficial over trichromatic vision to detect color-camouflaged objects.
Reports on improved foraging of dichromats under low-lighting are debated, but cannot be excluded. The better camouflage-breaking performance of dichromats is, however, an established phenomenon (Cain et al., 2010).
During the Second World War it was suggested that color-deficient observers could often penetrate camouflage that deceived the normal observer. The idea has been a recurrent one, both with respect to military camouflage and with respect to the camouflage of the natural world (reviewed in Morgan et al. (1992)
Outlines, rather than colors, are responsible for pattern recognition. In the military, colorblind snipers and spotters are highly valued for these reasons (source: De Paul University). If you sit back far from your screen, look at the normal full-color picture on the left and compare it to the dichromatic picture on the right; the picture on the right appears at higher contrast in trichromats, but dichromats may not see any difference between the two:
Left: full-color image, right: dichromatic image. source: De Paul University
However, I think the dichromat trait is simply not selected against strongly and this would explain its existence more easily than finding reasons it would be selected for (Morgan et al., 1992).
References
- Cain et al., Biol Lett (2010); 6, 3–38
- Morgan et al., Proc R Soc B (1992); 248: 291-5
The following is multiple choice question (with options) to answer.
An example of camouflage could be | [
"Cleaning make up off my face",
"Going naked outside on a rainy day",
"A sting ray covering itself in sand",
"Baking a cake for a birthday"
] | C | An example of camouflage is when something has the same color as its environment |
OpenBookQA | OpenBookQA-4291 | 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.
An example of a house hold item that could be an insulator could be | [
"Diamonds",
"Silver",
"Gold",
"Tupperware"
] | D | down feathers are a thermal energy insulator |
OpenBookQA | OpenBookQA-4292 | palaeontology, herpetology
Title: How big can cold-blooded animals get? It seems impossible to have reptiles the size of dinosaurs, just because they are really big! Did they have different systems of maintaining body temperature or maybe they weren't the exact type of animals that we today call reptiles? Answer is quite simple as from @Alan Boyd link. They are cold blooded and thus, can go out for hunt in cold, they need to stay put till they get some prey.
So, it mainly depend on the temperature of the outside, I found this interesting paper on relation of body sizes and latitude.
Body sizes of poikilotherm vertebrates at different latitudes
Maximum sizes of 12,503 species of poikilotherm vertebrates were
analyzed for latitudinal trends, using published data from 75 faunal
studies. A general trend appears which may be summarized by the rule
"among fish and amphibian faunas the proportion of species with large
adult size tends to increase from the equator towards the poles". The
rule holds for freshwater fish, deepsea fish, anurans, urodeles, and
marine neritic fish arranged roughly in order of decreasing clarity of
the trend). In general the rule applies not only within these groups
of families but also within single families. In reptile groups, the
rule holds weakly among snakes and not at all among lizards or
non-marine turtles. Possible explanations include an association
between small size and greater specialization in the tropics; the
possibility in poikilo-therms of heat conservation or of some other
physiological process related to surface/volume ratio; selection for
larger size in regions subject to winter food shortages; and an
association between large adult size and high reproductive potential
in cold regions. Other suggestions can be advanced, but all are
conjectural and few are subject to test. Global size - latitude trends
should be looked for in other living groups.
Cite: Lindsey, C. C., 1966: Body sizes of poikilotherm vertebrates at
different latitudes. Evolution: 456-465
Now lets compare some of the largest cold blooded Animals:
Reptiles
Amphibians
Fishes (Pisces)
The following is multiple choice question (with options) to answer.
The temperature of a monitor lizard will increase if it | [
"goes into a hole underground",
"hides under a tree",
"swims in a fountain",
"leaves a rainy forest for a sunny desert"
] | D | as temperature in the environment increases , the body temperature of a reptile in that environment will increase |
OpenBookQA | OpenBookQA-4293 | biochemistry, neuroscience, neurophysiology, vision, eyes
*Personally, I find it hard to grasp just how large the difference in Illuminance (and hence photon numbers) is for example between day and night. See here for a comparison. As you can see, our visual system has to deal with an enormous dynamical range of illuminance. The fact that we usually don't even think about these differences in light intensities in everday live is testament to how fantastic our visual system is in dynamically adapting to the huge differences in input.
The following is multiple choice question (with options) to answer.
A person may find themselves shading their eyes in the evening if they are driving | [
"from north to east",
"from west to east",
"from west to south",
"from east to west"
] | D | the sun sets in the west |
OpenBookQA | OpenBookQA-4294 | adaptation
Title: How do longleaf pine trees adapt to the florida keys rainforest? I know that longleaf pine trees can be found in rainforests, but I can't find anything. This is sort of a too broad question but here are a few ideas. The second most fragile part of plants are the leaves. In the latitudes and elevations that experience freezing, plants have learned to abscise their leaves and go dormant for the winter season. Conifers have thick, waxy, very thin leaves that most conifers do not need to shed.
In a rainforest there is no danger of too cold temperatures. That is why there is an abundance of broadleaf trees and plants in the rainforest. Most of our indoor plants are tropical rainforest species.
There is also an awful lot of rain in a rainforest. There is a problem with leaves covered with water, as it inhibits the absorption of CO2. Beneath the leaf, O2 is released as a by-product of photosynthesis. Broad leafed plants that have adapted to an environment with lots of rain, little wind, and being crowded together have leaves designed to 'wick' the rain water off the leaf to run down the midrib and off the pointy tip or lobed or curled under leaf margins. This clears off the water and allows the plant to take up CO2, or it would not be able to do photosynthesis to make its own food for energy.
The other cool thing I can remember, is that broad leafs of plants are able to 'adjust' to the light. Similar to a 'solar sail' in outer space. If in full sun, those leaves get thick and stay smaller. If in shade, very normal in a rainforest, those leaves can thin and get larger in order to capture as much light as possible.
A better wording for your question would be, 'why is there an abundance of broad leaf species versus conifers in a rainforest'? If I've been able to translate your question correctly?
Hope this helps.
The following is multiple choice question (with options) to answer.
every four seasons a cedar expands it's | [
"lung capacity",
"sight",
"vocal range",
"outer covering"
] | D | the number of rings in a tree trunk can be used to estimate the age of the tree |
OpenBookQA | OpenBookQA-4295 | experimental-chemistry, safety
Title: What components of safety should be included in a chemistry laboratory experiment conclusion?
The focus of my question here is this: In a laboratory there is a Bunsen burner, a hot plate, hydrochloric acid, and concentrated ammonia. What would you mention about safety precautions?
As students of chemistry and science, we often need to write detailed conclusions about our laboratory experiments. This eventually becomes second-nature, but to have an an idea of which of the safety measures taken to include are often useful to ensure ourselves that we have not left anything out.
I believe that the following are some of the the most important components of any well written conclusion in a lab entry, something that your lab instructor will read and grade you on.
Purpose: Explain the goal and purpose of the experiment in a clear and concise manner.
Findings: Presents a reasonable interpretation of, and logical explanation for all findings pertaining to the problem and stated purpose.
Discussion: Discusses possible sources of error in detail, including their effect on the results and ways of avoiding them in the future.
Referencing experimental findings and explaining the known/expected results we were looking for. Mentioning and discussing reasons for trends, if any.
In particular my instructors last year were often interested in:
Safety: This is often what I always got marked down for. I would explain that hydrochloric acid is a caustic substance and should be treated with care to not get on your tissue by wearing clothing that does not expose skin and closed toe shoes, and to always carry out the experiment with safety goggles securely fastened. It never seems to be enough for them, even if I mention eye flush and chemical shower in case of emergencies. Should I mention to not snort or freebase it? /end sarcasm
The following is multiple choice question (with options) to answer.
Which can happen during an experiment that might be dangerous? | [
"lemon juice splashing",
"students speaking",
"backpacks opening",
"ice melting"
] | A | chemical splashing sometimes occurs during experiments |
OpenBookQA | OpenBookQA-4296 | fluid-statics
Title: Is this watering with gravity concept possible with physics?
I was thinking of putting together a auto watering scheme for my plants. Main objective is to just have one place to fill water, and it will disperse to several cups equally. I might have the physics wrong but i remember some force which creates suction with gravity and keeps the containers equally filled. I tried to draw the idea, and i'm wondering if anyone have any feedback on if this is possible?
The idea here is that the gravity will bring the water from the top container which stands taller, and then fills the small containers with water. The sketch is of a high reservoir, with multiple level-controlled smaller tanks.
So, it implies that the (lower level) tanks are equipped with a valve that
shuts off the water when a target level is reached: it's just like the
shutoff mechanism in the tank of a toilet. There's a float, which operates
the valve. It doesnt equalize gallons per day, though, just level-in-a-tank.
So, you can definitely find items at a hardware store to build such a system.
If, on the other hand, you want to partition a water source to multiple
destinations based on delivered water volume being equal, the usual
approach is to use a timed valve to a pressurized manifold, and use
matched emitters (i.e. drip irrigation controlled-flow drip fittings).
The physical principle of these emitters is the Bernoulli effect, they
are fabricated so that too-fast water flow in the valve pulls the
aperture shut (this sounds hard, but it isn't). Over a range
of water pressure, the drip rate stays nearly constant. They usually
require pump pressure (or water-utility pressure) though, would clog
if you just used a few feet of gravity-driven flow.
The following is multiple choice question (with options) to answer.
Which is likely to have a means to transport water from the dirt to the rest of its body? | [
"the cows that humans eat",
"the crickets that owls eat",
"the roses a panda eats",
"the chicken that cats eat"
] | C | a plant stem is the vehicle for transporting water and food from roots to the rest of the plant |
OpenBookQA | OpenBookQA-4297 | homework-and-exercises, newtonian-mechanics, friction, rotational-kinematics
But, yes, to hit the nail one last time : There is a discrete behavior shift of the frictional force in the problem. If $\mu < \mu_c$, the frictional force is given by $(3)$ and if $\mu > \mu_c$, the frictional force is given by $(1)$.
The following is multiple choice question (with options) to answer.
A thing which makes shifts to different forms may be gaining the ability to do so due to | [
"ear changes",
"understanding chemistry",
"temperature changes",
"growing teeth"
] | C | heat can change the state of matter |
OpenBookQA | OpenBookQA-4298 | organic-chemistry, everyday-chemistry, rheology
And why does milk chocolate (tend to) melt faster than dark chocolate (higher-cocoa content)?
I don't know. If I were to hazard a guess, I would say it's because milk chocolate tends to contain more sugar than dark chocolate, and so you're seeing some form of freezing-point depression. However, if it turns out that, at similar concentrations of sugar, milk chocolate still melts more quickly, I'd have no idea.
The following is multiple choice question (with options) to answer.
A chocolate rabbit melts away from | [
"an icy pond",
"a freezer",
"snow",
"a curling iron"
] | D | heat can change the state of matter |
OpenBookQA | OpenBookQA-4299 | meteorology, atmosphere, geophysics, climate, geography
Finally, I have to note that I've interpreted "calmest" as the minimum mean wind speed. However, it would be sensible also to consider it as the place with the lowest maximum wind speed or some other metric, that would perhaps change the picture described above. And maybe using that metric one of the Antarctic domes could be the "calmest" place. But I won't extend the answer further with any possible interpretation for "calmest".
The following is multiple choice question (with options) to answer.
Where would a polar bear be happiest? | [
"wherever an igloo could be built",
"in a pile of fake snow in the desert",
"in the same country where kangaroos live in the wild",
"in a heated house"
] | A | polar bears live in cold environments |
OpenBookQA | OpenBookQA-4300 | thermodynamics, climate-science
Title: Where does all the heat go during winter? I do not understand where actually the heat in our surroundings go during the winter season. Is it radiated out into space? I know it cannot coz global warming would not be a issue then. It might get absorbed but where? I tried figuring it myself but couldn't please help.
Where does all the heat go during winter?
There is less energy coming from the sun in the form of electromagnetic radiation impinging on the land during winter.
Depending on the latitude, in regions where there is winter , the difference is large.
The closer to the equator the smaller the effect of "winter".
So it is not where the energy goes, but why it does not fall , and this is explained to first order by the inclination and the distance to the sun during the orbit of the earth.
In general , a body in space radiates energy away the rate depending on various conditions, like green house gases, cloud cover, convection , albedo ...the numbers change . It is the continuous radiation from the sun that keeps replenishing the energy so that the earth does not freeze. During winter at high lattitutes , less energy comes and cold settles.
The following is multiple choice question (with options) to answer.
Polar bears live in cold what? | [
"tropics",
"planets",
"locales",
"homes"
] | C | polar bears live in cold environments |
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