source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-901 | biochemistry
Title: Bradford Reagent Disposal I am a graduate student volunteering in a professor's lab being tasked with finding out how to dispose of certain hazardous materials. I have encountered a problem with disposing of Bradford's Reagent. I have checked online, but am running into problems due to the methanol component of this compound. Can someone help me with the proper disposal procedure? Thank you in advance. I would strongly suggest to ask someone in your lab about this, they will have a better idea about the different waste disposal methods you have available.
In general you would dispose anything that contains organic solvents like methanol in a waste container for generic solvent waste. You should have something like that somewhere in the lab.
One thing you always have to keep in mind is to never put anything still reactive into your waste container. A popular example would be a strong oxidizing agent, putting that into a solvent waste container is dangerous and could e.g. ignite the waste. This is not an issue in this case, but you should always keep that in mind.
Another aspect is the pH of the waste, in many cases the waste disposal facility will only accept reasonably neutral waste, so you should neutralize your waste before putting it into a container. Neutralizing it inside the container can be much more annoying. This might not be necessary if you have a dedicated acidic waste, you'll have to ask someone in your lab about that. The Bradford reagent is strongly acidic, so you'll have to pay attention to this aspect.
The following is multiple choice question (with options) to answer.
A landfill | [
"may cause an increase in loose detritus in the area",
"may lead to cleaner air",
"may lead to increase in property value",
"may lead to a nicer community"
] | A | landfills have a negative impact on the communities |
OpenBookQA | OpenBookQA-902 | agriculture
The primary cereals for making bread are wheat and rye, while barley and oats may be mixed in. Historically significant portions of the rural population of Europe were sustained by cereal-based food in the form of gruel and porridge rather than by bread, especially prior to the introduction of the potato. Barley can be consumed in the form of pearl barley and groats and oats in the form of oatmeal. Especially in cool and humid climates not very suitable for cultivating wheat and rye, oats were once commonly cultivated and consumed. When Samuel Johnson wrote his dictionary, he famously defined oats as: "A grain which in England is generally given to horses, but in Scotland supports the people." A major historical and modern use of barley has been as malted barley, the main ingredient in beer brewing.
In the case of Finland it is interesting to note how late the transition from slash-and-burn agriculture to the use of permanent fields occurred. According to Teija Alenius, Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish − Karelian inland area, Ph.D. thesis, University of Helsinki, 2007 (online)
The following is multiple choice question (with options) to answer.
The cultivation of a range of crop types in a specific order has a positive impact on | [
"soil quality",
"water quality",
"air quality",
"atmospheric conditions"
] | A | crop rotation has a positive impact on soil quality |
OpenBookQA | OpenBookQA-903 | 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 drives right past the gas station because it's motor is | [
"gas",
"diesel",
"coal",
"electric"
] | D | an electric car contains an electric motor |
OpenBookQA | OpenBookQA-904 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
What does a squirrel not eat? | [
"plants",
"seeds",
"fruits",
"animals"
] | D | squirrels eat edible plants |
OpenBookQA | OpenBookQA-905 | death
Title: What would cause crows to be attracted to a human body? On another SE site, there was a comment that told me something about biology that I already know:
"A man left murdered in the fields would soon have a flock of crows mobbing his fragrant corpse."
But I don't quite understand why. Is it the "death" part,the fact that someone was injured/bleeding or just the fact the he was immobilized,that would attract the crows?
That is suppose you tied up someone and left him on the field. Would that attract the crows?
Suppose this person fell down, was bleeding, and immobile, but not seriously injured? Or is it the death part? I think the key is "his fragrant corpse." When an animal dies and begins to rot, a number of quite smelly chemicals are given off, including putrescine and cadaverine. Crows and other carrion birds like vultures are probably very sensitive to these compounds, rather like sharks are to the smell of blood.
The following is multiple choice question (with options) to answer.
When you come across an animal that passed away, it sometimes smells awful because it died recently and has begun to what? | [
"whimper",
"Rot",
"die",
"cook"
] | B | dead organisms rot |
OpenBookQA | OpenBookQA-906 | magnetism
Diamagnetic materials have no free electronic spin in the system, therefore they do not interact with magnetic field as a first approximation. There is a very small repulsive interaction coming from the polarisation of paired spins, but it is very small compared to any other interactions. Most organic compounds are in this category.
Paramagnetic materials have free electronic spins, which can flip / rotate. When put the sample in magnetic field, this field polarises the spins which turns into an attractive interaction. This is analogous with the electric field induced dipole moments, but this is a magnetic interaction, not an electronic interaction. The alignment of spins are constantly changing, as simple thermal excitation can rotate them. Therefore paramagnetic materials has no permanent magnetic moments like magnets. Typical examples are molecular oxygen, transition metal complexes, etc.
In ferromagnetic materials the free electronic spins are having a strong interaction with each other, and aligned parallel in strict order. This alignment is so stable that the magnetic moment of spins adds up, and there can be a macroscopical magnetic field around the sample (i.e. it is a magnet).
When you see the attraction between paramagnetic and magnetic materials, you see the polarisation of the paramagnetic materials in the magnetic field of ferromagnetic materials, which is an attractive itneraction.
The following is multiple choice question (with options) to answer.
Magnetism | [
"requires full contact between objects",
"requires objects to touch",
"can act only on contact",
"can act without contact between objects"
] | D | magnetism does not require contact between objects to act |
OpenBookQA | OpenBookQA-907 | materials
The image is a modified version of an image found at www.geology.um.maine.edu. Original credit: Passchier and Trouw, pg 33 (2005).
The following is multiple choice question (with options) to answer.
A resource from nature are | [
"Styrofoam plates",
"briny waves",
"window pane",
"nylon pantyhose"
] | B | nature is the source of natural resources |
OpenBookQA | OpenBookQA-908 | 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.
Droughts can cause | [
"parched grass",
"lush lawns",
"overflowing ponds",
"blooming flowers"
] | A | drought means available water decreases in an environment |
OpenBookQA | OpenBookQA-909 | electrical-engineering, refrigeration
Title: Relative inefficiency of doorless fridges at supermarkets It appears to be a waste of electricity to keep a bank of refrigerators wide open with no doors or covers whatsoever on them.
They seem to be just blowing cold air out into the supermarket.
They are not turned off at night when the store closes. Even the "green" Whole Foods-type places do this.
But is it really that inefficient to operate them that way?
What is the relative efficiency between a refrigerator with a door and one without a door in a supermarket? The doorless models (this was the photo in the question when I answered it) aren't as inefficient as they appear to be.
Whenever someone opens a regular fridge door, its cold air pours out onto the floor and warm air replaces it inside the fridge. If the doors are opened frequently, or held open for significant time, there is a lot of waste.
On the other hand, the doorless models are designed to have a laminar flow of cold air from top to bottom. Most of the cold air emitted at the top is sucked back in at the bottom, with far less mixing with the surrounding warm air than one might think.
So for products where temperature control isn't critical, and where many people are likely to take the product or to spend a long time looking and deciding, the doorless models are a good choice.
(They're also good from a marketing perspective, as they provide an excellent view of the product and don't have doors that fog up, but that's not the question.)
The following is multiple choice question (with options) to answer.
A refrigerator | [
"requires an electrical outlet to work",
"requires an ice maker to work",
"requires AA batteries to work",
"requires a crisper to work"
] | A | electric devices require electrical energy to function |
OpenBookQA | OpenBookQA-910 | climate-change, sea-level, glaciology, ice-sheets, antarctica
Title: Where does the biggest land-based ice cap reside? I'm thinking biggest in volume, regarding which area of the planet will contribute more to a raising in sea level - were the ice in those regions to melt.
I can basically think of two candidates, namely Greenland and Antarctica. So maybe some comparison between the contributions of the two would be great. Antarctica is the ice sheet (cap) that will contribute most IF it would melt completely. The 2013 IPCC report (Ch. 4, the Cryosphere) provides an estimate of 58.3 m of sea level equivalent (sle). Greenland would if completely wasted away provide 7.36 m sle. Remaining glaciers provide an additional 0.41 m sle. The likelihood of Antarctica completely wasting away seems unlikely with our current understanding although the so-called West Antarctic Ice sheet (closes to the Antarctic Penninsula is sitting with its base deep below the current sea level) is far more likely to be lost than the East Antarctic Ice Sheet. Hence the contribution from Antarctica is likely less than the maximum number. Greenland on the other hand is thought to have a "point of no return" beyond which it will irreversibly be lost given the current or warmer climate. Since Greenland is mostly land-based, much of the mass loss will be by surface melting while West-Antarctica can lose much of its mass by ice berg calving which is likely a much faster loss mechanism. Estimates on the scenarios are emerging but there are still uncertainties and there may also be feedbacks that we either do not fully understand or have not yet seen that can change these scenarios (particularly for West-Antarctica). This Science article
published online May 12 2014 is a good example of emerging research on the stability issues of West Antarctica.
The following is multiple choice question (with options) to answer.
where do arctic animals reside? | [
"arctic fire",
"tropical jungles",
"chilly habitats",
"sahara habitats"
] | C | arctic animals live in an arctic environment |
OpenBookQA | OpenBookQA-911 | botany, plant-anatomy
Title: Why does spraying water on plants help them survive in case of frost? I've heard that spraying water on plants will help them survive the frost. Why is that?
Some say that you should do it in the morning right before the sun rises, and others spray water the whole time of low temperatures.
What is the explanation for why this spraying techniques works? The question has already been asked in Physics.
According to the information there and here the sprinkling must continue throughout the period when temperatures are below freezing, and is only effective for temperatures down to around -5 °C.
Explanations invoke three interrelated effects: when water freezes heat is released so there is a warming effect; the temperature of an ice-water mixture is 0 °C; and an ice layer will insulate the leaf. As long as the temperature of the leaf stays above freezing there will be no frost damage.
The following is multiple choice question (with options) to answer.
When a plant is watered, spraying water on leaves is less useful than | [
"spritzing the stem of the plant",
"putting the plant in the rain",
"using a sprinkler system",
"pouring water on soil"
] | D | roots are a vehicle for absorbing water and nutrients from soil into the plant |
OpenBookQA | OpenBookQA-912 | species-identification, zoology, marine-biology, ichthyology, bone
Title: Identification of a strange skull My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it? Looks like this is a neurocranium of a tuna or a similar species (dorsal view on this site).
I've also found a very similar picture of Atlantic blue tuna from USA, which seems to support that this is indeed a neurocranium.(source of the picture).
Thank you all for your help!
The following is multiple choice question (with options) to answer.
A pet with flippers is sometimes kept in a | [
"folding metal crate with door",
"cushioned pad with round opening",
"bean-shaped container with fake tree",
"cage with wheel and tubes"
] | C | flippers are used for moving in water |
OpenBookQA | OpenBookQA-913 | thermodynamics, water
Use case/origin of this question
I was getting water from the break room and I have the option of either hot or cold water... So if I had to pick, and not mix, which I do, then ... that's how I started wondering about this. :) For the original case, I would expect the warmer one to reach equilibrium quicker.
This for two (probably quite small in practice) reasons. First, the warmer one will evaporate more of it's water than the cooler one. It may not be a significant amount of evaporation; but any evaporating would reduce the amount of mass to be cooled. Depending on how you set up the scenario, getting the water to 10 degrees hotter would cause evaporation before you even start the timers.
The second reason is due to thermal convection. Heat rises, so when you have water warmer than the surroundings, this would cause more airflow upwards from the container, compared to cool water where the air would be more prone to stagnate on top, reducing the convection; thus reducing the heat transfer.
Increasing surface area of the water will only make these two effects more pronounced for the warm water, by increasing the surface area for evaporation and convection.
Increasing the ambient to 80 degrees shouldn't really change this.
The rate of change will not be completely constant. For starters, as both approach equilibrium, the heating and cooling will slow down. Also, the rate may be affected by stagnation in the water itself. The cooler bucket may decrease it's heat transfer rate as a layer of warmed water begins to develop on top. This would greatly reduce the heat transfer rate on top, only getting worse as that layer gets closer to equilibrium. This doesn't happen with the warmer bucket, because the cooler room cools the water surface, and that water sinks below the warmer water, leading to natural convection.
The only way I can think of that you might get different results is if you kept the water in a sealed container, and kept it closed with an insulated lid, while having the sides of it conductive. I'm not even sure if that would work though, it would just eliminate evaporation and reduce the effects of stagnant convection.
The following is multiple choice question (with options) to answer.
Water evaporates less | [
"on a hot street",
"in a basement",
"on a sunny day",
"next to a window"
] | B | the sun causes water to evaporate more quickly by adding heat |
OpenBookQA | OpenBookQA-914 | zoology, ornithology, ethology, behaviour
Title: Crow branch pecking behaviour I was walking through a small park when two crows started cawing at me, and followed me, flying from tree-to-tree as I walked. I speculate that this is a territorial or protective behaviour, but what I found different was the crows were violently pecking the branches nearby them. I have no memories coming to mind of seeing this behaviour beforehand. I speculate that this behaviour could be threat displays, but a quick search on Google did not reveal to me any authoritative studies on this phenomenon. I'd appreciate more information and sources.
This question has been added as a casual observation on iNaturalist. This is a good question. This type of behavior -- pecking at a branch, wiping the side of the beak on a branch, pulling off twigs and dropping them, or knocking off pieces of bark -- is quite common among many corvid species, particularly when they are interrupted by something or someone that they might consider a threat. This includes not only potential predators but also potentially hostile conspecifics.
It is typically considered to be a form of displacement behavior. The concept of displacement behavior, from classical ethology, posits that when an animal experiences two conflicting drives to do two different things, it doesn't know which to do and does a third thing instead to dissipate the drive or anxiety. For branch-pecking in crows, see E.g Kilham and Waltermire 1990 Ch. 12.
Referece: Kilham, L., & Waltermire, J. (1990). The American crow and the common raven. Texas A&M University Press.
The following is multiple choice question (with options) to answer.
The condor screamed in pain as its wing was singed by the | [
"ice",
"water",
"electricity",
"campfire"
] | D | fire causes harm to living things |
OpenBookQA | OpenBookQA-915 | thermodynamics, water
To answer the question directly, there are a few industrial situations where water is given enough heat to instantly evaporate if. For the case of hot oil systems in industry, a furnace heats up the oil to 450 deg F (maybe hotter), and sends the oil to process equipment for the purpose of boiling the process in a heat exchanger. Very infrequently (approximately 5 year cycles), the hot oil system is shut down for maintenance, and water is used to hydroblast equipment in order to clean it. This means that water collects in low points in the associated piping. After maintenance is complete, the proper start-up procedure calls for slowly heating the oil, checking all low points in the piping for water, and draining all water before the hot oil gets above the boiling point of water. On very rare occasions, there have been cases where a small slug of water was trapped in piping during startup without anyone knowing it. This slug of water was isolated from the hot oil by closed valves, so its temperature was too low to cause boiling. Unfortunately, in the event of a process operator opening those valves (for whatever reason), the trapped slug of water immediately contacts 450 deg F hot oil, causing an extremely rapid evaporation rate, and resulting in an explosion. And yes, this has indeed happened. So the answer is: if the water has access to enough heat, at a high enough temperature, it will indeed instantly vaporize.
The following is multiple choice question (with options) to answer.
The water treatment plant boiled all the water that came to them for what reason? | [
"add oxygen",
"add health benefits",
"to eliminate substances",
"mix the water"
] | C | treating water is used to remove harmful substances before drinking |
OpenBookQA | OpenBookQA-916 | co2, oxygen
Title: Could earth run out of O2? Death in a closed environment due to lack of O2 is actually not that bad:
https://www.youtube.com/watch?v=kUfF2MTnqAw
And as far as I know as we are cutting down our life saving woods and jungles less $O_2$ is being produced and more $CO_2$ is not converted back to $O_2$.
Greenpeace and others tell us how bad this fact is.
But: If it continues like this, is it possible for humanity to extinct itself because we run out of $O_2$ and breath in too much $CO_2$?
Wouldn't it be much nicer than like burning to death if the $O_2$ would disappear? No, that will not happen. There is just too much oxygen in the atmosphere.
Over 20% of our atmosphere is oxygen.
Only about 0.04 % of our atmosphere is CO2, so too much CO2 would kill us much sooner than the lack of oxygen.
If you reduced the oxygen concentration in the atmosphere from 20.8% to 19.8%, you wouldn't even feel the difference. If you reduced it to 15 %, you would still survive it. You could even survive 10 % for short time periods.
However, let's see what would happen if you added CO2 as a replacement for the oxygen you removed: at 1%, you would feel extreme dizziness. At 5% you would lose consciousness and die.
But the real danger in CO2 lies elsewhere. Even an increase from our current 0.040 % to 0.045 % could cause a lot of damage to the climate, and an increase above 0.055 % could be disastrous. Unless you are locked in a small room, the reason why the increase of CO2 and decrease of oxygen will be dangerous won't be because you wouldn't be able to breathe. Changes significantly smaller than those required to make breathing difficult, would be enough to wreck the ecosystem, cause drought, desertification, starvation, and economic collapse.
Also note, that trees are very important for the water cycle, as a habitat for many species, and for preventing soil erosion, but they play an insignificant role in producing oxygen. Most of our oxygen is produced by algae.
The following is multiple choice question (with options) to answer.
the earth's population could face severe depletion if which of these stopped happening? | [
"the running man dance",
"the American Idol show",
"human gene cloning research",
"the food pyramid structure"
] | D | green plants provide food for consumers by performing photosynthesis |
OpenBookQA | OpenBookQA-917 | electricity, electric-circuits, electrons, electric-current, charge
Title: Electrons in an electric circuit , its movement and power delivered Does an electrical appliance convert electrons into its respective work , I mean is electron being consumed by appliance (say bulb ) and then this mass gives us energy.
or the same number of electron , just revolve around the circuit, then from where does power comes from, Electrons have charge and so when there is a potential difference across a circuit, this charge moves through it. In an incandescent light bulb, there is a high resistance, meaning that there are many atoms with which the charges collide, transferring some of their kinetic energy. No electrons are being "consumed" by the light bulb, i.e. the number of electrons in the circuit does not change. The ability of the charges to do work is because of a potential difference, which can be achieved through a number of means, e.g. using voltaic cells or electromagnetic induction.
To gain a better idea of why potential difference moves charges, consider two isolated point charges of opposite charges, one positive and one negative. If you pull the negative charge away from the positive one, you are doing work on it in the form of potential energy, as you are opposing the electric field of the positive charge. If you let go, the negative charge will convert this potential energy into kinetic energy, as it is attracted to the positive test charge. A potential difference across a circuit, albeit simplified, essentially does this – it brings electrons from a higher potential to a lower potential, converting potential energy into the kinetic energy in the process.
The following is multiple choice question (with options) to answer.
What does electrical energy become when a light bulb is turned on? | [
"energy newly derived from radiation",
"energy derived from its motion",
"energy that can be seen and used to see the matter around us",
"solar and wind energy"
] | C | a light bulb converts electrical energy into light energy when it is turned on |
OpenBookQA | OpenBookQA-918 | charge, electric-current, flow
http://amasci.com/miscon/eleca.html#cflow
Energy, however, is not transmitted by one electron moving all the way around the circuit to the load, but rather through waves in the electrons and more importantly, the associated electric field. It's the same way that mechanical energy is transmitted in, say, a pole that is pushed from one end. The pole compresses slightly, and a sound wave thus appears, initially containing all the energy within your "push", and then travels down it, progressively distributing that energy amongst all the atoms within the pole until they are all moving in a single direction (here I imagine the pole pushed in a vacuum, as in interstellar space, with no other forces acting). The same goes with electrons in the circuit - though I should point out the following model is a bit simplistic but is more to convey the point of how the energy is transmitted than to detail the actual behavior of the electrons, which involves quantum mechanics and is subject to many of the same caveats as one sees within in an individual atom or molecule. But in this loose sense, when you throw the switch, now an electromagnetic wave travels down, setting the electrons ahead in motion and thus distributing its energy throughout the circuit. Of course, the core atoms of the metal are relatively fixed despite the electron motion, so the latter will tend to lose that energy to collision with them, unlike the pole where everyone, atoms and electrons together, start going in synchrony, and thus you have to keep supplying energy to them with a power source like a battery or generator which effectively keeps "pushing the pole" and thus keeps energy going into it - now think about a pole that is now not in vacuum but in molasses, and you have to keep pushing it to keep it moving. This pushing on atoms, of course, is how electrical devices can use electrically transmitted energy to do useful tasks.
Electromagnetic waves, and sound waves, thus energy, travel much faster than the electrons and the atoms in both the circuit and pushed pole. Energy is what lights up your light bulbs, and energy is what makes your computer operate. Since energy travels fast, these devices start operating "at the flick of a switch".
The following is multiple choice question (with options) to answer.
Switches can be used to cease electronic energy flow, such as when | [
"a button is pushed and a fan stops spinning",
"a fridge is running loudly",
"a freezer turns off in a power outage",
"a light is turned on"
] | A | a switch is used to stop the flow of current in an electrical circuit |
OpenBookQA | OpenBookQA-919 | species-identification, zoology, entomology
Title: Can you identify this red insect? Location: Lansdowne, Uttarakhand, India
Date: 27 May 2017
Time: 5.33 pm
The insect was found walking upwards on a plastic table. It was about 3-4cm long, as far as I remember; its been a long time since I encountered it.
Spotted near a small shack in the Terai forests. This is a nymph of a shield bug in the Tessaratomidae family, commonly called tassarotimids (or sometimes "giant shield bugs" due to typically being 1.5 - 4.5 cm long).
According to Wikipedia:
They are mostly found in tropical Africa, Asia, and Oceania though a few species can be found in the Neotropics and Australia. There are about 240 species known
Of the subtaxa, only a few genera are even found in India:
Empysarus, Neosalica, and numerous in the subtribe Eusthenaria (e.g., Asiarcha, Aurungabada, Carpona, and Dalcantha). A key (Leston (1955)+)to this group of insects is available for purchase or institutional subscription on Wiley
Specific Taxa:
Similar to a comment under the OP's post suggests, this page appears to suggest that the nymph of a Eusthenarian called Eurostus validus (shown below) appears quite similar to the OP's specimen. However, I cannot find definitive record of E. validus being in India.
Source: Vic wicked on Pinterest
the availability of useful information (keys, reputable websites, etc.) for this group of insects (especially for India and in English) are extremely limited, so I will just leave you here with the understanding that your insect is a tassarotimid nymph that is closely closely related to Eurostus validus, Eusthenes femoralis or some other member of the Eusthenaria.
The following is multiple choice question (with options) to answer.
Crickets live in forests in | [
"Rotting Trees",
"In the desert",
"In the snow",
"The sunlight"
] | A | some crickets live in forests |
OpenBookQA | OpenBookQA-920 | visible-light, atmospheric-science, sun
Title: Why is there less UV light on earth in winter? So I have often read that, at least in e.g. northern Europe, in the colder seasons, there is not enough UV (-B) light arriving from the sun, so many people have not enough vitamin-D from that.
At first I thought it was simply due to the sun "shining" for only a much shorter period of time in winter compared to summer and hence less possible exposure (not to mention that most of the skin area is covered then).
But I just had a thought coming to my mind, thinking about that in the mornings and evenings, we mostly see red light here, the higher end of the visible spectrum not getting through.
I am not familiar with the physics behind that phenomenon, but thought that the higher-end of the spectrum like the invisible UV light may not be getting through here for even longer parts of the day towards and away from high noon, and that in winter, the part of the day where UV gets through is maybe very narrow and that's why it's said not to be enough.
Is that correct? And how exactly does this work physically? The reddening of the sun has to do with Rayleigh scattering as the sun passes through more atmosphere. (see picture). This is in a sense, related to less energy but not the primary cause.
The reason we get less solar energy per square meter is that the angle of the sun in the sky affects how spread out the light is. (see updated picture). Ignoring atmospheric effects, it's the sin of the angle times peak energy. 90 degrees or directly overhead, figuring peak solar energy is 1,369 Watts per square meter (that also varies with distance), but the energy from the sun is mostly governed by the sin of the angle.
45 degrees: 1,369 * sin(45) W/m^2 or 71% of overhead or Zenith. 20 degrees above horizon, 1,369 * sin (20), just 34% of peak solar energy. Winter corresponds with the sun being lower in the sky, sunlight is more spread out. There is measurably less energy hitting the same area when the sun is low in the sky.
Passing through more atmosphere amplifies that somewhat, but the angle of the sun is the primary cause.
The following is multiple choice question (with options) to answer.
What will receive more sunlight? | [
"Elephant Ear Leaves",
"Blades of grass",
"A bat",
"A worm"
] | A | as the size of a leaf increases , the amount of sunlight absorbed by that leaf will increase |
OpenBookQA | OpenBookQA-921 | the-moon, moon-phases
Because the full Moon happens when the Moon and Sun are on opposite sides of the Earth, the Moon is most directly opposite the Sun near the Spring and fall equinox. That makes the Harvest Moon (full moon closest to the fall equinox) and the full Moon closest to the spring equinox, more directly opposite the sun, so they reflect slightly more light to the Earth. This effect basically just makes the Moon a bit rounder than other full moons. If you've ever noticed, mid summer or mid winter, the full moon can appear fatter than it is tall. That's not an illusion, it's due to the 5 degree inclination.
This effect on overall brightness is small, but your eyes might be noticing a rounder moon and seeing it as brighter. It's theoretically possible.
This year's largest moon was in March, so today's full moon is actually smaller than average. Astronomical measurements will always say that the closest full moon is the brightest one because it's larger in the sky and it reflects more total light towards the Earth, but apparent brightness to your eyes might have little to do with it's increasing or decreasing angular diameter and likely has more to do with how clear the night sky is. Our eyes can fool us. It's possible that the smaller moon appears brighter even though it reflects less light because it also scatters less light across the rest of the sky, similar to how a smaller flashlight might appear brighter if you stare into it, compared to a flashlight with a wider opening that gives off more total light.
A clear night is probably the best explanation. I'd pick that over smaller angular diameter or greater roundness. On a clear night, the Full Moon can appear brighter because less light gets scattered around it, making it look bright against a sky that's slightly darker, but you don't notice the sky's variation.
The full moon is also higher in the sky in winter, because it moves mostly opposite the sun. Being higher in the sky mans there's less atmosphere between the Moon and you. Directly overhead should be brighter than at an angle to a person viewing from Earth.
Edit
doing some looking I came across this website. It claims:
The following is multiple choice question (with options) to answer.
a full moon will block which of these | [
"global eclipse",
"lunar eclipse",
"twilight",
"solar eclipse"
] | D | a solar eclipse could only happen during the new moon |
OpenBookQA | OpenBookQA-922 | biochemistry, botany, plant-physiology, photosynthesis
What are typical characteristics of different plants in this regard? I.e., how do common species of plants manage their C consumption before (and after) the development of leaves? There are quite a few questions and thoughts in there, I'll try to cover them all:
First, to correct your initial word equation: During photosynthesis, a plant translates CO2 and water into O2 and carbon compounds using energy from light (photons).
You are correct to assume the C is further used for the growing process; it is used to make sugars which store energy in their bonds. That energy is then released when required to power other reactions, which is how a plant lives and grows. C is also incorporated into all the organic molecules in the plant.
Plants require several things to live: CO2, light, water and minerals. If any of those things is missing for a sustained period, growth will suffer. Most molecules in a plant require some carbon, which comes originally from CO2, and also an assortment of other elements which come from the mineral nutrients in the soil. So the plant is completely reliant on minerals.
Most plants, before a leaf is established or roots develop, grow using energy and nutrients stored in the endosperm and cotyledons of the seed. I whipped up a rough diagram below. Cotyledons are primitive leaves inside the seed. The endosperm is a starchy tissue used only for storage of nutrients and energy. The radicle is the juvenile root. The embryo is the baby plant.
The following is multiple choice question (with options) to answer.
A leaf absorbs sunlight to perform photosynthesis until | [
"a lounge chair obstructs the solar rays",
"solar lights line a path",
"solar panels are placed on the roof",
"solar tea is served in the garden"
] | A | a leaf absorbs sunlight to perform photosynthesis |
OpenBookQA | OpenBookQA-923 | electromagnetism, dielectric
Both effects are very notable for clear glass: some of the light is reflected instead of passing through, and the light that is passing through is refracted. Mind, for a glass pane the refraction doesn't do much, it just changes the direction a bit when the light enters and then back again to original when it leaves. But for materials that aren't so homogeneous, like styrofoam, you'll get not just one reflection and refraction but instead have lots and lots of microscopic surfaces, all aligned in different directions. As a result, even if each microsurface lets most of the light past, it doesn't actually manage to get very far into the material but is “reflected” in a completely scattered manner. And that's basically what's happening for all materials which look white. Most of them are still somewhat transparent, but if the components are sufficiently fine and refractive, it won't get further than a few micrometres.
For materials that look coloured or even black, something else happens in addition: the vibrating electrons actually take away some of the energy of the incoming wave and don't re-transmit it at all with that frequency, but instead “convert” to other forms of energy – usually, either lower-frequency light (fluorescence) or charge-neutral lattice vibrations (which manifest as heat). Explaining how this conversion works without quantum mechanics is problematic, but you can basically picture it as a damped vibration – there is “friction” in the oscillation. Often, this only happens to a significant level in a particular frequency band, due to molecular resonances; that's then how colour comes about, because different light-frequencies are damped to different fractions.
The following is multiple choice question (with options) to answer.
How does refraction affect the look of things | [
"They look black",
"They appear same",
"They just disappear",
"They appear different"
] | D | refraction causes something to look different |
OpenBookQA | OpenBookQA-924 | 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.
Birds feed their babies by | [
"telepathy",
"flying",
"osmosis",
"regurgitation"
] | D | birds sometimes eat berries |
OpenBookQA | OpenBookQA-925 | 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.
When the ground shakes, this will make | [
"the sun shake",
"a roof shake",
"an airplane shake",
"a fish shake"
] | B | an earthquake causes the ground to shake |
OpenBookQA | OpenBookQA-926 | newtonian-mechanics, forces, mass, acceleration
These properties are related by Newton's second law, as stated earlier. However, they seem to have a different status. We can change the mass of an object (by simply removing parts of the object) independently of the other two properties. We can also change the sum of forces on the object independently of the other two (e.g. by adding a new force). However we are unable to change the acceleration vector of the object directly, we would need to change either $\mathbf{F}$ or $m$ to do that.
This difference seems strange to me, because after all the equation treats all of these characteristics the same (we can choose to solve any of them by substituting for the other two). For example, in the model $V=RI$ of a resistor this doesn't happen. We can choose to alter directly any of the three properties of the resistor (the voltage across it, the current flowing through it or its resistance). Why is $\mathbf{a}$ in $\mathbf{F}=m\mathbf{a}$ different?
I know it's pretty common sense to us that we can't change acceleration directly (at least for me it is), but still the mathematical equation wouldn't suggest that. So is there a physical (theoretical) explanation as to why this third property (acceleration) can only be changed indirectly? Why does it seem to have a different status than the other two (in the sense that we humans can't alter it directly, only indirectly)? Your observations are spot on.
I usually write Newton's second law this way: $\vec{a} = \vec{F}/m$. This form makes it clear that the law is a relationship between the dynamic variables force and mass, and the kinematic variable, acceleration. $F$ and $m$ describe the situation, $a$ is the result. Cause and effect, if you will. In fact, that's one reason why it's a law that can't be derived from some other principle. It is based on observation: with $\vec{F}$ and $m$ I always observe $\vec{a}$
The following is multiple choice question (with options) to answer.
Which changes an object's shape and mass? | [
"smashing it",
"tossing it",
"rolling it",
"touching it"
] | A | breaking down an object changes that object 's shape and mass |
OpenBookQA | OpenBookQA-927 | mycology, microscopy, parasitology
Cross sections of leaves (hold between two thin pieces of polystyrene or cork and slice gently with a new single-edge razor blade or craft knife). . These will show the internal structure of the leaves - veins (xylem, phloem), cells etc. You can also use clear nailpolish to paint on the surface of a leaf (try the underside), then peel off and look at under the microscope - this should let you see the pores (called stomata) in detail, they look like pairs of lips usually. The fine tissue skin (not the brown bit, it's a very thin wet translucent bit) of an onion also looks pretty nice. Moss leaves also are fun to look at.
Along with mosses - take some dry moss, let it sit in water for 30 min or so and then squeeze out - you'll hopefully find tardigrades
Edited to add:
With respect to parasites in faeces; this requires a bit of expertise to get good at. There is a lot of matter in faeces and parasites are generally low abundance. Unless you know a host is infected and are willing to mix faeces with water, filter and do a bunch of screening, you might not find any actual parasites, though you might see things that look, to the untrained eye, like parasites but are really just debris. You also run a significant chance of infecting yourself with something, be it parasitic, bacterial or viral.
The following is multiple choice question (with options) to answer.
Plants may use leaves, especially waxy ones, in order to | [
"create a way to grow",
"collect and hold on to dampness",
"store food for themselves",
"water themselves in droughts"
] | B | waxy leaves are used for storing water by some plants |
OpenBookQA | OpenBookQA-928 | pain, death
Title: Normal death experience Consider a natural cause of death (no car accidents etc) -
Is it true that death is generally preceded by suffering? In other words, are we destined to experience the most severe suffering we could not ever imagine, that will ultimately end with death?
If this is true, is it true for all living things? No and no.
I'm not sure what is a "natural cause" in this context, but if it's cardiac arrest caused by age-related dystrophy of the cardiac muscles, then no, there is no suffering, at least not universally: Since age-related dystrophy hits all parts of the body, it's likely preceded by increasing amounts of bed rest, leading to quietly drifting off into the great sleep.
Of course, if you add on other natural causes like age-related diseases or being eaten by predators, the suffering can be great indeed, or not: A tiger will sneak up on you and crush your skull without you ever knowing what happened.
Adding on further causes still, like dehydration or hunger, and the suffering is back.
But is suffering a universal fixture of death? Emphatically no.
As for the "all living things" part of the question, the answer isn't just "no"; it's "that's nonsensical".
By individual count, practically no life is complex enough for suffering to be a relevant concept.
I don't have an exact number for you, because how would I get one, but at a rough estimate, bacteria, algae and archea constitute 100% of all individual life forms by count, and suffering is not a concept that makes sense for them.
If we ignore simple life, even among complex life there is so much variety of capabilities that basically nothing universal exists.
The following is multiple choice question (with options) to answer.
Death | [
"deducts from population total",
"leads to phoenix-like rebirth",
"adds to the population total",
"leads to population growth"
] | A | if an organism dies then the population of that organism will decrease |
OpenBookQA | OpenBookQA-929 | visible-light
Title: How does a flashlight work? How would that be effected in the vacuum of space or on another planet? I was wondering if it was possible to explore the dark side of the moon. I've been trying to figure out a light source so things there can be seen. What we call the "dark side" of the moon is just the side that is not visible from Earth. That side is illuminated by the sun just as often as the side that we can see. But when it is in the light, we don't see it.
As for your other question: conventional flashlights work by sending a current through a light source (incandescent bulb, or these days increasingly LEDs). Either of these will work fine in vacuum.
The following is multiple choice question (with options) to answer.
Flashlights | [
"illuminate ideas and thoughts",
"illuminate answers to questions",
"illuminate pathways in an overgrown forest",
"illuminate bright sunny days"
] | C | a flashlight emits light |
OpenBookQA | OpenBookQA-930 | thermodynamics, energy, earth, thermal-radiation
@Benjohn has given you the correct answer. Here is my take.
The ultimate heat provider of the earth ( except a small percentage of heat from the magma at the center of the earth) is the sun. It pours down at the surface about 1.2 kilowatts of energy per meter square ( which btw is directly used by solar panels). The same energy falls on the surface of the moon whose surface burns up during its daytime and freezes by black body radiation at night.
The earth is fortunate to have a gas atmosphere which mitigates the extremes of the possible temperatures that the ground would reach otherwise. An example of mitigation is what happens at the sea floor. Most of the energy is picked up by the water and the floor is kept at a steady temperature with small changes day and night in the first meters from the surface, depending on the season, radiating away with the black body radiation, but the body of water has such large heat capacity that variations are small.
The gas atmosphere is a more temperamental "blanket", its heat capacity depends on several gases , called green house gases from the bad impression that agricultural green houses work that way ( they do not, they work by inhibiting heat exchange by convection but that is another story, on which there is no controversy).
The main green house gas is water , H2O. It is worth contemplating this figure :
Solar irradiance spectrum above atmosphere and at surface. Extreme UV and X-rays are produced (at left of wavelength range shown) but comprise very small amounts of the Sun's total output power.
We see that H2O has the most absorption spectrum for infrared wavelengths, (which are the wavelengths of heat )and then comes CO2. Green house gases absorb both incoming and reflected from the surface of the earth infrared, and as most of the reflected wavelengths are in the infrared they act as a slowing down of the black body radiation that would finally leave the earth. As a blanket keeps a person warmer green house gases by playing ball with infrared radiation ( the wavelengths where heat is really transferred) keep the surface of the earth into a reasonable temperature for life, lucky us.
The following is multiple choice question (with options) to answer.
The Earth receives heat from: | [
"another nearby planet's sun",
"the star around which it orbits",
"the greenhouse gases in its atmosphere",
"solar eclipses occurring frequently"
] | B | a planet is exposed to the heat of the star around which it revolves |
OpenBookQA | OpenBookQA-931 | homework-and-exercises, newtonian-mechanics, friction, free-body-diagram
$$F_y - m_{min}g - \mu N= 0$$
$$m_{min} = \frac{F_y-\mu N}{g}$$
$$m_{min} = 0.53$$
Which pretty much fit the answer key you have been given. In conclusion, to prevent it from sliding the mass should be between $0.53$ and $2.1$, but the maximum mass to prevent from sliding down is the one you calculated.
The following is multiple choice question (with options) to answer.
The mass of ground sliding down an embankment can be propagated by what? | [
"a storm",
"forest fires",
"global warming",
"trees growing"
] | A | storms can cause a landslide |
OpenBookQA | OpenBookQA-932 | fluid-statics, flow, bernoulli-equation
Title: Flow rate of an open tap If I have an open tap such that there is a continuous stream of water falling through height $h$, is the flow rate the same at every point on $h$? The average flow rate must stay the same all the way down, unless water is piling up somewhere. A possible exception is if the fall is so far that some of the water evaporates on the way down. But all the water has to go somewhere.
If the falling water column has cross-sectional area $A$ and speed $v$, the volume flow rate is $Av$. If the water is in free fall, it will have speed $v=\sqrt{2g(h_0-h)}$, where $h$ is the height of interest and $h_0$ is a height-like parameter that you twiddle to get the flow rate right at the tap. The constant volume flow rate gives $A\propto 1/v$, and you can plot the radius $r\propto \sqrt A$ to get the characteristic wide-at-top trumpet shape of water falling from a slowly-running tap.
The following is multiple choice question (with options) to answer.
A creek flows slowly, and the water runs very gently, yet if a leaf tumbles into it | [
"it will relocate",
"it will melt",
"it will cry",
"it will hold"
] | A | flowing liquid can push objects |
OpenBookQA | OpenBookQA-933 | photosynthesis, botany
Title: Photosynthesis - Light Intensity Say I was conducting an experiment for photosynthesis. If I moved light closer to the plant, what effect would this have on the process of photosynthesis? The rate of photosynthesis varies from plant to plant. Some plants require more light and some require less. If you move light closer to the plant, in most scenarios the rate of photosynthesis is likely to be increased. For some plants a minimal light is enough for their photosynthesis, so for those plants, moving light source closer or further will have less effect.
The following is multiple choice question (with options) to answer.
What tool would be most helpful in aiding indoor plants in photosynthesis | [
"music",
"cover",
"Fertilizer",
"a large window"
] | D | photosynthesis means producers convert from carbon dioxide, water, and solar energy into food for themselves |
OpenBookQA | OpenBookQA-934 | cell-biology, microbiology
Title: Are there any organisms that are made of more than one (~5-12) cell? Prokaryotes and eukaryotes are unicellular, made of one cell. Great. Eukaryotes are unicellular or multicellular. But the typical examples of multicellular eukaryotes we have are made of, often, trillions of cells, like us humans. Ants must still be made of many millions of cells. Are there known eukaryotes with very few cells that make them up? Like, 5, or something? Or maybe a dozen cells making up the whole organism in its fully developed state? There's Trichoplax adhaerens, a Placozoa, made of a few thousand cells. Then there is Dicyema japonicum, a simple mesozoan, made up of 9 to 41 cells. Arguably, the simplest multicellular organism is the algae Tetrabaena socialis, whose body consists of 4 cells. Then, there's the parasitic Myxozoa which have 7 cells.
The following is multiple choice question (with options) to answer.
That which is alive is made of cells such as | [
"rocks",
"dirt",
"water",
"grapes"
] | D | a living thing is made of cells |
OpenBookQA | OpenBookQA-935 | [13]:
nutrients = pd.DataFrame(
index=[
"Vitamin A",
"Vitamin B1",
"Vitamin C",
"Calcium",
"Iron",
"Phosphorus",
"Potassium",
"Total fat",
"Carbohydrates",
"Proteins",
]
)
nutrients["DRI"] = [800, 1.1, 80, 800, 14, 700, 2000, 70, 260, 50]
nutrients["Chicken Breast"] = [0, 0.1, 0, 4, 0.40, 210, 370, 0.8, 0, 23.3]
nutrients["Milk"] = [37, 0.04, 1, 119, 0.1, 93, 150, 3.6, 4.9, 3.3]
nutrients["Pasta"] = [0, 0, 0, 22, 1.4, 189, 192, 1.4, 79.1, 10.9]
nutrients["Beans"] = [3, 0.4, 3, 135, 8, 450, 1445, 2, 47.5, 23.6]
nutrients["Oranges"] = [71, 0.06, 50, 49, 0.2, 22, 200, 0.2, 7.8, 0.7]
nutrients
[13]:
DRI Chicken Breast Milk Pasta Beans Oranges
Vitamin A 800.0 0.0 37.00 0.0 3.0 71.00
Vitamin B1 1.1 0.1 0.04 0.0 0.4 0.06
Vitamin C 80.0 0.0 1.00 0.0 3.0 50.00
Calcium 800.0 4.0 119.00 22.0 135.0 49.00
Iron 14.0 0.4 0.10 1.4 8.0 0.20
Phosphorus 700.0 210.0 93.00 189.0 450.0 22.00
Potassium 2000.0 370.0 150.00 192.0 1445.0 200.00
Total fat 70.0 0.8 3.60 1.4 2.0 0.20
Carbohydrates 260.0 0.0 4.90 79.1 47.5 7.80
Proteins 50.0 23.3 3.30 10.9 23.6 0.70
The following is multiple choice question (with options) to answer.
Nutrients in soil | [
"are used up immediately",
"are unimportant to the food chain",
"are passed on to first to apex predators",
"are passed on to the producer organisms"
] | D | if some nutrients are in the soil then those nutrients are in the food chain |
OpenBookQA | OpenBookQA-936 | #### OlderDan
Homework Helper
ehild said:
Sorry, I overlooked the "square top". Does that shape then look like in the picture? Now I am not sure, either, what "cross section" is.
ehild
That's really not it either. It does not have a flat top. It's more like a cylinder of length 2 and radius 1 that has been cut by a saw with a blade in the shape of half a 2 by 4 ellipse with the long axis of the ellipse parallel to the axis of the cylinder. You have to use a little imagination, but the first figure is an approximation showing only the positive x half of the solid. The corners of the squares are rounded in the figure, as if the cut out shape had the sharp edges sanded round. The actual shape has sharp corners. Draw vertical lines from the rounded corners down the the base to complete the square cross sections. Those extended lines to the base would lie on the circle at the base.
I changed the coordinates so that I could do a better looking plot. The second figure is a pretty fair rendition of the shape of half of the solid. The third shows just about all of it.
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### Physics Forums Values
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The following is multiple choice question (with options) to answer.
You couldn't discover the shape of an object if you had | [
"nose plug",
"tape over mouth",
"ear plugs",
"hands behind back"
] | D | the shape of an object can be discovered through feeling that object |
OpenBookQA | OpenBookQA-937 | isotope
On top of the previous 254, another 34 isotopes have half-lives which have actually been measured in laboratory, but are still large enough (>50 million years) so that a small fraction of the isotope could conceivably have survived since the creation of the Earth 4.6 billion years ago, and may be of interest in geological timescales. There are also isotopes with smaller half-lives, but which are continuously replenished by the decay of heavier atoms or by the action of cosmic rays, so they can still be found on Earth today. In all, about 339 different isotopes can be found naturally on our planet.
However, as many as 3100-3300 different isotopes of the first 118 elements are claimed to have been detected in laboratories, most of them with very small half-lives (seconds or less). Nobody knows for sure how many elements and how many isotopes can exist, though the number is finite.
The following is multiple choice question (with options) to answer.
How many ecosystems does the earth contain? | [
"a scant amount",
"a copious amount",
"a middling amount",
"a negligible amount"
] | B | the Earth contains many ecosystems |
OpenBookQA | OpenBookQA-938 | acoustics
It has a lot of mass, too.
If you were to persuade your elephant to lean on a resonant wall, it would damp the wall to some extent, depending on how hard it squished itself against it. It would be acting like the world's biggest lump of rockwool or neoprene rubber. It wouldn't really be fabulously efficient used in this manner.
If, however, we were to replace the wall with entirely elephant, you would very probably have a really, really good sound insulator. 8ft of varying densities & substrates, a lot of mass & not a lot of cohesion between each component & its resonant frequency. If we were to get a bit 'icky' then its lungs & rib cage would probably be the most resonant part - so let's wedge him into the wall facing the noise, & we can sit quietly in the room his butt protrudes into.
Sonic bliss, if not olfactory ;)
Note: I've not even touched on reflectivity or diffusion - that would turn this into a full novel ;))
After comments
It is remarkably difficult to achieve total sonic separation in a domestic environment. I once built a 'room within a room' as a home recording studio, in a house basement, of course surrounded by earth - lots of mass. I did manage to achieve sufficient reduction that you could no longer hear anyone shouting or singing as loud as they possibly could, from the room above. My bass (guitar) amp, however, still went through it like a knife through butter. It took the extra attenuation of the building [double skin of old Victorian brickwork] & earth itself to fully damp it to below audibility. You couldn't hear it from outdoors unless it was particularly quiet in the street.
The following is multiple choice question (with options) to answer.
What could be put on a wall so that a neighbor stops complaining about your guitar playing at night? | [
"paint",
"wallpaper",
"carpet",
"curtains"
] | C | carpet absorbs sound |
OpenBookQA | OpenBookQA-939 | structural-engineering, stresses, steel
Title: Why is the yield strength of steel assumed to be less for a thicker element?
The above image is part of table 3.1 of Eurocode steel design standard. Looking for example at the first row (steel grade S 235), we see that there are two values for yield strength $f_y$, one for element thickness $t < 40mm$ and another for thickness $t > 40mm$. But why is the yield strength less for the thicker element? I am aware that the yield strength depends on the manufacturing process of the element. For example, in hot rolled steel there are residual stresses due to uneven cooling of the steel element after hot rolling process. But I would assume that thicker elements require less rolling, and therefore less residual stresses. So why do we assume the value to be lower for these elements instead? Am I misunderstanding something? Thank you! There are at least two contributing factors to that:
a) development of grains (the following is mainly an excerpt from this question ) and this
Usually thinner steels exhibit higher yield points (see cold roll sheet catalog page.8) and ultimate tensile strengths (see Steel construction) because, sheets of steel, that come out of rolling processes (especially cold rolling processes), have their grains refined. In most cases what happens is that the grains of the material become more elongated.
The following is multiple choice question (with options) to answer.
Thicker objects have stronger resistance, as evidenced by | [
"thin tires popping sooner than thick ones",
"overweight dogs getting sick",
"thin pieces of wood being useful",
"thin people bruising easily"
] | A | as the thickness of an object increases , the resistance to damage of that object will increase |
OpenBookQA | OpenBookQA-940 | organic-chemistry, molecular-structure, molecules
Title: Complex organic molecules I am studying astronomy and came across the following term in the astrochemistry course called 'complex organic molecules' or also written as COMs. My question is: What is exactly meant with these molecules? Is it just a molecule with more than one carbon atom? tl;dr: two different definitions. Astronomy: multiple carbon atoms in molecule. Chemistry: polymer
Interestingly enough, after reading about COMs here, as well as reading the Wikipedia page and the corresponding arXiv paper, it seems like chemists and astronomers have different definitions of what a complex organic molecule should be!
As far as I knew, in chemistry complex organic molecules were long polymers, such as proteins, which were composed of thousands upon thousands of amino acid units. In the astronomy paper, however, they cite other types of molecules.
$\ce{CH3OH,
CH3CHO, HCOOCH3 and CH3OCH3}$, all cited as "complex" (haha) organic molecules in the paper, would appear to chemists as relatively simple molecules. (I read the paper, because it piqued my interest that something like a protein could be found in space). I then read the Springer article.
The term “complex organic molecules” is used differently in astronomy and chemistry. In astronomy, complex organic molecules are molecules with multiple carbon atoms such as benzene and acetic acid. These molecules have been detected in interstellar space with radio telescopes. In chemistry, “complex organic molecules” refer to polymer-like molecules such as proteins.
The following is multiple choice question (with options) to answer.
Molecules are known for having a | [
"Positive Charge",
"Neutral Charge",
"Friend",
"Negative Charge"
] | B | matter is made of molecules |
OpenBookQA | OpenBookQA-941 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
what kinds of things grow | [
"nutritional things",
"moving things",
"large things",
"breathing things"
] | D | all living things grow |
OpenBookQA | OpenBookQA-942 | magnetic-fields, laboratory-safety
Title: An appropriate way to store neodymium magnets Okay so I've bought a few small neodymium magnets to play around with, they're very powerful and I really like them, but I was wondering what's the actual best way of storing those magnets in a way that doesn't affect their magnetic fields or degrades them in any way.
I'm currently storing them stuck to one another, is it a good practice? Thanks a lot! Before modern rare earth permanent magnets, magnets required a 'keeper', metal bar that would shunt the flux between poles. This would prevent a loss in magnetization that could occur over time for materials like AlNiCo.
But with rare earth magnets like NdFeB keepers are not required. They will hold their strength, even when stacked.
Perhaps the most important thing regarding storage is to keep them stored in a secure place where small children cannot get to them. Swallowing these magnets can lead to pinching and internal bleeding of the gut. That's for small magnets.
For bigger rare earth magnets there is the danger of the magnet accelerating to high velocity, or metal objects around the magnet accelerating. Pinching forces can cut off circulation in fingers and bones can be broken! So these magnets require extreme care in handling to constantly make sure they are outside the range of other ferromagnetic objects. These magnets should be stored by themselves in sturdy, thick walled wooden boxes.
The following is multiple choice question (with options) to answer.
which of these will attract a magnet in a student's pocket? | [
"an old stapler pin",
"a piece of gum",
"all of these",
"a piece of chicken"
] | A | if a magnet is attracted to a metal then that magnet will stick to that metal |
OpenBookQA | OpenBookQA-943 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
The hamster was malnourished because | [
"There was a depletion in the corn supply",
"It went on a hunger strike",
"It was paralyzed in the mouth",
"It was waiting for the key to get the food"
] | A | as the amount of food an animal eats decreases , that organism will become thinner |
OpenBookQA | OpenBookQA-944 | evolution, biochemistry, physiology, speculative, bioinorganic-chemistry
While iron skeletons might seem to be an advantage, they are electrochemically unstable - oxygen and water will tend to oxidize (rust) them quickly and the organism would have to spend a lot of energy keeping it in working form. Electrical conductivity sounds useful, but the nervous system favors exquisite levels of control over bulk current flow, even in cases like electric eels, whose current is produced by gradients from acetylcholine.
What's more, biological materials actually perform as well as or better than metal when they need to. Spider silk has a greater tensile strength than steel (along the direction of the thread). Mollusk shells are models for tank armor - they are remarkably resistant to puncture and breakage. Bone is durable for most purposes and flexible in addition.
The time it would take for metallized structures to evolve biologically are likely too long. By the time the metalized version of an organ or skeleton got started, the bones, shells and fibers we know probably have a big lead and selective advantage.
The following is multiple choice question (with options) to answer.
The skeletal system protects | [
"pancreas",
"toenails",
"eyes",
"hair"
] | A | the skeletal system protects internal organs |
OpenBookQA | OpenBookQA-945 | everyday-chemistry, experimental-chemistry, water, home-experiment, melting-point
Title: What kind of string to use for the ice fishing experiment for kids? Classic ice fishing experiment for kids.
I used nylon because I saw it in a stationery, and apparently that doesn't work because I guess it's too slippery. I tried thread from my mom's sewing kit, but that doesn't work either.
I'm not sure I can find yarn or kite string in the stationery or nearby so please suggest alternatives expected to be found in the average household, supermarket, grocery store or convenience store.
Also how long should we wait? The above video takes only 10 seconds while this video takes about 2 minutes (off screen). What factors influence waiting time? Amount of salt? Type of string? This resource has an explaination of the behavior, which relies on the salt-dissolved water wicking into the string. This would mean that you need a type of string which will absorb water. It's surprising to me that your nylon string doesn't work (as long as it's thick/low-density enough to absorb water, probably unlike fishing line), is it possible it has a hydrophobic coating?
I would recommend any cotton-based string or twine. Cooking twine and sewing thread is often cotton, if you have access to that. I've had no problems with these.
Edit: I just thought, that you might want to try this not in a cup of water first (like in the link above). You might potentially run into not-string-related problems if your water isn't cold enough, or if your ice gets too submerged when you put the salt on it. It's possible your nylon string is fine.
The following is multiple choice question (with options) to answer.
A knife refuses to stick to a blanket due to | [
"luck",
"gravity",
"lack of magnetism",
"tension."
] | C | a magnet attracts magnetic metals through magnetism |
OpenBookQA | OpenBookQA-946 | optics, visible-light
You can probably work that out by yourself. Now consider a spherical container of diameter $1\,\mathrm{km}$. Then the light will always have to travel $1\,\mathrm{km}$ or less before it hits the wall again. In other words, it has to travel (at the highest) $n$ times $1\,\mathrm{km}$ before it has lost 90 percent of its original intensity. Using that the speed of light is approximately $300000\,\mathrm{km/s}$ you should find that it only takes the light about $0.77\,\mathrm{s}$ to do this.
The following is multiple choice question (with options) to answer.
when light hits a reflective object , that light | [
"never reaches it",
"illuminates the backside",
"goes above it",
"redirected from it"
] | D | when light hits a reflective object , that light bounces off that object |
OpenBookQA | OpenBookQA-947 | substance can be converted to other forms of energy by a chemical reaction. The full name of this effect is gravitational potential energy because it relates to the energy which is stored by an object as a result of its vertical position or height. ATOMIC PHYSICS — 10% (such as properties of electrons, Bohr model, energy quantization, atomic structure, atomic spectra, selection rules, black-body radiation, x-rays, atoms in electric and magnetic fields) SPECIAL RELATIVITY — 6%. Here are some practice questions that you can try. Output in Joules (J, kJ, MJ), Watt-hours (Wh, kWh), calories (Cal, kCal) and foot-pounds (ft-lbs). Engineering Physics Resources. 8 m//s^(2)). Can you calculate the energy needed to increase the temperature of 100kg of iron by 40°C? Extension. In physics , energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat , the object. Learn more Accept. KINETIC ENERGY CALCULATOR. 6x10^6 js / 18x10^3 js. If wavelength is measured in centimeters, then Planck's constant is 6. KE = 1/2*m*v^2. Physics Calculator is available here for free use. Energy can be in many forms! Here we look at Potential Energy (PE) and Kinetic Energy (KE). A particle in the lower energy state absorbs a photon and ends up in the upper energy state. This chemical energy in the cyclist is then converted to kinetic energy on the bike pedal due to the cyclist applying a downward force upon the bike pedal. ATOMIC PHYSICS — 10% (such as properties of electrons, Bohr model, energy quantization, atomic structure, atomic spectra, selection rules, black-body radiation, x-rays, atoms in electric and magnetic fields) SPECIAL RELATIVITY — 6%. To +W From -W - Constant force: F x ma x d v v v v axd ax 2 2 2 0 2 2 0 2 Work done by the force = Energy. Exothermic reactions release energy by transferring heat to their surroundings. In older works, power is sometimes called activity. the bungee cord has more potential energy when it is stretched out than when it is slack. , green plants convert solar energy to chemical energy (commonly of
The following is multiple choice question (with options) to answer.
an example of converting potential energy to kinetic energy is | [
"a resting bird",
"a still rock",
"our own sun",
"cars spinning tires"
] | D | potential energy changes to kinetic energy through motion |
OpenBookQA | OpenBookQA-948 | refraction, geometric-optics
=v_x\hat{i}+v_y\hat{j}+v_z\hat{k} \\
=v_x\hat{e}_1+v_y\hat{e}_2+v_z\hat{e}_3
$$
The following is multiple choice question (with options) to answer.
An example of refraction is | [
"The light that comes from the TV",
"The light from a fire",
"Turning the light on",
"Pickles seemingly bigger in the jar"
] | D | refraction is when light bends |
OpenBookQA | OpenBookQA-949 | geology, geomorphology, coastal
Title: What causes such a narrow slit in a cliff? (see photo)
I have this photo as a background image and I often wonder how such a narrow, well-defined slit could be formed. Is it natural or man-made? If natural, what processes could have formed it? The rest of the coastline is rugged but this appears very uniform. It is on the north-west coast of Jersey (UK). If you see the other user (Jan Doggen's) google maps link, you can see apparently similar features in different states - this is a particularly neat example of a general phenomenon.
These notches form when headlands are undercut by caves carved out by the sea. They may be initiated where there is a fault or jointing in the rock (northwest Jersey is granite, according to google).
In this particular case, the notch seems to have a rounded termination. Blowholes also form from undercutting of headlands producing caves whose roofs then collapse. It's possible this cave may have collapsed after a blowhole formed, so you get a notch where the inland end of the feature appears rounded. That bit is just speculation though.
I found this Jersey geology trail guide that might have more detail: http://jerseygeologytrail.net/Geomorph.shtml
The following is multiple choice question (with options) to answer.
In what way are valleys formed? | [
"the passage of water in a straight or winding path moving consistently",
"pools of water filling until a deep lake forms",
"rain water frequently raining down",
"high winds blowing rain and hail"
] | A | a valley is formed by a river flowing |
OpenBookQA | OpenBookQA-950 | optics
Title: What is the focal distance of an optical mouse? I am trying to build an optical sensor for my old school, state property, standard french watt-o-meter. EDF ( Electricité de France ) has a gig which turns a wheel depending on watt consumption. The higher the wattage, the faster a tiny disk turns.
Now the disk can be read by eye, so here is my question: why not use a hacked optical mouse to gather data ?
The contraints are:
can't open the gig
the wheel is 1.5 cm away from a protective glass
I have an optical mouse
The CMOS has a half milimeter opening, and a 2mm lens from the standard casing.
What optical system do I need to read half milimeters from 15 milimeter distance using a classic optical mouse?
Can anybody help me calculate the correct lenses for this, or point me in the right direction? The focal distance of the laser lens and the distance from the target (i.e. table) that an optical mouse will work with are two different things. You ask for the former, but it seems that you want the later.
To answer the question that you asked: Every mouse is different, but you can expect on the range of millimeters. If you can remove the lens from the mouse, then hold it with pliers and move it closer and further from a white sheet of paper under the sun. The height at which the sunlight makes a point on the paper is the focal distance. On a cheap mouse laser lens that I tried, I got about half a centimeter judging by eye.
To answer the question that you meant to ask: Every mouse is different, but you can expect on the range of millimeters to just a few centimeters. My nice modern Microsoft Curve wireless mouse fails to work at more than 2-3 millimeters above the mousepad. My Logitech G500 works a good centimeter above the mousepad, and I remember when optical mice first came out how I could hold the mouse a good 5 cm above the desk and still have it detect the motion.
I recommend trying to get the oldest optical mouse that you can, the sort with the bright red laser. By my own testing, these seem to work furthest from the targeting surface.
The following is multiple choice question (with options) to answer.
It would be unexpected to see a mouse with | [
"eggs",
"ears",
"teeth",
"a tail"
] | A | a mouse gives birth to live young |
OpenBookQA | OpenBookQA-951 | reproduction
Title: Can different kinds of dogs mate? This was inspired by a show in which two different kinds of dogs, who were neighbors, "dated," in order to bring their human neighbors together. This is a theme seen in Disney's "101 Dalmations" or "The Lady and the Tramp."
Can dogs of similar sizes, say Rotweilers or pitbulls actually interbreed? Can any of them mate with say, wolves? And under what circumances?
(I am "encouraged" by the fact that horses and donkeys can produce mules, and lions and tigers can produce "liger" or "tigons." Also of note is that dogs are of the same species as wolves, and "domestic dogs" are actually a subspecies.) Yes, the vast majority of dogs out there are not pure bred. They are therefore a cross between two breeds. Consider cockapoos for example. The offsprings of a Cocker Spaniel and a poodle is called a cockapoo.
The following is multiple choice question (with options) to answer.
A dog that has a very thick tail, that mates with another dog with a thick tail, has a strong likelihood of creating a litter of | [
"calico kittens",
"tailless pups",
"small tailed pups",
"dense tailed pups"
] | D | the thickness of the parts of an organism is an inherited characteristic |
OpenBookQA | OpenBookQA-952 | 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.
The changing of night to day occur | [
"three times a day",
"seven times a week",
"six times a week",
"twenty-nine times a month"
] | B | cycles of day and night occur once per day |
OpenBookQA | OpenBookQA-953 | bacteriology, ph, gut-bacteria
Any one of these is enough to have a bactericidal or bacteriostatic effect! This is also why cells that do live in slightly alkaline or acidic environments have to specialize, and they have narrow windows of pH that they can survive under, because they have to compensate so much to counteract the protonation or lack-thereof in their environments.
The following is multiple choice question (with options) to answer.
Some bacteria are beneficial and some bacteria | [
"cause droughts",
"cause thriving populations",
"cause rosacea",
"cause upset stomach"
] | D | bacteria cause food poisoning |
OpenBookQA | OpenBookQA-954 | Iv found the co-ordinates of Q relative to P at t=0
---->X=(10,10)km
iv also found the velocity of Q relative to P----> V= V[Q] -V[P]
-----.V= (0,40) - V(30,0)
----- V= (-30,40)km/h
4. Originally Posted by dopi
A ship P is travelling due East at 30 km/h and a Ship Q is travelling due South at 40 km/h.
Both ships keep constant speed and course. At t=0 they are each 10 km from the point of intersection of their courses and moving towards the point.
Hello, dopi,
with your problem you use automatically a coordinate system: The pos. x-axis points to East and the pos. y-axis points to North.
At the time t = 0 the ship P is at P(-10, 0) and the ship Q is at Q(0, 10). The movement of both ships is described by a straight line. The speed is described by a vector:
$\overrightarrow{v_P}=(30, 0)$
$\overrightarrow{v_Q}=(0, -40)$
Thus P is moving along the line:
$\overrightarrow{x_P}=(-10, 0)+t*(30, 0)$
and Q is moving along the line:
$\overrightarrow{x_Q}=(0, 10)+t*(0, -40)$
The distance between the ships is: $\vec{d}=\overrightarrow{x_P}-\overrightarrow{x_Q}$
Originally Posted by dopi
Iv found the co-ordinates of Q relative to P at t=0
---->X=(10,10)km
The following is multiple choice question (with options) to answer.
A ship navigates with a magnetic compass because it is | [
"unpredictable",
"waterproof",
"tradition",
"predictable"
] | D | when the needle of a compass lines up with Earth 's magnetic poles , the needle points north |
OpenBookQA | OpenBookQA-955 | thermodynamics, temperature, water, phase-transition, states-of-matter
Boutigny brachte flüssige SO$_2$, welche bei $-10^\circ$C siedet, in einen glühenden Platintiegel, $\ldots$
which in English translation roughly reads
Boutigny brought liquid SO$_2$ [sulphur dioxde], which boils at $-10^\circ$C, into a glowing platinum crucible, $\ldots$
The following is multiple choice question (with options) to answer.
A hot liquid would be | [
"an old cup of coffee",
"a tall glass of milk",
"pasta water bubbling on the stove",
"a warm cup of cocoa"
] | C | if liquid is boiling then that liquid is hot |
OpenBookQA | OpenBookQA-956 | biophysics, theoretical-biology, ecosystem
Systems ecology, especially with regard to energy and nutrient flow.
This type of ecology can be strongly influenced by physics. For one example see the book Theoretical Ecosystem Ecology: Understanding Element Cycles by Ågren & Bosatta (Ågren was originally a physicist)
Physical limitations to growth and transport
This can include for instance mechanical contraints on plant growth (see e.g. the book Plant Physics by Nicklas & Spatz), water transport in trees (see e.g. this BioSE question) or the biomechanics of movement (see e.g. Hudson et al (2012) on the speed and movement of cheetahs or Wikipedia: Biomechanics).
Allometric relationships between organisms, e.g. with regard to metabolism
To explain these types of relationships knowledge in physics is useful. See e.g. Kleiber's law for more.
MAXENT as a general approach to ecological patterns or to model species distributions
This is basically a tool lifted from physics that can be applied to ecological problems. There are many papers to look at, but Harte & Newman (2014) (Harte is another previous physicist) and Elith et al (2010) are two good starting points.
Dynamical modelling of populations and communities
This field use many of the same tools for analysis as physics, e.g. systems of differential equations. One of the pioneers in this field (among many) were Robert May (also started with a PhD in physics), and his classical book Theoretical Ecology: Principles and Applications is still a good starting point.
Energy harnessing and conversion by organisms
This can refer both to how organsims convert prey to energy (e.g. conversion efficiencies) and the physics of photosynthesis (which is an interesting intersection between physics and molecular biology). See Jang et al (2004) and O'Reilly & Olaya-Castro (2013) for examples of the how quantum mechanics can inform us about photosynthesis.
Hopefully this will give you a sense of some different ways that knowledge in physics can be useful for biology.
The following is multiple choice question (with options) to answer.
What is an example that ecosystems are an interconnected world? | [
"animals' numbers decreasing when food decreases",
"animals' numbers increasing when predator numbers increase",
"animals' numbers increasing when plants decrease",
"animals' numbers decreasing when food increases"
] | A | as the supply of food in an environment decreases , the population of animals in that environment will decrease |
OpenBookQA | OpenBookQA-957 | homework-and-exercises, thermodynamics, statistical-mechanics, thermal-radiation, ideal-gas
I think that b and c become pretty easy once you use this formula. Fortunately, we have a vacuum, so we don't have to consider energy absorbed or work done against vacuum.
The following is multiple choice question (with options) to answer.
if a student needed to warm up, which of these would help? | [
"all of these",
"sitting by the fireplace",
"sitting next to a running engine",
"turning up the room heater"
] | A | a warm something is a source of heat |
OpenBookQA | OpenBookQA-958 | temperature, measurements, error-analysis
So, in summary: the absolute temperature of an everyday substance can be measured to 0.1 mK at the very best, in practice more like 1 mK with significant effort. The change in temperature can however be measured with microkelvin resolution, if sufficiently isolated from the outside environment.
The following is multiple choice question (with options) to answer.
What is a thermometer used to measure? | [
"height",
"weight",
"oxygen density",
"warmness"
] | D | a thermometer is used to measure temperature |
OpenBookQA | OpenBookQA-959 | magnetic-fields, earth
Title: Would a compass on its side point at the ground? From a point just north of the equator, A straight line to the Magnetic North would be through the earth. If a compass was turned on it's side, would the north pointing arrow point toward the ground along that straight line? A compass is usually used to find the direction of the horizontal magnetic field of Earth at that point. The needle of a compass is very light and thus its efficiency decreases when the compass is not in the horizontal plane at that point (due to gravity).Therefore, where the compass would point will become unpredictable. But, yes, in ideal conditions, the compass would point along the straight line joining that point to the north pole.
The following is multiple choice question (with options) to answer.
A compass would be useful to | [
"Captain Planet",
"captain of industry",
"sports team captain",
"Navy captain"
] | D | a compass is used to navigate seas |
OpenBookQA | OpenBookQA-960 | algorithms, expert-systems
The simplest implementation strategy is to simply re-evaluate all the rules each time something changes. However, in some cases this might repeat work unnecessarily and there might be more efficient implement the rules.
For instance, if one of your rules is "IF the user has bought more than 1000 items today THEN sound an alarm", then re-evaluating this each time an item is bought might be unnecessarily inefficient. A more efficient approach would be to keep a counter for each user that keeps track of how many items the user has bought today; each time an item is bought, increment the counter and sound an alarm if it is over 1000; and each midnight, reset all counters to zero.
So in some cases optimizations might be possible. However, that is entirely depend on the specific of the rule, and there's not much we can say in general. If you have a question about how to implement a specific rule efficiently, you can ask a new question specifically about that particular rule.
The following is multiple choice question (with options) to answer.
Buying permanent things instead of disposable things is | [
"composting",
"conservation",
"recycling",
"returning"
] | B | An example of conservation is avoiding waste |
OpenBookQA | OpenBookQA-961 | 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.
Removing the tree an owl makes it's home in | [
"demolishes the owl's home",
"means the owl will go with the tree",
"allows the owl to remodel",
"causes the owl to perish"
] | A | if a habitat is removed then that habitat is destroyed |
OpenBookQA | OpenBookQA-962 | newtonian-mechanics
I should add that the above is simply what I, as a physicist with a fairly long experience, suspect is what is going on. It is not something I have read about and I am sure there is somewhere a more thorough discussion. So I hope I am right; I think I have a good argument. As I have described it above, I have in mind mainly the last part of the process where the wood only moves a little relative to the metal. In the earlier part, when the wood moves through a larger distance, it is inertia that is the main consideration, just like in the party trick where you abruptly whisk away a table cloth and the dishes on the table stay where there are. The more abrupt the better.
Added remark
It occurred to me that there is another thing worth mentioning here, that makes this method preferable to resting the axe head on something, or supporting the handle on a work top and hitting the head. It is that by hitting the end of the handle, with the head just hanging, you are going to deliver the force more accurately at the join, because it travels along the handle in exactly the direction you want. If instead you strike the head then there is a danger it will be knocked slightly obliquely, introducing a random tilt with each blow, which is liable to deform the wood and thus loosen the fit.
The following is multiple choice question (with options) to answer.
A thing's position is altered when | [
"the thing adjusts its location",
"the thing is in position",
"thing feels moved emotionally",
"things are considering moving"
] | A | moving changes position |
OpenBookQA | OpenBookQA-963 | friction
as expected.
So the blocks will slide over one another if
$\dfrac {F_1M + F_2m}{M+m} > Fr_{max} = \mu mg$
If $F_2 > F_1$ then a similar calculation gives the same condition.
The following is multiple choice question (with options) to answer.
If a rub two rocks together after awhile they will start to | [
"Get smooth",
"Become butterflies",
"Become art",
"Make a chair"
] | A | contact between rocks over long periods of time causes rocks to smooth |
OpenBookQA | OpenBookQA-964 | optics, visible-light, reflection, refraction
As apparently we are able to see blue and weak, but clear violet stripe in the rainbow, my understanding is wrong. So why don't we get red, yellow, green and blue light in it as well? Why do we see spectrum as if we were using prism, not the "cumulative spectrum"? With the addition of some good diagrams I think I now understand your question.
This diagram does not show a key feature of the reflections.
The intensity of the reflected rays varies and so you do not observe a uniform cone of reflected light.
Here is a gif animation to show you what I mean.
[Individual images were taken from an Atmospheric Optics webpage and combined to produce a gif file.]
Parallel rays are coming in at the top of a water droplet and refracted, reflected and refracted again to emerge from the bottom half of the drop.
What you should note is that for a given range of impact parameters of the incident rays the highest concentration of emergent rays occurs occurs around an angle of $137.5^\circ$, ie that is where the emergent light is brightest and light from around that angle swamps the light from that emerging at other angles.
So you diagram should show a high intensity of red light around a particular direction and and much lower elsewhere.
Here is a ray diagram to illustrate the "bunching" of light rays along a particular direction.
The following is multiple choice question (with options) to answer.
How can we see that refracting sunlight causes light to split into different colors? | [
"shining a light at a mirror",
"letting sunlight hit a broken mirror",
"setting a diamond outside on a bright day",
"shining a flashlight at broken glass on the floor"
] | C | refracting sunlight causes light to split into different colors |
OpenBookQA | OpenBookQA-965 | 51. Trisaba
thanks for the help
52. dan815
|dw:1441062793507:dw|
53. dan815
this is the full break down
54. dan815
they will probably ask u a final question like the chance it will rain, when there is a prediction of rain
55. Trisaba
60%
56. Trisaba
bayes' theorem
57. Trisaba
thanks for helping dan
58. dan815
wait i got 36% lemme see
59. dan815
okay think about it like this out of every 97 days, 5% of those days say it will rain, and it wont rain out of every 3 days, 90% of those days say it will rain, and it will rain! what is the total number of days it will rain to not raining then?
60. Trisaba
61. dan815
0.03*0.9 : 0.05*0.97 this means that (0.03*0.9)/((0.03*0.9)+(0.05*0.97)) = chance it rains when it say it rains
62. Trisaba
60% is what i got
63. dan815
what did u say p(b) was
64. Trisaba
P(B) is .0755
65. Trisaba
look at my sheet posted pic
66. dan815
hard to read, what did u say P(B|A) was then
67. Trisaba
.9
68. Trisaba
$\frac{ 90 }{ 151 }$
69. Trisaba
it rounds to 60%
70. dan815
hmm i am not seeing anything wrong with the way im finding the answer, ill think about this more later but for now for every 100 days 3 days really rain 90% of 3 days is 2.7 so every 2.7 days out of the 3 days it rains, it will predict right now an additional bad predictions of 5% of 97 days is thrown in there 0.05*97=4.85 right preiction and rain = 2.7 total prediction of rainy days = 4.85+2.7 therefore 2.7/(4.85+2.7)= ~36%
71. Trisaba
|dw:1441064489549:dw|
72. Trisaba
The following is multiple choice question (with options) to answer.
What is most likely to occur before a rainstorm? | [
"chlorine gas is released into the atmosphere",
"atmospheric water droplets collide",
"the electromagnetic field of the earth flips",
"rivers and lakes overflow"
] | B | precipitation is when water falls from the sky |
OpenBookQA | OpenBookQA-966 | photosynthesis, botany
Title: Photosynthesis - Light Intensity Say I was conducting an experiment for photosynthesis. If I moved light closer to the plant, what effect would this have on the process of photosynthesis? The rate of photosynthesis varies from plant to plant. Some plants require more light and some require less. If you move light closer to the plant, in most scenarios the rate of photosynthesis is likely to be increased. For some plants a minimal light is enough for their photosynthesis, so for those plants, moving light source closer or further will have less effect.
The following is multiple choice question (with options) to answer.
what can be found where photosynthesis takes place? | [
"some green pigmentation",
"some blue pigment",
"some chlorine pigment",
"some chloride"
] | A | a chloroplast contains chlorophyll |
OpenBookQA | OpenBookQA-967 | rotational-dynamics, torque, gyroscopes, precession
Title: Precessional motion of a spinning top In Feynman's book, when he talks about the motion of a rapidly spinning top, he mentions:
"When we apply a Torque to a rapidly spinning top, the direction of the precessional motion is in the direction of the torque or at right angles to the forces producing the torque."
That is, if a top is only spinning, then after applying a Torque, it will start precessing. However, I'm confused as to how the direction of torque and the precessional motion, the same? For simplicity let's say the spinning top is at a 45 degrees angle to the vertical.
The diagram shows that the precessing motion that sets in makes the spinning top sweep out a cone. That is, the center of mass of the spinning top goes around in a circle.
As the precessing motion commences the center of mass of the spinning top is moving in the direction that the torque vector is pointing. (The instantaneous direction of velocity of the center of mass is tangent to the circle of the precessing motion.)
As the precessing motion starts going the orientation of the spinning top changes, and the direction of the torque vector changes accordingly. From that point on the instantaneous direction of precessing motion is at all times in the direction of the torque vector.
To understand the onset of gyroscopic precession see my 2012 answer about the mechanics of gyroscopic precession.
The following is multiple choice question (with options) to answer.
which of these does a spinning motion? | [
"planet venus",
"the earth",
"planet mars",
"all of these"
] | D | the Earth rotates on its axis on its axis |
OpenBookQA | OpenBookQA-968 | evolution, zoology
Title: Why are hens so different from other birds? Hens lay many eggs during their lifetime (at least, I don't know of one which can lay more eggs) and they can't fly. Compared to other domestic animals it seems to me they are the least capable of defending themselves or escape if it comes to be left alone in open wild. What is their evolutionary story? Domestic organisms are bred to serve specific purposes for humans. Sheep are bred to produce wool; Cows are bred to provide meat and milk for human consumption; dogs are bred for service and companionship. Since domestic animal do need to survive in the wild in order to reproduce (ignoring feral animals, which is an interesting topic by itself), most of the other aspects of that animal relevant to its survival tend to be minimized.
So one could just as easily point out that there is no other animal that produces as much wool as a sheep, and yet producing copious amounts of wool isn't particularly useful to the animal itself (i.e. other than the fact that humans will tend to select good wool producers for breeding). So sheep are not particularly good at surviving in the wild, and yet they are incredibly successful as a species and are widely distributed, thanks to humans.
In short, domestic hens evolved to produce many eggs in their lifetime because over the past millennia since humans have started keeping them as livestock, humans tended to preferentially breed those individuals which produced more eggs and to eat those individuals which did not. Chickens tended to be kept in pens and guarded by humans or other animals, so the ability to defend themselves or flee from danger was not important to their survival, and in fact, those that did attack their handlers or escape were probably less likely to be bred.
This process is known as selective breeding or artificial selection.
The following is multiple choice question (with options) to answer.
What does an animal require to survive? | [
"interesting locations",
"sunlight",
"cable television",
"nutriment"
] | D | an animal requires nutrients for survival |
OpenBookQA | OpenBookQA-969 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
When eagles are hunting in a field, some of their nutrients come from | [
"beans",
"fish",
"deer",
"rodents"
] | D | eagles eat rabbits |
OpenBookQA | OpenBookQA-970 | 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.
Nighttime in the desert may cause animals to | [
"run",
"jump",
"get thirsty",
"shiver"
] | D | cool temperatures cause animals to shiver |
OpenBookQA | OpenBookQA-971 | 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.
What has a positive net impact on an environment? | [
"placing sapling seeds in the ground",
"deforesting a dry environment",
"introducing new species there",
"tilling the soil of the area"
] | A | planting trees has a positive impact on an ecosystem |
OpenBookQA | OpenBookQA-972 | quantum-mechanics, operators, quantum-information, quantum-computer, linear-algebra
For a given $x\in\mathcal H$, the decomposition in (2) is given by $x = u + v$ where $u = P(x)$ and $v = x-P(x)$. Note that $U=Ran(P)$ and $V=Ker(P)$.
The following is multiple choice question (with options) to answer.
Decomposition | [
"takes away from the soils ability to nourish plant life",
"adds to the components needed to sustain life in the soil",
"increases the rate of depletion of nutrients in the soil",
"decreases nutrients in the soil"
] | B | decomposition increases the amount of nutrients in the soil |
OpenBookQA | OpenBookQA-973 | Now we need to just pick two dogs for the first row so that remaining two dogs will be automatically be selected for other row = 4C2
Total ways = 8C4 * 4C2 = 70*6 = 420
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Re: Eight dogs are in a pen when a sled owner comes to choose four dogs to [#permalink]
### Show Tags
03 Oct 2017, 09:28
1
Bunuel wrote:
Eight dogs are in a pen when a sled owner comes to choose four dogs to form a sled team. If the dogs are to be placed in two rows of two dogs each and different pairings of dogs are considered different teams, how many different sled teams can the owner form?
A. 24
B. 70
C. 210
D. 420
E. 1,680
There are 8C4 = 8!/[4!(8-4)!] = (8 x 7 x 6 x 5)/4! = (48 x 7 x 5)/24 = 2 x 7 x 5 = 70 ways to choose 4 dogs from a total of 8 dogs. Once 4 dogs are chosen, let’s see how many pairings of two rows of 2 dogs are possible. Let’s say the 4 dogs are A, B, C, and D.
The following is multiple choice question (with options) to answer.
An animal needs another animal to | [
"fly",
"eat",
"eliminate waste",
"pass genetic information"
] | D | reproduction is when an organism passes genetic information from itself to its offspring |
OpenBookQA | OpenBookQA-974 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
An animal usually weighs the most if it has eaten | [
"a salad plate of food",
"a truck full of food",
"a dinner plate of food",
"a barrel of food"
] | B | as the amount of food an animal eats increases , the weight of that animal will increase |
OpenBookQA | OpenBookQA-975 | jupiter, planetary-atmosphere, astrochemistry
There are more polar molecules than non-polar, but outside of the somewhat odd CF2CL2, all polar gases are relatively light, SO2 being the most massive, molecular weight of 64.
You mentioned Methylamine which is basically ammonia (NH3) where one of the hydrogens is replaced by a methyl (CH3) group. NH2CH3.
DiMethylamine (CH3)2NH is also a gas at about 7 degrees C and up (boiling point).
Playing around with temperature and variations on the gas molecules (replacing H with CH3, replacing H with NH2, replacing H with OH, but remember, Oxygen tends to be spoken for, like a perfect 10 at a dance, so that's not a good one, unless there's life and a source of oxygen (photosynthesis).
Similarly the "Ane" series, more accurately called the Group 14 hydrides. Group 14: carbon, silicon, germanium, tin, and lead, and the hydrides, Methane, Silane, Germane, Stanane, Plumbane. All of these are polar and all are gas molecules. Most are very reactive with Oxygen. Methane requires a flame, but the other 4 react with Oxygen quite easily.
And as temperature goes up, you add new gases, but heat tends to destroy complex chemistry, so there's a bit of a trade-off. There's no easy answer as to what could be a gas and what couldn't, but starting with the building blocks and swaping might be a place to start. That doesn't always work though. CO2 is non polar and a gas. SO2, even though Silicon is in the carbon group, is polar and bent. It's not a gas (it's closer to sand) with a very high melting point.
The following is multiple choice question (with options) to answer.
Which of these is lacks molecules? | [
"a speech",
"a dog",
"a book",
"a grape"
] | A | matter is made of molecules |
OpenBookQA | OpenBookQA-976 | pressure, friction, material-science
Now we have a triaxial compressive stress state. If all stresses were equal, there would be no plastic deformation. But as the friction forces have a limit, the vertical stress increases until the difference to the horizontal stress is enough to deform the material (or break the roll...). That is the reason for the friction hill.
The following is multiple choice question (with options) to answer.
What causes rock layers to fold on top of each other? | [
"construction",
"Violent tremors",
"earthworms",
"tornados"
] | B | earthquakes cause rock layers to fold on top of each other |
OpenBookQA | OpenBookQA-977 | evolution, botany, photosynthesis, speculative, chloroplasts
Title: Why do plants have green leaves and not red? I know plants are green due to chlorophyll.
Surely it would be more beneficial for plants to be red than green as by being green they reflect green light and do not absorb it even though green light has more energy than red light.
Is there no alternative to chlorophyll? Or is it something else? Surely it would be even more beneficial for plants to be black instead of red or green, from an energy absorption point of view. And Solar cells are indeed pretty dark.
But, as Rory indicated, higher energy photons will only produce heat. This is because the chemical reactions powered by photosynthesis require only a certain amount of energy, and any excessive amount delivered by higher-energy photons cannot be simply used for another reaction1 but will yield heat. I don't know how much trouble that actually causes, but there is another point:
As explained, what determines the efficiency of solar energy conversion is not the energy per photon, but the amount of photons available. So you should take a look at the sunlight spectrum:
The following is multiple choice question (with options) to answer.
Plant cells can't perform photosynthesis | [
"in a backyard",
"in a desert",
"in a closet",
"in water"
] | C | plant cells can perform photosynthesis |
OpenBookQA | OpenBookQA-978 | physical-chemistry, thermodynamics, heat, mixtures
Where does this come from and what are the assumptions involved in treating it as an ideal mixture?
What deviations from this are observed in non-ideal mixtures? Can you easily predict the deviations based on the mixture and/or predict the actual specific heat capacity? Suppose you have $n_1$ mole of A and $n_2$ mole of B. If they are at temp. $T_1$ and you want to raise the temp. to $T_2$ then the amount of heat you need to add is
$$\Delta H~= n_1 \times c_{pA} \times \Delta T + n_2 \times c_{pB} \times \Delta T$$
$$\Delta H~= (n_1 \times c_{pA} + n_2 \times c_{pB}) \times \Delta T$$
$$\Delta H~= (n_1 +n_2)\times \frac{(n_1 \times c_{pA} + n_2 \times c_{pB})}{(n_1+n_2)} \times \Delta T$$
$$\Delta H~= n_{total} \times(y_1 \times c_{pA} + y_2 \times c_{pB}) \times \Delta T$$
$$\Delta H~= n_{total} \times c_{p,avg} \times \Delta T$$
So basically you are not losing any information in case of ideal situation where molecular interaction of two different species has no effect on each other's heat capacity. But from statistical mechanics we know,
$$C_v=\frac { <E^2>-<E>^2}{k_B \times T^2}$$
Now if we solve the schrodinger equation for individual species, we must include an extra potential energy term to account the interaction from other species, which in turn will result in fluctuation of $C_v$ from it's previous value.
The following is multiple choice question (with options) to answer.
An example of a mixture is | [
"gin and tonic martini",
"plant potted in soil",
"pebbles on a sandy beach",
"a leaf that fell in water"
] | A | An example of a mixture is clay mixed together |
OpenBookQA | OpenBookQA-979 | general-relativity, special-relativity, velocity, relativity, free-fall
This has a an intuitively obvious visual interpretation in terms of the size of the object, namely that dense objects with small surface area will have a better chance of breaking the sound barrier than light objects with large surface area. Additionally, letting the size of an object be sized by a length scale parameter $\lambda$, one also observes that the terminal velocity $v$ transforms under an increase in object size as
$$v\rightarrow \sqrt{\frac{2g \left(\lambda^3m\right)}{\left(\lambda^2A\right) C_D \rho }}=\sqrt\lambda v$$
which should also seem visually sensible.
If $v>v_s$, wave drag forces will need to be considered to determine if it's possible for the object to break the sound barrier, and in general there is a several-fold increase in drag at the transonic boundary which will need to be overcome.
The following is multiple choice question (with options) to answer.
Do objects change size with distance for Stevie Wonder? | [
"Yes",
"No",
"sometimes",
"maybe"
] | B | as distance to an object increases , that object will appear smaller |
OpenBookQA | OpenBookQA-980 | rotation, habitable-zone, weather, astrobiology
One of the interesting historical facts of life on Earth, at least to me, is how long it took what we might consider advanced life to develop. One celled life in various forms was around for over 3 billion years but the first fossils are about 650 million years old. It took life a very long time on earth to get from too small to see to large enough to leave a footprint . . . but, I digress.
I agree 100%, one celled life or Tardegrades could live on a planet with no tilt or 90 degree tilt. Easy. Ocean life in general should be fine cause oceans are more adaptive. Evaporation keeps ocean surfaces colder than land gets during peak heat and while a completely frozen over ocean isn't great for life, cold oceans hold more oxygen and CO2 which can be good for life. Oceans also circulate as an effective means of temperature moderation and fish don't really care how windy it is or how much or little it rains. The tilt question, I think, is really just about life on land.
Land life could be more vulnerable to high wind, extreme temperature shifts, droughts or floods, which could be driven by greater axial tilt, but I find it hard to believe that Axial Tilt is the be-all and end all. Day length and year length are key factors too.
One point I agree with the article on, is that a close to 90 degree tilt might not be ideal with one part of the planet always facing the sun and the other part never facing it but outside of extreme tilts, I don't see why it would be a big deal.
A thick cloud cover, for example, reduces seasonal changes. There's a number of factors.
The following is multiple choice question (with options) to answer.
Which life form is most likely to have changed its position? | [
"pine",
"carrot",
"aloe",
"tortoise"
] | D | moving changes position |
OpenBookQA | OpenBookQA-981 | species-identification, botany, ecology, trees
Title: Identifying a shrub with unusual "many shoots" growth behavior While recently hiking in the southern mountains of New Hampshire, we came across a plant, and some of them were exhibiting what we interpreted to be a disease, or least unusual growth. On some of the nodes, there were a large number of extra stalks:
On each plant, the number and locations of these things varied, and not all of them had it. And we first assumed it was some ivy, or parasite, or separate plant, but it seemed pretty clear to us that it was coming right from the same branch.
We soon saw there were dead versions of this plant, and all of them had this "extra shoot" variation:
So we reasoned that no matter what this thing was -- natural variation or some kind of disease -- it was killing the plants.
Google image search was no help. It possibly identified the plant as a "viburnum", but was unable to help with the growth.
Anyone know what plant this is, or what this growth behavior is the result of? Possibly an example of a "Witch's Broom."
Witch's Broom is a deformity in plants (typically woody species) which typically causes dense patches of stems/shoots to grow from a single point on the plant. The name comes from the broom-like appearance of the stems.1
Witch's broom may be caused by many different types of organisms, including fungi, oomycetes, insects, mistletoe, dwarf mistletoes, mites, nematodes, phytoplasmas, or viruses.2
Sources:
1. Wikipedia
2. Book of the British Countryside. Pub. London : Drive Publications, (1973). p. 519
Image1. Gardeningknowhow.com
Image2. Iowa state University
The following is multiple choice question (with options) to answer.
Which of the following are found in woodlands? | [
"Scorpions",
"Crickets",
"Camels",
"Whales"
] | B | some crickets live in forests |
OpenBookQA | OpenBookQA-982 | 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.
What might a blind person likely use to what sandpaper is? | [
"sight",
"sound",
"taste",
"touch"
] | D | touch can be used for detecting texture |
OpenBookQA | OpenBookQA-983 | mechanical-engineering, manufacturing-engineering, cnc
What minimum documentation of 'know how' should be provided for such a project, making complex mechanical parts out of aluminium?
Depends on what you mean by "minimum".
You could argue the drawing is the minimum...a bit lacking though if it doesn't have tolerances specfied and such. Just add process design experience.
Then there is the process manual which details the step-by-step the tooling and operation to be performed on the part, intermediary drawings, and tolerancing. Not cheap to develop, and also specific to the equipment you have available, but also not necessarily the only way to make to a part and not something you leave laying around. Used in industries like aerospace. I've been told each part actually has an its own copy of the manual following it around where the measurements after each process are filled in and signed off on.
The following is multiple choice question (with options) to answer.
In order to make a spiral notebook, it is imperative to use | [
"rubber",
"plastic",
"trees",
"cows"
] | C | if something is a raw material in a process then that something is required for that process |
OpenBookQA | OpenBookQA-984 | earth, amateur-observing, fundamental-astronomy
Title: Does weight influence Earth's spin? If put enough weight on a particular point on Earth's surface disturbing the balance between hemispheres, is it possible that the Earth's spin could change like an unbalanced spinning top? The Earth does spin like an unbalanced top. The Earth's rotation axis is not fixed. It instead moves in a complex manner due to a combination of external torques exerted by the Moon and Sun, a torque-free nutation due to the oblate shape of the Earth, and also due to changes on and in the Earth.
The torque-induced motions are called precession and nutation, distinguished by period. The largest and slowest of these motions is the axial precession. This causes the Earth's rotation axis to trace out a cone over the course of 26000 years.
(source: nasa.gov)
The torque-induced nutations are also cyclical motions induced by the Moon and the Sun. These are much smaller in magnitude and have a much shorter period. The largest of these has a magnitude of about 20 arc seconds and a period of 18.6 years. All other nutation terms have much smaller magnitude and have shorter period.
The torque-free nutation would have a period of about 305 days if the Earth was solid. The oceans, the atmosphere, and the outer core alter this. The Chandler wobble has a period of about 433 days and a magnitude of less than an arc second. Because the Chandler wobble isn't as predictable as are precession and nutation, it's lumped into a catch-all category called "polar motion." The redistribution of water over the course of a year (e.g., snow on Siberia in the winter but not in the summer) results in a yearly component of the polar motion.
There are lots and lots of other factors, all small. Polar motion is observed after the fact.
The following is multiple choice question (with options) to answer.
One full rotation on Earth's axis takes | [
"12 hours",
"1 month",
"2 days",
"1440 minutes"
] | D | a Rotation of the Earth on Earth 's axis takes 1 day |
OpenBookQA | OpenBookQA-985 | acoustics, resonance, vibrations
Title: How does a guitar work? Here are four different possible ways:
The plucked string vibrates longitudinally, vibrating the air around it. This vibrating air then causes the air inside the sound box to vibrate also, which vibrates the outside air also.
The plucked string vibrates longitudinally, vibrating the air around it. This vibrating air then causes the front wall of the sound box to vibrate also, which vibrates the outside air.
The plucked string has varying tension; when it is longer it has more tension and when it is at the middle of its cycle it has less. This changing tension causes the guitar to vibrate because of the effect at the bridge and/or the nut. The vibrating walls of the guitar, particularly the front wall of the sound box, vibrate the outside air.
The plucked string has transverse vibration, and that sideways motion at the bridge or the nut is somehow what makes the body of the guitar vibrate.
The following is multiple choice question (with options) to answer.
What is pulling your finger over a guitar string an example of? | [
"tightening a guitar string",
"Stopping a musical sound",
"making music with an instrument",
"Putting a guitar away"
] | C | An example of playing a musical instrument is strumming a guitar string |
OpenBookQA | OpenBookQA-986 | cell-biology, microbiology
Title: Are there any organisms that are made of more than one (~5-12) cell? Prokaryotes and eukaryotes are unicellular, made of one cell. Great. Eukaryotes are unicellular or multicellular. But the typical examples of multicellular eukaryotes we have are made of, often, trillions of cells, like us humans. Ants must still be made of many millions of cells. Are there known eukaryotes with very few cells that make them up? Like, 5, or something? Or maybe a dozen cells making up the whole organism in its fully developed state? There's Trichoplax adhaerens, a Placozoa, made of a few thousand cells. Then there is Dicyema japonicum, a simple mesozoan, made up of 9 to 41 cells. Arguably, the simplest multicellular organism is the algae Tetrabaena socialis, whose body consists of 4 cells. Then, there's the parasitic Myxozoa which have 7 cells.
The following is multiple choice question (with options) to answer.
Organisms with only one cell | [
"are prohibited from specializing",
"can freely specialize openly",
"are unsure what specializing is",
"learn how to specialize"
] | A | a single-cell organism cannot specialize |
OpenBookQA | OpenBookQA-987 | 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.
Mammals are one of a few animals that's core temp | [
"fluctuates",
"stays the same",
"drops suddenly",
"heats up"
] | B | a mammal is warm-blooded |
OpenBookQA | OpenBookQA-988 | human-biology, breathing
Our lungs work off of pressure. Specifically our lungs inflate by using "negative pressure" (a word I've always hated). The pressure is not actually negative it is simply lower than the surroundings. Since there is less air in your lungs the air from the atmosphere rushes in because the pressure is higher outside your lungs. This is Boyle's Law (not the pressure outside being higher, but what happens when your lungs expand). Where an increase in Volume means a decrease in Pressure (if all else remains unchanged). In fact plants pull water up using negative pressure.
However to push out the air from our lungs we supply pressure using our muscles that overcomes the outside pressure and forces the air out.
The reason you feel your breathing change is because when that train passes by you correctly observed the strong gust of wind. This gust of wind has some force behind it that normally is not in the air you are breathing from the atmosphere. It has more force which increases the air's velocity. This actually decreases the pressure, but there's no need to get into that here (Bernoulli's).
The reason it feels like your body is "fighting to breath" is because the air is traveling in a direction with some force that you need to overcome by opening up your lungs just enough to "suck" the air in with negative pressure. This is more than the pressure you usually need to produce in order to breath in air that is "still".
What is funny to think about is we don't really have a muscle that "pulls" air in, even though it feels like you are actively doing that. The air actually rushes in on its own. All you do is expand your rib cage, which your lungs are attached to (look up on how, it's actually pretty cool), thereby making inhalation occur.
Now an interesting question for you to ask yourself is why is cold air harder to breathe?
The following is multiple choice question (with options) to answer.
A ficus can help respiration because it: | [
"absorbs oxygen",
"releases oxygen",
"absorbs helium",
"releases carbon dioxide"
] | B | a leaf performs photosynthesis |
OpenBookQA | OpenBookQA-989 | 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.
Someone is driving at night. The day was warm, but now the night is cool, and there is a lot of mist that is difficult to see through. The mist is prevalent because | [
"humidity from the day condensed as night progressed",
"warm air is usually found in daytime",
"it is always misty at night",
"the cool air makes everything feel warm"
] | A | fog is formed by water vapor condensing in the air |
OpenBookQA | OpenBookQA-990 | 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.
How can you safely look at a solar eclipse? | [
"mirror",
"pinhole onto a screen",
"look directly at it",
"you can't look safely at a solar eclipse."
] | B | casting an image of an object through a pinhole onto a screen does not require looking directly at the object |
OpenBookQA | OpenBookQA-991 | Doing this for our $C = 3$ dataset in this case we end up learning 3 linear classifiers - here we use logistic regression for each subproblem, solving each using Newton's method.
With our classifiers trained we can now illustrate our learned decision boundaries - each learned to distinguish a single class from the remainder of the data. Below we plot two rows of images - in the top row our original dataset is plotted three times with each instance showing just one of the three two-class classifiers learned. The single class being distinguished is colored with its original color - with the corresponding learned decision boundary colored similarly - and all other data is colored gray. In the bottom row the dataset is shown with along with all three learned decision boundaries all at once.
In [3]:
## 7.2.3 Points on the positive side of a single classifier¶
With OvA we learn $C$ two-class classifiers, and we can denote the weights from the $c^{th}$ classifier as $\mathbf{w}_c$ where
$$\mathbf{w}_c=\begin{bmatrix} w_{0,c}\\ w_{1,c}\\ w_{2,c}\\ \vdots\\ w_{N,c} \end{bmatrix}$$
and then the corresponding decision boundary as
$$\mathring{\mathbf{x}}_{\,}^T \mathbf{w}_c = 0.$$
Now note how in the figure above how in each case - because each subproblem is perfectly linearly separable and because of our choice of temporary labels - that the class to be distinguished from the rest lies on the positive side of its respective classifier, with the remainder of the points lying on the negative side. This of course means that for the $j^{th}$ classifier we have for the $p^{th}$ point $\mathbf{x}_p$ that
The following is multiple choice question (with options) to answer.
a learned characteristic is a | [
"a baby having the same color eyes as parent",
"toddler banging with a stick while parent hammers",
"a child covered with freckles",
"infant diagnosed with sickle cell anemia"
] | B | using tools is a learned characteristic |
OpenBookQA | OpenBookQA-992 | theoretical-biology, hematology, red-blood-cell
**As an intern, I once had the very sorrowful experience of admitting an healthy appearing, exuberant 4 year old child to the pediatric surgical service. The only presenting symptom was that the child started squatting during exertion (not good), and on exam, had a murmur which was caused by aortic stenosis. This was long before imaging studies were as sophisticated as they are now. The pediatric cardiac surgeon took him to the operating room (OR) to replace the valve, but there was so much atherosclerotic aortic damage that there was no healthy tissue which could hold sutures in place. The child died in the OR. I don't know what would have been done today, but had the child stayed home, they might have had a couple more years with the parents, who hoped for an uneventful procedure. So the exercise involved in this answer was fun, but the memory it brought back is still quite sad.
The following is multiple choice question (with options) to answer.
A young boy is reprimanded by his mother for sleeping with his heavy blankets over his head. His mother is worried that if the boy continues to sleep like that, he will suffocate. This is because | [
"beds can cause issues with breathing",
"breathing at night is deadly",
"CO2 in large amounts is fatal",
"CO2 can be ambivalent"
] | C | carbon dioxide can be found in the air |
OpenBookQA | OpenBookQA-993 | organic-chemistry, aqueous-solution, ph, gas-laws
Title: Why does CO2 lowers the pH of water below 7? Ok so I understand that having a pH below 7 is considered to be acidic and I also understand that part of the definition of an acid is that it gives off H+ when dissolved in water(even though not all acids necessarily need to give off H+ when dissolved in water)
But I was the rather confused when I came upon this ( when they refer to the 2 gases they are talking about CO and CO2)
What I dont understand is how the equation came to be ? ( the product side of the equation)
And how would It have looked if CO was dissolved in H2O, would it have still lowered the pH?? Carbon Dioxide (CO2) readily dissolve in water and form Carbonic Acid (i.e H2CO3 (aq) )
This is the formation of bonds.
Then Carbonic Acid (i.e H2CO3 (aq) ) dissociate in water as follows.
So water gets H+ ions, so that cause water acidic.
The following shows dissociation of Carbonic Acid (i.e H2CO3 (aq) ) more clearly.
Carbon Monoxide (CO) do not readily react with water in room temperature in standard conditions. So it do not dissolve in water.
The following is multiple choice question (with options) to answer.
Carbonic acid dissolves what to form caverns? | [
"air",
"water",
"grass",
"sediment"
] | D | a cavern is formed by carbonic acid in groundwater seeping through rock and dissolving limestone |
OpenBookQA | OpenBookQA-994 | heat
Your thinking here:
Is it the one in the middle because it gets refrigerated by the other two?
is kind of interesting (but wrong). If the 2 outer bottles were not there, the middle bottle would cool much faster in fact. Use of words like "insulate", "refrigerate", and "cool" might get a little difficult in this discussion. One way or the other, the outer bottles don't help cool the inner one, although they cool slower than it does.
EDIT: The outer bottles do insulate the inner bottle. That is correct to say, although I should add that the effect could be mostly through radiative heat transfer. Convection is something you could get into but it's a little trickier. Fewer bottles will probably always cool faster, and this is due to both heat transfer and thermal mass reasons.
The following is multiple choice question (with options) to answer.
When two decorative items for a refrigerator are placed back to back, | [
"they will refuse to touch",
"they will stick together",
"they will be sticky",
"they will be charged"
] | A | if two objects have the same charge then those two materials will repel each other |
OpenBookQA | OpenBookQA-995 | resources, soil
Title: Is soil a renewable resource? My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.
Some soils take more than a human lifetime to regenerate. However, in crop production, it seems as if soil can be regenerated with additives.
In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists? Is there strong evidence to support this? Soil is an interesting case because although it is non-renewable (at any useful rate) as a 'bulk material' once removed from the ground, the nutrient content of soil can be renewed with fertilizers.
What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr.
In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion.
I think the additives you are referring to replenish the nutrient content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.
This site has links to more aspects surrounding this issue.
The following is multiple choice question (with options) to answer.
Which is the source of a nonrenewable resource? | [
"rain",
"the wind",
"the Sun",
"oil deposits"
] | D | plastic is a nonrenewable resource |
OpenBookQA | OpenBookQA-996 | evolution, botany, development, fruit, seeds
What is the point of fruit if not to be eaten? It’s my understanding that organisms will adapt to survive and thrive. I understand that being eaten can spread seeds, but this just seems like too much of a risky tactic to rely on.
Following on from part one: If being eaten is the best way to spread seed, why do some plants avoid this (such as by being poisonous or thorny)? Seeds are spread by many mechanisms
Wind dispersal: When air currents used to spread seeds. Often these plants have evolved features to facilitate wind catching, for example dandelions. Aka, anemochory.
Propulsion & bursting: When seeds are propelled from the plant in an such as in these videos. This is called Ballochory.
Water: Similarly to wind dispersal plants can spread seeds by water movement/currents, aka Hydrochory. This is used by many algae and water living plants.
Sticky Seeds: There are many ways a seed can attach to the outside of an animal - by using hooks, barbs, sticky excretions, hairs. Seeds then get carried by an animal and fall off later. This is epizoochory.
Fruiting: Plants can use seed-bearing fruit to encourage animals to eat the seeds. They will then be spread when the waste is excreted after digestion. This is a process of endozoochory.
More than one way to spread a seed
The following is multiple choice question (with options) to answer.
Seed dispersal | [
"benefits production of human offspring",
"decreases production of new plants",
"has no effect on plant reproduction",
"benefits production of plant offspring"
] | D | seed dispersal has a positive impact on a plant 's reproduction |
OpenBookQA | OpenBookQA-997 | cellular-respiration
Title: Do cold blooded animals generate any heat? In explaining energy and work to an 8 year-old I said that all conversion of energy generates heat as a by-product. For example, cars generate heat in their engines and running generates heat in our bodies. Then the 8 year-old said, except for cold-blooded animals.
So my question is, do cold-blooded animals generate any heat in their conversion of stored energy (food, fat, etc) into motion? If they generate heat, why are they cold-blooded? They do generate heat. They just do not SPEND energy specifically on heating their bodies by raising their metabolisms. This is a form of energy conservation. The metabolic rate they need to live is not nearly enough to heat their bodies.
An example of spending energy to heat the body is seen in humans shivering. Here muscle is activated not for its usual purpose, but to function as a furnace. "Warm-blooded" and "cold-blooded" is somewhat a misnomer. The correct way to think of it is...
Endotherm or ectotherm. Does the heat primarily come from within (endo) or from the surroundings (ecto). Endothermic animals include mammals. Most of their body heat is generated by their own metabolisms. Ectothermic animals include reptiles and insects. They absorb most of their body heat from the surroundings. This is not the same as saying they let their body temperature fluctuate with their surroundings, some avoid this by moving around to accomodate themselves.
Homeotherm or poikilotherm. Homeotherms want to maintain homeostasis for their body temperatures. They don't want it to change. Poikilotherms do not exhibit this behaviour, instead their body temperatures vary greatly with the environment.
We can have endotherm poikilotherms, such as squirrels, who let their body temperature drop while hibernating. Endotherm homeotherms, such as humans, where temperature is constant by means of complex thermoregulation. Ectotherm homeotherms, such as snakes (moving into shadow or into the sun to regulate temperature), and ectotherm poikilotherms, such as maggots.
The following is multiple choice question (with options) to answer.
What do some animals do to adjust to hot temperatures? | [
"they run",
"they hunt",
"they perspire",
"they fly"
] | C | sweat is used for adjusting to hot temperatures by some animals |
OpenBookQA | OpenBookQA-998 | black-holes, astronomy, supernova, elements
Supernovas are claimed to be manufacturing center of the heavy elements in the universe.And usually the remnants of such massive supernovas are black holes.
AndCygnus X-1is the closest black hole to the earth which is at a distance of $6,100 \pm 400$ light years.
If we imagine a sphere which have radius equal to 6,100 light years.The surface area of the sphere is $37875166695400,000,000,000000,000,000,000~\mathrm{km^2}$.
While compared to that,the cross section of the earth is almost insignificant($142334130.878~\mathrm{km^2}$) as it is just $0.0000000000000000000000003758 \%$ of the imaginary sphere's surface area.
How could earth have such a large amount of uranium and other heavy elements in spite of it's negligible size? There are many misconceptions in your question.
First: Most supernovae probably end up as neutron stars, not black holes.
Second: The nearest black hole is not CygnusX-1. It maybe the closest one we know about, but a simple calculation reveals that the nearest black hole is likely to be within 20pc and the nearest neutron star at about 10pc.
https://astronomy.stackexchange.com/questions/16678/how-far-away-is-the-nearest-compact-star-remnant-likely-to-be
Third: The chemical elements that make up the Sun and Earth are the products of many millions of dead stars. Supernovae scatter elements into the interstellar medium, gradually enriching it with heavy elements. There are mixing processes that take place on timescales of billions of years that mean this material is effectively homogenised, and there is little metallicity gradient in the Milky Way near the Sun. We cannot identify ancestors of the solar system.
Fourth: There are chemical differentiation processes in the protoplanetary disc and the planet formation phase that ensure heavy elements are very much over-represented say compared with the Sun.
The following is multiple choice question (with options) to answer.
The celestial object closest to Earth is | [
"Mercury and Venus are equally closest",
"the object the Earth orbits",
"the third planet from the Sun",
"the large object that illuminates a night sky"
] | D | the moon is the celestial object that is closest to the Earth |
OpenBookQA | OpenBookQA-999 | 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.
Bugs are sometimes eaten by | [
"blue jays",
"whales",
"elephants",
"aphids"
] | A | birds sometimes eat insects |
OpenBookQA | OpenBookQA-1000 | optics, geometric-optics, vision, microscopy
Title: Ray diagram of focussing on a compound microscope When we use a usual biology class compound microscope, we need to focus the stage (place the object) to the "correct" position. It is just in that sweet spot that the image is sharp and clear. So we are deciding the object distance.
Here is the ray diagram of a compound microscope.
So, when we are focussing, we move the objective lens which tweaks the image distance. My doubt is that, shouldn't the image be seen clearly, wheresoever the first real image forms, if within Fe (Focus of the eyepiece lens). Then, that would make it a range instead of a single point (shouldn't we be able to see a clear image not at a single point but a range?).
Whatever, the distance of the virtual image, the eye can accommodate it onto the retina, right?
If the first image (real image of the objective lens) goes behind Fe, or is on Fe, what happens? The eye will see a sharp final image as long as the final image is between infinity (real image in focal plane of eyepiece) and the near point (25 cm) of the eye (real image between $F_{\rm e}$ and eyepiece).
Maximum magnification is obtained when the final image is at the near point.
However it is often the case that the final image is made to be at infinity to reduce eye strain.
The following is multiple choice question (with options) to answer.
When a microscope magnifies, it is | [
"enlarging",
"enabling",
"viewing",
"observing"
] | A | magnifying makes seeing small things easier through using a microscope |
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