rajpurkar/squad huggingface dataset:
Title: Glacier

Glacial moraines are formed by the deposition of material from a glacier and are exposed after the glacier has retreated. They usually appear as linear mounds of till, a non-sorted mixture of rock, gravel and boulders within a matrix of a fine powdery material. Terminal or end moraines are formed at the foot or terminal end of a glacier. Lateral moraines are formed on the sides of the glacier. Medial moraines are formed when two different glaciers merge and the lateral moraines of each coalesce to form a moraine in the middle of the combined glacier. Less apparent are ground moraines, also called glacial drift, which often blankets the surface underneath the glacier downslope from the equilibrium line.

Question: When are glacial moraines visible?
Answer: after the glacier has retreated

Question: How are glacial moraines formed?
Answer: deposition of material from a glacier

Question: Where are lateral moraines found?
Answer: sides of the glacier

Question: How are medial moraines formed?
Answer: when two different glaciers merge and the lateral moraines of each coalesce to form a moraine in the middle of the combined glacier

Question: What are ground moraines also called?
Answer: glacial drift
Title: Glacier

Before glaciation, mountain valleys have a characteristic "V" shape, produced by eroding water. During glaciation, these valleys are widened, deepened, and smoothed, forming a "U"-shaped glacial valley. The erosion that creates glacial valleys eliminates the spurs of earth that extend across mountain valleys, creating triangular cliffs called truncated spurs. Within glacial valleys, depressions created by plucking and abrasion can be filled by lakes, called paternoster lakes. If a glacial valley runs into a large body of water, it forms a fjord.

Question: What shape do mountain valleys have pre-glacation?
Answer: characteristic "V" shape

Question: What gives mountain vallys their characteristic "V" shape before glacation?
Answer: eroding water

Question: How is a fjord formed?
Answer: a glacial valley runs into a large body of water

Question: What shape do glacial valleys have after being widened by glacation?
Answer: "U"-shaped
Title: Glacier

At the start of a classic valley glacier is a bowl-shaped cirque, which has escarped walls on three sides but is open on the side that descends into the valley. Cirques are where ice begins to accumulate in a glacier. Two glacial cirques may form back to back and erode their backwalls until only a narrow ridge, called an arête is left. This structure may result in a mountain pass. If multiple cirques encircle a single mountain, they create pointed pyramidal peaks; particularly steep examples are called horns.

Question: On which side is a cirque opened?
Answer: the side that descends into the valley

Question: Where does ice start accululating in a glacier?
Answer: Cirques

Question: What is a narrow ridge formed by two cirques eroding back to back called?
Answer: arête

Question: What are extremely steep cirques called?
Answer: horns

Question: How many sides are closed in a typical cirque?
Answer: three sides
Title: Glacier

Some rock formations in the path of a glacier are sculpted into small hills called roche moutonnée, or "sheepback" rock. Roche moutonnée are elongated, rounded, and asymmetrical bedrock knobs that can be produced by glacier erosion. They range in length from less than a meter to several hundred meters long. Roche moutonnée have a gentle slope on their up-glacier sides and a steep to vertical face on their down-glacier sides. The glacier abrades the smooth slope on the upstream side as it flows along, but tears loose and carries away rock from the downstream side via plucking.

Question: What is another name for roche moutonnee?
Answer: "sheepback" rock

Question: What are roche moutonnee?
Answer: elongated, rounded, and asymmetrical bedrock knobs that can be produced by glacier erosion

Question: How large are roche moutonnee?
Answer: less than a meter to several hundred meters long

Question: What shape do roche moutonnee have on their "up" side?
Answer: gentle slope

Question: What shape do roche moutonnee have on their "down" side?
Answer: steep to vertical face
Title: Glacier

Large masses, such as ice sheets or glaciers, can depress the crust of the Earth into the mantle. The depression usually totals a third of the ice sheet or glacier's thickness. After the ice sheet or glacier melts, the mantle begins to flow back to its original position, pushing the crust back up. This post-glacial rebound, which proceeds very slowly after the melting of the ice sheet or glacier, is currently occurring in measurable amounts in Scandinavia and the Great Lakes region of North America.

Question: Where is post-glacial rebound occuring most?
Answer: Scandinavia and the Great Lakes region of North America.

Question: What has the ability to depress the crust of the Earth into the mantle?
Answer: Large masses, such as ice sheets or glaciers

Question: With what speed does post-glacial rebound occur?
Answer: very slowly

Question: How much of a glacier's thickness is usually involved during crust depression into the mantle?
Answer: a third of the ice sheet or glacier's thickness
Title: Planck_constant

First recognized in 1900 by Max Planck, it was originally the proportionality constant between the minimal increment of energy, E, of a hypothetical electrically charged oscillator in a cavity that contained black body radiation, and the frequency, f, of its associated electromagnetic wave. In 1905 the value E, the minimal energy increment of a hypothetical oscillator, was theoretically associated by Einstein with a "quantum" or minimal element of the energy of the electromagnetic wave itself. The light quantum behaved in some respects as an electrically neutral particle, as opposed to an electromagnetic wave. It was eventually called the photon.

Question: What is considered the minimal energy increment of a hypothetical oscillator?
Answer: value E

Question: In what year was the value E associated by Einstein with quantum theories of energy?
Answer: 1905

Question: Who discovered an association between the value E and quantum energy?
Answer: Einstein

Question: What did the light quantum behave the same as in laboratory experiments?
Answer: neutral particle

Question: What type of charge did a particle have that behaved similarly to light quantum energy?
Answer: neutral

Question: What is energy abbreviated to in science?
Answer: E

Question: What is frequency also known as in science?
Answer: f

Question: What term describes a small amount of element?
Answer: quantum

Question: What did the light quantum, in some ways, behave as?
Answer: an electrically neutral particle

Question: What was later termed the photon?
Answer: The light quantum

Question: When did Max Planck first recognize the value of the Planck constant?
Answer: 1900

Question: Which scientist associated the Planck constant with a quantum five years after Planck's recognition?
Answer: Einstein

Question: Instead of an electromagnetic wave, what did the light quantum behave as in some regards?
Answer: an electrically neutral particle

Question: What is the simple name given to the light quantum today?
Answer: the photon
Title: Planck_constant

Classical statistical mechanics requires the existence of h (but does not define its value). Eventually, following upon Planck's discovery, it was recognized that physical action cannot take on an arbitrary value. Instead, it must be some multiple of a very small quantity, the "quantum of action", now called the Planck constant. Classical physics cannot explain this fact. In many cases, such as for monochromatic light or for atoms, this quantum of action also implies that only certain energy levels are allowed, and values in between are forbidden.

Question: What does classical statistics mechanics not define the value of?
Answer: h

Question: What is required to exist in classical statistics mechanics?
Answer: h

Question: After Planck's findings, what was determined could not take on an arbitrary value?
Answer: physical action

Question: What is the "quantum of action" called?
Answer: the Planck constant

Question: What does the Planck Constant refer to?
Answer: quantum of action

Question: Classical statistical mechanics requires the existence of what?
Answer: h

Question: What was realized after Planck's discovery?
Answer: that physical action cannot take on an arbitrary value

Question: What is the Planck constant formerly known as?
Answer: quantum of action

Question: Regarding atoms, what does the Planck constant imply?
Answer: that only certain energy levels are allowed

Question: Regarding atoms, what are values in between certain energy levels considered by the Planck constant?
Answer: forbidden

Question: Following Planck's discovery, what was realized about values of physical action?
Answer: physical action cannot take on an arbitrary value

Question: The Planck constant initially was given what name?
Answer: the "quantum of action"

Question: How is the proportional nature of the Planck constant explained?
Answer: Classical physics cannot explain this fact

Question: For certain cases of light or atoms, what does the quantum of action yield?
Answer: only certain energy levels are allowed, and values in between are forbidden.
Title: Planck_constant

Equivalently, the smallness of the Planck constant reflects the fact that everyday objects and systems are made of a large number of particles. For example, green light with a wavelength of 555 nanometres (the approximate wavelength to which human eyes are most sensitive) has a frequency of 7014540000000000000♠540 THz (7014540000000000000♠540×1012 Hz). Each photon has an energy E = hf = 6981358000000000000♠3.58×10−19 J. That is a very small amount of energy in terms of everyday experience, but everyday experience is not concerned with individual photons any more than with individual atoms or molecules. An amount of light compatible with everyday experience is the energy of one mole of photons; its energy can be computed by multiplying the photon energy by the Avogadro constant, NA ≈ 7023602200000000000♠6.022×1023 mol−1. The result is that green light of wavelength 555 nm has an energy of 7005216000000000000♠216 kJ/mol, a typical energy of everyday life.

Question: What are common things like furniture and stationary objects actually made of?
Answer: particles

Question: Which light wavelength is the human eye most sensitive to?
Answer: 555 nanometres

Question: What color of light is the human eye most sensitive to?
Answer: green

Question: What does the smallness of the Planck constant show?
Answer: the fact that everyday objects and systems are made of a large number of particles

Question: At about what wavelength of light are human eyes most sensitive?
Answer: 555 nanometres

Question: What frequency does green light with a wavelength of 555 nanmetres have?
Answer: 7014540000000000000♠540 THz

Question: How is the energy from one mole of photos computed?
Answer: by multiplying the photon energy by the Avogadro constant

Question: How much energy does a green light of wavelength 555 nm contain?
Answer: 7005216000000000000♠216 kJ/mol

Question: What is the wavelength of light to which human eyes are most sensitive?
Answer: 555 nanometres

Question: What is the frequency of the light to which the human eye is most sensitive?
Answer: 7014540000000000000♠540 THz

Question: What is the energy of a photon?
Answer: 6981358000000000000♠3.58×10−19 J

Question: How much energy is contained in the light to which human eyes are most sensitive?
Answer: 7005216000000000000♠216 kJ/mol
Title: Planck_constant

In the last years of the nineteenth century, Planck was investigating the problem of black-body radiation first posed by Kirchhoff some forty years earlier. It is well known that hot objects glow, and that hotter objects glow brighter than cooler ones. The electromagnetic field obeys laws of motion similarly to a mass on a spring, and can come to thermal equilibrium with hot atoms. The hot object in equilibrium with light absorbs just as much light as it emits. If the object is black, meaning it absorbs all the light that hits it, then its thermal light emission is maximized.

Question: What type of radiation was Planck studying in the late 19th century?
Answer: black-body

Question: How many years prior to Planck's study had the scientific community first discussed black body radiation?
Answer: forty

Question: What scientist first studied black body radiation?
Answer: Kirchhoff

Question: What is required for the electromagnetic field to come to thermal equilibrium?
Answer: hot atoms

Question: What does a hot object in equilibrium absorb as much as it emits?
Answer: light

Question: What was Planck studying in the last part of the nineteenth century?
Answer: the problem of black-body radiation

Question: Who posed the problem of black-body radiation?
Answer: Kirchhoff

Question: Cooler objects glow less than objects that are what?
Answer: hotter

Question: What does a black object do to any of the light that hits it?
Answer: it absorbs all the light

Question: What is maximized as a result of a black object absorbing all the light that hits it?
Answer: thermal light emission

Question: Planck studied what problem posed originally by Kirchhoff?
Answer: black-body radiation

Question: If an object is black, what is known about its thermal light emission?
Answer: its thermal light emission is maximized.

Question: What is known about the light absorption of a hot object in equilibrium with light?
Answer: absorbs just as much light as it emits

Question: Electromagnetic fields obey what laws?
Answer: laws of motion
Title: Planck_constant

The assumption that black-body radiation is thermal leads to an accurate prediction: the total amount of emitted energy goes up with the temperature according to a definite rule, the Stefan–Boltzmann law (1879–84). But it was also known that the colour of the light given off by a hot object changes with the temperature, so that "white hot" is hotter than "red hot". Nevertheless, Wilhelm Wien discovered the mathematical relationship between the peaks of the curves at different temperatures, by using the principle of adiabatic invariance. At each different temperature, the curve is moved over by Wien's displacement law (1893). Wien also proposed an approximation for the spectrum of the object, which was correct at high frequencies (short wavelength) but not at low frequencies (long wavelength). It still was not clear why the spectrum of a hot object had the form that it has (see diagram).

Question: What do scientists assume black body radiation is?
Answer: thermal

Question: What kind of prediction does the assumption that black body radiation is thermal lead to?
Answer: accurate

Question: What type of changes in the light a hot object emits as the object's temperature changes?
Answer: colour

Question: What law describes the changes in light emitted by a hot object?
Answer: Stefan–Boltzmann law

Question: What assumption that black-body radiation is what leads to an accurate prediction?
Answer: thermal

Question: What does the Stefan-Boltzmann law state?
Answer: the total amount of emitted energy goes up with the temperature according to a definite rule

Question: What about a hot object changes with the temperature?
Answer: the colour of the light

Question: What color is hotter than "red hot"?
Answer: white hot

Question: What did Wilhelm Wien discover?
Answer: the mathematical relationship between the peaks of the curves at different temperatures

Question: What rule predicts that emitted energy increases with temperature?
Answer: the Stefan–Boltzmann law

Question: What characteristic of the light emitted by a hot object changes with temperature?
Answer: the colour of the light given off

Question: Who discovered the mathematical relationship between peaks and curves of light at different temperatures?
Answer: Wilhelm Wien

Question: The rule that adjust the curve at different temperatures is known as what?
Answer: Wien's displacement law

Question: Wien's spectrum model could not predict accurate at what end of the spectrum?
Answer: at low frequencies (long wavelength)
Title: Planck_constant

Prior to Planck's work, it had been assumed that the energy of a body could take on any value whatsoever – that it was a continuous variable. The Rayleigh–Jeans law makes close predictions for a narrow range of values at one limit of temperatures, but the results diverge more and more strongly as temperatures increase. To make Planck's law, which correctly predicts blackbody emissions, it was necessary to multiply the classical expression by a complex factor that involves h in both the numerator and the denominator. The influence of h in this complex factor would not disappear if it were set to zero or to any other value. Making an equation out of Planck's law that would reproduce the Rayleigh–Jeans law could not be done by changing the values of h, of the Boltzmann constant, or of any other constant or variable in the equation. In this case the picture given by classical physics is not duplicated by a range of results in the quantum picture.

Question: Before Planck, it was assumed that the energy of a body could take on what value?
Answer: any

Question: The Rayleigh-Jeans law makes close predictions for what amount of values?
Answer: a narrow range

Question: What does Planck's law correctly predict?
Answer: blackbody emissions

Question: In making Planck's law, what was in both the numerator and denominator of the formula that was used?
Answer: h

Question: Planck's work disproved what assumption?
Answer: that the energy of a body could take on any value whatsoever

Question: What rule predicted narrow range of energy values at lower temperatures?
Answer: The Rayleigh–Jeans

Question: Planck's law involved what necessary mathematical step to correctly predict blackbody emission?
Answer: multiply the classical expression by a complex factor that involves h in both the numerator and the denominator

Question: Changing values of n, the Boltzmann constant, or other variables resulted in learning what about Planck's law?
Answer: Making an equation out of Planck's law that would reproduce the Rayleigh–Jeans law could not be done

Question: The disparity between Planck's law and the Rayleigh-Jeans law led to what conclusion?
Answer: the picture given by classical physics is not duplicated by a range of results in the quantum picture
Title: Planck_constant

The black-body problem was revisited in 1905, when Rayleigh and Jeans (on the one hand) and Einstein (on the other hand) independently proved that classical electromagnetism could never account for the observed spectrum. These proofs are commonly known as the "ultraviolet catastrophe", a name coined by Paul Ehrenfest in 1911. They contributed greatly (along with Einstein's work on the photoelectric effect) to convincing physicists that Planck's postulate of quantized energy levels was more than a mere mathematical formalism. The very first Solvay Conference in 1911 was devoted to "the theory of radiation and quanta". Max Planck received the 1918 Nobel Prize in Physics "in recognition of the services he rendered to the advancement of Physics by his discovery of energy quanta".

Question: Einstein and what other two individuals revisited the black-body problem in 1905?
Answer: Rayleigh and Jeans

Question: Who came up with the term, "ultraviolet catastrophe"?
Answer: Paul Ehrenfest

Question: When did Paul Ehrenfest come up with the name "ultraviolet catastrophe"?
Answer: 1911

Question: When was the first Solvay Conference held?
Answer: 1911

Question: Who received the Nobel Prize in Physics in 1918?
Answer: Max Planck

Question: What did Rayleigh & Jeans and Einstein prove independently in 1905?
Answer: classical electromagnetism could never account for the observed spectrum

Question: What name did Paul Ehrenfest give to the proofs from Einstein and Rayleigh & Jeans?
Answer: the "ultraviolet catastrophe"

Question: When was the first Solvay Conference held?
Answer: 1911

Question: What was the topic of the first Solvay Conference?
Answer: "the theory of radiation and quanta"

Question: In what year did Planck receive the Nobel Prize in Physics for his discovery of energy quanta?
Answer: 1918
Title: Planck_constant

The photoelectric effect is the emission of electrons (called "photoelectrons") from a surface when light is shone on it. It was first observed by Alexandre Edmond Becquerel in 1839, although credit is usually reserved for Heinrich Hertz, who published the first thorough investigation in 1887. Another particularly thorough investigation was published by Philipp Lenard in 1902. Einstein's 1905 paper discussing the effect in terms of light quanta would earn him the Nobel Prize in 1921, when his predictions had been confirmed by the experimental work of Robert Andrews Millikan. The Nobel committee awarded the prize for his work on the photo-electric effect, rather than relativity, both because of a bias against purely theoretical physics not grounded in discovery or experiment, and dissent amongst its members as to the actual proof that relativity was real.

Question: Who first observed the photoelectric effect?
Answer: Alexandre Edmond Becquerel

Question: When was the photoelectric effect first observed?
Answer: 1839

Question: Who published the first thorough investigation of the photoelectric effect?
Answer: Heinrich Hertz

Question: Who received the Nobel Prize in 1921 for his work on the photoelectric effect?
Answer: Einstein

Question: What did Einstein with the 1921 Nobel Prize for?
Answer: his work on the photo-electric effect

Question: What is the photoelectric effect?
Answer: the emission of electrons (called "photoelectrons") from a surface when light is shone on it

Question: Who first observed the photoelectric effect?
Answer: Alexandre Edmond Becquerel

Question: Einstein's paper on the photoelectric effect earned him the Nobel Prize in what year?
Answer: 1921

Question: Einstein's photoelectric effect work was rewards as opposed to his work on what other topic?
Answer: relativity
Title: Planck_constant

Prior to Einstein's paper, electromagnetic radiation such as visible light was considered to behave as a wave: hence the use of the terms "frequency" and "wavelength" to characterise different types of radiation. The energy transferred by a wave in a given time is called its intensity. The light from a theatre spotlight is more intense than the light from a domestic lightbulb; that is to say that the spotlight gives out more energy per unit time and per unit space(and hence consumes more electricity) than the ordinary bulb, even though the colour of the light might be very similar. Other waves, such as sound or the waves crashing against a seafront, also have their own intensity. However, the energy account of the photoelectric effect didn't seem to agree with the wave description of light.

Question: Before Einstein, electromagnetic radiation was considered to behave as what?
Answer: a wave

Question: What terms describe different types of radiation?
Answer: "frequency" and "wavelength"

Question: What other types of wave besides light has its own intensity?
Answer: sound

Question: What is the energy transferred by a wave in a given time called?
Answer: intensity

Question: Prior to Einstein's work, light behavior was modeled as what?
Answer: a wave

Question: What is the name for the amount of energy transfered by a wave in a given time?
Answer: intensity

Question: What portion of the photoelectric effect was in disagreement with the believed description of light behavior?
Answer: the energy account

Question: What does it mean for a light source to be more intense than another?
Answer: gives out more energy per unit time and per unit space