source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-3301 | telescope, mars
Have a look at this guide explaining how consumer-grade computer webcams can be used. It contains a neat comparison of a single frame and a stacked image.
Please note that I'm merely speculating as to which techiniques could be used to obtain such images. I can see that the author posted their email on the S&T site and that there's a comments section as well. Feel free to ask them yourself.
The following is multiple choice question (with options) to answer.
What is used to record images? | [
"sunlight",
"calculators",
"nikon devices",
"camera batteries"
] | C | a camera is used for recording images |
OpenBookQA | OpenBookQA-3302 | Now, imagine that we clap at every time point following the first clap and that the intensity of each clap is given by the function $$f(t)$$, then the resultant sound intensity heard at time $$t=\kappa$$ will be given by
$(f*g)(\kappa) = \int_{0}^{\tau}f(\tau).g(\kappa - \tau) \,d\tau.$
For the discrete case, we have
$(F * G)[i] = \sum_{j=0}^{N}F[j].G[i - j]$
where, $$(F*G)[i]$$ denotes the $$i$$th element (assuming indexing begins at 0) of the $$F*G$$ convolution vector; similarly, for $$F$$ and $$G$$ vectors. The constant $$N$$ gives the number of elements in $$F$$. As before, value of $$G[i]$$ is assumed zero if the index $$i$$ is outside the valid range determined by the size of the convolution kernel $$G$$.
For our example, which produced the convolution $$A * B = \begin{bmatrix}4 & 13 & 28 & 27 & 18\end{bmatrix}$$, we can see the indexing as follows:
The following is multiple choice question (with options) to answer.
Clapping in an auditorium will yield this for a few moments afterwards: | [
"solar flares",
"urine",
"indignant",
"echo"
] | D | when a sound is produced inside of a room , there is sometimes an echo after the sound |
OpenBookQA | OpenBookQA-3303 | tidal-forces, trappist-1
Overall, and this is entirely opinion based and from my calculations above, but I'd say the chances of the inter-planetary tidal heating having significant effects on the interior heat of of these planets is negligible. More than likely the biggest contributing factor is radioactive decay, followed by tidal heating from the star (but this is amplified by the eccentric orbits induced by planetary gravitational perturbations)
1 Note that this calculation involves using the eccentricity and the paper only provides an upper limit. These distances then represent an upper limit as well and the final answer will also be an upper limit. It may be less.
Values used in calculations:
$G = 6.67\times10^{-11}\:\mathrm{m^3 kg^{-1} s^{-2}}$
$M_b = 5.075\times10^{24}\:\mathrm{kg}$
$M_c = 8.239\times10^{24}\:\mathrm{kg}$
$M_* = 1.604\times10^{29}\:\mathrm{kg}$
$R_b = 7.34\times10^{6}\:\mathrm{m}$
The following is multiple choice question (with options) to answer.
for warmth, we depend on the closest star to our planet, which is also | [
"the red planet mars",
"the moon of the earth",
"the Orion star cluster",
"a major player in photosynthesis"
] | D | a planet is exposed to the heat of the star around which it revolves |
OpenBookQA | OpenBookQA-3304 | $$p_6 = \frac{1+9+36+84+126+126}{2^9} = \frac{382}{512} = \frac{191}{256}$$
Here's how this comes about: There are only two possible final states: certain drought, and certain rain. For any $k, 0 \leq k \leq 10$, let $p_k$ be the probability that the final state will be certain rain, given that the initial probability of rain is $\frac{k}{10}$. (Here, initial only means "current" since the process is homogeneous in time.)
Then, there is a simple set of linear equations relating the $p_k$. Suppose $k = 1$ initially. That is, the current rain probability is $\frac{1}{10}$. Then with probability $\frac{1}{10}$, the next rain probability will be $\frac{2}{10}$, and with probability $\frac{9}{10}$, the next rain probability will be $0$ (and the final state is certain drought). We can represent this as follows:
$$p_1 = \frac{1}{10} p_2 + \frac{9}{10} p_0$$
where $p_0 = 0$, naturally.
Now, let us suppose that $k = 2$ initially. Then with probability $\frac{2}{10}$, the next rain probability will be $\frac{3}{10}$, and with probability $\frac{8}{10}$, the next rain probability will be $\frac{1}{10}$. We can represent this as follows:
$$p_2 = \frac{2}{10} p_3 + \frac{8}{10} p_1$$
Proceeding along these lines, we can write equations of the form
$$p_k = \frac{k}{10} p_{k+1} + \frac{10-k}{10} p_{k-1} \qquad 1 \leq k \leq 9$$
The following is multiple choice question (with options) to answer.
If a patch of land gets six inches of rainfall each month, then that is the amount of the | [
"storm",
"quiet",
"gathered moisture",
"puddles"
] | C | rainfall is the amount of rain an area receives |
OpenBookQA | OpenBookQA-3305 | electricity
Title: Why can touching an iPod charger sometimes cause one's skin to tingle? I was visiting Shanghai recently. One afternoon, while sitting on the sofa, I inadvertently brushed a family member's arm. To my surprise, I felt an unnatural tingling from his skin—quite like a mild version of the shock from a (toy) shock pen or the slightly numbing vibration from an electric shaver. I could consistently feel the tingling by running my knuckle lightly across the family member's skin.
The family member had been using an iPod Touch plugged into a Chinese power strip via the stock Apple charger. The tingling persisted as long as at least one part of his body contacted the iPod and even when he touched the metal end of the charging cable directly with his fingertips.
More observations:
The tingling persisted when he stood on a plastic stool instead of the sofa.
The tingling did not appear when we plugged the iPod into a power outlet at a hotel we later visited in a different city in China.
The following is multiple choice question (with options) to answer.
If you touch a wall wart which hasn't been on in weeks, it'll feel | [
"very warm",
"cold",
"hot",
"moderately warm"
] | B | electrical current running through a wire causes that wire to heat up |
OpenBookQA | OpenBookQA-3306 | optics, everyday-life, reflection
Title: What are natural retro-reflectors? Recently I was on an airplane on a sunny day. The sun was shining on the other side of the plane and noticed a bright patch on the ground following beside us. Eventually I noticed a dark centre to this bright patch, the plane's shadow, which became more distant as the plane descended. When the plane flew over a city road signs in this bright patch lit up brightly because of their retro-reflective paint.
My question is, what was acting as a retro-reflector to produce this bright patch when it wasn't passing over a road sign? When flying over water the bright patch disappeared, or was very faint. I could see it over forests, more clearly over cut grain fields and, at least faintly over a wide range of terrain. It sounds like a version of the glory, or more likely heiligenschein, due to spherical droplets of water in the air or dew on the ground.
The following is multiple choice question (with options) to answer.
If a plane is landing on a strip where someone is standing, the plane's blinking will look | [
"more intense",
"duller",
"more distant",
"more dim"
] | A | as a source of light becomes closer , that source will appear brighter |
OpenBookQA | OpenBookQA-3307 | 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.
A way in which seeds are frequently spread is | [
"pigs rolling in mud",
"floors being swept clean",
"people eating deli ham",
"voles consuming oak pips"
] | D | An example of seed dispersal is animals eating seeds |
OpenBookQA | OpenBookQA-3308 | electromagnetism, electricity, insulators
Title: How can a glass rod become charged if it is an insulator? I was reading some of the other questions, and I found this one about a glass rod and how it gains a net charge when rubbed with a silk scarf. I learned from working in a shop one summer that most solids are insulators, because their electrons are tightly bound, so it is hard to knock them off. Why would such a simple motion (like a moving scarf) knock electrons from an insulator (I looked it up and glass is an insulator)? Conductivity is not just about how tightly bound electrons are, but equally about how easy it is for them to travel.
Example: a bunch of islands in a shark-infested sea. You cannot swim from one island to the next although it is close. At low tide you can walk across no problem. The first example is an insulator, the second is a conductor.
Rubbing (google triboelectricity) causes unlike atoms to stick and unstick frequently. Atoms "fight" over electrons, and the stronger one gets to take the electron home. It is like air lifting them from the island - shark infested waters or not.
There are lists of materials (the triboelectric series) that tell you which material will give up its electrons when in contact with another material. Glass is high on the list - it loses electrons easily. The can't move sideway, but they can be picked off the surface.
The following is multiple choice question (with options) to answer.
This is likely to be an insulator | [
"a flip flop",
"a can",
"water",
"a car"
] | A | rubber is an thermal insulator |
OpenBookQA | OpenBookQA-3309 | heating-systems
Comparison between the two.
So you can see that, while you use more efficiently the primary energy with the steam boiler, if the electricity you get is from a renewable source then the ceramic might be more environmentally friendly.
Of course, I avoid going into the discussion about carbon emissions, or the total impact on the environment (e.g. consider if your electricity came from nuclear). That makes the problem even more complex.
A Better solution
If you live in a relatively warm climate (i.e. you don't get temperatures under 0 more that a few days per year), a better alternative for electrical power can be a heat pump.
The difference with heat pumps, is that they don't use the electrical energy directly for heating. (Simply put) What they do is they use the electrical energy to mechanically move an arrangement of pumps/compressors/condensors to pump heat energy from one side of the wall to the other. Heat energy that would not usually be inclined to flow towards that direction. More specifically, they take heat from the colder environment and pump it inside a warmer room.
That process, in ideal conditions, is very efficient. For example, for one unit of electrical energy you can nowadays move up to 4 units of heat energy. That ratio of useful energy to energy expended is the basic formula for the famous COP - Coefficient of performance. In this specific example COP would be 4.
So in ideal conditions, if you used 100 units of fossil fuel, and got 35 units of electrical energy, in theory you could get 140 units of heat energy pumped in your room.
Of course, there are limitations. E.g. at cold climates using a heat pump would create ice/frost on the heat pump, which ultimately would lower significantly the COP.
The following is multiple choice question (with options) to answer.
Which would most rely on a coal-fire power station? | [
"a nuclear sub",
"the space shuttle",
"a locomotive",
"a solar panel"
] | C | coal is used to produce electricity by burning in coal-fire power stations |
OpenBookQA | OpenBookQA-3310 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
In a drought, a resource that will be lacking is | [
"soil",
"land",
"droplets",
"cheese"
] | C | drought means available water decreases in an environment |
OpenBookQA | OpenBookQA-3311 | visible-light, electromagnetic-radiation, speed-of-light, everyday-life, atmospheric-science
If the blocking occurred close to the sun, you would see the opening of the blocking ca. 8 minutes after it happened, but you would also feel it 8 min after it happened. Thus you would experience both at the same time.
An analogy:
Imagine a car standing at a tunnel entrance that is blocked. You are standing at the opposite end of the tunnel. Now the road is opened and the car drives through the tunnel towards you. The car reaches you ("warmth") at the same moment that you receive the information that the tunnel is not blocked anymore. It does not matter how long the tunnel is or how fast the car is driving.
The following is multiple choice question (with options) to answer.
When we are unable to look up and see the sun during the day it is blocked by | [
"lava",
"seashells",
"rocks",
"water"
] | D | cloudy means the presence of clouds in the sky |
OpenBookQA | OpenBookQA-3312 | waves, acoustics, perception, harmonics
Does an object have a single timbre or multiple timbres?
Does an randomly evolving noise have timbre? (Is timbre applicable where there is no consistency and recognizability?) Timbre does not have a precise formal definition in physics, in sense that concepts such as force, mass, charge etc have precise definitions. The word timbre is typically used to describe qualities of musical sounds other than their pitch and volume. To take your example of the violin and the didgeridoo- both instruments could play the same note at the same volume but they would sound unalike, and the differences we would refer to as their timbres.
Timbre can be used to refer to the sensory experience or to the characteristics of a musical instrument, voice etc. You could use the word timbre to describe the qualities of other sounds if you wished.
Timbre arises because sounds are very complicated waveforms which our brains classify in three quite different ways. We think of sounds as being quiet or loud, which very broadly equates to the average magnitude of the peaks of the waveform. We think of sounds being 'high' or 'low' in pitch, which broadly equates to the frequency of the most dominant component of the waveform. That leaves lots of other characteristics of waveforms that sound different to us, and we label those the timbre of the sound.
In physics, a waveform that isn't a pure sine function can be modelled as a spectrum of lots of superimposed sine functions of different frequencies, and it is the brain's response to different spectra that give the sense of timbre. If, for example, you pluck the string of a guitar at the midpoint of the string, the spectrum of the resulting sound will be dominated by the fundamental frequency of the string. However, if you pluck it closer and closer to the bridge, you will set off more overtones in the spectrum, so the resulting sound will be more 'twangy'.
With an electric guitar, or a synthesiser, the range of sounds that can be produced is extraordinarily wide, with any number of effects achievable. In physical terms, they represent waveforms that result from the superposition of different blends of pure notes.
The following is multiple choice question (with options) to answer.
What is an example of playing a musical instrument? | [
"blowing pipes",
"sleeping",
"walking",
"talking"
] | A | An example of playing a musical instrument is strumming a guitar string |
OpenBookQA | OpenBookQA-3313 | optics, visible-light, vision, absorption, laboratory-safety
Title: Why are UV protective eyeware Orange? Many industrial processes use uv as a curing agent. When one uses such a process, one must protect one's eyes from the radiation. Most uv protective gear I have seen is tinted orange?
Does this orange color come from the actual uv blocking chemicals, or is that color added for some user related reason (like being confident you picked up the right glasses) For typical laser goggles the color of lens is the color of light that is transmitted through the lens. Thus if the lens is red, it will not protect you from laser beams that are in the red portion of the spectrum.
The color you are looking for will be, in some sense, the complementary color; since red-orange-pink are far from blue-violet-ultraviolet, these are the lens colors you would expect to work for UV light.
I have often worked with high power, class 3B and class 4, UV lasers, from 405 nm, which is UVA, down to 264 nm, which is beyond the UVB. The typical goggles which cover these ranges are orange to pink.
Your hypothesis is correct: the color comes from an absorptive dye which is incorporated into the plastic or glass.
It is also possible to apply multi-layer optical coatings to the lenses of spectacles which will preferentially reflect in the UV; this is a more expensive approach (hence dyes), and relies on destructive interference for the transmitted waves. The goal is to make make it transparent in the visible spectrum.
The following is multiple choice question (with options) to answer.
If I want to protect myself from the ultra violet rays I can wear | [
"a bird",
"a sweater",
"a cat",
"a dog"
] | B | tinted lenses reflect ultraviolet rays |
OpenBookQA | OpenBookQA-3314 | entomology, ethology, habitat
Title: Preferred criteria for new bee colony location As a human I want a house with a roof, indoor plumbing, bug free, and make my wife happy. I don't want to drive too far to work, and it has to be well-suited for offspring.
What are the criteria that define a "good spot" for a new location for honey bees. I'm sure it involves water, shade, access to nectar, and defensibility, but I don't know any of the details.
Has anyone ever made measures of this? Beekeepers? Apiologists? What are the things bees think are important, and what values of those do they think are "best"? According to Thomas Seeley, in his book, Honeybee Democracy, he gives the following as important criteria for honeybees when selecting a nest site when a bee colony moves to swarm:
Larger volume (the minimum nesting capacity was found to be around 14 liters with more preference to nests with a capacity of approximately 30 to less than 100 liters)
Relatively small entrance (10 to 30 centimeters squared)
Nest with the entrance located near the floor of a tree cavity
Direction of the nest entrance (south facing for thermoregulation during the winter)
Nest height (preference given to higher nests for colony defense)
Remnants of previous honeycombs (saves work and energy in building the nest structure)
Interestingly enough, bees did not necessarily display a preference for the shape of the entrance, the shape of the nest, the draftiness or dryness of the nest cavity (they are able to plug and waterproof nests).
Flower/nectar/food availability is not necessarily a direct factor as this changes quite frequently throughout the seasons and honeybees are not able to leave their honey stores (which are necessary to sustain the colony throughout the winter) or take them with them every time the colony has trouble finding food. Honeybees have a complex and efficient system for optimized location and sharing of food sources, therefore distance is not as large a factor.
The following is multiple choice question (with options) to answer.
A bee may be vital for | [
"time travel",
"metal",
"cars",
"basil"
] | D | An insect is a pollinating animal |
OpenBookQA | OpenBookQA-3315 | electromagnetism, electricity, energy-conservation, perpetual-motion
Title: Auto spinning turbine generator This might be dumb question but I'm so curious to know if this actually works or is impossible. I was researching how you could generate electricity from magnets and copper wire and also have read how the hydroelectric generators work and it seems like they share the same concept. So if we are able to generate electricity by moving the turbine with water then why not have a some sort of motor which will make the turbine spin by getting power from the generator. I mean first there needs to be some sort of initial mechanical source to make the turbine spin then once the turbine starts moving and the generator gives power, the other motor gets power and it will take over the spinning of the turbine. So that way it will auto spin itself and basically means free energy. Can someone explain why this is not possible? As with virtually all perpetual motion machines, the reason becomes obvious once you consider the thermodynamic efficiency of the components involved. No turbine is 100% efficient, and also no motor is 100% efficient. This means that out of the initial energy you put in to make the turbine spin, only a certain percentage will be converted to electricity, with the rest being converted to heat. Then, out of that electricity, only a certain percentage is converted to mechanical energy to drive the turbine again. Then we go round again, losing some of that energy to heat until pretty soon the whole thing stops turning.
Of course, it would work just fine if you had an engine or a turbine that was more than 100% efficient, putting out more energy than you have to put in to drive it. But then, that's exactly the reason why we know that efficiencies over 100% are impossible: we observed that perpetual machines seem to be impossible, and from that Carnot derived his thermodynamic limits. The resulting theory has stood the test of time since the 19th century.
The following is multiple choice question (with options) to answer.
A person needs to make a stove run with only energy that will run forever, so they make a | [
"propane stove",
"gas stove",
"corn stove",
"solar stove"
] | D | solar energy is an inexhaustible resource |
OpenBookQA | OpenBookQA-3316 | temperature, water
Title: Sudden Localized Surface Water Temperature Increase In Eastern Lake Superior, Canada As can be seen in the below sequence of NOAA images spanning 15 hours (most recent at top), in extreme eastern Lake Superior the surface water (but not bottom water) temperature increased dramatically in a localized area. Can anyone confirm or rule out that this is a real event? If it is real, what is the explanation?
Link to source and additional information (Additional information includes lake-bottom temperature maps and additional time points) NOAA revised the data.
The map below is for the same date and time as the first map in the question, but with the anomaly gone. So I'll have to assume the event wasn't real.
The following is multiple choice question (with options) to answer.
As a lake increases in size, there are more | [
"English Premier Leagues",
"catfish",
"airplanes",
"volcanoes"
] | B | as water increases in an environment , the population of aquatic animals will increase |
OpenBookQA | OpenBookQA-3317 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
A wolf feels the snow with | [
"morality",
"skis",
"ethics",
"touch"
] | D | feeling is when an living thing senses through touch |
OpenBookQA | OpenBookQA-3318 | radiation
Title: Why can sunlight heat an object on the other side of glass? Q1. Why can sunlight heat an object on the other side of glass, but normal light from a CFL or Incandescent Light bulb can't.
Q2. Do they make a light bulb that can do this? I need to increase the tempature and objects inside a glass tank.
I'm fully aware of bulbs like the Floureon Ceramic Infrared Bulb Heat Emitter Reptile Lamp. Different types of "glass" transmit and block different types of radiation. When astronomers are making infrared instruments and they need to place a window in the instrument, they use sapphire. Ordinary glass, similar to borosilicate in the plots on this page, blocks infrared radiation that we normally think of as heat.
The way the sun heats up objects behind glass is by pouring enough visible and UV light through the glass to do the heating. The glass then blocks the infrared radiation from escaping, causing the heat to build up.
The following is multiple choice question (with options) to answer.
You can bake cookies with the sun using | [
"melting ice",
"aluminium foil",
"blocks of ice",
"soft cheese"
] | B | a thermal energy conductor transfers heat from hotter objects to cooler objects |
OpenBookQA | OpenBookQA-3319 | geology, volcanology, mineralogy, minerals
Title: Where can obsidian be found? Where is obsidian found?
Is it typically found on the surface or underground?
If underground, how far under (meters or feet would be perfect)?
Also, is it found everywhere on Earth, or just in areas where volcanic activity is (or was recently) high? Obsidian is formed when a rhyolitic (or felsic) lava flows cool rapidly. This must mean that it's mostly available on the surface (and I think if you go near volcanos you can find pieces of Obsidian on the ground) because molten rock cools much faster above ground than it does below, allowing the melt to cool with small crystals (as opposed to intrusive rocks which have larger crystals). This means that Obsidian is an extrusive igneous rock.
I am betting that Obsidian is very common around most active volcanos around the world!
The following is multiple choice question (with options) to answer.
What is lava found above? | [
"natures floor",
"grounded lightning",
"sky",
"ground images"
] | A | lava is found above the ground |
OpenBookQA | OpenBookQA-3320 | synthesis, safety, polymers, green-chemistry
They are divided into two distinct groups, with very different applications, toxicological properties, and classification, based on the number of carbon atoms in their alcohol chain.
Phthalates aren't covalently bonded to the matrix of PVC. Therefore, the lighter ones can leach relatively very easy, usually due to heat or strong solvents.
The most common phthalate is diethylhexyl phthalate(DEHP). Studies show that Americans are exposed to DEHP. DEHP is believed to cause health complications in a variety of ages.
Oh, wait: Issue 3: PVC itself! But when it degrades
PVC is known for its strong linear polymer; but when it degrades (usually due to careless use or disposal) it degrades! Degradation is excessive reduction in a plastic's average molar weight. PVC will "microcrack" when it's degraded, into macroparticles that are a big threat to the environment. These particles "soak up" POPs and afterwards are usually ingested by living things, making it a big deal of our everyday plastic pollution exposure. (as wikipedia puts it)
What should I do now?! Panic?
Considering the advancement of technology and our anxiety to preserve our health we humans aren't sitting around to watch ourselves getting sick! I don't mean the hard-to-come-by sites that say overexposure to PVC isn't carcinogenic, but real efforts into solving the problem. News has been spread that REACH attempts to authorize DEHP and two other phthalates and ban their use in specific materials. DINP is another plasticizer, approved by the EU risk assesment, that will eventually replace the former plasticizers, hopefully.
Scientific researches for over ten years have proven that the amount of exposure to the chemicals mentioned is far from dangerous in current conditions and uses. So sit back relaxed; it's true that these dangers exist, but they're not serious threats to a healthy person, at least not yet.
The following is multiple choice question (with options) to answer.
What product eventually will become human waste? | [
"stars",
"unicorns",
"black holes",
"corn"
] | D | processes sometimes produce waste products |
OpenBookQA | OpenBookQA-3321 | 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.
Chloroplasts in shrubs scrub carbon from the air and return | [
"breathable air",
"tears",
"sweat",
"water"
] | A | plants are a source of oxygen through photosynthesis |
OpenBookQA | OpenBookQA-3322 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
If a large glacier is moving passed a beach, it can deposit this because it is made of ice | [
"fluid",
"corn",
"meat",
"trees"
] | A | a glacier is made of ice |
OpenBookQA | OpenBookQA-3323 | proteins, digestive-system
Title: Why do humans cook animal meat Why do humans "need" to cook animal meat?
It seems there's an aspect of safety to it: are other animals (eg, house cats, dogs) not vulnerable to the same diseases we get from modern food processing of meats?
But it also seems there's something else to it: is raw animal flesh is harder to digest for us, no matter how fresh or processed?
I've read so many conflicting things about it, like how cooking is really a way to avoid disease, but that the human body is capable of processing protein from raw meat just the same. An example is how other countries eat raw meats that Americans would not. But then I've also read things about how cooking meat is what allowed humans an energy advantage early in our development as a species (I'm not clear how more calories are "unlocked" by cooking) or how denatured protein plays some role in usability. I also know that my person experience with raw meats doesn't help me understand it, because sushi seems to be fine but raw eggs will upset my stomach. Humans do not "need" to cook food, but in general cooking food facilitate digestion and absorption of nutrients.
Heat cause denaturation of proteins. Once denatured, proteins are more susceptible to the enzymatic digestion. Thus, more nutrients are absorbed. There are also macroscopic phenomena in play, for example, a cooked piece of meat is more tender than the raw one, making mastication easier and less energy consuming.
The fact that you may feel your stomach upset because of raw food is probably due to the fact that you were never used to it. Your intestinal flora has been selected during the year to deal with the food you usually eat, any "new" food may cause the same symptoms. Humans that eat regularly raw food will not feel the same way.
The following is multiple choice question (with options) to answer.
How can you help to ensure that you will stay free from becoming ill after eating meat? | [
"cover it with ketchup",
"eat it when it's raw",
"take the meat from a dead raccoon in the road",
"cook it very thoroughly"
] | D | bacteria cause food poisoning |
OpenBookQA | OpenBookQA-3324 | astronomy, everyday-life, popular-science, climate-science
It is for much the same reason that Winter is colder than Autumn, even though they have the same amount of daylight hours.
The following is multiple choice question (with options) to answer.
Animals need to get ready for the changing seasons in various ways. One way bears get ready for the Winter is by having their | [
"ears fall off",
"fur get thinner",
"fur get thicker",
"nose get blue"
] | C | An example of a seasonal change is an animal growing thick fur for keeping warm in the winter |
OpenBookQA | OpenBookQA-3325 | biochemistry, food
Title: Who creates first nitrogen compounds in the food supply chain As I understand the food supply chain, organic compounds have to be created from a unlimited source (air, water...).
For instance, I figure that plants transform CO2 from air to organic carbon compounds, mainly carbohydrates, which are then the main source for most other life forms.
But I never heard about a plant turning atmospheric N2 to nitrogen compounds.
Where nitrogen compounds come from, and from which source ? There are nitrogen fixing bacteria who turn N2 into NH3. Some are free-living in soil, others live symbiotically with plants.
https://en.wikipedia.org/wiki/Nitrogen_fixation
The following is multiple choice question (with options) to answer.
What is a source of nectar? | [
"daffodils",
"flower toys",
"sunlight",
"groundwater"
] | A | a flower is a source of nectar |
OpenBookQA | OpenBookQA-3326 | Note:
Depending on where, and how frequently, you round during this function, your answers may be off a few cents in either direction. Try rounding as few times as possible in order to increase the accuracy of your result.
The following is multiple choice question (with options) to answer.
Which is most accurate? | [
"dams can capture powerful gusts and harness their power",
"windmills can capture lightning bolts and harness their power",
"dams can capture lightning bolts and harness their power",
"windmills can capture powerful gusts and harness their power"
] | D | wind is a source of energy |
OpenBookQA | OpenBookQA-3327 | evolution, ornithology, ethology, sexual-selection
Bateson P. 1978. Sexual imprinting and optimal outbreeding. Nature 273, 659 - 660.
Bereczkei T, Gyuris P, Weisfeld GE. 2004. Sexual imprinting in human mate choice. Proceedings of the Royal Society of London, Series B: Biological Sciences 271: 1129–1134.
Immelmann K. 1972. Sexual and Other Long-Term Aspects of Imprinting in Birds and Other Species. In Advances in the Study of Behavior, Vol. Volume 4 of, pp. 147–174, Academic Press
The following is multiple choice question (with options) to answer.
Once the egg has hatched a swan has given birth to | [
"a chick",
"a rock",
"a human baby",
"an egg"
] | A | a mother births offspring |
OpenBookQA | OpenBookQA-3328 | newtonian-mechanics, newtonian-gravity, air, drag
$$\frac{v}{v'} = \frac{60 m/s}{15 m/s} $$
$$ \frac{g}{g'} = \left(\frac{60}{15}\right)^2 = 16$$
So my answer is quite simply that gravity would have to be 1/16th as strong as it is on Earth, or $0.6 m/s$. Are there any bodies in the solar system quite like this? Wikipedia is helpful here. Several bodies come close, like Pluto, Eris, or Triton, but none of them have much of an atmosphere. It is fun to think about, but I doubt that an atmosphere of such a high density with such a low gravity will be found in our local celestial neighborhood.
Walking would be difficult if such a planet existed, but not impossible. The moon is 1/3rd the gravity of Earth, so this hypothetical planet would be roughly 5 times less gravity than the moon. It would be very bouncy, but still very different from zero-gravity.
The following is multiple choice question (with options) to answer.
if these animals were planetary bodies, which of them would have the most gravitational pull? | [
"a bull on the couch",
"a mouse in the wall",
"a duck in the pond",
"a dog in the field"
] | A | the mass of a planet causes the pull of gravity on that planet |
OpenBookQA | OpenBookQA-3329 | zoology
Title: What is the reason for cats not liking water? I have two cats myself, a Siberian and a Maine Coon, neither of which like water. In fact, they detest it - like most cats. I was wondering what the reason for this was and if any of you have any interesting theories as to why this is the case.
Thanks in advance! First, some cats do like water. But it seems true (from personal observation and most people's opinion) that most cats don't.
The question has already been asked many times online. Just Google your question!
I doubt one will find peer-reviewed papers on the question but below is a summary of what seem to be the most often mentioned possible reasons I could find. Of course, these bullet points are very hypothetical and I don't know of any research presenting evidence for or against these hypotheses.
Their fur is not really adapted for the water and will very quickly become waterlogged and heavy making it uncomfortable.
Cats are generally speaking quite skittish
Cats may not like the odour of chemicals we put in the water.
Cats love to groom themselves. It is an aweful lot of work to do the grooming after a bath.
Note also that domestic cats are descendent from cats living in very arid areas. The most closely related species with cats are the African Wildcat living in Northern Africa, the Near East and around the periphery of the Arabian Peninsula.
Source
My non-peer reviewed sources are
http://www.petful.com/behaviors/why-do-cats-hate-water/
http://www.animalplanet.com/pets/healthy-pets/do-cats-really-hate-water/
http://www.petguide.com/blog/cat/why-do-cats-hate-water/
The following is multiple choice question (with options) to answer.
If a cat has a body temp that is below average, it is in | [
"good health",
"a good place",
"danger",
"safe ranges"
] | C | an animal usually requires a warm body temperature for survival |
OpenBookQA | OpenBookQA-3330 | If $\lambda$ is the expected times that you get spotted every hour, then $\theta=\frac{1}{\lambda}\$ is the expected time between events.
The number of events given in $t$ can be modeled by a random variable $N \sim Poisson(\lambda·t)$ where $t$ is the amount of time (in hours) elapsed, and the time between events can be modeled by a random variable $X\sim Exponential(\theta)$.
So, the probability of getting $n$ tickets in $t$ hours, with an expected probability of $\lambda$ that you get a ticket in one hour is: $$Pr\{N=n\ |\ \lambda, t\}=\frac{e^{-\lambda·t}·(\lambda·t)^{n}}{n!}$$ Since we need to calculate the probability of being spotted at least once, we can calculate $1-Pr\{N=0\}$. Then, for $n=0$, $\lambda=0.8$ and $t=0.5$, then: $$1-Pr\{N=0\ |\ \lambda=0.8, t=0.5\}=1-\frac{e^{-0.4}·(0.4)^{0}}{0!}=1-e^{-0.4}\approx0.4918$$
You should notice that, even if you "get spotted" more than once per day, this model still holds, since this process is memoryless.
Further reference: Ross, Sheldon, "Introduction to probability models", Ninth edition, Chapter 5.
(I really hope this is not your homework)
The following is multiple choice question (with options) to answer.
Which two events are guaranteed to each happen in a 24 hour cycle? | [
"a large star appearing and disappearing",
"an earthquake and a tornado",
"a rainbow and a tsunami appearing",
"a dog barking and a vitamin being eaten"
] | A | the sun setting occurs once per day |
OpenBookQA | OpenBookQA-3331 | experimental-physics, astronomy
This comment from Count Iblis, above,
You should just assemble a few devices that are as powerful as you can make them, perhaps 100 Gigaton TNT. Then you get an output that is 20 times the power emitted by the Sun, albeit for a fraction of a second. That will generate enough of a signal that can be easily detected from Earth
may support my argument that it may be possible to detect NEOs.
This comment from Dwin is also relevant in establishing the orbital parameters involved:
There's nothing that says that you cannot have multiple detonations. That way you could then "see" reflections at several times and thereby calculate trajectories
The following is multiple choice question (with options) to answer.
Which would be most effective way of being detected after the sun has set? | [
"having water",
"having reflectors",
"having signs",
"having books"
] | B | a reflector is used to reflect light especially on vehicles |
OpenBookQA | OpenBookQA-3332 | genetics, epidemiology, biostatistics
That is the denominator.
Taking that group of people, we can then ask:
Of those people that have the disease, what proportion of this affected group has a full sibling that also has the disease?
That is the numerator.
So if we have a population of 100 people, say 10 people have the disease. The denominator is then $0.1$. We might then observe that 4 of those cases are two pairs of siblings (and there are no other siblings). So
$$risk\ in\ sibling = Pr(sib\_has\_disease | person\_has\_disease) = \frac{4}{10} = 0.4$$
And thus
$$ \lambda_s = \frac{\text{risk of sibling}}{\text{risk in population}} \
= \frac{0.4}{0.1} = 4$$
It's worth pointing out that we are not controlling for environment or for pedigree or anything like that here. The null hypothesis of what $\lambda_s$ should be without any genetic risk is a complex function of prevalence and family structure (what if everyone is an only child, or the whole population is all siblings?). So it's not even clear how to interpret it, except to say that you might intuitively guess that a disease that strikes purely randomly might have $lambda_s = 1$. But I'm not even sure that that's true! All that this ratio is measuring is a rough estimate of how clustered the disease is within families within a population.
The following is multiple choice question (with options) to answer.
which of these people would be most susceptible to disease? | [
"a person with a healthy white blood cell",
"a person with optimal conditions",
"a person with a weak white blood cell",
"an athlete with a clean bill of health"
] | C | white blood cell destroys pathogens in the body |
OpenBookQA | OpenBookQA-3333 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A learned behavior | [
"newborn turtles crawling towards the sea",
"seals clapping to the delight of an audience",
"ducks sitting on their eggs (D) baby birds chewing worms",
"mother dogs nursing their pups"
] | B | if an animal is trained to do something then that something is a learned behavior |
OpenBookQA | OpenBookQA-3334 | home-experiment, oxidation-state
Title: the perfect campfire As far as chemistry goes, there are laws or observations that can be useful to determine the perfect shape and disposition of the wood in a campfire ?
For example what chemistry says about the 2 most popular "shapes"
teepee
log cabin
or even other variations such as the swedish stove ( 1 log with the top splitted in multiple segments )
The properties that I'm looking for:
- easy to start
- long lasting
The properties that I would like to have but I can discard:
- significant heat generation From many years as a trained firefighter, I can tell you that there is certainly science involved. There are a number of very heavy calculations for calculating things like solid combustible burn time and heat release rates for combustible materials, which might possibly be useful to predict the perfect shape, fuel size and arrangement for a campfire, but are probably well beyond the scope of producing the perfect sausage sizzle. However, a number of key factors that influence fire behaviour, and which must be considered in building the best campfire include:
The following is multiple choice question (with options) to answer.
A person puts a potato in some embers on the edge of a campfire and the potato gets hot. The embers are | [
"good for food",
"a cool source",
"meant to sleep",
"a exothermic reaction"
] | D | an exothermic reaction increases the amount of heat |
OpenBookQA | OpenBookQA-3335 | glaciology, glacier, ice
What would be a good average to take? This is a non-trivial issue. When you look at volume change of a glacier, you typically subtract two digital elevation models to obtain the difference between the two. First, you must differentiate between ice sheets where ice berg calving reduces volume and more ordinary glaciers with melt processes. There are of course calving glaciers as well so it is possible to get into great detail for any one specific glacier, so here I will just discuss the most common case which is a smaller glacier with melt-freeze conditions.
The change in elevation differs in magnitude across the glacier surface due to the movement of the glacier and accumulation-melt processes. The surface material can be (1) glacier ice, (2) snow, (3) firn snow that has survived a melt season) or (4) super imposed ice all with more or less differing densities, you need to assess what sort of material has been removed.
Ice can be approximated by a density of 900 kg/m3, firn has a density of about 600 kg/m3 but it must be remembered that the firn is converted to glacier ice by metamorphic processes so that the density changes with depth from 600 to 900 kg/m3. the transition to ice occurs at depths of about 30 m in temperate glaciers although few studies exist on the actual processes that occur. Snow have very differing densities but considering averages, I would say that it would vary between 350 to maybe 500 kg/m3 for winter (cold) conditions and around 550 kg/m3 for a melting snow pack. Super-imposed ice is closer to ice and probably varies in the upper range of 800--900 kg/m3.
To make matters worse, snow superimposes firn which in turn superimposes ice. This means that in the accumulation area, volume change can result from both a reduction in a snow cover and the firn layer. In the zone near the equilibrium line there can be a loss of both firn and ice. this is also where the superimposed ice will play a role.
So there is no simple density to use since the loss you try to estimate will involve varying types of densities spatially as well as vertically. For annual changes, you can largely ignore the vertical distribution, but with volume changes covering larger periods where climate change influences the longer term location of the equilibrium line and the size of the accumulation area, vertical layering also has to be included.
The following is multiple choice question (with options) to answer.
A glacier moves like a | [
"crocodile",
"tortoise",
"Komodo dragon",
"rattlesnake"
] | B | a glacier moves slowly |
OpenBookQA | OpenBookQA-3336 | thermodynamics, entropy, evaporation
Title: Does $dS = \frac{dQ}{T}$ explain why evaporation increases total entropy? When a cup of water evaporates into air, water molecules collide near the water-air surface in such a way that enables one of the water molecules to escape the water surface. In each such collision, a little kinetic energy $\Delta KE$ is transferred to the energetic molecule that escapes. This process does not require an addition of heat $Q$ from the surroundings, because the kinetic energy $\Delta KE$ is transferred between two water molecules and is not transferred from the surroundings.
This post and this post seem to state that the process of evaporation increases the total entropy of system + the surroundings. The posts/answers in those links offer a variety of ways of explaining this, including that (a) the increase in total entropy is due to a difference in chemical potential µ, and (b) the increase in total entropy is due to the fact that gases have a higher specific entropy. I believe I read elsewhere that gases generally have more microstates than liquids, which would also why the total entropy increases during the transformation of a liquid into a gas.
My question doesn't relate to these answers, but instead is about how the equation $dS=\frac{dQ}{T}$ applies to evaporation. In particular: how does this equation explain why total entropy increases during evaporation? What are the correct values for $dQ$?
One guess that I have is: $dQ$ equals the kinetic energy $\Delta KE$ transferred to the energetic water molecule during the collision at the surface. On the one hand, substituting $\Delta KE$ in for $dQ$ makes some sense to me because I don't know of any other energy exchanges that occur during evaporation except the transfer of $\Delta KE$. On the other hand, my statement $dQ = \Delta KE$ seems wrong because $dQ$ is supposed to be the heat transferred between the surroundings and the system, and $\Delta KE$ is energy transferred within the system. (Only once evaporation occurs does the escaped particle become part of the 'surroundings.')
The following is multiple choice question (with options) to answer.
What kind of energy causes evaporation? | [
"hot",
"cold",
"sound",
"kinetic"
] | A | as temperature in an environment decreases , the amount of water an animal in that environment will lose will decrease |
OpenBookQA | OpenBookQA-3337 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
humans will have to flee if their home is | [
"being built",
"being painted",
"demolished",
"prepared"
] | C | shelter can protect humans from weather |
OpenBookQA | OpenBookQA-3338 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
Porpoises move fastest in | [
"dungeons",
"lava",
"deserts",
"saltwater"
] | D | large fins can be used to move quickly through water |
OpenBookQA | OpenBookQA-3339 | paleontology, fossils, desert
Title: Why are many fossils found in deserts? Why are deserts famous for fossils? Is it a coincidence? Some examples:
Giant Catfish Fossil Found in Egyptian Desert
Chile's stunning fossil whale graveyard explained
Giant Dinosaur Fossil Found in Sahara Desert I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location. Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago. The fact that a location today is a desert has no indication of what the climate, or even where on the globe that location was 50 or 100 million years ago.
Do not forget about plate tectonics and climate change. One can go to places like the Judith Basin in Montana, a relatively harsh area of North American Bad Lands, desert or near desert like conditions with cold winters and find fields of fossils from animals that are believed to have lived in tropic marshes of in oceans, because at the time those animals lived, what is now Montana was not inland, and was not at a Northern location. Millions of years ago it was an undersea plate, thus it has layers of limestone made from ancient single cell sea creatures and sometimes larger objects that were entrapped and preserved as larger fossils. At other times, those plates rose from the sea floor and homed some of the large creatures, like T-Rex that lived, thrived and sometimes survive as fossils.
Later, that plate move and ended up inland, in what is not North America. Glaciers, wind, and water may have stripped off many layers of deposits and left exposed or close to exposed the layers of interest to fossil hunters. Desert regions tend to be subjected to this type of erosion and exposure making such finds easier. If those same fossils were in and area such as a rich planes area with plentiful plant growth and never subjected to glacial scouring, they could be, and may very well be, right below your feet but under many layers of soil and decaying vegetation, river sediment and other deposits rendering them out of sight and out of reach.
The following is multiple choice question (with options) to answer.
Nearly all prehistoric bones are found in | [
"granite",
"shale",
"trees",
"marble"
] | B | nearly all fossils are found in sedimentary rock |
OpenBookQA | OpenBookQA-3340 | soft-question, theory-of-everything
Title: Physics after a Theory of Everything There is a lot of controversy over the existence of a Theory of Everything (ToE), and as far as I know, we are a long way from having a possible candidate. But what interests me is, what after that? If a Theory of Everything is truly found, will there be anything left for physics to do? Is a ToE actually the end of Physics? Or are there things that will remain unexplained even after a ToE is found out?
Edit (7/1/2016):
Just to make it fit for this site, my question is What are the areas of physics that would require working on, even if a ToE is discovered?
I hope I have been able to "isolate an issue that can be answered in a few paragraphs". No, I think. There are many open problems in condensed matter physics. For example, I heard from my professors that the mechanism behind new superconductors is still a mystery.
Also. To understand the underlying rules does not always explain the system as a whole. There are complex systems that obeys simple underlying rules but cannot be explained directly by these simple rules, like biological systems.
And even simple rules could develop complex results. Examples like the game of life and the cellular automata. So I think there are still much more for physicists to explain.
The following is multiple choice question (with options) to answer.
After life all things | [
"decompose",
"freeze in time",
"become lively",
"regenerate"
] | A | dead organisms decay |
OpenBookQA | OpenBookQA-3341 | 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.
Pollution is caused by using what? | [
"chevy rides",
"car pictures",
"sunlight",
"plants"
] | A | using a car causes pollution |
OpenBookQA | OpenBookQA-3342 | 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.
Polar bears grew thick fur because | [
"they wanted to be hunted and end up on someone's living room floor",
"it helps them survive in frigid places",
"it helps them live in the desert",
"it's helpful in a rain forest"
] | B | adaptations are used for survival |
OpenBookQA | OpenBookQA-3343 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
What would have a better chance of survival if predators decreased? | [
"Hamsters",
"Snakes",
"Killer Whales",
"Tigers"
] | A | as population of prey decreases , the population of predators will decrease |
OpenBookQA | OpenBookQA-3344 | It just turns out nicely for C that he is one of the people whose hat colors D and C both know about.
To introduce a modified challange: if the task were to yell out C's hat color right away, D would know for certain, C would have the increased probability of $2/3$ and A and B would be stuck with the random guess of $1/2$. D still knows more.
The following is multiple choice question (with options) to answer.
A learned characteristic could be | [
"Eye color",
"a cartwheel",
"freckles",
"Hair color"
] | B | doing chores is a learned characteristic |
OpenBookQA | OpenBookQA-3345 | 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.
Unlike CO2, oxygen is a waste product of | [
"the moon",
"rocks",
"cactus",
"hair"
] | C | In the photosynthesis process oxygen has the role of waste product |
OpenBookQA | OpenBookQA-3346 | # Logic problem
##### Active member
Consider the following sequence of statements:
$$S_1: \text{at least 1 of the statements }S_1-S_n \text{ is false}\\ S_2: \text{at least 2 of the statements }S_1-S_n \text{ are false}\\ \vdots \\ S_n: \text{at least } n \text{ of the statements }S_1-S_n \text{ are false}$$
Where $n$ is some integer.
Question: for which $n$ are these statements self-consistent? In those cases: what is the truth value of each statement?
I got this off of a blog I tend to frequent. I will wait before posting the solution this time.
EDIT:
Changed the question; I had written the statements wrong
Last edited:
#### Klaas van Aarsen
##### MHB Seeker
Staff member
Suppose $k$ out of $n$ statements are true.
Then $S_1$ up to $S_k$ have to be true and the rest has to be false.
This appears to be consistent for any $n$ and any $0\le k \le n$.
##### Active member
Suppose $k$ out of $n$ statements are true.
Then $S_1$ up to $S_k$ have to be true and the rest has to be false.
This appears to be consistent for any $n$ and any $0\le k \le n$.
Sorry about that, you were absolutely right about the question as phrased.
However, this new version should prove to be a bit more interesting. This is what I had meant; I had accidentally written "true" instead of "false".
#### Klaas van Aarsen
##### MHB Seeker
Staff member
If $S_n$ is true, then $n$ statements are false, including $S_n$.
Therefore $S_n$ is false.
We now know that at least $1$ statement is false.
Therefore $S_1$ is true.
For $n=1$ this is a contradiction, and for $n=2$ this is a consistent solution.
The following is multiple choice question (with options) to answer.
What is the most accurate statement? | [
"without global warming, most days would be hotter",
"without underground water reservoirs, most days would be hotter",
"without the Sun, most days would be hotter",
"without the ocean, most days would be hotter"
] | D | water absorbs solar energy in the water cycle |
OpenBookQA | OpenBookQA-3347 | botany, terminology, trees
Title: Branch taking over a tree trunk I stumbled upon a birch growing in sandy soil in a coniferous forest in central Russia.
It looks like over time the tree trunk got bent towards the trail and one of the branches became the new trunk as it now grows straight up, whereas the old trunk is pointing sideways.1
The tree isn't dead, I visited that place during summer time and it was covered with green foliage.
I'm wondering what's the name of such phenomena, how common it is and what usually causes the tree "to change it's mind"?
The following is multiple choice question (with options) to answer.
A fallen tree may provide what? | [
"Hope",
"Happiness",
"Love",
"Thriving life"
] | D | if a tree falls then that tree is dead |
OpenBookQA | OpenBookQA-3348 | climate-change, climate, paleoclimatology, carbon-cycle
Title: Did climate cool down when underground hydrocarbons stocks formed? As far as I understand, the dominant theory of modern climate change says that recent warming is mainly caused by the massive burning of hydrocarbons that used to be stored in solid form mostly underground as petroleum, coal, etc.
This suggests that the reverse process should contribute to a cooling of the climate (or to a slowed down warming if other processes are at play at the same time).
In particular, a cooling should have occurred throughout the period when the stocks of underground hydrocarbons were formed by the "pilling" of organic remains.
My questions:
The following is multiple choice question (with options) to answer.
which of these eventually form crude oil after millions of years in the earth? | [
"a plastic set of cups",
"a family of dogs",
"a twelve pack of beer cans",
"a set of silverware"
] | B | an organism is a source of organic material |
OpenBookQA | OpenBookQA-3349 | ### Show Tags
23 Dec 2016, 09:03
2x+50/5x+40=4/6, find x, then don't get into decimals, approx 17.something then 2(17)+5(17)= approx 122
Veritas Prep GMAT Instructor
Joined: 16 Oct 2010
Posts: 9558
Location: Pune, India
Re: Two mixtures A and B contain milk and water in the ratios [#permalink]
### Show Tags
09 Nov 2017, 02:28
4
bmwhype2 wrote:
Two mixtures A and B contain milk and water in the ratios 2:5 and 5:4 respectively. How many gallons of A must be mixed with 90 gallons of B so that the resultant mixture contains 40% milk?
A. 144
B. 122.5
C. 105.10
D. 72
E. 134
Responding to a pm:
Here is the weighted average method of solving it:
Concentration of milk in the first mixture = 2/7 = 18/63 = 90/315
Concentration of milk in the second mixture = 5/9 = 35/63 = 175/315
Concentration of milk in the resultant mixture = 2/5 = 126/315
w1/w2 = (A2 - Aavg)/(Aavg - A1)
w1/w2 = (175/315 - 126/315) / (126/315 - 90/315) = 49 / 36
So 36 gallons of mixture B needs 49 gallons of A
90 gallons of B will need (49/36)*90 = 122.5 gallons
The numbers in the question are hard to work with. In most GMAT questions, the numbers fall easily in place. It is the concept that you have to focus on.
_________________
Karishma
Veritas Prep GMAT Instructor
Senior SC Moderator
Joined: 22 May 2016
Posts: 3284
Two mixtures A and B contain milk and water in the ratios [#permalink]
### Show Tags
09 Nov 2017, 11:23
1
1
bmwhype2 wrote:
Two mixtures A and B contain milk and water in the ratios 2:5 and 5:4 respectively. How many gallons of A must be mixed with 90 gallons of B so that the resultant mixture contains 40% milk?
The following is multiple choice question (with options) to answer.
If a baby needs to have milk every hour and is only given it every six hours | [
"it will be glad for it",
"it will be negatively effected",
"it will be positively effected",
"it will be overweight"
] | B | the decrease of something required by an organism has a negative impact on that organism 's survival |
OpenBookQA | OpenBookQA-3350 | sleep
Title: What are the essential criteria for sleep in living organisms? I was reading this fascinating article about how sleep evolved before brains, and it got me thinking "can plants sleep" and "what is sleep anyway".
A line in the article states:
Studies by a team in South Korea and Japan showed that the hydra
periodically drops into a rest state that meets the essential criteria
for sleep.
But after looking around I am unable to find the "essential criteria for sleep" - Before I am able to answer questions like "can plants sleep" I think I first need to understand what these essential criteria for sleep actually are.
Can anyone here help me out? Many thanks in advance. I take it you did not even read the article. The article quite nicely expounds on this question. The whole idea is that sleep used to be considered as a human or psychological phenomenon that could only be studied by EEG, and clearly sleep was a phenomenon that goes deeper and wider in biology than just EEG waves. From the same article, just a little below:
She distilled a set of behavioral criteria to identify sleep without the EEG. A sleeping animal does not move around. It is harder to rouse than one that’s simply resting. It may take on a different pose than when awake, or it may seek out a specific location for sleep. Once awakened it behaves normally rather than sluggishly. And Tobler added a criterion of her own, drawn from her work with rats: A sleeping animal that has been disturbed will later sleep longer or more deeply than usual, a phenomenon called sleep homeostasis.
The keyword is behavioral criteria.
This is cited, I recommend a read-through.
I also recommend reading the rest of the article, it guides you through the status quo in sleep science which may further answer more of your questions. At the end, there is an exposition on animals without brains that seem to be sleeping. The hydra is one of them.
The following is multiple choice question (with options) to answer.
What can help you sleep soundly? | [
"torture",
"anxiety",
"ear plugs",
"stress"
] | C | when sound reaches the ear , that sound can be heard |
OpenBookQA | OpenBookQA-3351 | population-dynamics, population-biology
Title: Spread of a benign virus in a population over time This is a somewhat difficult (for me) population dynamics question and I wonder if someone with experience in this area could suggest a reasonable approach?
My simplifying assumptions: As a gross oversimplification, let p(k) be the world's population at generation k, and assume a smooth exponential curve that models p(k) from $k=0$ at 10,0000 B.C.E to generation $k=600$ in 2000 C.E. A generation is 20 years, and in acc. with this Wiki there are about 4 million individuals at $k=0$ and 6070 million at $k=600.$
(Of course the exponential model is bad, as world population growth appears to have been sluggish before recorded history.)
Now assume a benign virus infects 120 individuals in $k=0.$ It benignly infects all individuals who have at least one infected parent. Perhaps unimportantly, it also continues to infect 30 new individuals per million in each generation (because its found in the soil), but would not infect those already exposed.
Call infected individuals II and non-infected NI. They are indistinguishable without clinical tests--which are not done, since the virus is harmless. Since II individuals are almost certain to mate with NI individuals, in earlier generations, the number of II will grow very quickly. For a time the growth rate of II will exceed that of p(k). At some point it will be unlikely that an II individual will encounter an NI mate, however a few NI persons will still pair with NI mates--for a while.
My question is, after 600 generations, what is a reasonable estimate of the percentage of II in the population? Is is possible that there would be any NI individuals left? Or would we have some sort of dynamic equilibrium between II and NI in which (I think) the former would strongly dominate?
FWIW, the population growth model is $p(k)=4e^{0.012 k}$ with $p(k)$ in millions. For simplicity, I denote the population of non-infected individuals by $N$ and the infected ones by $I$.
Model without soil infection
The following is multiple choice question (with options) to answer.
Overpopulation may result | [
"from the deaths of many organisms",
"from a boom in reproduction of an organism",
"from natural predators hunting organisms",
"from organisms self regulating their population"
] | B | if the population of an organism increases then the ecosystem may become overpopulated with that organism |
OpenBookQA | OpenBookQA-3352 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
A creature with ability to lose hair is the | [
"clam",
"fly",
"fish",
"dalmatian"
] | D | shedding is when an animal loses hair |
OpenBookQA | OpenBookQA-3353 | human-biology, brain
So back to your original question: why don't we consciously know how our bodies work? Because it's completely unnecessary to know this for normal day to day operation in the context in which animals evolved.
The following is multiple choice question (with options) to answer.
how does an animal know to perform certain crucial life actions before exposure to it? | [
"it is built into their very being",
"it is taught in school",
"they are trained at a special school",
"they have magical powers"
] | A | An example of an instinct is the kangaroo 's ability to crawl into its mother 's pouch to drink milk |
OpenBookQA | OpenBookQA-3354 | 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.
During photosynthesis plants make their own | [
"magic",
"candy",
"sustenance",
"cars"
] | C | a leaf performs photosynthesis |
OpenBookQA | OpenBookQA-3355 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
Which is likely to occur as leaves fall off the trees and food becomes less plentiful? | [
"a hare grows longer fur",
"a worm grows longer fur",
"a worm sings louder",
"a hare sings louder"
] | A | seasonal changes are made in response to changes in the environment |
OpenBookQA | OpenBookQA-3356 | metabolism, ecology, photosynthesis
Title: Why isn't phosphorus or nitrogen a limiting nutrient for animals? Nitrogen and Phosphorus are usually the limiting nutrient for plants, especially for algae. Phosphorus is used for DNA, ATP and phospholipids, and Nitrogen is used for pretty much every protein a cell might want to produce. That is, their need for biological processes is not tied specifically to photosynthesis: anything that lives is going to need them, pretty much for anything it might want to do. It would make sense for them to be a limiting nutrient for almost anything that's trying to grow, plant or animal.
Yet for animals the limiting "nutrient" seems to always be energy, ie: food. Why aren't animals limited by lack of nutrients in the same way that plants are? Obviously animals need these nutrients, too. Or to reverse the question, why do plants need so much more phosphorus/nitrogen than animals do?
My best guess is that an animal's digestion of plant material is relatively inefficient energy-wise but relatively efficient nutrient-wise. So for an animal to eat enough food to have sufficient energy to survive, it's probably eaten more than enough Nitrogen and Phosphorus for its needs. But I'm just guessing and I can't find any data that would back up that guess. Phosphorus
Your suggestion that if we are meeting our calorific requirement we will be getting enough is true for phosphorus.
Most foods contain lots of phosphorus. The maximum dietary requirement occurs during adolescent growth, estimated at 1250 mg per day. Assuming a calorie intake of 2500 kcal we can calculate a 2500 kcal equivalent phosphorus content for various foods:
skimmed milk contains 7,400 mg phosphorus per 2500 kcal
roasted chicken breast contains 7,500 mg phosphorus per 2500 kcal
cooked white rice contains 3840 mg per 2500 kcal
(Calculations are based upon values obtained via this site.)
Nitrogen
Our requirement for nitrogen is met by our protein intake: inadequate protein intake manifests as kwashiorkor which is essentially due to a dietary deficiency of essential amino acids. In other words, the only way to achieve a nitrogen-deficient diet is to not eat protein, and this would not be alleviated by any inorganic source of nitrogen, even if we could consume enough of such a N source.
The following is multiple choice question (with options) to answer.
Corn would likely provide nutrients to | [
"a rock",
"a ice",
"a waterfall",
"a raven"
] | D | an animal requires nutrients for survival |
OpenBookQA | OpenBookQA-3357 | species-identification
Title: What bird / animal has this call? USA MA NE
I have a bird / animal coming to the trees in the backyard making this call (see link to audio file), which does not really sound like a bird - it's fairly low frequency. I have not seen it. Sometimes it sits in a young tree, where you can almost see through to the trunk. But I cannot make it out, so it's not very big (like a turkey). It comes at late afternoon and stays around until ~11PM. It switches trees fairly quickly, so I assume it can fly. The call is always the same. Sometimes another one of its kind answers.
Bird_animal_call_mp3
You don't need dropbox. Ignore "suspicious link". Close login popup. Click download arrow. Direct download.
I added a Soundcloud link:
Bird_animal_call_mp3 It is a grey tree frog's mating call. See youtube link:
Grey tree frog mating call
Source for finding the answer: Audubon Society
The following is multiple choice question (with options) to answer.
How can you get more song birds to visit your yard? | [
"put out some hamburgers to attract them",
"adopt some large dogs to stay in the yard",
"call Here birdy birdy! out the window",
"hang an open box containing tasty seeds from a tree"
] | D | feeders attract animals to a location |
OpenBookQA | OpenBookQA-3358 | mountains, rainfall
Title: Could a waterfall lashing onto a road lead to a landslide? Here is a video of a waterfall lashing on to a mountain road, with vehicles driving under it.
https://youtu.be/cHaguj--YBc
There appears to be a big hole carved out right next to the road, possibly by the force of the waterfall.
Is this a ticking time bomb for a landslide? Potentially, a landslide could occur. Whether it would be a minor slip or a major fall depends on the geological conditions at the site, the force of the water and the duration that the site is impacted by the water.
In the video in question, the rock face above the road appears competent, but there are not guarantees. The main issue would be is the water undermining the road which could cause a slip and the road to slide.
The more loose the geological material is, the easier it is to dislodge it. Once one item moves a chain of events can occur where additional items are dislodged and a slide occurs.
In addition to high pressure water dislodging material, water acts as a lubricant, making it easier for rocks and regolith to be dislodged.
To minimise the potential for a slide to occur in such a situation, the surface of the road would need to be sealed very well and a very good drainage system installed that would move the water away from the road and the slope below the road
The following is multiple choice question (with options) to answer.
if a local pond by the road receives unusual amounts of rainfall, what could happen? | [
"there could be a tsunami",
"there could be a road blockage",
"there could be an earthquake",
"there could be a volcanic eruption"
] | B | when a body of water receives more water than it can hold , a flood occurs |
OpenBookQA | OpenBookQA-3359 | This lets them bring a 15th bar and catch the train with less than 5 minutes to spare.
It is not possible to move all 16 bars.
Consider the total distance that each person moves, in each direction, carrying each possible number of bars. For example $$R_2^+$$ is the total distance that Rod moves forward while carrying 2 bars. We can set up a system of equations. Both Rod and Lia must move a net distance of $$1$$ mile forwards: $$R_0^+ - R_0^- + R_1^+ - R_1^- + R_2^+ - R_2^- = 1 \\ L_0^+ - L_0^- + L_1^+ - L_1^- = 1$$ Both of them must spend less than $$370$$ minutes moving (note we have taken the reciprocals of their speeds in minutes per mile): $$20(R_0^+ + R_0^-) + 30(R_1^+ + R_1^-) + 60(R_2^+ + R_2^-) \le 370 \\ 30(L_0^+ + L_0^-) + 40(L_1^+ + L_1^-) \le 370$$ Finally, the total net distance moved by all the bars must be $$16$$ miles forwards: $$R_1^+ - R_1^- + 2(R_2^+ - R_2^-) + L_1^+ - L_1^- = 16$$ And of course each distance must be nonnegative.
Next (thanks to RobPratt) we multiply these equations by $$\frac{1}{2}$$, $$\frac{3}{7}$$, $$\frac{1}{40}$$, $$\frac{1}{70}$$, and $$-1$$ respectively, and sum them, yielding:
The following is multiple choice question (with options) to answer.
if a person travels on foot from home to school, which of these is given off? | [
"a release of vitamins",
"a release of water vapor",
"a blaze of fire",
"a release of heat"
] | D | moving changes stored energy into motion and heat |
OpenBookQA | OpenBookQA-3360 | orbit, the-sun, earth
Notes:
It takes the Earth 365.256363004 days to revolve around
the Sun with respect to the fixed stars, but the time
between vernal equinoxes is slightly less (365.242190402
days) because the position of the vernal equinox moves
(precesses) with respect to the stars. Source:
http://hpiers.obspm.fr/eop-pc/models/constants.html
The Gregorian calendar's average day length of 365.2425
is much closer to 365.242190402 days than the Julian
calendar's 365.25 average day length, but it's still not
perfect. As noted in
Do solstices and equinoxes shift over time?
if we continue using the Gregorian calendar in the far
future, the equinoxes and solstices will drift
backwards. By 17090 (the limit of DE431), they will look
like this:
EQU 476198945887.238159 A.D. 17090-02-22 08:56:59
SOL 476207018540.040894 A.D. 17090-05-26 19:21:11
EQU 476214808218.146362 A.D. 17090-08-24 23:09:09
SOL 476222655067.609985 A.D. 17090-11-23 18:49:59
about a month behind their "regular" times.
MY EARLIER PARTIAL ANSWER FOR REFERENCE:
Since HORIZONS (http://ssd.jpl.nasa.gov/?horizons) and SPICE (http://naif.jpl.nasa.gov/naif/tutorials.html) can compute the ecliptic and solar position back that far, it should be possible to compute equinoxes and solstices with reasonable accuracy. However, I haven't been able to find a site that actually lists these dates (I'm pretty sure USNO did this at one point, but I can't find their list). Other possibly helpful sources/questions:
The following is multiple choice question (with options) to answer.
What is the proper ratio of weeks to the Earth's revolution around the Sun? | [
"365 :: 1",
"52 :: 1",
"33 :: 1",
"1 :: 1"
] | B | a complete revolution of the Earth around the sun takes one solar year |
OpenBookQA | OpenBookQA-3361 | species-identification, botany, ecology
Title: Algae or Lichen identification. Coastal BC, Canada I have tried all books and internet resources I know of, but I still have no idea what this might be — a lichen or something else.
At first glimpse, I thought it was something man-made and unnatural, but then I looked closer and saw how it appears to be attached and growing. It grows on exposed rocks well above the high tide. The photo is taken in late March, on northern Vancouver Island. It's loosely attached to the rock.
It was somewhat abundant around the general area (within of a few km), but I haven't seen it elsewhere - although I'm not from BC so there might be a lot of this around.
The water droplet in the lower right corner give a rough sense of scale.
Edit:
Adding another photo in which I just noticed a streak of white, which I included in original resolution. I want to propose you expand your search to a broader taxonomic scope. Specifically, I think you might be looking at a species of "red" green algae (family: Trentepohliaceae).
From Nelson et al. (2011):
All Trentepohliaceae have filamentous growth forms and often contain large amounts of carotenoid pigments (ß-carotene and hematochrome), causing the algae to appear yellow orange in color (Thompson and Wujek 1997, Lo´pez-Bautista et al. 2002).
The Trentepohliaceae contains five genera: (Trentepohlia, Printzina, Phycopeltis, Cephaleuros and Stomatochroon) and 70+ species worldwide.
For example, the following algae (picture from England) looks fairly similar to your specimen:
Trentepohlia aurea
Source: David Fenwick
If your specimen is a species in this family of algae, it is most likely in the Trentepohlia genus (or possibly Printzina genus).
Trentepohlia is a genus of filamentous chlorophyte green algae in the family Trentepohliaceae.
Typically orange or yellow in color.
Live on tree trunks and wet rocks or symbiotically in lichens.
Here's a picture of a free-living Trentepohlia species from coastal Oregon, USA:
Source: Richard C. Hoyer (2015)
The following is multiple choice question (with options) to answer.
Coral gets some help with algae for their | [
"love",
"dating advice",
"happiness",
"vibrance"
] | D | usually coral lives in warm water |
OpenBookQA | OpenBookQA-3362 | thermodynamics, energy, power
Toyota Corolla, 13 gallon tank, 20% efficiency, 103 kWh usable energy
Tesla Roadster, 56 kWh battery capacity
Chevy Volt, 16 kWh battery capacity
If we compare a liquid Nitrogen car to the Chevy Volt it might not be so bad. But why would we do that? That car can still augment its range with gasoline. A part of the argument for electric cars is that you don't have the same energy loss from idling. Would that be true for a liquid Nitrogen car? There is no reason to believe that.
Let's say we assume a reasonable efficiency of half the isothermal process, which is illustrated in Figure 2 of the reference. Let's also say we'll hold 50 kWh of usable energy in the tank (even though this could still cause range problems). We've increased the tank size by a factor of 4 and the weight of the full tank is now around $1000 kg$. This is close to what many cars weigh.
The energy content relative to gasoline, as well as the alternatives, kills the idea. It would seem to require extremely optimistic assumptions to make it a reasonable proposal before we even get into the discussion about infrastructure needed to make it happen. The most fair comparison would be to other cars that also use alternative fuels, but it fails there too. EVs seem to have better viability on the basis of simple energetics. Maybe you're concerned that we'll run out of Lithium. A vehicle powered by compressed natural gas (not even the super-high pressure tanks that many have hope in) would blow it away, and the tank would be more manageable. Plus the fuel would be (dramatically) cheaper. Plus the infrastructure would be there. Plus, the engine is a proven design. We could do better with coal-to-liquids, we could probably do better with biofuels.
The following is multiple choice question (with options) to answer.
Fueling an electric vehicle requires | [
"a socket",
"petroleum products",
"a gasoline pump",
"fossil fuels"
] | A | an electric car contains an electric motor |
OpenBookQA | OpenBookQA-3363 | infection, amphibians
Title: What is this toad suffering from? Myiasis or chytridiomycosis? I found this toad on Aug. 29th at this location: position on osm
I think it is a bufo bufo, approx. 10 cm long. The nostrils seemed to be completely filled with a grey matter and from the activity of the floor of the mouth it apparently tried to breathe againgst this obstruction. It probably had enough oxygen via its skin though.
I tried to remove the obstruction using a blade of grass but this seemed to produce some pain as the toad closed its eyes on contact, so I stopped. The skin looked fairly normal and the toad was able to walk away after a while.
I can think of two causes for this condition.
Batrachochytrium dendrobatidis infestation
Lucilia bufonivora larvae
I could not see properly, if there were any larvae or unhatched eggs inside the nostrils, but as the rest of the skin seemed unharmed I assume the latter.
Is my assumption valid or is there even a third possibility? It is a female Bufo Bufo and you are right, there are toad fly (Lucilia bufonivora) larvae/eggs inside her nostrills. These flies lay their eggs inside toads' nostrills (specifically on Bufo Bufos) and the larvae start eating them. Sadly this disease ends up by the death of toad. They slowly eat nostrills, then mouth, eyes, and all the head.
Here's a photo of a male bufo bufo, without a head. Someone found it walking around at this situation. https://i.stack.imgur.com/I6twl.jpg
The following is multiple choice question (with options) to answer.
If a frog is a baby, then it has | [
"zero legs",
"four legs",
"two legs",
"zero parents"
] | A | amphibians hatch from eggs |
OpenBookQA | OpenBookQA-3364 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
If a tree is growing in an area that is most ideal to it, the dirt will be | [
"firm",
"loose",
"packed tight",
"airless"
] | B | the looseness of soil has a positive impact on a plant 's roots' growth in that soil |
OpenBookQA | OpenBookQA-3365 | 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 the | [
"ears",
"stomach",
"nose",
"thighs"
] | B | the skeletal system protects internal organs |
OpenBookQA | OpenBookQA-3366 | ecology, database, biodiversity, species-distribution
Title: Database of Geographic Range of Species Is there a database of organisms which would contain their queriable geographic location?
I would need to perform a rather simple query, such as Animals of <Location>, where Location is some well defined geographic area such as Czech Republic or Europe.
So far I have found multiple lists on Wikipedia and other webpages, however they seem to be quite incomplete as their intersect is quite small. Moreover, I have found EOL (Encyclopedia of Life) collections but they appear to struggle the same way. This is to a large extent a question of how reliable the data in the database needs to be. Reliability (and spatial scale) will differ between datasets and between species groups within datasets, and it is difficult to give a general recommendation. I doubt that you will find a single database with good coverage over all taxonomic groups, even if it is in the form of country checklists. For the most reliable information, curated country checklists for specific taxonomic groups will probably be best, but these have to be searched for individually for each taxonomic group of interest.
As a starting point, you might want to look at the occurence data that can be found in gbif.org (The Global Biodiversity Facility). The data found there is certainly not complete, and it will be misleading for many species. However, for the current distribution of relatively well-known groups of species it will give you a good idea of their distribution. This has to be evaluated on a case-by-case basis though. You can access the data in gbif using external tools, for instance using R through rgbif (there is also tools for python or other languages). At the blog recology.info you can find a tutorial on how to get a species list for a particular country using rgbif (more specifically the function density_spplist).
The following is multiple choice question (with options) to answer.
Which is likeliest to provide a home for many species? | [
"a fish tank",
"human hair",
"a fish",
"a log"
] | D | a tree is a source of food for birds in an ecosystem |
OpenBookQA | OpenBookQA-3367 | evolution, human-evolution
Title: Can there be significant new changes in physical features of Humans due to evolution in 10000 years of span? Humans migrated from Africa about 60000 years. And in these years humans physical features undergone significantly in terms of skin color, hair, eye color and facial features.
So, with this we can say that given 10000 years of span we can see a significant noticeable new changes in physical features of humans? like some humans with new skin color (apart from today's white, black and brown), new color eye balls, big heads etc.? Yes & perhaps (or probably?) no, depending on what you define as significant changes.
Less than 10,000 years ago everyone in the british isles & the rest of europe were dark skinned so the answer if (unlike me) you consider the change in skin color a significant change is obviously a resounding yes.
Here's what English people looked like 10,000 years ago
Darker skinned than you were expecting perhaps.
If as suggested in this article white skin arrived in Europe around 5,000 years ago that only leaves 2,000 years before early Greek & Roman art we have available which shows it as ubiquitous, so it perhaps took only 2,000 years or so (maybe less) to become dominant in europe, that's fast.
Using 20 years as the measure of a generation that's only 100 generations, so, very fast.
Timeline of human prehistory
The first reconstruction in the link below is a reconstruction of a Neanderthal woman found in a cave in Gibraltar. She died at least 30,000 years ago.
Here she is, the skin tone may not be accurate but we do know from gene's recovered from Neanderthal remains that they were relatively light skinned.
Personally I don't consider her appearance to be significantly different from modern humans.
29 Reconstructed Faces Of Ancient People
So my answer based on what I consider significant changes would be no.
But for you or others the answer may well be yes.
And of course a mutation for a new eye colour could appear at any time in one individual & spread like wildfire practically overnight just because we think it's unusual & 'cool' (aka sexual selection) so if eye color ticks your boxes it's a very definite yes.
The following is multiple choice question (with options) to answer.
The face of the sphinx has changed from | [
"wearing away",
"boredom",
"social media",
"being sued"
] | A | wind and rain cause erosion |
OpenBookQA | OpenBookQA-3368 | [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.
Which of the following is likely to reject nutrients from food? | [
"bamboo",
"a human",
"a lion",
"a horse"
] | A | roots are a vehicle for absorbing water and nutrients from soil into the plant |
OpenBookQA | OpenBookQA-3369 | entropy, potential-energy
A more prosaic answer is that life doesn't seem to have much of a choice about what it's made of. All life on Earth is made of water, proteins, and smaller amounts of lipids and other organic compounds. At the origins of life this probably wouldn't have been so far from equilibrium, since in a reducing atmosphere amino acids can form spontaneously. However, the combined result of photosynthesis and limestone formation is that the atmosphere is now highly oxidising, which means that on today's Earth protein burns rather nicely.
In summary, the reasons that living organisms are made of unstable matter are that (i) if they didn't extract energy from their environment, we wouldn't consider them alive; (ii) if you extract energy from your environment, you become thermodynamically unstable; (iii) it's difficult if not impossible to have a complicated, yet organised, molecular structure without being far from equilibrium; and (iv) the decision to be made of proteins, which are particularly unstable, was made a long time ago, when they weren't anywhere near as flammable as they are today.
The following is multiple choice question (with options) to answer.
Which is likely made of molecules? | [
"empty space",
"an osprey",
"one's soul",
"nothingness"
] | B | matter is made of molecules |
OpenBookQA | OpenBookQA-3370 | fluid-mechanics, fluid
Title: Why does this glass tend to stick on surfaces I have a glass here.
This is the bottom face of the glass.
Now this is on what I had kept my glass. There is a little much of water spilled on it. Let us call this thing as C
Now , when I lifted the cup. The C on which I had kept my glass also lifted up. The bottom portion of glass and the top portion of the thing were in contact. They did not leave each other.
Now , the bottom portion of the cup is flat. So, I kept my glass on that C. The cup and the C both lifted up. Why is it like that ? They should not do this. The surface of C where the glass sat is smooth, then the glass may have a slightly concave bottom and the water, with capillary action, managed to form a seal between the two surfaces. Even if the glass bottom and surface C are both flat, capillary action can still form a seal around the edge leaving a void in the centre, causing the same effect of lower v. higher pressure.
If the air trapped in there then cools down a few degrees - the outside air pressure holds the two items together. Until of course mass or vibration takes over and the item C falls off.
Happens often with coasters and glasses.
A hot cup of tea can show bubbles when there is some spilt tea in the saucer - the trapped air is being heated, until the tea in the cup cools and we have the same situation as above.
The following is multiple choice question (with options) to answer.
The most common way for a glass to break is when someone is holding it and then drops it, which makes it what to the ground | [
"cries",
"plunge",
"Sells",
"laughs"
] | B | dropping something causes that something to fall |
OpenBookQA | OpenBookQA-3371 | organic-chemistry, molecular-structure, molecules, intermolecular-forces, catalysis
It is also important to note that cavity size of CD seems to depend on the method used by the researcher (Ref.4). For instance, Ref.2 reported that inner diameters of $\pu{5.7 Å}$ for $\alpha$-cyclodextrin, $\pu{7.8 Å}$ for $\beta$-cyclodextrin, and $\pu{9.5 Å}$ for $\gamma$-cyclodextrin, but did not verify each was the upper or the lower or middle diameter. Meantime, Ref.3 reported that top and bottom inner-diameters of $5.3$ and $\pu{4.7 Å}$ for $\alpha$-cyclodextrin, $6.5$ and $\pu{6.0 Å}$ for $\beta$-cyclodextrin, and $8.3$ and $\pu{7.5 Å}$ for $\gamma$-cyclodextrin. Therefore, it is hard to predict which molecule would bind to appropriate CD without knowing exact parameters of their cavity. Regardless of the reported cavity sizes, Ref.3 shows that the grafting of $\beta$-cyclodextrin to silica gel conveniently removed water soluble organic molecules with different sizes such as p-nitrophenol, p-nitroaniline, m-nitrophenol, p-chlorophenol, and phenol.
It is also evident that cyclodextrin-catalyzed organic synthesis can be achieved using $\beta$-cyclodextrin as the catalyst. In these reactions, you may find part of starting materials with different sizes making stable host-guest complexes with $\beta$-CD (Ref.5).
The following is multiple choice question (with options) to answer.
Which are likely slightly larger in size than its liquid counterparts? | [
"solid steel",
"solid wood",
"solid glaciers",
"solid mercury"
] | C | when water freezes , that water expands |
OpenBookQA | OpenBookQA-3372 | inorganic-chemistry, acid-base, everyday-chemistry
$$\ce{H2O + CO2(aq) <=> H2CO3}$$
and the protolysis of true $\ce{H2CO3}$
$$\ce{H2CO3 <=> H+ + HCO3-}$$
For a weak acid
$$\begin{align}
\log[\ce{H+}]&\approx\frac12\left(\log K_\mathrm a+\log[\ce{H2CO3^*}]\right)\\
&=\frac12\left(-6.3-5.0\right)\\
&=-5.65\\
\mathrm{pH}&=5.65
\end{align}$$
Thus, pure rain in equilibrium with the atmosphere has about $\mathrm{pH}=5.65$. Any acid rain with lower $\mathrm{pH}$ would be caused by additional acids.
The following is multiple choice question (with options) to answer.
Acid rain could effect | [
"an indoor pizza",
"an indoor TV",
"inside the house",
"a car's color"
] | D | acid rain has a negative impact on water quality |
OpenBookQA | OpenBookQA-3373 | mechanical-engineering, car, transmission
Title: Friction clutch and the force required I recently learned the basics of automotive clutches, more specifically friction clutches. Here is a simplified version of their operation explained to me (the car starts at rest): The engine and the transmission are connected via friction plates. When the clutch is pressed down, the plates are separated. When to clutch is released slowly, the plates press harder together and the friction between them causes the car, via transmission, to gain speed.
But what confuses me is this: The car weights many tonnes, and the engine spin very fast. When the plates are coming into contact with each other, they are slipping until the car begins to move. Isn't this causing a huge amount of heat to be produced? And most of all, how are the friction plates manufactured so that they don't "smoothen out" very quickly, reducing the friction coefficient between them? I understand that they do wear out and need to be replaced sometimes, but considering the high torque and speed of the engine, you would think they'd wear extremely quickly.
Also, isn't the force needed to press the plates together enormous? Considering the large mass of the car, how kind of mechanism is used inside to car the press the plates together? And how can a person then, using only one foot, be able to again separate these plates? I assume the clutch pedal is connected to some kind of hydraulic system to amplify the force?
I've Googled a lot and watched several Youtube videos on the matter but they all simply show that friction holds the plates together and pressing the clutch releases them. To answer your questions:
Yes, a lot of heat gets produced. Most of it will sink into the flywheel, but the clutch does get very hot. That's why it's good to keep the revs low when feathering the clutch. Don't pull away revving more than 1200rpm. Better to keep it at 1000, also with a petrol car. That may require some practice, though. It's not hard at all to burn the clutch and flywheel. Your flywheel then will look like this:
The following is multiple choice question (with options) to answer.
Which of these are essential to people who commute to work in an automobile? | [
"cats",
"clouds",
"dogs",
"dead dinosaurs"
] | D | oil is a source of gasoline |
OpenBookQA | OpenBookQA-3374 | human-anatomy
Taken from here such people would be able to dislocate then get their hands in front and relocate.
The body can be trained to be quite flexible through training like gymnastics etc...
The following is multiple choice question (with options) to answer.
If too many humans move into to an given area they may take more resources then possible to sustain themselves, which is what concept? | [
"illness from malnutrition",
"reproduction going over",
"population just right",
"death"
] | B | as available resources increases , the population of an organism that uses those resources will increase |
OpenBookQA | OpenBookQA-3375 | organic-chemistry, synthesis, plastics, fuel
Title: Can plastic be used as fuel for vehicles? I don't have much of a background in chemistry, but I know that plastics are largely made of carbon, as is oil. Is there any way to "covert", i.e. a plastic water bottle, into a substance that can be used as fuel for ? Thanks. There are many ways to recycle different types of plastic, and conversion to liquid fuels suitable for internal combustion engines is currently done on an industrial scale. The key to converting the carbon contained in long-chain polymers that make up the plastics is called pyrolysis, which is essentially a way to thermally decompose these products into shorter chain hydrocarbons suitable for use as liquid (or even gaseous or solid) fuel. According to this Wikipedia article:
Anhydrous pyrolysis can also be used to produce liquid fuel similar to diesel from plastic waste, with a higher cetane value and lower sulfur content than traditional diesel.
An example of a current commercial waste-plastic-to-fuel operation is the Canadian corportion Plastic2Oil, Inc., who claims to "convert waste plastic to ultra clean oil" in their 250,000 gallon fuel production and blending facility.
The following is an excerpt from the description of the patent-pending process used by Plastic2Oil:
The following is multiple choice question (with options) to answer.
Which of the following likely uses an alternative fuel? | [
"a vintage motorcycle",
"an older car",
"an 1800's train",
"a modern bus"
] | D | as the use of alternative fuels increases , the use of gasoline will decrease |
OpenBookQA | OpenBookQA-3376 | quantum-mechanics, optics, photons, quantum-optics, thought-experiment
Update So in searching a reliable way to make the estimation, I found this discussion where different approaches are given. I think this is better than any estimation I can sketch at this point.
As for the feasibility of all this, I think the closest you would get is having a material with very high reflection for a wide range of the EM spectrum, but still will absorb a fraction, even a tiny one. Thus it would heat up and radiate part of the energy to the exterior, until some stationary situation is achieved where a balance is determined by the actual values of the absorption/reflection coefficients.
The following is multiple choice question (with options) to answer.
What is least likely to absorb light? | [
"windows",
"space",
"glass",
"foil"
] | D | shiny things reflect light |
OpenBookQA | OpenBookQA-3377 | # Thread: physics tourist & bear problem
1. ## physics tourist & bear problem
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
2. Originally Posted by rcmango
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
The maximum value of d is such that the bear gets to the car at the same time the tourist does.
So set up a coordinate system such that the bear is at the origin and positive x is in the direction from the bear to the tourist.
Both are moving at a constant speed. The bear has to cover 27 + d meters in the same time the tourist covers d meters.
So for the tourist:
[tex]d = v_t t = 3.5t[tex]
Thus
$t = \frac{d}{3.5}$
For the bear:
$27 + d = v_b t = 6 \left ( \frac{d}{3.5} \right )$
Now solve for d.
-Dan
3. Hello, rcmango!
Another approach . . .
A tourist being chased by an angry bear is running in a straight line
toward his car at a speed of 3.5 m/s. .The car is a distance $d$ meters away.
The bear is 27 meters behind the tourist and running at 6.0 m/s.
The tourist reaches the car safely.
What is the maximum possible value for $d$?
The tourist has a 27-meter headstart.
Relative to the tourist, the bear has a speed of 2.5 m/s.
To cover 27 meters, it takes the bear: . $\frac{27}{2.5} \:=\:10.8$ seconds.
The following is multiple choice question (with options) to answer.
A bear is fortunate enough to | [
"see a rainbow",
"learn history",
"time travel",
"have magic"
] | A | bears eat insects |
OpenBookQA | OpenBookQA-3378 | homework-and-exercises, radiation
Title: light beams of the sun
We receive sunlight on earth surface. What type of light beams are these?
Random/Parallel/Converging/Diverging
I think it should be Diverging as Sun is radiating these beams away. But in one book, answer is given as Random, in another it's Parallel. It is difficult to answer this question. An EM wave is generated by vibrating charges and nuclear reactions. Sun is full of vibrating charges and nuclear fusions. Because of this full range of frequencies are emitted. At distances close to sun we observe the directions of waves to be random. But at far away distances the direction of waves seem parallel. Since only parallel waves can have constant separation between them. Converging and diverging waves become distant at longer distances.
The following is multiple choice question (with options) to answer.
Sunlight is a source of light from what? | [
"local star",
"moonbeam",
"lamps",
"lightbulbs"
] | A | when the season changes , the amount of daylight will change |
OpenBookQA | OpenBookQA-3379 | thermodynamics, energy, temperature, estimation
Title: What would happen if a 10-kg cube of iron, at a temperature close to 0 kelvin, suddenly appeared in your living room? What would be the effect of placing an object that cold in an environment that warm? Would the room just get a little colder? Would it kill everyone in the room like some kind of cold bomb? What would happen?
Don't think about how the cube got there, or the air which it would displace. Nothing overly dramatic, though it would be cool to look at. The cube would very quickly become covered by a layer of nitrogen/oxygen ice as the air which came into contact with it froze. Further away, you'd see condensation of water vapor into wispy clouds, which would swirl around the block due to the air currents generated by the sudden pressure drop.
Other than that, as long as you aren't in immediate thermal contact with the block, you wouldn't notice much other than that the room cools down. Here's a video I took of a vacuum can that was just removed from a dewar of liquid helium at 4 kelvin. It's maybe 5 kg of copper, not 10 kg of lead, but I'd say that's close enough to get the idea.
You can see one of my coworkers climbing down into a pit below it; he had to be careful not to bump his head on it, which would have really ruined his day, but there was no fatal cold bomb :)
The following is multiple choice question (with options) to answer.
if the particles in an electric rig were immobile, what would result from that? | [
"there will be a shock current",
"the circuit will fail to power",
"there would be a short circuit",
"there would be current overload"
] | B | electricity is made of moving charged particles |
OpenBookQA | OpenBookQA-3380 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
A skunk produces a bad what? | [
"job",
"plastic",
"energy",
"nose experience"
] | D | a skunk produces a bad odor |
OpenBookQA | OpenBookQA-3381 | material-science, elasticity, continuum-mechanics, stress-strain
In short, once you properly glue the bottom of the cube to the floor, you can expect something more similar to what visible here
rather than in the picture above.
It is just funny that sketches like the one above are so widely used to explain shear stress. I think it is kind of risky and can lead to inconsistencies and (legitimate) doubts in students, I wonder how many persons are aware.
I have to say that some texts indicate the presence of vertical external forces also on those two lateral surfaces (then it all works and the uniform deformation above is correct)... but more often this is neglected.
The following is multiple choice question (with options) to answer.
If a thing is being drawn to another thing of the same material, they are probably | [
"quartz",
"plastic",
"diamond",
"iron"
] | D | a magnet attracts magnetic metals through magnetism |
OpenBookQA | OpenBookQA-3382 | geothermal-heat, open-data, mining, canada
Title: Canadian equivalent to AMLIS database? I am interested in in situ coal fires. In furtherance of this, I am hoping to find a database of Canadian mine reclamation sites, complete with incident or status reports and descriptions of specific problems.
I've poked around a very small bit in the Federal Contaminated Sites Inventory, but I'm hoping there might be something a bit more specific or targeted out there -- something more like the equivalent of the United States' Abandoned Mine Load Inventory System (AMLIS) database.
Any pointers? Try:
Federal Contaminated Sites Inventory
as well as
Crown Contaminated Sites Database (British Columbia)
Orphaned/Abandoned Mine Site Rehabilitation (Manitoba)
Abandoned Mines Information System-AMIS (Ontario)
The following is multiple choice question (with options) to answer.
Coal mines are an essential for what industries? | [
"soft drink manufacturing",
"textiles",
"energy generation",
"powering airplanes"
] | C | coal mine is a source of coal under the ground |
OpenBookQA | OpenBookQA-3383 | botany, methods
I think it really depends on the type of plant whether its stems will root or not and how long the stem will retain its rooting potential after being cut.
If possible, you can try the following. Put the cut stem in a small plastic pot (they are very cheap) with soil and see if it roots (leaves will begin growing). If it does, transfer it into a larger pot later once it has grown. Wait for it to grow big enough to spread its roots thoughout the pot, then shift it into a big pot.
I believe if a plant roots, then all stems of that plant will root. Plus, congratulations on your first plant.
The following is multiple choice question (with options) to answer.
One way to see how a plant stem works could be | [
"eating the plant entirely",
"putting the stems in food colouring",
"throwing the plants away",
"pulling out the petals"
] | B | a plant stem contains a system of tubes for transporting water and nutrients to other parts of the plant |
OpenBookQA | OpenBookQA-3384 | 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.
Unless the animal is native to a cold climate like Antarctica, it is going to need to stay warm enough in winter so it | [
"Stays alive",
"stays dead",
"in cream",
"in juice"
] | A | an animal requires warmth for survival |
OpenBookQA | OpenBookQA-3385 | ecology, trees
Title: Why do some trees in California have dead brown leaves but also new green leaves? It's Autumn 2015, and I just saw a tree that had mainly dead brown leaves but also some new small green leaves growing. Why didn't the tree just keep its old leaves? Does it think we are in spring already?
EDIT: To be clear, I had always thought that in autumn that all the leaves of a tree would fall off together, as a preparation for winter. It seems silly that the tree would then immediately grow some new leaves when it just decided to let all those previous leaves die. Why not just use that same energy to maintain those leaves?
I've taken some photos of the leaves and the trunk for help with identification.
The following is multiple choice question (with options) to answer.
If a leaf falls off a tree then the leaf is what? | [
"vibrant",
"decisive",
"unliving",
"flowering"
] | C | if a leaf falls off of a tree then that leaf is dead |
OpenBookQA | OpenBookQA-3386 | everyday-life
Due to friction effects though, option c is still best. Pedaling hard will quickly deplete energy reserves while pedaling at a slow but steady rate will allow you to cycle for much longer. From a physics point of view, we cannot help you spend less energy, it will inevitable take about the same amount of energy regardless of your method (some +/- due to friction, etc). But by keeping your power usage low, you can go much farther before needing a rest. It is much the same as with running and walking. Simplistic physics says both use the same amount of energy, but you won't get as far by running due to the massive power requirements.
The following is multiple choice question (with options) to answer.
If I wanted to maintain energy I could | [
"Jump for hours",
"carry heavy weights",
"Run for hours",
"leisure nap"
] | D | a human requires rest to be healthy |
OpenBookQA | OpenBookQA-3387 | soft-question, research-practice, writing, paper-review, conferences
However, that doesn't mean that you have to partition your work into least publishable units as you describe your coworkers doing, and it also doesn't mean that saving up multiple small results into a single paper is a good way of making your papers stronger. It's certainly possible to publish papers like that but to my mind the better ones are often the ones that have a single strong main result, perhaps with additional results on the side not to strengthen the paper but rather to provide more complete coverage of its subject.
The following is multiple choice question (with options) to answer.
Reusing your paper plates is a good way to avoid making excess | [
"stars",
"rubbish",
"ears",
"mice"
] | B | An example of avoiding waste is using an object more than once |
OpenBookQA | OpenBookQA-3388 | the-sun, space, stellar-atmospheres
However, when you have something the Sun or even fog, the optical depth varies with the distance you're looking into that object. I'll talk about fog since it's familiar, but the same idea applies to the Sun's atmosphere. Say you're standing in a forrest and its very foggy out. There's a tree 1 meter away from you that you can see. You could measure your optical depth, $\tau$, of the fog between you and tree and might find that $\tau = 0.15$. Since $\tau$ is less than one, that implies you can see the tree, but the value of $\tau$ also implies how well you can see it. If $\tau = 0$, there's nothing between you and the tree to impede your ability to see it. Let's say there's another tree that's 5 meters away. Now there's more fog between you and the tree and while you can still see it, it is harder to see it. The optical depth of the fog between you and the tree 5 meters away might be $\tau = 0.75$. It's still less than one, implying the tree is visible, but because there's more fog between you and the tree, the optical depth is higher. Finally, there may be a tree 10 meters away with so much fog between you and the tree that the optical depth is $\tau = 1.5$. You can't see this tree because there's too much fog in the way. Hopefully you now realize that anything which is at a distance where $\tau > 1$ is not visible to you. That effectively defines a "surface" around you precisely when $\tau = 1$. Anything beyond that point is not visible and anything closer is visible.
If you're talking about the Sun, you can look at the Sun, but you'll only see light which originates from a point where $\tau < 1$. There are countless photons bouncing around inside the Sun, but you can't see them because they're in an opaque part of the Sun. Astronomers use the optical depth as a metric for defining the "surface" of the Sun.
The following is multiple choice question (with options) to answer.
If you're stuck outside on a sunny day, the coolest place would be under a tree because they do what to the sunlight | [
"sell it",
"climb it",
"block it out",
"smell it"
] | C | large trees block sunlight from reaching the ground |
OpenBookQA | OpenBookQA-3389 | 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.
Some flowers are unable to get enough sunlight because trees hover over them and do what to it | [
"sing to it",
"nothing",
"sell it",
"intercept it"
] | D | if a tree falls then sunlight becomes available to the surrounding plants |
OpenBookQA | OpenBookQA-3390 | 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.
An example of pollution might be | [
"recycling old glass to make a house",
"throwing plastic in the ocean",
"donating clothes to a thrift shop",
"Using old shirts to make a blanket"
] | B | pollution is a source of pollutants |
OpenBookQA | OpenBookQA-3391 | evolution, homework
Title: Can someone help me analyze this article? I need to read this article — "Beyond the rainbow" by
Marie-Claire Koschowitz et al., for an exam.
Following are some questions for which I could not figure the answer out after reading.
1) Why does this miniaturization necessitates insulation ? Following is quote from article: "For fast-growing, presumably warm- blooded animals , such miniaturization would only have been possible with sufficient body insulation. "
2) Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ? Why does the article mention reptiles before that ? Are birds reptiles ?
3) The article starts talking about how mammals develop fur and lost their highly differentiated color vision because they gave up structural color signaling. What is the direct connection between mammals and the dinosaurs ? I don't see the parallel here....why bring the mammals into the discussion ?
4) What is the connection between pennaceous feather and planar feathers ?
Any or all questions answered is welcome ! Thanks ! I will answer the questions one by one-
Why does this miniaturization necessitates insulation ?
An organism's volume determines the total amount of heat that can be stored. The loss (exchange) of heat between the body and external environment mainly occurs on the skin's surface. Hence, body volume determines how much heat is stored, while body surface determines how fast that heat is dissipated to the environment. Volume increases with a power of three with radius, while surface increases with a power of two. Hence, smaller animals have large surface-to-volume ratios, which decreases rapidly with body size. Hence, small animals will dissipate relatively more heat per unit of time.
Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ?
No, birds are the closest living relatives to dinosaurs, and birds can be said to have inherited tetrachromacy from dinosaurs - see the cladogram below.
The following is multiple choice question (with options) to answer.
a reptile that was brown an hour later is now green because | [
"red paint was poured over it",
"it's green with envy",
"it's sitting in a leafy shrub and using camouflage",
"it is feeling nauseous"
] | C | An example of camouflage is when something changes color in order to have the same color as its environment |
OpenBookQA | OpenBookQA-3392 | polymers, plastics
Title: What is Polymer Environmental Resin (PER)? I'm no chemist and I probably wouldn't understand any technical answer but...
I'm investigating the environmental impacts of various materials as compared to PVC and this is one that crops up regularly as a more environmental alternative.
Unfortunately there does not seem to be any authoritative information on the web concerning this material.
I'm beginning to think that this is a green-washing propaganda move by the phthalate/heavy metal free PVC industry as a move avoid mentioning PVC in product advertising.
Anyway I would welcome any information on what exactly PER is and what it is made from.
Thank you. PER is essentially PVC which has been plasticized and stabilized with acetyl tributyl citrate, instead of the host of phthalate-based plasticizers such as bis-diethylhexyl phthalate (DEHP) whose endocrine-disrupting properties give PVC its well-deserved bad reputation.
Citrate salts tend to be readily water soluble, and therefore this material is touted to be more biodegradeable than phthalate-plasticized PVC. I certainly cannot find any information to refute that claim. ATBC will further degrade into other acetates and butyrates, most of which are relatively common and harmless in the environment (though butyl compounds are infamously stinky; butyric acid is a favorite less-lethal offensive-odor weapon of law enforcement and groups like the Sea Shepherds). All PVC will eventually degrade as the plasticizer leaches out over time, unlike other types of plastics that are so ridiculously inert they'll likely be the fossils of our modern era, but again, the phthalates just aren't a great idea to have in the environment.
The following is multiple choice question (with options) to answer.
By picking up polypropylene we can make our ecosystem | [
"ugly",
"worse",
"dead",
"better"
] | D | An example of protecting the environment is reducing the amount of waste |
OpenBookQA | OpenBookQA-3393 | zoology, ethology, learning
Title: How do beavers learn how to build dams? I was wondering whether all beavers, from all around the world, know how to build dams and lodges? Do they need to learn it from their parents? If you release a group of beavers in the wild that haven't been in contact with their parents, would they start to build stuff? or just hopelessly die/starve to death? Question summary: is dam building learned or instinctive in beavers?
A blog post from 2011 references an article in the Juneau Empire titled Running water is sound of spring for beavers. This article is no longer hosted on the Juneau Empire website, but archived versions are available.
Here's an excerpt (emphasis mine) --
Swedish biologist Lars Wilsson spent years studying captive and wild beavers, and he gained remarkable insights into their behavior. He raised beavers in an outdoor enclosure and in a large indoor terrarium ...
Wilsson initially captured four adult beavers and later he raised a number of beavers from infancy, some in small colonies with their parents and some completely isolated from adult beavers. He isolated the young beavers to see what beavers learn from their parents and what behaviors are instinctive.
He found that young beavers - who had never even seen a beaver dam - were able to build almost-perfect dams at the first opportunity.
The foundation of sticks and logs anchored to the stream bottom, the interwoven lattice of trimmed branches, the mud chinking, every aspect of dam building was hard-wired. Beavers do get more skilled at dam building as they gain experience, but the building behavior is instinctive.
Wilsson learned that the sound of running water is the cue for dam building and dam repair. In one experiment, he played a recording of running water, and the young beavers built a dam in a tank of still water in the terrarium. In another peculiar experiment, his captive beavers built a "dam" on a concrete floor against a loudspeaker that played the sound of running water.
The following is multiple choice question (with options) to answer.
If a beaver does what it does in order to build its home, then near the river will form | [
"a large H2O source",
"a den for tigers",
"a small military camp",
"a giant black hole"
] | A | damming a river can cause a lake to form |
OpenBookQA | OpenBookQA-3394 | water-resources
Location
This plant requires a hot location with large area of cheap land by the ocean and a relatively consistent wind.
Stage 1 - Wave Pump
A wave-powered pump raises sea water into a large lake on land. Here is an example of a direct wave-powered pump, other types of wave power harnessing typically convert mechanical motion into electricity. However, that motion can be easily used to directly drive a pump.
Stage 2 - Evaporation Lake
The evaporation lake is a large shallow area, covered in a greenhouse-like way to aid evaporation. The sea-water flows away from the ocean along channels in the lake-bed then back again towards the ocean in the next adjacent channel where it drains back into the sea. This prevents the build-up of deposits as the returning sea-water will take them with it and return to the sea more concentrated. The roof may contain Fresnel lenses or other solar concentrators to help evaporation.
A wind-catching tower blows air across the lake to lower air pressure and aid in evaporation. This tower could be like those used in Masdar City, or a standard wind turbine tower with either electrical or direct transmission to a series of fans. The result is a continuous airflow across the lake which carries the water vapor to the far side where it is channeled up a wide column into the next stage.
Stage 3 - Condensing Tower
The water vapor is channeled up a large column to a condensing chamber high on the tower. Here, a series of fins are cooled by a heat-pump driven directly by a wind-turbine on top of the tower. the water condenses on the fins and drains into a fresh-water tank near the top of the tower.
Stage 4 - Power Generation
The water from the condensing tower is lowered to a height suitable for a standard water-tower through one or more water turbines to generate power.
Stage 5 - Filtering and treatment
The salty sea-air will also condense on the fins, and there may be small airborne particles and particles from wear on stages within this process that get into the water, so it will probably need further filtering and treatment to make it drinkable. Some of the power from the water turbine may be used for this.
There you have it, you have clean water, above ground level so pressure is already available, and hopefully some excess electricity and cool dry air as by-products.
The following is multiple choice question (with options) to answer.
Solar pumps move liquids continuously from the | [
"space",
"glaciers",
"sky",
"ground"
] | D | renewable resources can be used over again |
OpenBookQA | OpenBookQA-3395 | thermodynamics, temperature
Layout
In the night, the outside temperature is lower compared to both Room, but since I live on top floor, the above slabs get heated and it starts radiating heat. I want to cool all my room. It seems like you want to transfer heat from Room 2 to Room 1, but you haven't mentioned the reason behind it. Are you trying to cool down Room 2 or warm up Room 1? Depending on the goal, the approach may vary.
In scenario 1, using the evaporative cooler with the vent facing Room 1 will result in the air in Room 1 being cooled down by the water flowing through the honeycomb structure. However, this may not be an efficient way to transfer heat from Room 2 to Room 1 as the cooler may not have enough cooling capacity to offset the heat generated in Room 2.
In scenario 2, using the cooler as a fan and facing the vent towards Room 2, will allow the air in Room 2 to circulate to Room 1, but again, it may not be an efficient way to transfer heat from Room 2 to Room 1. In this case, you may end up just circulating warm air from Room 2 to Room 1 without actually cooling Room 2.
There are other ways to transfer heat from one room to another, such as using a heat exchanger or a duct system. However, the best way to cool both of your rooms will depend on the specific conditions and layout of your house.
Edit
Based on the information you provided, one option that could be effective in cooling down both rooms to the outside temperature is to use a combination of natural ventilation, shading, and thermal insulation.
During the day, when the outside temperature is hotter than the inside of your home, you can close the windows and curtains or blinds on the sun-facing side of your home to keep the heat out. You can also use reflective film on the windows to reduce the amount of heat that enters your home.
At night, when the outside temperature is cooler than the inside of your home, you can open the windows and use fans to draw in the cool air and circulate it throughout your home. You can also use thermal insulation, such as ceiling insulation or insulation on the roof or walls, to prevent the heat from entering your home during the day and to keep the cool air in at night.
The following is multiple choice question (with options) to answer.
If I wanted to transfer warmth another being I might | [
"pour cold water on them",
"put ice in their pants",
"touch their sides with mine",
"let them sit outside in snow"
] | C | as heat is transferred from something to something else , the temperature of that something will decrease |
OpenBookQA | OpenBookQA-3396 | javascript, object-oriented, reinventing-the-wheel
const get = () => elements;
return {
push,
join,
get,
};
};
const myArray = Errey("3","blue","1","brown")
console.log(myArray.join(", "));
console.log(myArray.push("Subscribe", "To", "Him"));
console.log(myArray.get());
The following is multiple choice question (with options) to answer.
pushing an object requires | [
"studying",
"dancing",
"singing",
"exherted effort"
] | D | pushing an object requires force |
OpenBookQA | OpenBookQA-3397 | 1-5 Intervention Activity 1-5 Ready to Go On? NO INTERVENE YES ENRICH N 1 2 P L M-4-3 2-1 012345-1. The value of b is 3. sides and the other with 1-in. Chapter 11. Some of the worksheets for this concept are Area of composite figures name answer key, Perimeter and area of composite figures, Area and perimeter of composite shapes word, Area and perimeter of composite shapes word, Area ws answers, Practice a 10 3 composite figures answers, Area of. 2- Place Value Lesson 1. area of the base of the triangle with the length of the poster. Lesson 3 Homework Practice Area of Composite Figures Find the area of each figure. Figure (1) is a plot, with its caption, of power and efficiency of a gyroklystron as calculated by simulation, and the experimental results taken from (2). Answers will vary. 1 _ No; 51 5. Sample writing items for grades 3 - 8 revising and editing are now available on the new Reading Language Arts STAAR Sample Items page. 8 ASSESSMENT ENRICHMENT/RETEACHING Key: Power Standard * Assessed Standard Strikethrough: Topic not taught or assessed this quarter ** Dates to be determined at school site LAUSD Mathematics Program Instructional Guide, Grade 5. Lesson 10-9 Surface Area. 2 Reflections 11. Each answer shows how to solve a textbook problem, one step at a time. Number & Operations - Links to previous number and operations standards (e. 60 mi/h 3 3. •A 1-page chapter review(13 in all) for each chapter. amount bar graph beads blue bought cards Check students Circle coins colored cost Count cubes cubic units decimal dimes Divide dollar dollar sign Draw a Picture equal groups Example feet figure Find a Pattern Find each product Find the missing flag fraction gallons greatest green Guess and Check Hancock Park inches length Logical Thinking. 450+ mathematics lessons, worksheets and whiteboard resources for teachers and schools from only £40 per year. Tell whether the number is odd or even. At the end of each writing lesson, there are opportunities for students to share. and height 11 in. What number is 20% of 625? 6. Select Page We are having significant delays in processing and shipping due to extreme demand and the ongoing effects of COVID-19. Afrikaans Stompi Worksheets 55; 8. 9, what digit (number) is
The following is multiple choice question (with options) to answer.
if a student asked a teacher about the size of a certain item, what could be an indicator? | [
"the volume of the item",
"the color of the item",
"the luster of the item",
"the depth of the item"
] | A | the volume of an object can be used to describe the size of that object |
OpenBookQA | OpenBookQA-3398 | entomology
Title: Constantly wiggling moth pupa - will it emerge soon? Today I found a moth pupa in the soil in my garden in western Sweden. It's about 15 mm long.
I have found similar ones before, but this one is wiggling a lot more, even after I put it down and put a bit of dirt over it. It's been moving for more than an hour now, but less now than in the beginning.
I was hoping to see it emerge, but if it will take more than a day or so, I will probably put it back. So, what I'm wondering is if this wiggling is any indication of how soon it will emerge. Or if there are other ways to tell.
Update: an hour later it has stopped moving. Maybe it was just very disturbed by my presence. I'm keeping it in a jar with soil and a stick for climbing up on, and I'll decide what to do with it tomorrow.
Update: 12 hours later and it seems very still. But I'm letting the question remain since I really want to know if there are any signs to look for.
Final update: After 16 days it had turned almost black, and was still very active when handled.
And after 17 days this moth came out: I posted the same question on tumblr and got an answer:
It depends on the species. This one looks like a Noctuid. I’d give it
two weeks to a month or so. You may be able to see its wings showing
through the darkening pupal case when the time draws near! Just make
sure you give it somewhere to climb up and expand its wings when it
ecloses.
After keeping it until the moth emerged, I now know that wiggliness is not an indication of maturity, but turning dark is.
The following is multiple choice question (with options) to answer.
What are created during the pupa stage in a life cycle? | [
"warmth",
"water",
"eggs",
"hard shells"
] | D | the cocoons being created occurs during the the pupa stage in a life cycle |
OpenBookQA | OpenBookQA-3399 | genetics, botany, senescence, telomere
Do Plants Get Cancer?
It seems to me the next obvious question. One of the first papers I came across (published in 1916 by the Journal of Cancer Research!) talks of Crown Gall in plants and its relation to human cancer (Smith, 1916). Many websites cite galls as being the equivalent to cancer in plants, but it appears that the outgrowths (galls) that appear very tumour-like are in fact caused by bacteria encouraging their surrounding cells to proliferate. (See this question for more detail on galls).
I later found an abstract (I cannot access the full paper) from a paper published in Nature in 2010 called “Walls around tumours — why plants do not develop cancer” (Doonan, 2010). It appears that Plants can and do develop tumours, but they are less frequent and less lethal due to fundamental differences in development between plant and animal cells. Singh and colleagues found that in 2 plant species (Arabidopsis and rice) there were DNA damage repair pathways well conserved but with variation; there were several gene duplications in different DNA repair pathways (Singh, 2010).
Plants Do Not “Age” As We Do
Although I could find no conclusive evidence, it seems to me likely that plants may also have enhanced maintenance against other cellular stresses than DNA damage, such as build-ups of aberrant proteins. It therefore appears that in a protected environment some plants could live indefinitely. I say some, because others deliberately end their lives after reproduction. Traits such as longevity are inherently hard to be selected for, as the advantages come long after reproductive maturity and are therefore under much less selective pressure.
We see plants wither and die, but this is because they are constantly subject to environmental insult. Animals and insects may eat them, there may not be enough food or water, or sunlight, or the plant may become infected. All of which are at the macroscopic level. Due to completely different evolutionary constraints and pressures plants are highly resilient to cellar stresses, possibly due to differences in metabolic rate, and apparently have indefinite replicative potential.
Edit:
The following is multiple choice question (with options) to answer.
changes in an environment cause plants to | [
"morph for continuation",
"boogie",
"bake cakes",
"take long naps"
] | A | changes in an environment cause plants to adapt to survive |
OpenBookQA | OpenBookQA-3400 | zoology, species-identification, ornithology, behaviour
Title: What is this crow eating, and is it a common part of the corvid diet? Here's a picture (by Rob Curtis) of a crow carrying and eating the corpse of what looks a bit like a small hawk or falcon:
Other pictures clearly show the crow is eating the dead bird. This image shows the underside of the head and beak; this one shows its legs, which are grayish.
What bird is being eaten?
Is this bird a usual part of the corvid diet? Or did the crow just opportunistically scavenge a dead bird? Crows are omnivorous, and will eat almost anything they find or can kill.
In this case the prey looks like a Yellow-Shafted Flicker.
The following is multiple choice question (with options) to answer.
A predator eats other animals for what? | [
"food charts",
"entertainment",
"enrichment",
"expectations"
] | C | a predator eats other animals for food |
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