source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-3201 | power-engineering, inductive-charging
Title: Efficiency of wireless charging for moving cars The UK is about to start trials of wireless charging for moving cars.
What kind of power transfer efficiency is likely to be achievable in such a system, compared to just plugging in the car directly? This is not exactly a comprehensive answer, but I found an interesting article on The Institution of Engineering and Technology's website. It is fairly interesting, if not incredibly technically detailed, and I encourage you to check it out for projects to learn more about. I'll talk about the most interesting parts here.
It has many interesting projects listed. Some are for bus routes, and rather than charging along the whole route, they use 'opportunistic charging' to charge at key places (presumably bus stops and traffic lights) to rapidly transfer energy. This is intended to minimize the disruption and possibly cost of construction (imagine having to dig up an entire busy road to add charging coils). This is called "semi-dynamic charging" by Transport Scotland, who are working on one such project.
However, it sounds like in Korea, a more full route system has been operating.
[T]he Korea Advanced Institute of Science and Technology (KAIST) is running two online electric vehicle (OLEV) buses on a 12km continuous charging route in the city of Gumi. It claims 85 per cent maximum efficiency in power transfer.
You're question is focused on the pure efficiency of the charging capacity, but I think also interesting to consider (or possibly implied in the question) is for what cases these technological limitations make actual use a practical exercise. On that note, I will add that this technology may prove of more usefulness on highways, where range is of particular concern in the arena of electric vehicles, leading to projects going to great lengths to provide very close charging stations (25 to 50 miles) like West Coast Green Highway.
The following is multiple choice question (with options) to answer.
An electrical conductor is a vehicle for what? | [
"people",
"water",
"sunlight",
"zapping energy"
] | D | An electrical conductor is a vehicle for the flow of electricity |
OpenBookQA | OpenBookQA-3202 | respiration
Here is what happens at the molecular level.
The $\rm CN^-$ ions diffuse into the mitochondria. They have high affinity to the ferrous ion of the mitochondrial enzyme cytochrome c oxidase involved in the electron transport chain (ETC), one of the phases of cellular respiration where $\rm ATP$ is generated from $\rm NADH$ and $\rm FADH_2$. And it is this process that actually requires oxygen. The inhibited cytochrome c oxidase is of no good in transporting electrons, thus no $\rm ATP$ molecules are generated. The oxygen molecules waiting for those electrons remain empty handed resulting in the increase in the concentration of molecular oxygen. Remember, ETC occurs in almost all living cells except a few like RBC which get their major share of ATP from the highly inefficient anaerobic glycolysis. Also, $\rm ATP$ is the energy currency of our body and is required in a wide variety of bodily processes like osmotic balance, nerve impulse transmission, muscle contraction etc. With no $\rm ATP$ your heart and respiratory muscles can't contract, your medulla can't regulate breathing, your kidneys can't concentrate urine and the list goes on. Death is imminent if a high concentration of cyanide gets into your blood.
The symptoms of panic like tachypnea and tachycardia (that result due to low oxygen in blood) are not usually seen unless the victim himself knows he is poisoned. The end effects like cardiac and respiratory arrest, seizures and coma, however, are similar to those of suffocation.
For further read:
The Mechanism of Cyanide Intoxication and its Antagonism
The following is multiple choice question (with options) to answer.
During cellar respiration I might find myself with | [
"candy",
"natural face water",
"magic",
"time travel powers"
] | B | all cells perform cellular respiration |
OpenBookQA | OpenBookQA-3203 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
If a hog is going to eat dinner it can | [
"produce fresh food",
"make a reservation",
"search for it",
"make its own"
] | C | a consumer can not produce its own food |
OpenBookQA | OpenBookQA-3204 | air-pollution
Title: Less pollution: moving hurricane debris to other regions for use, or burning? When a big hurricane hits, it can create debris on the scale of $\mathrm{10^8 yd^3}$. Cities in Florida, Texas, and other affected areas are struggling to hire enough trucks and drivers to pick it up quickly. But aside from that, I noticed many of the areas have started to burn the debris once it starts building up.
Got to wondering... typically mulch comes in modestly pricey, and when free mulch is offered, it often goes quickly.
So assuming a fair portion of debris is mulchable and is of interest to other areas, and that we can acquire typical transportation resources, then we'll set up transfer from collection sites to those other regions rather than burning it. What would be the net pollution result?
If removed for mulch and such: trucking pollution + decomposition (- trees saved locally??)
If burned: the burning pollution.
Obviously it's about approximation rather than exacts, it's probably hard to appraise the different byproducts from burning versus decomposition, and a lot probably depends upon the way it is burned. But as a whole, can we get a rough estimate of comparable quantities/damage done... is it less pollution/damage even to truck it an average of 3000 miles? 1000 miles? 100 miles? 10 miles? Should it be burned on the spot (if done safely)? Would think there's got to be some way to get a very rough idea.
Certainly the best option if viable might be leaving it in place to decompose. But considering how upset people are getting at having debris around these parts a month later, exclude that option from the possibilities.
Trucking or burning, how do they compare? As the question was changed, my answer attempts to evaluate only the difference between burning and transporting. Please correct my values if my quickly found sources are inaccurate or you find more representing. I know there is quite a few unwritten assumptions that simplify this problem.
The following is multiple choice question (with options) to answer.
Trees are mulched and liquefied before being dried to make | [
"houses",
"paper",
"toothpicks",
"floors"
] | B | creating paper requires cutting down trees |
OpenBookQA | OpenBookQA-3205 | behaviour
Title: What happens to silverfish when we throw them out the window? I'll find a silverfish from time to time in my flat. I don't mind them but usually I catch them and throw them off the balcony (second story) into the bushes and lawn below.
I was wondering, since they seem to live in the water conduits in the house, if they can survive outside or if they die/get killed instantly.
Thx for your help! Silverfish prefer high humidity and warmth. Ctenolepismacalvum (Ritter, 1910) was recently found in Japan at a temperature of 20-30°C and 50-60% RH. As long as there are pieces of bark, wet grass or other organic or human-made structures that retain humidity after each raining event, the likelihood that they will survive long enough to complete their cycle is high.
They could face dessiccation if they are not able to find a damp spot in time, depending on their tolerance to it. However, it was not possible for me to find information about their dessiccation tolerance.
The Zygentoma (silverfish order) have high tolerance to low humidity and most of the species inhabit dry and hot environments (it's just a few that like humidity), which again makes me think that those silverfish propelled out the window will survive.
The following is multiple choice question (with options) to answer.
What do cactuses do when the monsoons come to their habitat? | [
"sell precipitation to someone else",
"use precipitation right away",
"store precipitation for future use",
"give precipitation to their friends"
] | C | a cactus stores water |
OpenBookQA | OpenBookQA-3206 | java, object-oriented, fluent-interface
public Builder withCustomizedToppings(ArrayList<String> toppings) {
this.toppings = (ArrayList<String>) toppings.clone();
return this;
}
}
public String toString() {
StringBuilder description = new StringBuilder();
description.append(String.format("%s %s",
wellBaked? "Super Summer Hot Pizza": "A Little Scorched Pizza",
withRecipe? "With Zorua Special Recipe": "By Heart"));
description.append(String.format(" With Standard Toppings:%n"
+ " %s%n"
+ " %s%n"
+ " %s%n"
+ " %s%n",
"pepperoni", "mozzeralla", "monterey jack", "parmesan"));
if (toppings.size() > 0) {
description.append(String.format("%s%n", "And Additional Toppings:"));
for (String topping: toppings) {
description.append(String.format(" + %s%n", topping));
}
}
return description.toString();
}
}
Result:
Makeing your pizza by Heart...
A Little Scorched Pizza By Heart With Standard Toppings:
pepperoni
mozzeralla
monterey jack
parmesan
And Additional Toppings:
+ Mushrooms
+ Onions
+ Black olives
+ Pineapple
The following is multiple choice question (with options) to answer.
To prepare hamburgers and hot dogs for eating you need | [
"glitter",
"a firepit",
"snowmen",
"arsenic"
] | B | cooking food requires adding heat energy |
OpenBookQA | OpenBookQA-3207 | heat, wavelength
Title: Is carbon dioxide a greenhouse gas?
Possible Duplicate:
What experiments prove the greenhouse effect?
I am seeking for a proof that CO2 is a greenhouse gas. I posted this on Skeptic.SE recently but found no help in seeking for proof:
I assisted to a physicist conference in my university a few years ago
against the case that carbon dioxide was a cause of global warming.
The main point was that CO2 is not a greenhouse gas. I did a
research to find evidence for either side and found absolutely
nothing.
So, is carbon dioxide a greenhouse gas? If yes, has it been
demonstrated in a scientific paper?
Here are some discussion articles describing arguments against CO2
being a greenhouse gas:
The following is multiple choice question (with options) to answer.
which one of these is false about the greenhouse effect? | [
"it could cause polar melting",
"it causes green air in the sky",
"it causes overall temperature rise",
"it heats up the atmosphere"
] | B | the greenhouse effect is when carbon in the air heats a planet 's atmosphere |
OpenBookQA | OpenBookQA-3208 | acoustics, string, wavelength, resonance
This is true only for very simple resonators. The shape of the guitar body is such that it has a different size at different angles. This corresponds to different resonant frequencies. In addition, the top has a supporting bracing that is very different on different models and is critical for the sound.
Furthermore, a guitar is nor necessarily a resonator, but a converter of the mechanical energy of the strings to the acoustic energy of the air. You are absolutely correct that a strong resonance at a certain frequency would help this frequency at the expense of other frequencies and thus would be detrimental for the sound of a broad spectrum instrument. Therefore the objective of the guitar design (counter intuitively at first) is not to create, but to avoid strong resonances.
There are two parts in a guitar relevant here. One is the top made either of softer ceder for a warmer sound or harder spruce for a brighter sound (sometimes a two-layer top has both). The purpose of the top is to move air with its large area thus converting the mechanical energy of the strings to the acoustical energy of the sound. However, the top radiates both forward and back, plus the sound radiated back is out of phase with the sound radiated forward.
The second important part is the body. Historically the most popular material for the body had been the Brazilian rosewood before Brazil prohibited exporting it. Similar results are achieved with the rosewood from India, Madagascar, and other areas. Mahogany is also popular along with other wood species.
The main purpose of the body is to reflect forward (through the sound hole) the sound emitted back by the top and do it while inverting the phase, so that the sound emitted by the sound hole would be in phase with the sound emitted forward by the desk. Thus the guitar body is not a resonator, but a phase inverter very similar to common speakers with a PORT. Phase inversion depends on the internal dimensions of the body and is a compromise in order to optimize all frequencies equally. Although this is more important for lower frequencies (again, similarly to speakers).
The materials, shape, and bracing have been perfected by generations of guitar makers resulting in specific sound signatures. One example is the 1A model with a ceder top by Jose Romirez. Its sound is mesmerizing.
Bass Reflex
The following is multiple choice question (with options) to answer.
Which of these has resonating wood? | [
"a lute",
"a bell",
"a metal flute",
"a saxophone"
] | A | strumming a string can cause that string to vibrate |
OpenBookQA | OpenBookQA-3209 | 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.
All predators are also carnivorous because predators | [
"murder other beings",
"Count stuff",
"cook veggies",
"listen to music"
] | A | carnivores are predators |
OpenBookQA | OpenBookQA-3210 | human-biology, reproduction, anthropology
Note: here is a link about multiple pregnancy : https://www.healthline.com/health/pregnancy/chances-of-having-twins#assisted-reproduction. 49 - 19 = 30
So the 1st Child would be 30 when the last children would be born, as long as the parents stay healthy and the mother delivers the child in a natural way (No Surgical Procedure to deliver the child) and the Mother has not had Menopause (Menopause usually happens around 50 Years of age) the sibling age gap would be very possible, but lets take a look at how many children the mother had, if I am correct they had about 16 Children, many people in countries that have a considerably low life expectancy have many children, lets take a look at the world record for most children born from one mother...a person named Valentina Vassilyev, gave birth to 69 Children! Thats a lot of children, so giving birth to 16 children with a 30 age gap should be very possible and realistic as well.
The following is multiple choice question (with options) to answer.
What births live young? | [
"a feathered animal with a beak",
"a tail having tree dweller",
"a modern sport utility vehicle",
"a planet close to the sun"
] | B | a monkey births live young |
OpenBookQA | OpenBookQA-3211 | 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.
A landslide may bring immense problems to | [
"living regions",
"Jupiter",
"space",
"time travel"
] | A | a landslide is when gravity rapidly moves rocks or soil downhill especially after a rain storm |
OpenBookQA | OpenBookQA-3212 | image-processing
Title: High Dimensional Spaces for Images Can anyone explain why pictures are not considered 2D, but rather high dimensional? Especially with regards to CV and AI. From one perspective, a picture is a 2D image, because it has height and width.
But from a machine learning perspective, we can think of a picture as a point in a high-dimensional space. In particular, suppose we have a greyscale picture that is $m\times n$ pixels, i.e., $m$ pixels wide and $n$ pixels high. Then there are a total of $mn$ pixels in the image. Each pixel has a greyscale intensity, which we can think of as a real number in the interval $[0,1]$. Therefore, we can think of the picture as being a collection of $mn$ real numbers. In other words, the picture can be treated as a $mn$-dimensional vector -- as an element of $\mathbb{R}^{mn}$. Thus, any particular picture can be thought of as an element of a high-dimensional space.
The latter perspective arises natural for some machine learning approaches to computer vision, e.g., where we feed the pixels of the image into the machine learning algorithm, where each pixel value is treated as a separate pixel.
(A color image can be thought of as an element of $\mathbb{R}^{3mn}$: for each pixel, we have three numbers, corresponding to the intensity in the red, green, and blue channels.)
The following is multiple choice question (with options) to answer.
High areas can be visually represented by: | [
"deep sea",
"mountains",
"valleys",
"basins"
] | B | the Himalayas were formed by rock folding |
OpenBookQA | OpenBookQA-3213 | # Thread: Most likely of two examples
1. ## Most likely of two examples
Hi My instructor gave us two examples and posed a question:
We have a fair coin which is more likely?
1. We flip the coin 100 times and see exactly 50 heads.
2. We flip the coin 1000 times and see exactly 500 heads.
Someone in the class said immediately that 1 is more likely by a factor of sqrt(10). Why is sqrt(10) the difference? Now explanation was given.
2. ## Re: Most likely of two examples
Hint: Try calculating the actual probability using the PDF (or by using a Normal distribution approximation with continuity correction).
Have you come across using the Normal distribution to approximate a binomial distribution for large values of n?
3. ## Re: Most likely of two examples
The binomial distribution with N= 100, p= 1/2 has mean 50 and standard deviation $\sqrt{(100)(1/2)(1/2)}= \sqrt{25}= 5$. To approximate that with the Normal distribution, use a normal distribution with that mean and standard deviation and find the probability that x is between 50- 1/2= 49.5 and 50+ 1/2= 50.5.
To do the same with N= 1000, p= 1/2, mean is 500 and standard deviation $\sqrt{1000}(1/2)(1/2)}= \sqrt{250}= 5\sqrt{10}$. Find the probability of x between 500- 1/2= 499.5 and 500+ 1/2= 500.5.
The following is multiple choice question (with options) to answer.
Which of the following is most likely to occur? | [
"rice grains absorb other rice grains",
"humans absorb other humans",
"Play-Doh absorbs other colors of Play-Doh",
"sponges absorb other sponges"
] | C | if something absorbs something else then that something will contain that something else |
OpenBookQA | OpenBookQA-3214 | newtonian-mechanics, rotational-dynamics
is correct.
Looking from the top the angular momentum of the wheel changes from $\vec L_{\rm old}$ to $\vec L_{\rm new}$.
The change in angular momentum is $\Delta \vec L$ as is shown in the vector diagram on the right.
Now change position and look at the wheel from the side.
The change in angular momentum is out of the screen and this must be the direction of the torque $\vec \tau$ which causes that change in angular momentum.
So about the left hand pivot point the torque has to try and rotate the wheel anticlockwise which must mean that $N >W$ remembering that when the wheel was not moving $N=W$
So the normal reaction force on the wheel $N$ is greater than the weight of the wheel $W$.
If the wheel is made to go round faster the magnitudes of $\vec L_{\rm old}$ and $\vec L_{\rm new}$ are larger and so the magnitude of $\Delta \vec L$ must be larger.
In turn the torque must have a larger magnitude and so $N-W$ must be larger with $W$ constant.
So $N$ does increase as the speed of the wheel increases.
The following is multiple choice question (with options) to answer.
The wheels of a skateboard spin around a | [
"shaft",
"street",
"person",
"board"
] | A | a revolution is when something revolves around something else |
OpenBookQA | OpenBookQA-3215 | equilibrium, water, salt
Title: Would adding a water soluble salt (e.g. NaCl) affect a water sensitive reaction? Let's take for example a reaction that would benefit from having less water in it, ester formation from alcohol and acid. We know that the equilibrium can be shifted to the right (ester formation) if water is constantly removed through distillation. My question is: would adding an excess of NaCl affect the reaction and push the reaction to the right?
The water would solvate the NaCl and theoretically be "preoccupied." I would like to think that water adding back to the ester to form an alcohol and acid would be more energetically favourable, but I don't really have enough knowledge to answer that on my own. Any thoughts? Esterification
$\ce{R_1-COOH + HO-R_2 <=> R1-COO-R2 + H2O}$
has the equilibrium constant, expressed in compound activities:
$$K = \frac{a_\mathrm{ester} \cdot a_\mathrm{\ce{H2O}} }{ a_\mathrm{acid} \cdot a_\mathrm{alkohol}}$$
The water activity is decreased by dissolved salts by 2 ways:
decreasing the molar fraction of water by dissolved salt
decreasing its activity coefficient by bounding it by ion hydration.
As the result, dissolved salts decrease the numerator of the equilibrium expression and shift the equilibrium toward production of ester.
Present dissolved salts will partially affect activities of the acid and the alcohol as well, but in lesser extend.
The following is multiple choice question (with options) to answer.
Adding salt to liquid decreases what? | [
"light",
"energy",
"magnetism",
"thawing temp"
] | D | adding salt to a liquid decreases the melting point of that liquid |
OpenBookQA | OpenBookQA-3216 | optics, visible-light, reflection, refraction, geometric-optics
Title: Image formation at surface of water Consider a lake full of water which has an object immersed in it. Now, if an observer was at the surface at a sufficient distance so that the light ray from the object is internally reflected, would he be able to see the object? If not, then why?
Conversely, would the fish see the observer (since the visibility is constrained to a small area)? Let's draw an image to show the observer above the lake looking at an object in the lake:
where the angles $i$ and $r$ are given by Snell's law. You say:
Now, if an observer was at the surface at a sufficient distance so that the light ray from the object is internally reflected
but there is no position for the observer where they cannot see the fish and likewise the fish can always see the observer. All that happens is that as the distance between the observer and fish increases, so the angle $i \rightarrow \pi/2$, to the observer the fish appears to be nearer and nearer to the surface. This is the well known phenomenon of water appearing to be shallower than it really is.
From the fishes point of view all the light from above the water is compressed into a cone of half angle equal to the critial angle. At values of $r$ greater than the critical angle the fish sees a reflection of the lake bottom.
The following is multiple choice question (with options) to answer.
Which of the following reasons would an angler fish use a light? | [
"attracting researchers",
"attracting humans",
"attracting predators",
"attracting sardines"
] | D | producing light is used for attracting prey by some deep sea animals |
OpenBookQA | OpenBookQA-3217 | electromagnetism, magnetic-fields, everyday-life
Title: How is magnetism ''conducted'' through a non-magnetic metal? I have a ball of metal about an inch in diameter and a concave disc of another metal (which is magnetic) around the ring of the disc (about $12 {\rm mm}$ in diameter). I don't know which metals they are. The ball is not magnetic on its own. That is paramagnetism, right?
The magnetic ring is strongly attracted to the surface of the ball, 'sticking' to it. However, I can stick a paperclip on the opposite side of the ball as if it has become magnetic itself, until I remove the magnetic ring from the ball.
When I wave the paperclip the same distance from only the ring itself, I feel no force at that distance.
Has the strong magnetic field of the ring caused a temporary magnetic alignment through the metal of the ball, allowing the paperclip to be attracted to it while the ring remains? The phenomenon you describe is ferromagnetism not paramagnetism.
Ferromagnetic materials like iron behave as if they contain many tiny bar magnets (called magnetic domains if you're interested to pursue this further), but because the magnet domains are aligned randomly the fields cancel out and there is no net magnetic field.
However if you put a ferromagnetic material in a magnetic field the external field will cause partial alignment of the magnetic domains. This induces a magnetic field in the originally unmagnetised iron, and that's why your paper clip sticks to the ball. However if you remove the external magnetic field the domains will go back to their original alignment, the net magnetic field will go back to zero and the paper clip will fall off again.
If you apply a very strong field and/or combine it with heating and cooling you can permanently change the alignment of the magnetic domains so they remain aligned when the external field is removed. This is how you make permanent magnets.
The following is multiple choice question (with options) to answer.
A magnet would most likely stick to | [
"a noodle",
"a chopstick",
"a girder",
"a plastic cup"
] | C | carbon steel is always magnetic |
OpenBookQA | OpenBookQA-3218 | java
if (orderedProdNameList.contains((Object) prodName)) {
int indexOfProdName = orderedProdNameList.indexOf((Object) prodName);
ProductView.addPurchaseDetails(itemData, vendorno);
if (eoq > 0) {
items.set(indexOfProdName, itemData);
ProductView.updatePurchaseDetails(itemData, vendorno);
} else if (eoq == 0) {
for (int i = 0; i < items.size(); i++) {
if (items.get(i).getProdname().equalsIgnoreCase(prodName)) {
items.remove(i);
ProductView.removePurchaseDetails(itemData, vendorno);
}
}
}
} else {
orderedProdNameList.add(prodName);
items.add(items.size(), itemData);
ProductView.addPurchaseDetails(itemData, vendorno);
}
if (items.size() > 0) { calculateTotal(); }
}
The following is multiple choice question (with options) to answer.
If a thing is seen, then | [
"the pupil was studying",
"the pupil absorbed light",
"light was put out",
"the pupil was gone"
] | B | light enters the eye through the pupil |
OpenBookQA | OpenBookQA-3219 | newtonian-mechanics
I should add that the above is simply what I, as a physicist with a fairly long experience, suspect is what is going on. It is not something I have read about and I am sure there is somewhere a more thorough discussion. So I hope I am right; I think I have a good argument. As I have described it above, I have in mind mainly the last part of the process where the wood only moves a little relative to the metal. In the earlier part, when the wood moves through a larger distance, it is inertia that is the main consideration, just like in the party trick where you abruptly whisk away a table cloth and the dishes on the table stay where there are. The more abrupt the better.
Added remark
It occurred to me that there is another thing worth mentioning here, that makes this method preferable to resting the axe head on something, or supporting the handle on a work top and hitting the head. It is that by hitting the end of the handle, with the head just hanging, you are going to deliver the force more accurately at the join, because it travels along the handle in exactly the direction you want. If instead you strike the head then there is a danger it will be knocked slightly obliquely, introducing a random tilt with each blow, which is liable to deform the wood and thus loosen the fit.
The following is multiple choice question (with options) to answer.
Burning wood was the only way to do what to your house back in the day? | [
"make it tasty",
"make it rain",
"raise the temperature",
"decrease the temperature"
] | C | burning wood is used to produce heat |
OpenBookQA | OpenBookQA-3220 | The population of a culture of bacteria, P(t), where t is time in days, is growing at a rate that is proportional to the population itself and the growth rate is 0.3. The initial population is 40. (1) What is the population after
6. ### calculus
The population of a certain community is increasing at a rate directly proportional to the population at any time t. In the last yr, the population has doubled. How long will it take for the population to triple? Round the answer
7. ### Maths
The population P of a particular city, Metropia, is growing at a rate proportional to the current population. The population at time t years is modelled by the equation P=Ae^kt where A and k are constants. With the aid of
8. ### Maths B - Population Growth
The population P of a particular city, Metropia, is growing at a rate proportional to the current population. The population at time t years is modelled by the equation P=¡¼Ae¡½^kt where A and k are constants. With the aid of
9. ### Maths B question - population
The population P of a particular city, Metropia, is growing at a rate proportional to the current population. The population at time t years is modelled by the equation P = Aekt where A and k are constants. (a) With the aid of
10. ### Population growth
The population P of a particular city, Metropia, is growing at a rate proportional to the current population. The population at time t years is modelled by the equation P = Aekt where A and k are constants. (a) With the aid of
More Similar Questions
The following is multiple choice question (with options) to answer.
what is the proportionality of a rise in bacteria content and human health? | [
"they are inversely proportional",
"they are in direct proportion",
"they both cancel each other out",
"they lack a relationship"
] | A | reducing bacteria in food prevents illness in people |
OpenBookQA | OpenBookQA-3221 | particle-physics
Title: Explanation for self-rupture glass is needed I witnessed a phenomenon that I couldn't conclude its cause. Please bear with me for the length of the recall, for I merely want to include any details that might help us to investigate. I had a cooking glass lid sat on a wooden shelf that is away from the stove and oven and other heating objects. The shelf is nailed on the wall and is situated just above my eye level, and a counter top is also on the same side of the wall where the shelf is installed.
Now here comes the surprise. In a winter afternoon 2011, my room had almost the same temperature as an autumn morning, and while I was cutting my lettuce on that counter top which I pointed out in above passage, a pounding sound, as if a heavy car door slam or a tree trump falling on top of the roof, knocked its introduction from the shelf that was just above my eye level. First, I thought I may had knocked something around me off(which I didn't believe that for there wasn't anything around me to knock off); then I thought it may be my neighbor next door dropping a heavy box; last, I suspected somewhere my roof top collapsed.
But it was my third suspicion directed me to meet that glass lid I mentioned above, and I found it had ruptured completely like glacier creaked BUT still having all broken pieces bounded without any pieces scattering toward random direction! Only the nob of the lid popped out partially. Before this happened, I hadn't used that lid for cooking for years, and I didn't removed it from any heating object nor there was something on top of the lid that day, and I believe what the lid had maybe just an invisible layer of dust.
I was glad my face hadn't been stung by any glass residues, but ponder what really happen to that glass lid and why it ruptured without collapsed. Below, I attached 2 pictures of the scene from that day. If you have any similar experience or know the theory behind it, may you please drop me an explanation to this incidence? Thank you in advance.
The following is multiple choice question (with options) to answer.
A thing that is near a running wood stove will discover when touching the stove | [
"that it is cool",
"that it is safe",
"that it is chilly",
"that it will sear"
] | D | if an object is exposed to a source of heat then that conductor may become hot |
OpenBookQA | OpenBookQA-3222 | electromagnetism, electrostatics, electricity, everyday-life
Title: Can sugar be affected by a magnetic field? While I was making a morning coffee at work, some sugar from the spoon started to fly away, seemingly towards some foam cups. Can this be explained by magnetism? Electro-magnetism is a good guess, simply because it's the only force you commonly see that's powerful enough. It's not very useful as an explanation, though, because almost everything you see around you is due to electro-magnetism (e.g. the way the spoon holds together in the first place, or the light that allows you to see the sugar, or the way the water "sticks" to having a fluid surface, or the way the individual atoms of the sugar stick together...). The real question is "What kind of EM is responsible?"
It's not ferro-magnetism (the kind you see with old-school fridge magnets) - neither the foam nor the sugar are ferro-magnetic. It's not para-magnetism either.
It's not due to molecular nor atomic bonds (the kind that holds molecules together, or the residual force that causes e.g. hydrogen bridges) - the distance involved is too large.
It's not dia-magnetism (remember those frog levitation videos?). That would require massive magnetic fields.
I could go on, but there's plenty of other cases that obviously don't apply, so let's skip to the end:
The interesting point is that plastics are usually electric isolants. This is very important, because it means that when they acquire a charge imbalance, it's not equalised very quickly - the current can't flow readily. This means that it's possible for one side to have a slight positive charge, while the other side has a slight negative charge (in a metal, in contrast, the charges would "mix" to maintain an overall neutral charge).
The following is multiple choice question (with options) to answer.
If a thing creates sugars in a natural system, then it is likely a | [
"daffodil",
"wolf",
"rabbit",
"deer"
] | A | a producer is a source of sugar in an ecosystem |
OpenBookQA | OpenBookQA-3223 | life, abiogenesis, artificial-life
Title: Synthetic life creation - status of attempts First I apologize for my incorrect English and for lack of modern knowledge regarding the subject (I studied biology a long time ago).
I'm interested to find out:
if there were successful attempts of life creation from conditions that we suppose were dominant on early Earth
if there were not, are such attempts still being conducted?
To clarify, by "life creation" I mean the accidental creation of entire organism in conditions of organic compounds, water, electricity, radiation etc. being present (Abiogenesis).
If this is already answered here, I'm sorry for asking, I have researched this, this, this and this question with no luck. There have been lot's of attempts, no success so far, a few groups are still working on. However, many steps forward have been done in the last decades.
Starting from the Miller experiment which demonstrated that the building blocks of life chemistry can be obtained starting from fairly simple chemical compounds. Following, Luisi and Szostak showed that 1) nucleic acids can polymerize without the help of enzymes and 2) autocatalytic micelles form spontaneously in many different conditions. It is also important to remember the work of Otto that showed how different molecules can self-replicates.
There are many more examples reported in the literature, still, the complete "creation" of life from matter has not been yet accomplished. However, the results from the experimental work done so far suggest that it is only matter of time and lots of combinatorial work. Unfortunately, there are little to no investments in this field. It's very hard to get the funds needed to start an international cooperation (like the one made to sequence the human genome or to build the CERN's Large Hadron Collider) with the goal of actually making life in the lab. I think that the work of a few (uncoordinated) groups will not get to the goal in the next few years.
The following is multiple choice question (with options) to answer.
What activity is a part of the wheel of organic life? | [
"having sex",
"black holes",
"nuclear meltdowns",
"supernova"
] | A | reproduction is a stage in the life cycle process |
OpenBookQA | OpenBookQA-3224 | quantum-spin, atoms
The bonds between the atoms are obviously split when the paper is torn, but is there a way to put them back together?
the answer is yes, because this is precisely why paper recycling works. The incoming used paper is washed, to remove ink and other contaminants, and then left to soak in a particular solution (the composition of which partly determines the color, consistency, strength, etc. of the resulting paper), where it eventually turns into a slurry. Paper is made of long fibers of cellulose arranged essentially randomly; when immersed in water, those fibers spread out throughout the solution. Then the slurry is rolled into sheets and left to dry; as the water leaves, the cellulose fibers end up weakly attracted to each other (the "weak" part is important; it's why you can easily tear a piece of paper in the first place), which leads to a similar kind of random arrangement of weakly-bonded cellulose fibers that we start with.
The following is multiple choice question (with options) to answer.
Turning a piece of paper into a ball is an example of | [
"folding",
"flattening",
"squashing",
"restoring"
] | C | crumple means change shape from smooth into compacted by physical force |
OpenBookQA | OpenBookQA-3225 | electromagnetic-radiation, electrons, wavelength, microscopy
Title: What if $\gamma$-rays in Electron microscope? I was referring Electron microscopes and read that the electrons have wavelength way less than that of visible light. But, the question I can't find an answer was that, If gamma radiation has the smallest of wavelengths of all, why can't it be used to reach to even finer details in microscopy? As X-Rays & $\gamma$-rays have very low wavelength, one could think of building an X-Ray or gamma-ray microscope. But, the problem only arrives at focusing both. They can't be focused as visible light is focused using refractive convex lenses (in microscope) thus providing a magnification of about 2000. Another problem with gamma rays is that they've very high ionizing power and interact with matter to the maximum extent thereby destroying it (causing atomic decay).
But on the other hand, we've Electron microscopes which work on the principle of wave nature of moving electrons. Electrons accelerated through a potential difference of 50 kV have a wavelength of about 0.0055 nm. (which is according to de-Broglie relation of wave-particle duality - $\lambda=\frac{h}{\sqrt{2meV}}=\frac{1.227}{\sqrt{V}}$nm) This is $10^5$ times less than the wavelength of visible light there by multiplying the magnification by $10^5$.
If you've read enough about electron microscopes, you should've known the fact that Electrons could be easily focused using electric & magnetic fields than going into a more complex one... :)
Even if these great physicists try something of focusing the gamma rays, it's production and maintenance would be far too difficult and expensive either. Because, we know that $\gamma$-rays could be produced only by means of radioactive decays which is biologically hazardous...
The following is multiple choice question (with options) to answer.
An electron microscope can look at | [
"my emotions",
"an elephant",
"a dog",
"my common cold"
] | D | an electron microscope creates a picture |
OpenBookQA | OpenBookQA-3226 | desert
Title: When was the first not-icy desert formed? For how long have deserts existed and which one would be the first to be created? I'm talking about arid, dry deserts, not the Antarctic or Arctic or any other icy deserts. Deserts have existed since at least the Permian period (299-251 million years ago) when the world's continents had combined into the Pangaea supercontinent. Stretching from pole to pole, this land mass was large enough that portions of its interior received little or no precipitation, according the University of California Museum of Paleontology.
Pangaea broke into smaller land masses which were moved across the surface by tectonic forces, a process that both changed global climate patterns and the climate those continents were exposed to. As a result, current desert regimes date back to no more than 65.5 million years, according to this Encyclopedia Britannica article:
The desert environments of the present are, in geologic terms,
relatively recent in origin. They represent the most extreme result of
the progressive cooling and consequent aridification of global
climates during the Cenozoic Era (65.5 million years ago to the
present), which also led to the development of savannas and scrublands
in the less arid regions near the tropical and temperate margins of
the developing deserts. It has been suggested that many typical modern
desert plant families, particularly those with an Asian centre of
diversity such as the chenopod and tamarisk families, first appeared
in the Miocene (23 to 5.3 million years ago), evolving in the salty,
drying environment of the disappearing Tethys Sea along what is now
the Mediterranean–Central Asian axis.
Which would put the oldest of "modern" desert somewhere in the region of what later became North Africa or South Asia.
The following is multiple choice question (with options) to answer.
deserts are known for having what type of climates? | [
"scorching",
"comfortable",
"average temps",
"lush"
] | A | a desert environment usually has a lot of sunlight |
OpenBookQA | OpenBookQA-3227 | visible-light
But in the real world, that yellow light represented by yv, would be a light with two wavelengths (red and green). But if it was a pure yellow light, with a narrow band (like a sodium lamp), the reflected light on the green surface would be almost null, and the surface would appear as black instead of green. I feel this is a little too short for an answer, but "yes." You are correct.
Now this goes against intuition, so it helps to remember two details:
The following is multiple choice question (with options) to answer.
a lack of illumination would result in which of these? | [
"the restroom overflowing with water",
"a principal's door being locked",
"a student unable to view what he is writing",
"a teacher being unable to transport to school"
] | C | eyes are used for seeing by animals by sensing light |
OpenBookQA | OpenBookQA-3228 | 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.
Which animal is likely hotter than it should be if its tongue is sticking out? | [
"a lizard",
"a golden retriever",
"a rabbit",
"a human"
] | B | panting is when an animal hangs its tongue out of its mouth to adjust to hot temperatures |
OpenBookQA | OpenBookQA-3229 | life, extremophiles
Title: How close to Earth's core can organisms live? We don't to know much about organisms living deep below the Earth's crust. Recently a team led by S. Giovanni discovered some microbes 300 m below the ocean floor. The microbes were found to be a completley new and exotic species and apparently they feed off hydrocarbons like methane and benzene. Scientists speculate that life may exist in our Solar System far below the surface of some planets or moons. This raises some questions:
What is the theoretical minimum distance from Earth's core where life can still exist. Please explain how you came up with this number. For example, there are temperature-imposed limits on many biochemical processes.
Is there the potential to discover some truly alien life forms in the Earth's mantle (by this I mean, life which is not carbon based, or life which gets its energy in ways we have not seen before, or non DNA-based life, or something along these lines)?
What is the greatest distance below the Earth's crust that life has been discovered? I believe it is the 300 m I cited above, but I am not 100% sure. There's a lot we don't know about life in deep caves, but we can bound the deepest living organism to at least 3.5 kilometers down, and probably not more than 30 kilometers down.
The worms recovered from deep mining boreholes are not particularly specifically adapted to live that far down: they have similar oxygen/temperature requirements as surface nematodes.
The Tau Tona mine is about 3.5 kilometers deep and about 60˚ C at the bottom. Hydrothermal vent life does just fine up to about 80˚C, and the crust gets warmer at "about" 25˚C per kilometer. It's entirely reasonable to expect life to about 5 kilometers down, but further than that is speculation.
Increasing pressure helps to stabilize biological molecules that would otherwise disintegrate at those temperatures, so it's not impossible there could be life even deeper. It may even be likely, given that the Tau Tona life breathes oxygen.
I am certain no life we might recognize as life exists in the upper mantle.
The following is multiple choice question (with options) to answer.
What might you find in the depths of the ocean? | [
"Mountainous ranges",
"magic",
"Unicorns",
"Love"
] | A | oceans cover 70% of the surface of the earth |
OpenBookQA | OpenBookQA-3230 | volcanology, volcanic-hazard, volcanic-eruption
Title: Would a Yellowstone eruption destroy global agriculture? Someone recently claimed in my hearing that if the Yellowstone caldera were to erupt, the resulting ash cloud would end all agriculture for a year or two. (The speaker is not a scientist, and neither am I.)
Is that accurate?
Are there reasonable scenarios (i.e., not this) worked out for the effects of a supervolcano eruption?
I did see this question, where one of the commenters points out that such an event would be unprecedented, so our ability to predict is limited, but I'm still curious about whatever we do know at this stage. An eruption of the Yellowstone super volcano would cause agricultural disaster over a very large area. Its global effect would be significant, but not totally devastating.
The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.
But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.
Eruption of super volcanoes is rare which makes it difficult to ascertain what exactly would happen when the Yellowstone super volcano eventually erupts - which won't be any time soon.
Yellowstone last erupted 174 000 years ago, which was a minor eruption. Lava from Yellowstone won't be the problem, but the ash and gases will be.
The last major eruption, 630 000 years ago, covered much of western and central United States with ash. The maximum thickness of the ash from that eruption is 660 ft. The eruption was a double eruption, 170 years apart. The amount of ash thrown into the atmosphere with each eruption caused the ocean to cool by 3 degrees Celsius with each eruption.
The following is multiple choice question (with options) to answer.
The pine farms experience destruction yearly due to | [
"a water bottle",
"rubbing two sticks",
"abrupt electric discharge",
"loose gas cans"
] | C | lightning can cause a forest fire |
OpenBookQA | OpenBookQA-3231 | sexual-reproduction
So when it's not maintained -- when there's no selection pressure on two populations -- inevitably there will be genetic drift that will randomly disrupt this fine-tuned system. If a population of, say, voles is isolated on an island, they will continue to have pressure to be able to interbreed with other voles on the island, but if they can't interbreed with those on the mainland there won't be any consequences, and so over long enough time they'll drift and lose that ability -- just as many apes, not suffering any consequences from not synthesizing vitamin C, gradually lost that ability from random drift.
There's another side to it. Two populations in the same location may be positively selected to not be able to interbreed. Think about two groups of finches, one with small fine beaks that eat tiny seeds deep inside pine cones, and one with heavy beaks that crush and eat thick-shelled nuts. They each do fine, but they can interbreed and produce offspring that have intermediate beaks -- too thick to reach the fine seeds that one parent eats, but too delicate to crush the nuts that the other parent eats. Those intermediate offspring will die off, and both parents will have wasted their resources raising them. Both parents would be better off not breeding with each other, but only breeding with their own kind to produce specialized and efficient offspring. There is now selection pressure on the birds to recognize their own kind (perhaps through songs or mating displays) and ultimately to be inter-sterile, so they never waste resources on the un-fit offspring. There's a gradation of separation over time, in which the different populations become more and more distinct. Eventually, at some arbitrary point, humans start calling them "species", but that's just us, not biology.
"Species" is an important concept, but it's not special in evolution; speciation is just one aspect of natural selection, there's nothing magical about it.
The following is multiple choice question (with options) to answer.
which pairs would likely be consumed by squirrel families? | [
"bones and feathers",
"turkey and rocks",
"cardboard and sand",
"peanuts and crackers"
] | D | squirrels eat edible plants |
OpenBookQA | OpenBookQA-3232 | astronomy, time, scales
Title: How can physicists observe events at large scales such as a star birth? I read recently multiple articles about physicists observing the birth of a star, or a star swallowed by a black hole.
However I can't manage to understand how these phenomena are observable at such scales. Common sense would lead me to think that the bigger the object you observe is, the bigger the timeframe of associated phenomena are.
I mean it seems that when you look at the micro-/nanoscopic world, phenomena happen very very fast. So when you look at galaxies it should be very very slow from our point of view.
So if we can watch the process of a star's birth, does it mean that such events have a timeframe similar to the phenomena that we observe at our scales? Typically astronomical events do not happen on the time scale of humans. So what scientists do, is look at a large sample of events each at a different time in the evolution of the event. So for example to see 'stars' being born they would look in a gas nebula and see several examples of stars being formed in the different stages of coalescing. However, some portions of these events can be on a human time-scale. A supernova can be seen over a period of several weeks to months. This would be rather boring to watch in real-time but if you use time-lapse 'photography' of about 1 day per sample you could see the event quite clearly.
The following is multiple choice question (with options) to answer.
To witness physical change you would need to observe the life cycle of a | [
"chicken",
"monkey",
"alligator",
"newt"
] | D | amphibians undergo metamorphosis |
OpenBookQA | OpenBookQA-3233 | optics, geometry
(I apologize for the not very beautiful drawing)
$h=$ oberver's eye height; $r=$ earth's radius; $a=$ distance to horizon; $d=$ distance to the lowest visible point of the object; $x=$ height of the hidden part of the object. Note that $d$ does not have to be the same as $2a$ although it looks like so in my drawing.
We start by calculating $a$, the distance to the horizon. From the Pythagoream Theorem, it follows that $$(h+r)^2=a^2+r^2$$ thus $$a=\sqrt{(h+r)^2-r^2}\tag{1}$$
For an observer with eye height $1.7m=0.0017km$, this gives $a \approx 4.65km$ which by the way is about the same as given in the wikipedia article.
Now we want to know how much of an object at known distance $d$ (where $d$ isn't actually the distance, but the distance to the lowest visible point of the object; but the difference should in most cases not be very large).
Again, using the Pythagoream Theorem, we can write $$(x+r)^2=r^2+(d-a)^2$$
Since we want to know $x$, let's first multiply out the right side using the 2nd of the binomial formulas:
$$(x+r)^2=r^2+d^2-2da+a^2$$ so $$x+r=\sqrt{r^2+d^2-2da+a^2}$$ and $$x=\sqrt{r^2+d^2-2da+a^2}-r\tag{2}$$
The following is multiple choice question (with options) to answer.
By finding the distance of something you are | [
"totally clueless",
"gathering data",
"playing around",
"wasting time"
] | B | An example of collecting data is measuring |
OpenBookQA | OpenBookQA-3234 | hydrology, rivers, geomorphology
Mountain ranges are often formed from orogeny, where tectonic plates collide. Rivers starts at high altitude, radiating out in all directions from mountains, but as collisions in the present continental settings are often on the rim of large plates (e.g Andes, Alps, Himalaya), and the rivers can't cross the range, it will have to travel the whole continental plate to reach ocean level. In the case of Asia, most large rivers starts in Himalaya (or other tectonic active regions, as Altai), in Europe large rivers starts in the Alps. In Africa, they start in the tectonic active rift zone.
This map shows the ocean drainage dividers. The border between the drainage areas are the line where rivers start.
The following is multiple choice question (with options) to answer.
if a river ran through a region, what would be found close by? | [
"land mass susceptible to water encroachment",
"active life coral reef",
"acid rain susceptible area",
"very active volcanic mountains"
] | A | flood plains are located near rivers |
OpenBookQA | OpenBookQA-3235 | fluid-dynamics, water, phase-transition
Yes, it will. The more important question is, "How much better will it dry?".
Some simple intuition may be garnered from dishwashers. When a thick ceramic plate or bowl goes through a dishwasher, it winds up hot and covered in water by the end of its journey. When you open the dishwasher and wait for 15 minutes, you will find the thick plate or bowl will be almost completely dried. For a thin plastic dish, something entirely different happens: it still remains mostly wet by the time it has cooled down.
Why? The thick ceramic bowl has a greater thermal mass per surface area than the thin plastic plate, where thermal mass is defined to be $m C_p$ with $C_p$ being the constant pressure heat capacity. The thick bowl holds enough heat to evaporate its coat of water and dry in the presence of air; the thin plate simply doesn't hold enough heat to drive off its water.
Ignoring heat loss due to radiative effects, the ability of an object to hold enough heat to drive off its water is entirely determined by the ratio of its thermal mass to its water content. To be specific, the fraction of water which will be lost is approximately given by
$$x=\frac{m_oC_p\Delta T}{m_w\Delta H}$$
where $m_o$ is the object mass, $m_w$ is the water mass adsorbed, $\Delta T$ is the difference between the object initial temperature and ambient temperature, $C_p$ is the heat capacity of the object (not the water), and $\Delta H$ is the latent heat of vaporization of water in units of energy per mass per Kelvin, which for water happens to be 2260 Joules per gram per Kelvin.
For an object with a typical heat capacity of 1 Joule/gram/Kelvin with 5% water content heated initially to 373K, a drop to room temperature will be achieved with about 60% water loss. So your object had better be less than 3% water if you want it to dry effectively just from its thermal heat.
The following is multiple choice question (with options) to answer.
A ceramic dish from the dishwasher will be | [
"dirty",
"cold",
"clear",
"warm"
] | D | a hot plate is a source of heat |
OpenBookQA | OpenBookQA-3236 | species-identification, ornithology
Title: House sparrow or something else? These little flying fellows seemed to have made themselves a small nest in the crevices of the roof of my house (I live in Poland). I don't know if this makes a difference, but I do live near a small park.
I'm wondering if this is a house sparrow or something else.
On one of the photos I could swear these look like common sparrows, but on another (the one where the wings are apart) it seems like a different species. It also seemed larger than a sparrow, but is hard to tell due to the distance at which I've seen the birds and the photos were taken. One other notable feature was that they seemed very loud...
Any help? Based on your image I would rather identify it as an Eurasian Tree Sparrow. They are pretty similar to the House Sparrow, but have a distinct black spot below their eyes which is missing for the House Sparrows (image from the Wikipedia):
The following is multiple choice question (with options) to answer.
A person can find a sparrow's home by | [
"looking at its face",
"looking at a detailed map",
"seeing where it was born",
"noting where it frequently consumes"
] | D | animals live and feed near their habitats |
OpenBookQA | OpenBookQA-3237 | meteorology, severe-weather
The lack of rich low-level moisture is due in large part to the lack of accessibility from warmer moisture sources, particularly the Gulf of Mexico; the Rockies provide a barrier to much of the moisture reaching further west.
As you note, parts of Wyoming and Montana do see supercells and tornadoes a bit more often... but on a good topographic map, fair parts of those states are east of the Continental Divide, and so still on an "upsloping" area and thereby not blocked by sinking regions which prevent full moisture progress. They're still less-tornado prone due to elevation and increased distance from moisture, but it does happen.
The desert southwest also does manage to get monsoon moisture sneaking around the terrain further south... but further north that monsoon moisture sees additional blocking by the more elevated terrain across Nevada and Utah. (And in the southwest, a different key ingredient in tornadic supercell development is typically missing in the summer monsoon: upper-air winds sufficient for supercell development)
The Pacific Coast does see a few occasional tornadoes. But from what I've seen, they typically form from smaller storms with much less classical and intense mesocyclones. As you mention, they're a bit more in line with cold-core setups, which usually produce weaker short-lived tornadoes than classic supercells of the Plains and on east. If you plug in the events you speak of into SPCs Severe Weather Events archive, [pick the date, then click Obs and Mesoanalysis on the left, then use the dropdowns to find various parameters]
you can see that CAPE was typically very meager (well short of 1000 J/kg) and the storm structure quite weak in reflectivity in comparison to a classic supercell, more indicative of such cold-core setups.
Capping inversions may be helpful to "keep the lid on the pot" if you have strong CAPE (and therefore quality moisture) and intense updrafts to erode the cap during the day. But as it is, there isn't enough moisture typically for the cap to be a positive factor.
The following is multiple choice question (with options) to answer.
Why are there more deer when there's a lot of rain? | [
"all the dolphins fly south for the winter",
"more rain means nothing grows",
"A biblical character took every other animal with him",
"abundant water means more vegetation"
] | D | the increase of something required by an organism has a positive impact on that organism 's survival |
OpenBookQA | OpenBookQA-3238 | navigation, move-base
Comment by hc on 2018-10-19:
Indeed how do you make sure that the min velocity (forward or backward) is enough to overcome friction?
Comment by RicoJ on 2020-09-07:
Overcoming friction is more related to the lower level motor controls of your application. If you're using Gazebo, there are ways to set joint controllers to achieve that. See here
The following is multiple choice question (with options) to answer.
If I wanted to add friction to a subject to get it to slow down I could | [
"embrace it",
"throw it",
"push it",
"roll it"
] | A | friction causes the speed of an object to decrease |
OpenBookQA | OpenBookQA-3239 | galaxy
Luminosity could be more likely a factor than gravity, as a sun with 100 solar masses would be about a million times as luminous as our sun, and 1 million solar luminosity, to equal the solar output from our sun it would only need to pass within 1,000 AU or 1/60th of a light-year, and a sun that bright would put out lots of UV light. But even so, fly-bys that close would be very rare, but we would still be more likely to be cooked by a large star than orbitally perturbed by one. Smaller stars would need to fly much closer to have an effect, but smaller stars are also much more common.
Outer planets would be more vulnerable and oort cloud objects even more so, to near fly-bys and orbital perturbations, but again, that kind of near fly-by wouldn't happen often.
The following is multiple choice question (with options) to answer.
the closest star to the human planet delivers solar energy to the planet | [
"maybe",
"the moon",
"this is uncertain",
"this is affirmative"
] | D | the sun transfers solar energy from itself to the Earth through sunlight |
OpenBookQA | OpenBookQA-3240 | evolution, theoretical-biology, human-evolution
So yes, given the our knowledge of quantitative and population genetic theory, predicting evolution of a given trait is possible. Just as predicting the future is possible with the laws of physics if you know the position of every atom in the universe. It's important to remember that organisms are constellations of 'traits', so predicting the evolution of all traits which make up the individuals within a species could be similar to predicting the futures of several multiverses.
The following is multiple choice question (with options) to answer.
Which would be a learned trait? | [
"skin color",
"nose shape",
"hair color",
"favorite cookie variety"
] | D | preferences are generally learned characteristics |
OpenBookQA | OpenBookQA-3241 | optics, water, evaporation, gas
Title: How are water vapors not visible? This site says that water vapor isn't visible.
However, take a look at this picture:
Isn't that water vapor? Water vapour is a clear and colourless gas, so it can't be seen by the naked eye.
What you see in the photo in your second link is (partially) condensed water vapour, i.e. fog (or mist). Fog contains tiny, discrete water droplets and light bounces off their surface in random directions, causing the visibility.
Water vapour by contrast only contain free molecules, too small for light to bounce off, so pure water vapour (without any condensate) is invisible, like most gases (some gases are clear but coloured like chlorine gas).
The following is multiple choice question (with options) to answer.
What can you point to as an example of water vapor? | [
"a mountain that looks like a bear",
"the smoke coming from a distant fire",
"a group of birds that looks like a wine glass",
"a white puff in the sky that is shaped like a bird"
] | D | An example of moisture is water vapor in the atmosphere |
OpenBookQA | OpenBookQA-3242 | combustion
Title: What happens when you 'burn' ash? This popped into my my mind while watching a match burn (don't ask me what I was doing with a burning match...).
Now as I know it, 'ash' is what you call the residual, grey-black powdery material left over following the combustion of wood.
I'm under the impression that ash is largely just carbon, with little or no organic constituents present along with it (since I'm pretty sure that pure powdered carbon is black, not grey-black).
Now I heated what remained of the matchstick with, well...another matchstick and found out, unsurprisingly, that the ash underwent practically no visible change. So I scooped up some ash into a crevice in a concrete block and then blow-torched it for about 2 minutes. Same result. However, while I was heating it this time, it glowed orange, it subsided as soon as I turned off the torch.
Thinking about it, if I did heat it strong enough it should decompose completely to black colored elemental carbon. If that is the case, to what temperature should you heat it?
I don't think I've considered everything there is to consider in this situation, which is why I've adopted a tentative tone while typing out this question.
Could there be other, side-reactions/effects as well? What would they be?
Additionally if anyone happens to know; what is it that contributes to the grey color that ash normally assumes? The principal component of wood ash appears to be calcium carbonate. (Wiki entry, "wood ash".) Other components include compounds of potassium and phosphorus. If you heat the calcium carbonate strongly enough, it will decompose into CO2 and calcium oxide. Apparently, strong heating is likely to result in less carbon instead of a larger percentage. The remaining calcium oxide is pretty stable as to temperature although addition of water will readily convert it to calcium hydroxide.
Calcium carbonate is white. White mixed with the black of any carbon present would result in a grey color.
The following is multiple choice question (with options) to answer.
A forest was turned to mostly charcoal overnight. What happened? | [
"a spaceship took the trees and put charcoal in their place",
"the trees died of old age",
"someone was careless with a match",
"the trees were chopped down"
] | C | fire causes burning |
OpenBookQA | OpenBookQA-3243 | 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.
In an arid location, any various lifeforms will have to | [
"work harder for nutriment",
"find food quite easily",
"find fast, easy nutriment",
"always eat their fill"
] | A | a desert environment contains very little food |
OpenBookQA | OpenBookQA-3244 | analytical-chemistry
Title: Easy method of analysing iodine content in supplements? Most health-food stores carry supplements supposedly containing iodine for people with iodine deficiency. I recently bought some kelp tablets that are supposed to have iodine but as a consumer how can I be sure that there is any iodine in them at all, let alone the claimed minimum daily requirement.
How do I know that I'm not just taking green-colored sawdust? Is there a cheap way to test a kelp tablet for its iodine content? If not are there testing labs that I could send some kelp to for testing that isn't going to cost me thousands of dollars? Take some potato starch dissolved in water (you can easily get it from the water when you boil potatoes), and put a tablet into the water. If the water becomes bluish black, there is iodine in the tablet.
Yes, there are testing labs that will determine the amount of iodine in the tablets which will cost somewhere around \$100 to \$200.
The following is multiple choice question (with options) to answer.
Kelp has to have provisions to | [
"maintain life",
"die",
"hibernate",
"relocate"
] | A | an plant requires food for survival |
OpenBookQA | OpenBookQA-3245 | This has been offset by payments, whose value at the time of the $$(k)$$-th payment is
$$\displaystyle P[(1+j)^{k-1} + (1+j)^{k-2} + \cdots + 1] = P\left[\frac{(1+j)^k - 1}{(1 + j) - 1}\right] = P\left[\frac{(1+j)^k - 1}{j}\right].$$
This means that the loan balance, immediately after your $$(k)$$-th payment is
$$\displaystyle L(1 + j)^k - P\left[\frac{(1+j)^k - 1}{j}\right].$$
During the period between the payments $$(k)$$ and $$(k+1)$$, the interest on this loan balance is
$$\displaystyle \left\{L(1 + j)^k - P\left[\frac{(1+j)^k - 1}{j}\right]\right\} \times j$$
$$\displaystyle = \left\{L(1 + j)^k j - P\left[(1+j)^k - 1\right]\right\}.$$
Therefore, the principal reduction for payment $$(k+1)$$ is
$$\displaystyle P - \left\{L(1 + j)^k j - P\left[(1+j)^k - 1\right]\right\}$$
$$\displaystyle = P - L(1 + j)^k j + P\left[(1+j)^k - 1\right]$$
Using equation (1) above, this equals
$$\displaystyle = P - P \left[\frac{(1 + j)^{100} - 1}{j(1 + j)^{100}} \right](1 + j)^k j + P\left[(1+j)^k - 1\right]$$
The following is multiple choice question (with options) to answer.
An item placed on a balance will be | [
"broken",
"measured",
"sorted",
"classified"
] | B | a balance is used for measuring weight of a substance |
OpenBookQA | OpenBookQA-3246 | roslaunch
I do not know if I should give you now the concrete solution. Perhaps you can try it on your own after this explaining and if you have further problems we can talk about it.
Didnt mentioned or checked the correctness of mimic by now. We talk abut this later too.
The following is multiple choice question (with options) to answer.
If I wanted to disguise myself, what might be something I do? | [
"Nothing",
"Take off clothes",
"Smile",
"Color my epidermis"
] | D | disguise means change appearance to hide |
OpenBookQA | OpenBookQA-3247 | evolution, mammals, marine-biology
The question remains: why? The most likely explanation is that cetaceans evolved to exploit an unfilled ecological niche or adapted to new niches that formed as a result of plate tectonics or other types of environmental changes that occurred 50-55 million years ago. The niche describes all of the living and non-living resources needed by an organism to survive. Although land-based mammals were increasing in diversity, few or none were present in the oceans. The basic hypothesis is that the early whale-like artiodactyls, like Indohyus and Pakicetus were land-based (terrestrial) mammals that spent most of their time near the water's edge. Over time, they adapted to the niches in the ocean. Fossils like Ambulcetus and Rodhocetus showed clear evidence of swimming ability, with flattened tails and the enlarged rear feet. In addition, the nostrils shifted from the front of the face to the top of the head, which we recognize as the blowhole.
The shift to the aquatic habitat allowed these species to exploit resources that were not available to land-based mammals, thereby reducing competition for the resources. Reduced competition allows more individuals to survive and reproduce.
Similar scenarios are very likely for other marine mammals, such as seals or manatees. They evolved to take advantage of ecological niches that were not filled by other organisms. This basic concept, evolving to fill available niches, is a common outcome of the evolutionary process.
The of adaptation of cetaceans and other mammals to the oceans may be similar to that of the hippopotamus. Hippos spend most of their time in the water, and they show many adaptations that allow them to live in the aquatic environment. The eyes and nostrils of the hippo are high on the head, which allows them to remain almost entirely submerged but still see and smell, as shown below.
(Hippo photo by Johannes Lunberg, Flickr Creative Commons.)
Hippos feed underwaters, they are heavy enough to walk on the bottom of the river, and the mate and give birth underwater. The young can suckle underwater. Clearly, hippos seem to be another mammal that is "returning to water." Similar types of processes must have occurred in cetaceans for them to adapt to the marine habitat.
The following is multiple choice question (with options) to answer.
A creature's habitat would be like what, if it has wide appendages that grasp liquids well? | [
"salt water",
"salty",
"mountainous",
"dry"
] | A | flippers are used for moving in water |
OpenBookQA | OpenBookQA-3248 | thermodynamics, entropy
The tree dies, which is pretty irreversible (entropy grows at the cell scale, because cells are ordered structures when they are alive while the atomic structure remains similar because you don't let the tree rot). For this part you can actually approximate the tree as being a closed system.
Processing the tree to make the house and furniture. After reading about how the process of making wood works, I would say that you have to cut and throw away a substantial part of the initial tree (without producing any change on its atomic structure), so that the entropy of the remaining part is notably less than the initial one.
All the other processes involved (such as the form of the furniture and house, or the placement of these) are subleading.
Thus, accepting that the house has less entropy than the tree, there is a lot of entropy generated in the second process above, so that the net entropy of house + woodcuter + rest of the tree (useless to make the house) + heat is bigger than the intial entropy of the tree.
The following is multiple choice question (with options) to answer.
Wood can be reused to make a | [
"dresser",
"plastic bottle",
"candy cane",
"glass bottle"
] | A | wood is a renewable resource |
OpenBookQA | OpenBookQA-3249 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is the most accurate statement? | [
"rocks grow to reach the size they are today",
"oaks grow to reach the size they are today",
"cell phones grow to reach the size they are today",
"plastic forks grow to reach the size they are today"
] | B | all living things grow |
OpenBookQA | OpenBookQA-3250 | botany, plant-physiology, plant-anatomy
Title: How do plants grow year after year even though they die? How do plants grow, die, and then grow again? For instance, when my plants die during the winter, how do they grow again next year? Does it have something to do with the root system? Or do they even die? It depends on the type of plant, but basically not all of the plant dies. Plants have evolved a number of strategies for winter* dormancy. These are common ones, but probably not an exhaustive list.
Deciduous trees and bushes simply drop their leaves in the fall, and so may look "dead" to the unskilled eye - though with practice, it's usually easy to distinguish between dead and dormant. Then when the weather warms in the spring, new leaves grow.
Other perennial plants may lose some or all of their top growth, even dying back to ground level, but the roots will be alive, and will start growing when the ground warms.
Still other plants have developed specialized underground structures like bulbs & rhizomes - think daffodils, tulips, irises, and similar. The rest of the plant dies, only to grow again from the bulb when conditions are right.
It's worth noting that most, if not all, of these are used for propagation as well, often naturally, and frequently with a bit of human help. Bulbs and rhizomes multiply: the daffodil bulb you planted a few years ago may now be a dozen bulbs, each of which can be moved to grow new ones. Many perennials can be increased by dividing the root mass into pieces, each of which will become a new plant. And cuttings from many trees & bushes can be induced to form new root systems, and become new plants.
Or summer, dry season, &c. For simplicity, I'll just say "winter".
The following is multiple choice question (with options) to answer.
Many things happen when the seasons change. One example is when plants go from big and bloomed to | [
"space",
"bigger",
"dead",
"gigantic"
] | C | An example of a seasonal change is plants becoming dormant in the winter |
OpenBookQA | OpenBookQA-3251 | zoology, ethology, sociality
Canfield, J., Hansen, M. V., Becker, M., & Kline, C. (1998). Chicken Soup for the Pet Lover’s Soul. Deerfield Beach, FL: Health.
The following is multiple choice question (with options) to answer.
If a person wants to feed their pet alligator, they will stock up on | [
"broccoli",
"sand",
"guppy",
"bread"
] | C | alligators eat fish |
OpenBookQA | OpenBookQA-3252 | black-hole, observational-astronomy, radio-astronomy
Takekawa explains, “Detailed kinematic analyses revealed that an enormous mass, 30,000 times that of the Sun, was concentrated in a region much smaller than our Solar System.”
Questions: How do they know that the central mass is "concentrated in a region much smaller than our Solar System"?
This answer about the paper and subsequent discussions below it don't seem to shed any light on this particular question. The NAO page does not indicate the origin of the quote, I'm wondering if it is a translation of a corresponding Japanese language page on the same site that explains further. The authors were able to successfully model the motion of the gas streams as Keplerian orbits around an object of $\sim30000M_{\odot}$. In doing so, they derived some key quantities, such as the pericentric distances of these two gas components (the "Balloon" and the "Stream"). One has its closest approach at $\sim0.21$ pc; the other has its closest approach at $\sim0.07$ pc ($14000\text{ AU}$). This places the pericenter well inside the Oort Cloud, and therefore inside the Solar System.
Therefore, given that it's highly unlikely that the Balloon skims the surface of the central object, we can say that the object's radius is certainly less than that of the Oort Cloud, and by extension, the Solar System. This is a key part of the argument that the object is, in fact, an intermediate mass black hole, as they note on Page 5. It's basically the same logic used to constrain the size of Sagittarius A* based on those infrared flares observed last year.
The following is multiple choice question (with options) to answer.
the central object of our solar system is also | [
"the smallest object in the solar system",
"the coldest heavenly body",
"the farthest star from us",
"the closest star from us"
] | D | the Earth revolves around the sun |
OpenBookQA | OpenBookQA-3253 | zoology, species-identification, marine-biology, invertebrates
Title: Species identification - greenish blue ocean worm (nudibranch?) in Perhentian Islands, Malaysia We found this on a beach at the Perhentian Islands, Malaysia in March, 2016 and cannot identify it. It's some sort of worm-type creature with many legs and bluish back about 15cm long. The legs undulated along the body as it swam.
back:
belly side: It's hard to identify from the photos provided, but I think it is Chloeia flava (a species of polycaete worm, within the phylum Annelida), also known in English as the "Golden Fireworm".
The size is roughly similar to what you describe (they are typically about 7-10 cm long). The individual you observed looks like it lives in sandy bottom environments (not a typical environment for a nudibranch), and this worm does also. It is commonly found all across the warmer Indo-Pacific as well, and looks like the individual observed in your photo.
If it is not this species, I think it is another species of the same family, Amphinomidae.
The following is multiple choice question (with options) to answer.
which one of these animals lives deepest in the ocean? | [
"an african parrot",
"gold fish",
"a tuna fish",
"a vampire squid"
] | D | deep sea animals live deep in the ocean |
OpenBookQA | OpenBookQA-3254 | heat, plastics
Title: Searching for a fireproof sponge? (I know this is a bit off topic, but I don't know where else to ask. If you know a better StackExchange site, please tell me)
I'm working on a project, and I want to basically create a "flaming sail". For this, I'm planning to drench a cloth in methanol and then lighting it, and for this, I need a fabric that both retains a lot of moisture and is flame proof, as this should be reusable. One possibility is to imbue with Sodium bicarbonate. The action of heating the Baking Soda, $\ce{NaHCO3}$, as a powder absorbs energy while releasing $\ce{H2O}$ and $\ce{CO2}$ to assist in retarding the flame per the reaction:
$\ce{2 NaHCO3 (s) -> Na2CO3 (s) + H2O (l) + CO2 (g)}$
Also, lesser-known, but important per a source, to quote:
Even though the exact modes of action are not well established, the $\ce{NaOH}$ formed may promote catalytic recombination of the radical species needed for flame propagation, causing the flames to extinguish [23]
Note, it is known that heating Sodium carbonate in the presence of $\ce{H2O}$ can be a source of $\ce{NaOH}$ (see comments here) to facilitate the above cited mechanism.
So, safe inexpensive Baking Soda is my recommendation.
The following is multiple choice question (with options) to answer.
Putting heat on and around something like the following can cause a chemical reaction: | [
"a marble slab",
"carrot cake batter",
"a stone",
"a dirt patch"
] | B | adding heat to an object sometimes causes chemical reactions |
OpenBookQA | OpenBookQA-3255 | astronomy, reflection, moon
Title: How does the moon reflect light? We can see the moon in the night because it reflects sunlight. But the light is incident on the opposite side of moon with respect to the observer in the night.
In this case, how does the moon reflect light?
I am not sure if I have articulated my question correctly. The problem with most of the earth-moon pictures is that they show the Earth and moon very close together - which suggests that the moon is in the earth's shadow for almost half of the time.
So in the picture linked to above - it looks like a full moon should be dark.
The real picture is more like this
The following is multiple choice question (with options) to answer.
The moon reflects rays of sun from our | [
"red giant",
"jupiter",
"yellow dwarf",
"whit dwarf"
] | C | the sun is a source of light called sunlight |
OpenBookQA | OpenBookQA-3256 | 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 get energy after a hard work out I could do what? | [
"Go bike riding",
"Go swimming",
"Consume bread",
"Run again"
] | C | food is a source of energy for animals |
OpenBookQA | OpenBookQA-3257 | atoms
Title: Conversion atom to another One child has claimed to have find a solution to all physical problems. On asking for details, he said that all periodic elements has common components, i.e. electrons, protons, neutrons.
The child has suggested a solution: convert atom to another by adding electron. This way one can get substance like $\ce{H2O, Au, He}$ in abundance.
How can it be done? While what you suggest may sound nice on paper, it has some serious problems.
Getting the elements. Let's say that we're talking about purifying water to remove toxic elements such as Hg or Cd. Extracting the elements out of the water is a feat by itself, for example using reverse osmosis methods. This is a method used for seawater desalination - to turn them from salt water filled with all kinds of elements into drinkable water. This process is very expensive, and a very polluting one as well. Desalination just the amount of water you need for drinking water is complicated, so desalinating an entire reservoir is simply not going to happen.
Let's say you did somehow manage to extract the element in question. Now you need nuclear reactions to transmute one element to another. Not all are possible. For some elements, like Tc or Am this is the only way you can produce them. However, you are going to end up with radioactive nuclear waste.
To sum it up, even if it was possible, you would need so much power and to do it and you will produce some much pollution that it's simply not worth it. Just going and mining the gold will be orders of magnitude cheaper (and probably cleaner) than producing it using nuclear reactions.
If you do manage to somehow extract the the polluting elements, you usually do something else with them (aka recycling) and you do not attempt being an alchemist. Another example is soils contaminated with lead. The solution is to just dig it up, put it somewhere where it is not hazardous to anyone and replace it with clean soil.
The following is multiple choice question (with options) to answer.
An element from the periodic table is used to transfer | [
"light",
"sound",
"air",
"voltage"
] | D | wiring requires an electrical conductor |
OpenBookQA | OpenBookQA-3258 | 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 | [
"throwing a gum wrapper in the ocean",
"trees in a forest",
"Fish swimming in the sea",
"The wind carrying seeds"
] | A | many vehicles emit pollution into the air |
OpenBookQA | OpenBookQA-3259 | game, objective-c, ai
//otherwise if one can be built, build one
} else if ([self floorsWithRooms].count > 0) {
DTTowerFloor *floor = [[self floorsWithRooms] firstObject];
_moveToPerform = [[DTGameAIJob alloc]initWithFloor:floor.floorNumber AIJobToDo:GamePlayingAIJobTypeRoomUpgrade jobToDo:0 roomType:RoomTypeFarm];
//otherwise expand the tower
} else {
//eventually this will not always happen
self.state = GamePlayingAIStateExpandTower;
}
[self finalizeStateForConcreteMove];
}
-(void) addMoveToMineFloor {
NSMutableArray *floorsNeedingMining = [self floorsForDigging];
if (floorsNeedingMining.count > 0) {
DTTowerFloor *floor = [floorsNeedingMining firstObject]; //add method to pick the closest to 0 or closest to a stockpile
_moveToPerform = [[DTGameAIJob alloc]initWithFloor:floor.floorNumber AIJobToDo:GamePlayingAIJobTypeBasicJob jobToDo:JobTypeMining roomType:0];
}
[self finalizeStateForConcreteMove];
}
-(void) addMoveToBuildLadder {
NSMutableArray *floorsNeedingLadders = [self floorsWithoutLadders];
if (floorsNeedingLadders.count > 0) {
DTTowerFloor *floor = [floorsNeedingLadders firstObject]; //add method to pick the deepest floor
_moveToPerform = [[DTGameAIJob alloc]initWithFloor:floor.floorNumber AIJobToDo:GamePlayingAIJobTypeBasicJob jobToDo:LadderJob roomType:0];
}
The following is multiple choice question (with options) to answer.
If a person wants to make house from something that is unable to be endlessly produced, they would build a | [
"tin shack",
"pallet structure",
"log cabin",
"wood house"
] | A | metal is a nonrenewable resource |
OpenBookQA | OpenBookQA-3260 | If the question is asking for the probability that either of the two cows is 2-coloured, we have
$$P(\text {1 cow is 2-coloured | both visible sides are black}) = \frac{P(\text {1 cow is 2-coloured and other is black}) \times P(\text {the black side of the 2-coloured cow is seen})}{P(\text{both visible sides are black})}=\frac{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}}{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}+\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}}=\frac{1}{2}$$
where $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when one is 2-coloured and the other is black and $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when both cows are black (these exhaust all possibilities for both visible sides being black).
The following is multiple choice question (with options) to answer.
If a zebra has more black than white on its body and has a calf, that calf | [
"will be dark brown",
"will be mostly white",
"will be quite bald",
"will be mostly black"
] | D | reproduction is when an organism passes genetic information from itself to its offspring |
OpenBookQA | OpenBookQA-3261 | cell-biology, nutrition, blood-circulation, liver
Title: How do nutrients get to the cells they need to get to? I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that guides these nutrients to the proper receiving location? Broadly speaking, nutrients that enter the blood from the gut, and those that are released into the blood by the liver, are available to any cells that require them. So there is no "guiding to the correct location" in the sense that you suggest.
Lipids for example are present in the various lipoproteins and can be acquired from these by all cells. Iron is bound to transferrin, and any cell with transferrin receptors can internalise the transferrin and take the iron. Glucose is available in solution in the plasma, and free fatty acids are bound to serum albumin in the blood. During starvation the liver produces ketones ("ketone bodies") which are taken up by many different tissues/cell types.
The following is multiple choice question (with options) to answer.
in order for the body to absorb nutrients, where does the food typically enter from? | [
"the mouth of the organism",
"the skin of the organism",
"the ear of the organism",
"the anus of the organism"
] | A | digestion is when an organism takes in nutrients from food into itself by eating |
OpenBookQA | OpenBookQA-3262 | homework, embryology
Title: Why are Birds and Reptiles with abundant yolk sac polyspermic? I was given an explanation that birds and reptiles are polyspermic because they have an abundant yolk sac. But how does it explain the thing?
Chicken as an adult is not using in my opinion yolk as an energy source.
Yolk is used during embryogenesis as the primary energy source with blastula and gastrula -stages and during organogenesis, since the embryo needs proteins and energy somewhere.
How does abundant yolk sac make birds and reptiles polyspermic? My professor says that
The yolk sac is not connected to the mechanism of polyspermy or
monospermy. [Amount of yolk inside the oocyte is then again.] The
oocytes of reptiles and birds are yolk rich - polylecithal for instance.
where
lecithal = yolk containing and some pieces of information about here.
The following is multiple choice question (with options) to answer.
Some lizards form eggs where | [
"in space",
"in fire",
"in ice",
"in their interiors"
] | D | reptiles lay eggs |
OpenBookQA | OpenBookQA-3263 | aqueous-solution, solubility, phase
Whereas the IUPAC Gold Book defines a chemical reaction as:
A process that results in the interconversion of chemical species.
One aspect of solvation vs. reaction that may seem confusing is the solubility of ionic species. Even though $\ce{NaCl}$ becomes $\ce{Na+}$ and $\ce{Cl-}$ in an aqueous solution, this does not constitute a chemical reaction as defined above, and we say that $\ce{NaCl}$ is soluble in water. The same is true of your example of $\ce{H2SO4}$; even though it dissociates in water, it is not converted to a new chemical compound. One way to think of this is if you remove the solvent, the solute should typically resume to it's original form. From our previous example, if we evaporate the water from our aqueous solution of $\ce{Na+}$ and $\ce{Cl-}$, we just get the solid $\ce{NaCl}$ back.
Your examples of solubility in hydrochloric acid are a bit complex because that is a two-component system of water and $\ce{HCl}$. All of the compounds you discuss are water soluble and it doesn't matter if the $\ce{HCl}$ is there or not. One slight exception in your examples is ethylamine. Ethylamine itself is miscible with water, but many higher molecular weight amines are not water soluble, but are soluble in hydrochloric acid. In this case, the $\ce{H+}$ from $\ce{HCl}$ protonates the amine, making the hydrochloride salt. This is still an example of solubility however, as once you remove the solvent, you are left with the original compound, in this case the amine.
The following is multiple choice question (with options) to answer.
An example of a chemical reaction might be | [
"a rusty knife",
"Water",
"Grass",
"Smiling"
] | A | combining two substances chemically causes chemical reactions |
OpenBookQA | OpenBookQA-3264 | homework, cell-membrane, human-physiology, lungs
Title: How many cell membranes are oxygen and carbon dioxide diffuse through in the lungs? In the lungs, oxygen and carbon dioxide pass through cell membranes by diffusion.
Which row is correct?
The correct answer is D, but I think it should be B. I can only think about three layers as maximum which are; epithelium of alveolus, endothelium of capillaries and the membrane of red blood cell. I don't know what are remainings.
Any help would be much appreciated! Oxigen goes from the alveolar's lumen to the cytoplasm of the erythrocyte, and that's 5 membranes:
the "top" of the alveolar epithelial cell
the "bottom" of such cell
the "top" of the endothelial cell (capillary)
the "bottom" of such cell
the erythrocyte membrane
You got all the cells right, but your only problem was this: oxygen diffuses through the cell membrane entering the cell, moves through the cytoplasm, and diffuses through the membrane again exiting the cell. So, for each cell, you have to count 2 membranes. For the last one, the erythrocyte, you have only 1 membrane (because it is $\ce{O2}$ final destination).
For the $\ce{CO2}$ the situation is a little bit more tricky. We have the same 4 membranes (2x epithelial cell and 2x capillary), but $\ce{CO2}$ can come from 2 locations:
from the erythrocyte, where it is formed from $\ce{H2CO3}$ (by the reaction $\ce{H2CO3 -> H2O + CO2}$) or released from the N-terminal group of proteins, like haemoglobin (where it has previously bound)
from the plasma (around 9% of the $\ce{CO2}$).
In the first case we have 5 membranes, and in the second case just 4.
So, the correct answer is D.
The following is multiple choice question (with options) to answer.
The lungs give O2 to the | [
"bloodstream",
"neighbor",
"ozone",
"poor"
] | A | the respiratory system transfers oxygen to the circulatory system |
OpenBookQA | OpenBookQA-3265 | • Assuming D is greater than A and B, is D less than the new thermal environmental temperature? And extracting time from an exponential growth type of function is going to yield a logarithm. Jun 26 '17 at 12:19
• @BillN "is D less than the new thermal environmental temperature" I was interested in the simplest case where the bottles are hot and the target is between T_0 and the new ambient temperature. The target cannot be lower then A and B in this case. It would be interesting to analyze the case where the bottles start colder than the freezer and must get to a temperature higher then their starting point (I think the target D must be "less than the new thermal environmental temperature" in this case otherwise it cannot be reached) Jun 26 '17 at 12:28
Let's make some simplifying assumptions about the thermal evolution:
• heat transfer coefficient is the same for both cases
• perfect mixing of substance in bottle so there is no "insulating" effect of more rapid cooling (eg if ice formed on the inside wall of the bottle without all the liquid reaching 0 °C, it could act as an insulating blanket)
• Heat transfer proportional to the temperature difference
Call the target temperature $T_1$ and the temperature of the fridge $T_A$ and freezer $T_B$. Then the equation for temperature with time is:
$$T(t) = T_A + (T_0-T_A)e^{-t/\tau}$$
Where $\tau$ is the time constant for the cooling curve, which depends only on factors that are the same for both bottles.
Rearranging, we find the time needed to reach $T_1$ by setting $T(t)=T_1$. Then you get
$$\frac{T_1-T_A}{T_0-T_A}=e^{-t/\tau}\\ t = \tau\left(\log{\frac{T_0-T_A}{T_1-T_A}}\right)$$
As you can see, when $T_1$ gets close to $T_A$, the time grows.
The following is multiple choice question (with options) to answer.
If a log is cold it is in | [
"an oven",
"a fire",
"a toaster",
"a tundra"
] | D | something in a cold place becomes cold |
OpenBookQA | OpenBookQA-3266 | everyday-life, diffusion, navier-stokes, convection
Diffusion in still air over distances of 400m usually takes a few hours rather than seconds, so I think that advection (the bulk movement of air) is likely to have been the dominant factor in the reported cases (as you suggested). Windspeeds at 10m above ground are typically 5m/s, decreasing downwards, so a transport time on the order of 100s is reasonable. Strong winds would reduce this time, but the descriptions "within seconds" and "almost instantly" seem somewhat exaggerated.
The following is multiple choice question (with options) to answer.
Wind can be used to | [
"make pasta",
"turn back time",
"make magic",
"time travel"
] | A | wind is an inexhaustible resource |
OpenBookQA | OpenBookQA-3267 | meteorology, atmosphere, geophysics, climate, geography
Finally, I have to note that I've interpreted "calmest" as the minimum mean wind speed. However, it would be sensible also to consider it as the place with the lowest maximum wind speed or some other metric, that would perhaps change the picture described above. And maybe using that metric one of the Antarctic domes could be the "calmest" place. But I won't extend the answer further with any possible interpretation for "calmest".
The following is multiple choice question (with options) to answer.
Which of the following would be considered the most windy | [
"a light drizzle",
"a light breeze",
"a powerful front",
"a tremendous hurricane"
] | D | windy means high wind speeds |
OpenBookQA | OpenBookQA-3268 | safety, home-experiment, amines
Title: Safety when handling cyclohexylamine in non-industrial amounts Today I was pipetting some cyclohexylamine into smaller bottles so that I don't have to use the liter flask every time I need a little bit of catalyst or plasticizer. I pipetted several 10-20 mL portions in the open air on a regular table.
Because I lack experience I'm extra precautious with what I do. From the MSDS's of cyclohexylamine I found that 10 mL will kill an adult male, which if you look at is isn't very much, less than a swig of water.
Of course I'm wearing a lab coat, safety goggles and chemical resistant gloves, but a few things concerned me (or at least made me wonder if it was the right/safe way to handle). According to the MSDS of ScienceLab the odor threshold is 26 ppm, while according to CAMEO, the PAC-3 for cyclohexylamine is 30 ppm, which Wikipedia defines as:
PAC-3 : Life-threatening health effects.
The following is multiple choice question (with options) to answer.
Make sure to protect your eyes when working with chemicals because they can easily do what if handled wrong | [
"nothing",
"fly",
"run away",
"spatter upward"
] | D | chemical splashing can cause harm to the eyes |
OpenBookQA | OpenBookQA-3269 | meteorology, weather-forecasting, barometric-pressure
Title: Do high pressure systems draw air towards them? I refer to the this very recent article, which quotes Andrew Watkins (Manager of Climate Prediction Services at the Australian Bureau of Meteorology).
My understanding has always been that air flows away from high pressure towards lower pressure, so the following quote from the referenced article confuses me. Can anyone explain it for me?
"There's been a big high pressure system drawing air in off the ocean,
keeping it a bit cooler for Sydney," Dr Watkins said. As Fred said, it's just an unfortunate word choice that makes you think the professor is suggesting air flows towards the high.
Indeed, a surface high pressure south of Sydney would be the circumstance to have the air circulate around it in such a way as to "draw" air onshore from off the shore... even as it's actually really flowing somewhat away from the high.
There's a long-range model forecast showing exactly this setup building after a strong low potentially passes by this week... and so Sydney may be held cooler again just in time for Boxing Day:
from www.pivotalweather.com
(This is only one model's long-range forecast, and the skill in such forecasts is quite low. I present it to show this scenario, not to make any forecast as to whether it'll actually happen next week)
You can see the green arrows are bringing air onshore. This link suggests current ocean surface temperatures are around 23°C (73°F). So that would likely reduce the temperature slightly (if you explore the plots at pivotalweather.com for Australia, it currently shows a forecast high closer to 23°C for the day, rather than nearer the 30s many spots in the area see tomorrow).
The following is multiple choice question (with options) to answer.
When I hear news of a warm front I make sure to bring | [
"game boy",
"clocks",
"guns",
"waterproof appendage covers"
] | D | a warm front causes cloudy and rainy weather |
OpenBookQA | OpenBookQA-3270 | microscopy, materials
Title: Opening coverslip package I feel pretty silly for asking this but I don't want to damage these coverslips.
I just ordered a 100ct box of coverslips and see no way to open them without destroying the container they are in. How are these little boxes typically opened? It seems smooth and sealed on all sides. Looking at the container from the side, it's probably a situation like this:
There might be some clear plastic wrap around the entire thing as well that you would need to cut/break.
The following is multiple choice question (with options) to answer.
After several months, a cardboard box left outside is all misshapen and has holes in it | [
"the elements broke it down",
"radiation completely destroyed it",
"an elf messed with the box",
"bees ate holes in it"
] | A | breaking down an object changes that object 's shape and mass |
OpenBookQA | OpenBookQA-3271 | astronomy, everyday-life, popular-science, climate-science
Title: Why is the summer, in the temperate latitudes, in average, hotter that the spring? It is common knowledge that the transition from the Spring to the Summer season occurs in the Summer Solstice when the "Sun reaches its highest excursion relative to the celestial equator on the celestial sphere" (as stated in Wikipedia).
It is also stated in Wikipedia' Summer page:
"Days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring."
My question is: why is the summer, in the temperate latitudes, in average, hotter that the spring? A major part of the reason for this is due to the temperature of the ground. While the length of days in the Summer are effectively a mirror of those in Spring, you must take into consideration more than that.
When Spring commences in temperate climates, it is (usually) immediately preceded by winter. Due to the Winter, the ground and/or surrounding bodies of water are very cold. This has the effect of cooling the air for the first part of Spring while the ground/water begins to thaw/warm up. Furthermore, it takes much longer to warm or cool a body of water than a mass of air; even longer to warm or cool the ground and water. Therefore, as Spring progresses and the days become longer (also meaning the Sun is higher above the horizon, thus providing more heating power), the sunlight must first overcome the cooling effects of the ground and water bodies. Near the end of Spring - when the days are sufficiently long and the Sun is much higher above the horizon - you should notice the weather becoming hotter. This is because the ground and water has had time to warm up, which means it is not constantly cooling the air and making it feel colder.
When you then transition to Summer, the ground is already sufficiently warm but the days are still long and the Sun is still high in the sky. This means the Sun can heat the ground, water, and air even more and without any cooling effects. This allows the Summer temperature to be easily higher than that of the Spring temperatures. If Summer were immediately preceded by winter, you might notice the weather getting warmer much more quickly, but the average temperature would be very close to that of the Spring.
The following is multiple choice question (with options) to answer.
On June 1st, it's the first day of winter in | [
"the sun",
"the Kepler belt",
"the southern hemisphere",
"the northern hemisphere"
] | C | winter is when a hemisphere is tilted away from the sun |
OpenBookQA | OpenBookQA-3272 | thermodynamics, temperature, phase-transition
Title: The temperature a liquid would boil: question incorrectly formulated or not? I have met a question in a high school physics book which I think is incorrectly formulated.
The question is this: In order to reach boiling temperature, a certain liquid requires twice the amount of energy compared to water. At what temperature does it boil?
The book says the answer is 200 Celsius.
It seems wrong to me because it does not mention the specific heat of the liquid. Knowing only the amount of heat provided is not enough to know the temperature it will reach, I think.
Am I wrong or is the book wrong? The book is wrong in the sense that it has made a lot of assumptions without actually accounting for all of them. So you are right that the question has incomplete information.
The inaccuracies in the question are as follows:
In such questions, you must refer to the principle of calorimetry.
$$m_1s_1t_1=H=m_2s_2t_2$$ where $H=$heat absorbed by the body, $m=$mass of that body, $s=$specific heat of the body, $t=$change in temperature of body and the indices $1,2$ refer to the two bodies in contact
The question does not mention the mass of the liquid, whether it is the same as that of water or anything else.
In a similar manner, the question does not mention the specific heat of the liquid, whether it is the same as that of water or not.
Also no mention of initial temperature of liquid.
So the question is quite vague.
The following is multiple choice question (with options) to answer.
Which is likely to boil? | [
"a cup of dirt",
"a cup of tacos",
"a cup of plasma",
"a cup of Earl Grey"
] | D | boiling is when liquids are heated above their boiling point |
OpenBookQA | OpenBookQA-3273 | optics, visible-light, reflection, refraction
As apparently we are able to see blue and weak, but clear violet stripe in the rainbow, my understanding is wrong. So why don't we get red, yellow, green and blue light in it as well? Why do we see spectrum as if we were using prism, not the "cumulative spectrum"? With the addition of some good diagrams I think I now understand your question.
This diagram does not show a key feature of the reflections.
The intensity of the reflected rays varies and so you do not observe a uniform cone of reflected light.
Here is a gif animation to show you what I mean.
[Individual images were taken from an Atmospheric Optics webpage and combined to produce a gif file.]
Parallel rays are coming in at the top of a water droplet and refracted, reflected and refracted again to emerge from the bottom half of the drop.
What you should note is that for a given range of impact parameters of the incident rays the highest concentration of emergent rays occurs occurs around an angle of $137.5^\circ$, ie that is where the emergent light is brightest and light from around that angle swamps the light from that emerging at other angles.
So you diagram should show a high intensity of red light around a particular direction and and much lower elsewhere.
Here is a ray diagram to illustrate the "bunching" of light rays along a particular direction.
The following is multiple choice question (with options) to answer.
Where might you see light reflect? | [
"rocks",
"bottled liquid",
"sand",
"wood"
] | B | when light hits a reflective object , that light bounces off that object |
OpenBookQA | OpenBookQA-3274 | glaciology, antarctic, ice, sea-ice, ice-shelf
Title: Is this 70km crack in an ice shelf of Antarctica remarkable, or a regular occurrence? I've just seen the LiveScience article 70-Mile-Long Crack Opens Up in Anatarctica. I'm not sure if the title is a bit sensational or not, the crack is in an ice shelf, not the continent of Antarctica.
An ominous crack in an Antarctic ice shelf as wide as a football field is long takes on an otherworldly beauty in a new aerial image.
Snapped by scientists on NASA's IceBridge mission, the shot shows a rift in Larsen C, an ice shelf that is floating off the Antarctic Peninsula. When the crack eventually spreads across the entire ice shelf, it will create an iceberg the size of the state of Delaware, according to IceBridge. That's around 2,491 square miles (6,451 square kilometers).
As of Nov. 10, when the IceBridge scientists observed this crack, it was 70 miles (112 km) long and more than 300 feet (91 meters) wide. The dark depths of the crack plunge down about a third of a mile (0.5 km), all the way through the ice to the ocean below.
[...] Larsen C is Antarctica's fourth-largest ice shelf, and it holds back the land-based glaciers just behind it: Once the ice shelf goes, those slow-flowing glaciers have one less barrier in their journey toward the sea.
My primary question: is this a remarkable event, or something that over time happens regularly? Isn't this just a natural part of "those slow-flowing glaciers... journey toward the sea." ?
I'm also wondering 1) Is an iceberg the size of Delaware actually remarkable, or something that just happens from time-to-time? And 2) how they (actually) know the crack goes all the way to the ocean - can they actually see the water in images, or is this a hypothesis based on understanding of cracks of this length and width? I can ask as a separate questions if it's too much to ask here.
above: Image from here. "A huge crack can be seen in the Antarctic Peninsula's Larsen C ice shelf in this aerial image snapped on Nov. 10, 2016, as part of NASA's IceBridge mission. Credit: NASA/John Sonntag"
The following is multiple choice question (with options) to answer.
The shelf of the continent is close to? | [
"whales",
"island changes",
"oceanic frontier edge",
"boats"
] | C | the continental shelf is located near the shore |
OpenBookQA | OpenBookQA-3275 | newtonian-mechanics, friction
Title: Why is kinetic friction less than static friction? Ex: A wooden block is lying on a table.
I am told that because the block is still, the microscopic surface irregularities form more complicated interlocking structures. Is it because the force of the block on the table deforms the molecular structure of the table and wood to eventually reach an equilibrium state? This state then is more connected and harder to change than a block simply gliding over the table?
Also, how fast does this happen? A body in motion tends to stay in motion.
Suppose the peaks of one surface aligned with the valleys of another surface, and you applied enough force to start slipping. One of two things must happen. Either the peaks get shaved off (which takes a lot of force), or the average distance between the two objects increases. Even if there is a little shaving taking place, the distance between the objects is increasing. If the objects start separating, they cannot suddenly return to have the peaks and valleys line up. It takes time, just like it takes time for a ball thrown into the air to return to earth. If the surfaces are kept in motion, the distance between them will reach some average that is greater than the average when they are at rest. Greater separation means that only the peaks of the surfaces are coming into contact at points closer to the tips of the peaks. There will be a reduced attraction between the molecules of the two objects, and a reduced component of the microscopic normal forces parallel to the direction of motion. This results in a lower component of force parallel to the direction of motion, i.e., less friction.
Reference https://www.physicsforums.com/threads/why-is-the-kinetic-friction-always-smaller-than-the-static-friction.140426/
The following is multiple choice question (with options) to answer.
Which of the following most likely led to certain rocks having less friction? | [
"a babbling brook",
"people",
"a light wind",
"money"
] | A | sometimes weathering rounds rocks |
OpenBookQA | OpenBookQA-3276 | thermodynamics, infrared-radiation
$$W = \sigma T^4 4 \pi R^2\\
T = \sqrt[4]{\frac{W}{4 \sigma \pi R^2}}$$
More importantly, if you assume that there will be convective heat losses, then the increased area again plays a role - but now $T$ will scale with $1/R^2$ and therefore go down substantially more quickly.
Note that multilayer insulation doesn't just have to be reflector-void-reflector; it could equally be reflector-insulator-reflector, and for the purposes of camouflage you might want the outermost layer to be similar to the background (rather than a reflector which would presumably stand out in daylight or under spot illumination). A video showing the effect of some approaches to insulation / thermal invisibility is given here - with a tip of the hat to Dirk Bruere who made me aware of it.
The following is multiple choice question (with options) to answer.
Which is most likely a cause of camouflage's effectiveness? | [
"a predator's eye sight",
"a predator's sense of hearing",
"a predator's sense of style",
"a predator's poor smelling"
] | A | camouflage is a kind of protection against predators |
OpenBookQA | OpenBookQA-3277 | The first one gives the minimum volume, so you don't want that. Take the second.
-
Thank you Jerry. :) Cheers! You get the right answer, because you actually gave me two value and described them really nice! I could follow the process very easily! – user31113 Apr 7 '13 at 11:46
You're welcome! – Jerry Apr 7 '13 at 11:47
If you cut the corner in the manner shown, by trigonometry at any corner, the new side length is smaller by $2 \sqrt3 h$. (Let me know if you have difficulty with this.)
Hence the box's volume is proportional to $\left(a-2 \sqrt3 h\right)^2 h$, which we try to maximise. Let $V(h) = \left(a-2 \sqrt3 h\right)^2 (4 \sqrt3 h)$. The value of $h$ which maximises $V(h)$ is exactly same as that maximising the volume we desire, due to proportionality. Now $V(h)$ can be looked at as the product of $3$ terms, $(a-2 \sqrt3 h), (a-2 \sqrt3 h)$ and $(4 \sqrt3 h)$, which sum to a constant $2a$. Hence the product is maximised when these three terms are equal. i.e.
$a-2 \sqrt3 h = 4 \sqrt3 h$ or when $h = \dfrac{a}{6\sqrt3}$.
-
Oh woops, yours is definitely more elegant! – Jerry Apr 7 '13 at 11:26
@Jerry Thanks. It's just that I like inequalities a lot. – Macavity Apr 7 '13 at 11:32
Thank you Macavity. :) Cheers! – user31113 Apr 7 '13 at 11:44
@Macavity Your solution is certainly neat, but I get a slight butterfly feeling when you pull that factor out of the air. I seem to get the same numbers by a method at least I find simpler. Any comments? – Brian Chandler Dec 20 '14 at 16:24
The following is multiple choice question (with options) to answer.
which of these would be easiest to measure in volume terms? | [
"the bumper of a car",
"the wheel of a car",
"a freshly made wine",
"a round soccer ball"
] | C | Matter in the liquid phase has definite volume |
OpenBookQA | OpenBookQA-3278 | 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.
Why does a turkey thermometer plunger cap come off? | [
"cold uranium ore",
"expanding air",
"expanding lead",
"contracting gas"
] | B | if gas is heated then that gas will rise |
OpenBookQA | OpenBookQA-3279 | newtonian-mechanics, electromagnetism, forces, solid-state-physics, interactions
My next assumption would be that the pushed molecules somehow push the molecules next to it and so with the other side, and therefore the scale reads my "push".
At first this seems pretty logical, but after further thoughts, I then questioned my self, if the molecules could affect other molecules, don't they sum up? In other words, if that single molecule that was directly "in contact" with the source of the $80\ \mathrm N$ (let's say my hypothetical microscopic finger) could cause other molecules on that object to experience the same force, this means that every molecule on that object experiences $80\ \mathrm N$ of downward pushing force, and the weighting scale would read an astonishing force of $720\ \mathrm N (80\times9)$, which is simply impossible as it'll break the fundamental laws of Physics.
Possibility 2
The assumptions below are based on my logic which frankly, I doubt, which simply means a force is divided equally amongst each individual molecules, meaning that an object with less mass, let's say 5 molecules, would experience more "individual" force then a "10 molecule" object as the main force is divided less and thus higher acceleration.
Now moving to the 2nd possibility, which for me is slightly more sensible. Here, I assume that the force divides equally to each of the molecule, so even if it was in the weighting scale scenario, the sum exerted would always be equal to my push which is $80\ \mathrm N$.
Unfortunately, this assumption has its weakness also, and this doesn't go along with my intuition. Here's my explanation.
The following is multiple choice question (with options) to answer.
O2 molecules stacked on top of each other create weight which is then tallied by a | [
"speedometer",
"odometer",
"barometer",
"a microscope"
] | C | a barometer is used to measure air pressure |
OpenBookQA | OpenBookQA-3280 | quantum-spin, atoms
The bonds between the atoms are obviously split when the paper is torn, but is there a way to put them back together?
the answer is yes, because this is precisely why paper recycling works. The incoming used paper is washed, to remove ink and other contaminants, and then left to soak in a particular solution (the composition of which partly determines the color, consistency, strength, etc. of the resulting paper), where it eventually turns into a slurry. Paper is made of long fibers of cellulose arranged essentially randomly; when immersed in water, those fibers spread out throughout the solution. Then the slurry is rolled into sheets and left to dry; as the water leaves, the cellulose fibers end up weakly attracted to each other (the "weak" part is important; it's why you can easily tear a piece of paper in the first place), which leads to a similar kind of random arrangement of weakly-bonded cellulose fibers that we start with.
The following is multiple choice question (with options) to answer.
One way to recycle paper is by using it to | [
"build oceans",
"build spaceships",
"wipe grime",
"build cars"
] | C | paper is recyclable |
OpenBookQA | OpenBookQA-3281 | geology
Title: Where do riverbed stones come from? Have they always been here since the river was formed? Are some newer than others? Riverbed 'stones' - I assume you mean things like pebbles, boulders, etc. are pieces of rock that have weathered out and been deposited in the river. Some come from rock that is very close to where they are located and some have been transported from very far away. In general (and it is a very broad generalization) the rounder the stone, the longer it has been in the river and the more likely it is to have come from far away. Of course that depends on the hardness of the rock, and other factors, too.
Some rocks are newer than others. Some have been formed quite recently and some are billions of years old.
The following is multiple choice question (with options) to answer.
What is a riverbank made of? | [
"oceans",
"loam",
"rivers",
"dirty clothing"
] | B | a riverbank is made of soil |
OpenBookQA | OpenBookQA-3282 | solutions, filtering
Title: Home made dispersion/solution with detectable >0.1μm particles Sorry for the possibly wrong terminology. I'm not a chemist and I'm not a native English speaker.
Please edit the question as needed. Thank you.
Is it possible to buy or prepare a dispersion with the following properties?
the particles should be >0.1μm in size, for example 0.11μm - 0.2μm
there must be a way to detect them - even in a small amount (colour, taste, chemical reaction with something else, ...)
it mustn't be a "glue"; it must be possible to flush them completely away with water or something else readily available
it mustn't be a toxic or corrosive substance
the dispersion (or components to prepare it) should be readily available (drugstore, grocery etc.)
the total price shouldn't be higher than $20 (I know this difficult with prices different in every country - this is just a guideline)
Why do I need it?
There's a very slight chance that a Sawyer Micro Squeeze Water Filter might have been exposed to a below zero temperature and might have been damaged by frozen residual water.
The manufacturer says there's no way to test the filter functionality in that case and a new filter should be bought instead. I wonder if this is really needed or there's a way to test the filter at home. Try to get some clay and shake it vigorously with water. Let it settle for a several hours. Test your filter with the supernatant water and collect the filtrate in a very clean glass tumbler. Colloids have an interesting property of scattering light. In a dark room, try to shine light (ordinary flashlight might work or perhaps an ordinary pointer used in presentations/offices). Be careful, never ever look at the pointer directly. Look at the filtrate at $90^o$ (right angles to the light beam), if you see a light beam travelling in water, it means that colloidal particles are seeping through the filtrate and the filter is damaged.
Read more about the Tyndall Effect https://www.sciencesource.com/archive/Tyndall-Effect-SS2423500.html or on Wikipedia before doing anything.
The following is multiple choice question (with options) to answer.
Treated water is unlikely to have | [
"drinkable fluid in the system",
"a clear color throughout",
"harmful contaminants flowing within it",
"better water then pretreatment"
] | C | Vitamin D heals bones |
OpenBookQA | OpenBookQA-3283 | photosynthesis, chloroplasts
Title: Chloroplasts in an animal cell What would happen if we inject a chloroplast organelle into an animal cell?
Will the animal cell destroy it? Or is it possible that the chloroplast will somehow survive, and even replicate? Could there be photosynthesis in such a cell, or will some of the necessary mechanisms be missing? To answer your bigger question:
Yes, most of this is possible - under some conditions -, and animals and animal cells can acquire chloroplasts, and use them.
E.g.: see Elysia chlorotica whose cells actively take up chloroplasts and use them, and keep them alive (though not replicating). - Though some genes of algae are also contained in the Elysia chlorotica genome - which may be considered as partial replication.
Also there are salamanders that have replicating algae within them (since embryogenesis) - even algae (with chloroplasts) within animal cells - though here the algae might be rather understood as symbionts or "cell types", and the animal cells don't have the chloroplasts by themselves.
The following is multiple choice question (with options) to answer.
What raw material is consumed by chloroplast | [
"flour",
"stone",
"CO2",
"lava"
] | C | In the photosynthesis process carbon dioxide has the role of raw material |
OpenBookQA | OpenBookQA-3284 | human-physiology, digestion, stomach
The stomach accomplishes much of its function by mechanically breaking down the swallowed food particles and mixing them with acid and enzymes into a sort of slurry. To do this, there are three major layers of muscle surround the stomach - from the outside, the longitudinal layer, the circular layer, and the oblique layer. The stomach also has two holes in it - the gastroesophageal opening, coming from the esophagus with the swallowed food/saliva mix, and the pylorus, where the food/acid/enzyme slurry exits into the duodenum, which is the beginning of the small intestine.
Due to the three layers of (rather strong) muscle, the stomach doesn't have a lot of expansion capability once it is filled completely to capacity. Fortunately, this almost never occurs (despite how we may feel after a large meal) because material is always leaving the stomach on its way to enzymatic digestion in the intestines. Additionally, once the stomach is filled to a certain extent, hormones such as leptin are secreted that give you the feeling of being sated, or full, triggering the brain to make you stop eating.
Of course, as we can see with the current epidemic of obesity around the world, the stomach can change its size over time. However, this is a rather slow process (weeks to months to years) of adapting to continuously consuming large meals.
But what would happen if you completely ignored these internal warnings, or were being force-fed, or whatever? Instead of rupturing (the biological equivalent of "exploding"), food would most likely be expelled either into the small intestine or back into the esophagus and back up the way it came down, i.e. causing vomiting.
The following is multiple choice question (with options) to answer.
If food is being digested then it is in the body | [
"under foot",
"in the ear",
"in the leg",
"above the knees"
] | D | the digestive system breaks food into nutrients for the body |
OpenBookQA | OpenBookQA-3285 | homework-and-exercises, thermodynamics, temperature, everyday-life
Title: Why is my hand not burned by the air in an oven at 200 °C? I have this problem from University Physics with Modern Physics (13th Edition):
The inside of an oven is at a temperature of 200 °C (392 °F). You can put your hand in the oven without injury as long as you don't touch anything. But since the air inside the oven is also at 200 °C, why isn't your hand burned just the same?
The following is multiple choice question (with options) to answer.
A potato that is placed in a roaring bonfire, when compared to a potato left in a warm oven for an hour, will | [
"chill",
"freeze",
"scorch",
"float"
] | C | if too much heat is transferred to an object then that object may burn |
OpenBookQA | OpenBookQA-3286 | 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.
Which has a positive impact on the environment in the world? | [
"building large numbers of cars",
"contaminating the ground with poisonous substances",
"dumping toxic waste in ocean",
"making sure trash is reused for new purposes"
] | D | humans discarding waste in an environment causes harm to that environment |
OpenBookQA | OpenBookQA-3287 | zoology, ichthyology, marine-biology
Switek goes on to to talk about exceptions in some marine mammals:
At this point some of you might raise the point that living pinnipeds like seals and sea lions move in a side-to-side motion underwater. That may be true on a superficial level, but pinnipeds primarily use their modified limbs (hindlimbs in seals and forelimbs in sea lions) to move through the water; they aren’t relying on propulsion from a large fluke or caudal fin providing most of the propulsion with the front fins/limbs providing lift and allowing for change in direction. This diversity of strategies in living marine mammals suggests differing situations encountered by differing ancestors with their own suites of characteristics, but in the case of whales it seems that their ancestors were best fitted to move by undulating their spinal column and using their limbs to provide some extra propulsion/direction.
The following is multiple choice question (with options) to answer.
Which creature is built to move though wet currents? | [
"a human",
"a porpoise",
"a cat",
"a bird"
] | B | swimming is when humans can move in water |
OpenBookQA | OpenBookQA-3288 | zoology, ethology, behaviour, psychology, death
I can't prove it to you, but I know that my Beagle had a rich emotional life. I know this because I spent huge amounts of time with him. He was a close friend of mine. I would just as soon question whether my wife has real emotions as my dog. I can't prove that my wife's emotions are real either, but I don't have to. It would be silly to assume that everything she shares with me is some sort of evolutionary programming, and not real emotion. Now, when I extend this to cetaceans, I must admit that I don't have any friends in those circles. So I can only guess.
The following is multiple choice question (with options) to answer.
The sloth's lack of urgency is a great example of | [
"stimuli",
"adaptation",
"movies",
"adoption"
] | B | adaptation is when an organism develops a trait over time for survival |
OpenBookQA | OpenBookQA-3289 | plant-physiology
Title: Would a plant survive if it was watered using hard-water? Hard water is water with high mineral/salt content. I'm told that a potted plant watered with a salt solution dries out sooner or later. Is this true?
If so, would a plant survive if watered using hard-water? It would depend on the content of the hard-water. If the water contained heavier metals like lead or radioactive elements like tritium (Hydrogen-3), the plant would most likely die. Most land plants cannot survive when watered with massive amounts of salt water as the salt would absorb the water from the leaves.
The following is multiple choice question (with options) to answer.
If you are stuck in the desert and need your water to last you, it is best to | [
"throw it away",
"hit it",
"safeguard it",
"sell it"
] | C | conserving water can be used for survival in a dry environment |
OpenBookQA | OpenBookQA-3290 | hydrology, gis, watershed
Title: To delineate the drainage basin for a lake, would the pour point be the inlet or the outlet? I am interested in the area draining into and affecting a particular lake. Delineating this drainage basin, should I use the lake's inlet or outlet to best capture the relevant drainage basin? I think including the lake is valuable in this exercise, as events on or in the lake itself also affect the lake.
I'd think outlet, but want to double check with you all. To complicate things, most lakes have more than one inlet and outlet. I guess I'd go with the lowest outlet in order to avoid missing any land which may drain into the lake. I think there are a few things to consider. First, a drainage basin is defined as the area upstream of the point to which all precipitation converges. Flow does not converge at the outlet - flow converges at the lake. Outlets don't contain any additional information of the upstream area draining into the lake. This implies that to find the area draining into a lake, you would necessarily have to proceed beginning from each and every inlet.
Here's another way to see this. Approximately 20% of all land drains to lakes with no outlets. These are referred to as endorheic lakes or endorheic basins. Even though there is no outlet, there is absolutely still a definable drainage basin area.
The following is multiple choice question (with options) to answer.
If a lake is fully drained and evaporated, then the lake will | [
"be full",
"be gone",
"be moist",
"be wet"
] | B | if a body of water loses all water then that body of water does not exist any more |
OpenBookQA | OpenBookQA-3291 | volcanoes, pyroclastic-flows
Edit: In a research* it is suggested that a turbidite current can flow over barriers, if the thickness of the flow exceeds %65 of the barrier. One may interpret this that, after a pyroclastic current dives to shallow water it may come back to the surface again.
The following is multiple choice question (with options) to answer.
If silt and such is making its way down a flowing path | [
"water will flow backwards",
"bugs will eat rocks",
"sand will be stacked",
"streams will be orange"
] | C | a sandbar is formed by water moving sediment downstream |
OpenBookQA | OpenBookQA-3292 | 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.
What requires nutrients to grow and gets nutrients with use of beak apparatus? | [
"dirt",
"birds",
"computers",
"metals"
] | B | a beak is used for catching prey by some birds |
OpenBookQA | OpenBookQA-3293 | cc.complexity-theory, big-picture, physics
Title: Energy considerations on computation In order to check my understanding, I would like to share some thoughts about energy requirements of computation. This is a follow up to my previous question and might be related to Vinay's question about conservation laws.
It occourred to me that, from a thermodynamical point of view, running a computation can be considered, to some extent, analogue to moving a weight along an horizontal line: The only energy loss is due to frictional forces, which can be, in principle, made arbitrarly small.
In an ideal setting without dissipative forces (the mechanical analogue of a reversible
computer), no energy expenditure is required at all. You still have to supply energy in order to accelerate the weight, but you can recover it all when decelerating it. The running time can be made arbitrarly small by investing enough energy (more precisely, if relativity is taken into account, running time is bounded from below by $d/c$, where $d$ is the distance).
Similarly, a reversible computer requires no energy expenditure but an energy investment that is recovered at the end of the computation, and running time can be made arbitrarly small by investing enough energy, up to relatvistic limits (as described in http://arxiv.org/abs/quant-ph/9908043 by Seth Lloyd).
There is, however, and energy cost associated with the construction of the computer. In general, this will depend on the implementation details, but I conjecture that we can state a lower bound for it:
Assume that our computer has three (classical or quantum) registers: Input, Output and Ancilla.
The Input and Output registers can be read and written to by the user, while the Ancilla register is inaccessible.
At the begining of each computation, the Ancilla register starts in a fixed (e.g. all zeros) state, and by the end of the computation it will have returned to the same fixed state. Thus, barring external noise, the Ancilla state needs to be initialized only once, when the computer is built.
The following is multiple choice question (with options) to answer.
Which is most reliant on nonrenewable resources? | [
"a solar panel",
"an electric car",
"an 1800s train",
"a modern bus"
] | C | coal is a nonrenewable resource |
OpenBookQA | OpenBookQA-3294 | quantum-mechanics, operators, measurement-problem, eigenvalue, observables
If you measure the length of a piece of paper with a ruler for example, you will not obtain a different result when you measure it again.
When you now measure a quantum system, you have two types of statistics in there. First, your particle exhibits certain probabilities to be at a certain location. Secondly, your measurement apparatus is never 100% precise. The best you can do is perform lots of different measurements of identically prepared systems which is also a source of uncertainty because identical preparation might be difficult in real life. You will obtain the probability of presence of the particle at a certain position. But since the position is a continuous variable, there will always be an error. You can never measure "true values" but you will not be "limited by the collapsed state" as you formulated it.
The following is multiple choice question (with options) to answer.
If a ruler is going to measure something, it will most likely be used to measure a | [
"gram of salt",
"liter of gasoline",
"curtain",
"ounce of milk"
] | C | a ruler is used for measuring the length of an object |
OpenBookQA | OpenBookQA-3295 | atmosphere, carbon-cycle
Title: For a tree over its entire existence, does it actually have a net negative effect on atmospheric CO2? A tree while alive converts CO2 + water -> carbohydrates + O2. However, once the tree dies, it decays, releasing CO2 back into the atmosphere. My question is, over an individual tree's overall existence, does a tree actually contribute to a reduction in atmospheric CO2?
I'm aware there's other pathways a tree could end up as a more long term carbon store (carbonaceous rocks), but mostly interested in if a tree were to die and fall in a forest, decay in 50-150 years, would it have contributed to a net reduction in CO2, or does a tree typically act as more of a temporary 100+ year store of CO2? A brief review of recent non-paywalled available literature indicates that such an effect likely exists but that it is difficult to quantify based on currently available data.
Some amount of carbon from trees can be sequestered in the soil for periods time significantly longer than the typical above-ground decomposition time of organic matter, potentially for millennia. This clearly lengthens the carbon cycle time, but it is not clear to me whether this represents carbon storage, as there does not seem to be a well established minimum cut-off time for this. The primary source for soil-sequestered carbon are tree roots, with leaf litter constituting a secondary source.
The following paper (preprint online) addresses the question in the specific context of agroforestry, i.e. cropland interspersed with trees. The paper notes multiple times that the processes involved in soil sequestration are not well understood and that quantitative measurements and estimates vary widely, as one would expect based on differences in climatic and soil condition. Note on units: A Mg corresponds to a metric ton.
Klaus Lorenz and Rattan Lala, "Soil organic carbon sequestration in agroforestry systems. A review." Agronomy for Sustainable Development, Vol. 34, No. 2, April 2014, pp. 443-454.
The following is multiple choice question (with options) to answer.
Trees take in CO2 from the atmosphere for | [
"ransom",
"synthesizing food",
"money",
"fun"
] | B | a plant absorbs carbon dioxide from the air for photosynthesis |
OpenBookQA | OpenBookQA-3296 | atmosphere, wind, geography, convection, mesoscale-meteorology
Title: How big does a lake have to be to have its own Sea Breeze? How big does a body of water need to have a sea breeze? Is there a chart on sea breezes wind speed that include lakes?
Could a circular lake create enough sea breeze to create a wind vortex in the center of the lake?
https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons Lake breezes(similar to sea breezes) are fundamentally a feature of mesoscale meteorology and the peer reviewed reference Small Lake Daytime Breezes:
Some Observational and
Conceptual Evaluations details both the observational studies of lake breezes and the conceptual understanding behind the formation of the lake breeze.
Since OP's question is
How big does a body of water need to have a sea breeze?
The following is multiple choice question (with options) to answer.
If you want to walk over a lake, which of these is necessary? | [
"happy dogs",
"freezing temperatures",
"meowing cats",
"hot lava"
] | B | freezing point means temperature below which a liquid freezes |
OpenBookQA | OpenBookQA-3297 | aerodynamics
Title: How do eagles fly slowly for a long time? Eagles fly slowly for a long time.
Many other species fly faster and move their wings faster. But eagles keep their wings steady, and move only their tail.
How do they move slowly in the air, without falling down?
Can this eagle flying technique be used in aviation? How does they move slowly in air, without falling down?
One possibility is soaring using a ridge lift - typically a situation when the wind is approx. perpendicular to a mountain ridge. The air is lifted at the front side of the ridge and an eagle can soar in the lifting air stream. This can also work without the wind,
Which is a situation of thermal flying. Typically, the ground is heated by the Sun, the air layer just above the ground is heated by conduction and at some moment it forms a kind of bubble that starts to rise. This bubble is usually long, resembling a column and lasts until the warm air is depleted. The situation can repeat (this behavior is called an interval). If a ridge is oriented south, then the Sun can create a thermal wind (intervals) that enables a bird to soar.
Can we use eagle's flying technic for flights? Yes, however, man will never be that good.
soaring: https://www.youtube.com/watch?v=63qJn9HrB7E
thermal flight: https://www.youtube.com/watch?v=KXqTCM0-zXQ
Edit: Just for completness - there exists also a wave soaring, that is reachable for gliders and maybe for hangliders, probably not possible for birds and paragliders - see pictures here : http://www.ssa.org/GliderLiftSources
The following is multiple choice question (with options) to answer.
Eagles survive by dining on | [
"salmon",
"bears",
"humans",
"moose"
] | A | eagles eat fish |
OpenBookQA | OpenBookQA-3298 | wildfire
There are detailed satellite imagery with PM2.5 monitor overlay at Aerosol Watch, if you would like to see how the event progressed through time.
The following is multiple choice question (with options) to answer.
The cause of a wildfire could be as simple as | [
"A water puddle",
"tons of ice",
"snow",
"a ciggy"
] | D | wildfire is when a forest catches fire |
OpenBookQA | OpenBookQA-3299 | magnetic-fields, gas
Title: Do Magnetic Solids exhibit their Magnetic properties in their Gaseous state? Example
Does cobalt, a solid exhibit Magnetic properties when converted to its Gaseous State. I assume the magnetic property you're thinking of is ferromagnetism. If so then no, a gas of cobalt atoms would not be ferromagnetic.
If you take a single cobalt atom you'll find it has a magnetic moment i.e. it behaves like a tiny magnet. This is because the cobalt atom contains unpaired electrons, and there are lots of atoms like this. However if you take two bar magnets and let them come together you'll find they naturally arrange themselves like this:
Because the North and South poles attract the two magnets line up anti-parallel and their magnetic fields cancel out. So if you took a million bar magnets and jumbled them all up together they would pair up and cancel out and the overall magnetic field would be very small.
Atoms that have a magnetic moment behave in a very similar way. For example the aluminium atom has one unpaired electron so it has a magnetic moment. However in aluminium metal the atoms arrange themselves with their magnetic moments aligned anti-parallel like the diagram above, and aluminium metal has no overall magnetic field. We call materials like this paramagnetic.
However for a very few materials called ferromagnets there is an extra interaction between the electrons in neighbouring atoms called an exchange interaction that makes the magnetic moments line up in parallel rather than anti-parallel, so they look like:
In ferromagnets the magnetic moments of the individual atoms line and reinforce each other, and that gives the material the large overall magnetic field that we get in a bar magnet.
But this exchange interaction is highly dependent on the exact details of the crystal structure i.e. the way the atoms are positioned relative to each other. As soon as you destroy the crystal structure by melting or vaporising the material the exchange interaction disappears and the material reverts to being just paramagnetic with no large overall magnetic field.
So the bottom line is that molten or gaseous cobalt would be paramagnetic not ferromagnetic. It would still have some interesting magnetic properties, but it wouldn't have a strong overall magnetic field like a ferromagnet.
The following is multiple choice question (with options) to answer.
An example of a ferromagnetic metals could be | [
"wood",
"a coin",
"plastic",
"china plates"
] | B | a paper clip is often made of ferromagnetic metals |
OpenBookQA | OpenBookQA-3300 | 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.
What is the most likely cause of split rocks on a mountain slope? | [
"pine tree roots",
"true enlightenment",
"sea urchins",
"heavy metal music"
] | A | a plant 's roots slowly break down rocks as the roots grow |
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