rajpurkar/squad huggingface dataset:
Title: Vacuum

In the medieval Middle Eastern world, the physicist and Islamic scholar, Al-Farabi (Alpharabius, 872–950), conducted a small experiment concerning the existence of vacuum, in which he investigated handheld plungers in water.[unreliable source?] He concluded that air's volume can expand to fill available space, and he suggested that the concept of perfect vacuum was incoherent. However, according to Nader El-Bizri, the physicist Ibn al-Haytham (Alhazen, 965–1039) and the Mu'tazili theologians disagreed with Aristotle and Al-Farabi, and they supported the existence of a void. Using geometry, Ibn al-Haytham mathematically demonstrated that place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body. According to Ahmad Dallal, Abū Rayhān al-Bīrūnī also states that "there is no observable evidence that rules out the possibility of vacuum". The suction pump later appeared in Europe from the 15th century.

Question: Al-Farabi concluded a perfect vacuum was incoherent using what?
Answer: handheld plungers in water.

Question: Ibn al-Haytham used geometry to demonstrate  what?
Answer: place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body

Question: who stated that there was no evidence to rule out a vacuum?
Answer: Abū Rayhān al-Bīrūnī

Question: what did Al-Farabi say expanded to fill available space
Answer: air's volume

Question: What type of pump appeared in the 15th century?
Answer: suction pump
Title: Vacuum

Medieval thought experiments into the idea of a vacuum considered whether a vacuum was present, if only for an instant, between two flat plates when they were rapidly separated. There was much discussion of whether the air moved in quickly enough as the plates were separated, or, as Walter Burley postulated, whether a 'celestial agent' prevented the vacuum arising. The commonly held view that nature abhorred a vacuum was called horror vacui. Speculation that even God could not create a vacuum if he wanted to was shut down[clarification needed] by the 1277 Paris condemnations of Bishop Etienne Tempier, which required there to be no restrictions on the powers of God, which led to the conclusion that God could create a vacuum if he so wished. Jean Buridan reported in the 14th century that teams of ten horses could not pull open bellows when the port was sealed.

Question: Who required no restrictions regarding God's power?
Answer: Bishop Etienne Tempier

Question: When did Buridan state that teams of ten horses could not open a bellow with a sealed port?
Answer: 14th century

Question: the 1277 Paris Condemnations led to what conclusion?
Answer: God could create a vacuum if he so wished.

Question: What was a common belief about vacuums and nature?
Answer: nature abhorred a vacuum

Question: what was the belief that nature abhorred a vaccuum called?
Answer: horror vacui
Title: Vacuum

In 1654, Otto von Guericke invented the first vacuum pump and conducted his famous Magdeburg hemispheres experiment, showing that teams of horses could not separate two hemispheres from which the air had been partially evacuated. Robert Boyle improved Guericke's design and with the help of Robert Hooke further developed vacuum pump technology. Thereafter, research into the partial vacuum lapsed until 1850 when August Toepler invented the Toepler Pump and Heinrich Geissler invented the mercury displacement pump in 1855, achieving a partial vacuum of about 10 Pa (0.1 Torr). A number of electrical properties become observable at this vacuum level, which renewed interest in further research.

Question: What was the vacuum created by the mercury displacement pump?
Answer: partial vacuum of about 10 Pa (0.1 Torr).

Question: What year was the Toepler Pump invented?
Answer: 1850

Question: What was first invented by Otto von Guericke ?
Answer: vacuum pump

Question: Who conducted the Magdeburg experiment?
Answer: Otto von Guericke

Question: What was made visible at a partial vacuum of 10 Pa?
Answer: A number of electrical properties
Title: Vacuum

While outer space provides the most rarefied example of a naturally occurring partial vacuum, the heavens were originally thought to be seamlessly filled by a rigid indestructible material called aether. Borrowing somewhat from the pneuma of Stoic physics, aether came to be regarded as the rarefied air from which it took its name, (see Aether (mythology)). Early theories of light posited a ubiquitous terrestrial and celestial medium through which light propagated. Additionally, the concept informed Isaac Newton's explanations of both refraction and of radiant heat. 19th century experiments into this luminiferous aether attempted to detect a minute drag on the Earth's orbit. While the Earth does, in fact, move through a relatively dense medium in comparison to that of interstellar space, the drag is so minuscule that it could not be detected. In 1912, astronomer Henry Pickering commented: "While the interstellar absorbing medium may be simply the ether, [it] is characteristic of a gas, and free gaseous molecules are certainly there".

Question: What was originally believed the heavens were filled with?
Answer: aether

Question: Why were experiments done on luminiferous aether in the 19 Century?
Answer: "While the interstellar absorbing medium may be simply the ether, [it] is characteris

Question: Who stated that the character of a gas and free molecule were in ether?
Answer: Henry Pickering

Question: Where are the highest amounts of naturally occurring partial vacuums?
Answer: outer space

Question: What was ether originally thought to be made of?
Answer: rigid indestructible material
Title: Vacuum

The quality of a vacuum is indicated by the amount of matter remaining in the system, so that a high quality vacuum is one with very little matter left in it. Vacuum is primarily measured by its absolute pressure, but a complete characterization requires further parameters, such as temperature and chemical composition. One of the most important parameters is the mean free path (MFP) of residual gases, which indicates the average distance that molecules will travel between collisions with each other. As the gas density decreases, the MFP increases, and when the MFP is longer than the chamber, pump, spacecraft, or other objects present, the continuum assumptions of fluid mechanics do not apply. This vacuum state is called high vacuum, and the study of fluid flows in this regime is called particle gas dynamics. The MFP of air at atmospheric pressure is very short, 70 nm, but at 100 mPa (~6997100000000000000♠1×10−3 Torr) the MFP of room temperature air is roughly 100 mm, which is on the order of everyday objects such as vacuum tubes. The Crookes radiometer turns when the MFP is larger than the size of the vanes.

Question: What indicated the quality of a vacuum?
Answer: amount of matter remaining in the system

Question: How is vacuum generally measured?
Answer: its absolute pressure

Question: What does the MFP of residual gases show?
Answer: average distance that molecules will travel between collisions with each other.

Question: What is particle gas dynamics?
Answer: study of fluid flows
Title: Vacuum

The SI unit of pressure is the pascal (symbol Pa), but vacuum is often measured in torrs, named for Torricelli, an early Italian physicist (1608–1647). A torr is equal to the displacement of a millimeter of mercury (mmHg) in a manometer with 1 torr equaling 133.3223684 pascals above absolute zero pressure. Vacuum is often also measured on the barometric scale or as a percentage of atmospheric pressure in bars or atmospheres. Low vacuum is often measured in millimeters of mercury (mmHg) or pascals (Pa) below standard atmospheric pressure. "Below atmospheric" means that the absolute pressure is equal to the current atmospheric pressure.

Question: Absolute pressure  being equal to current atmospheric pressure means what?
Answer: "Below atmospheric"

Question: What is a torr equal to?
Answer: displacement of a millimeter of mercury

Question: What is another often used options to measure vacuum?
Answer: barometric scale
Title: Vacuum

Hydrostatic gauges (such as the mercury column manometer) consist of a vertical column of liquid in a tube whose ends are exposed to different pressures. The column will rise or fall until its weight is in equilibrium with the pressure differential between the two ends of the tube. The simplest design is a closed-end U-shaped tube, one side of which is connected to the region of interest. Any fluid can be used, but mercury is preferred for its high density and low vapour pressure. Simple hydrostatic gauges can measure pressures ranging from 1 torr (100 Pa) to above atmospheric. An important variation is the McLeod gauge which isolates a known volume of vacuum and compresses it to multiply the height variation of the liquid column. The McLeod gauge can measure vacuums as high as 10−6 torr (0.1 mPa), which is the lowest direct measurement of pressure that is possible with current technology. Other vacuum gauges can measure lower pressures, but only indirectly by measurement of other pressure-controlled properties. These indirect measurements must be calibrated via a direct measurement, most commonly a McLeod gauge.

Question: Why is mercury the better option for liquid used in a Hydrostatic gauge?
Answer: its high density and low vapour pressure

Question: What is a vertical column of liquid in a tube which has different pressures at each end called?
Answer: Hydrostatic gauges

Question: What is a hydrostatic gauge used for?
Answer: measure pressures ranging from 1 torr (100 Pa) to above atmospheric

Question: Why is the McLeod gauge special?
Answer: can measure vacuums as high as 10−6 torr

Question: An indirect measurement of pressure is most often calibrated by what?
Answer: McLeod gauge
Title: Vacuum

Thermal conductivity gauges rely on the fact that the ability of a gas to conduct heat decreases with pressure. In this type of gauge, a wire filament is heated by running current through it. A thermocouple or Resistance Temperature Detector (RTD) can then be used to measure the temperature of the filament. This temperature is dependent on the rate at which the filament loses heat to the surrounding gas, and therefore on the thermal conductivity. A common variant is the Pirani gauge which uses a single platinum filament as both the heated element and RTD. These gauges are accurate from 10 torr to 10−3 torr, but they are sensitive to the chemical composition of the gases being measured.

Question: The fact that gases ability to conduct heat decreases with pressure is used by what form of measurement?
Answer: Thermal conductivity gauges

Question: How is the wire filament in a Thermal conductivity gauge heated?
Answer: by running current through it

Question: What is a Pirani gauge sensitive to?
Answer: chemical composition of the gases being measured

Question: What is a RTD used for on a Thermal Conductivity gauge?
Answer: to measure the temperature of the filament

Question: A Pirani gauge is accurate within what ranges?
Answer: 10 torr to 10−3 torr
Title: Vacuum

Ion gauges are used in ultrahigh vacuum. They come in two types: hot cathode and cold cathode. In the hot cathode version an electrically heated filament produces an electron beam. The electrons travel through the gauge and ionize gas molecules around them. The resulting ions are collected at a negative electrode. The current depends on the number of ions, which depends on the pressure in the gauge. Hot cathode gauges are accurate from 10−3 torr to 10−10 torr. The principle behind cold cathode version is the same, except that electrons are produced in a discharge created by a high voltage electrical discharge. Cold cathode gauges are accurate from 10−2 torr to 10−9 torr. Ionization gauge calibration is very sensitive to construction geometry, chemical composition of gases being measured, corrosion and surface deposits. Their calibration can be invalidated by activation at atmospheric pressure or low vacuum. The composition of gases at high vacuums will usually be unpredictable, so a mass spectrometer must be used in conjunction with the ionization gauge for accurate measurement.

Question: What affects the number of ions in a gauge?
Answer: the pressure in the gauge

Question: What must be used for accurate measurement on the composition of gases at a high vacuums?
Answer: mass spectrometer must be used in conjunction with the ionization gauge

Question: What gauge is accurate from 10-2 torr to 10-9 torr?
Answer: Cold cathode gauges

Question: Why does a mass spectrometer need to be used with gauge to be accurate at high vacuum gas measurement?
Answer: composition of gases at high vacuums will usually be unpredictable

Question: What are the two types of Ion gauges?
Answer: hot cathode and cold cathode.
Title: Vacuum

Cold or oxygen-rich atmospheres can sustain life at pressures much lower than atmospheric, as long as the density of oxygen is similar to that of standard sea-level atmosphere. The colder air temperatures found at altitudes of up to 3 km generally compensate for the lower pressures there. Above this altitude, oxygen enrichment is necessary to prevent altitude sickness in humans that did not undergo prior acclimatization, and spacesuits are necessary to prevent ebullism above 19 km. Most spacesuits use only 20 kPa (150 Torr) of pure oxygen. This pressure is high enough to prevent ebullism, but decompression sickness and gas embolisms can still occur if decompression rates are not managed.

Question: density of oxygen like that of sea-level atmosphere is needed to do what?
Answer: sustain life at pressures much lower than atmospheric,

Question: What is the lowest altitude where acclimatization or a suit is not needed to prevent sickness in humans?
Answer: of up to 3 km
Title: Vacuum

Humans and animals exposed to vacuum will lose consciousness after a few seconds and die of hypoxia within minutes, but the symptoms are not nearly as graphic as commonly depicted in media and popular culture. The reduction in pressure lowers the temperature at which blood and other body fluids boil, but the elastic pressure of blood vessels ensures that this boiling point remains above the internal body temperature of 37 °C. Although the blood will not boil, the formation of gas bubbles in bodily fluids at reduced pressures, known as ebullism, is still a concern. The gas may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Swelling and ebullism can be restrained by containment in a flight suit. Shuttle astronauts wore a fitted elastic garment called the Crew Altitude Protection Suit (CAPS) which prevents ebullism at pressures as low as 2 kPa (15 Torr). Rapid boiling will cool the skin and create frost, particularly in the mouth, but this is not a significant hazard.

Question: When will a person or animal lose consciousness  when exposed to a vacuum?
Answer: after a few seconds

Question: A shuttle astronauts prevents ebullism at 2 kPa with what item?
Answer: the Crew Altitude Protection Suit (CAPS)

Question: What is the forming of gas bubbles in body fluids at a lowered pressure called?
Answer: ebullism

Question: What prevents body rupture at low altitude when human body is bloated by gas bubbles?
Answer: tissues are elastic and porous
Title: Vacuum

In ultra high vacuum systems, some very "odd" leakage paths and outgassing sources must be considered. The water absorption of aluminium and palladium becomes an unacceptable source of outgassing, and even the adsorptivity of hard metals such as stainless steel or titanium must be considered. Some oils and greases will boil off in extreme vacuums. The permeability of the metallic chamber walls may have to be considered, and the grain direction of the metallic flanges should be parallel to the flange face.

Question: What can boil away in extreme vaccum exposure?
Answer: Some oils and greases

Question: How should the grain direct of metallic flanges run to flange faces?
Answer: parallel

Question: What are 2 metals that can be absorbed in an ultra high vacuum system?
Answer: stainless steel or titanium

Question: What becomes a concern in an ultra high vacuum system regarding aluminum or palladium?
Answer: water absorption
Title: Vacuum

In quantum mechanics and quantum field theory, the vacuum is defined as the state (that is, the solution to the equations of the theory) with the lowest possible energy (the ground state of the Hilbert space). In quantum electrodynamics this vacuum is referred to as 'QED vacuum' to distinguish it from the vacuum of quantum chromodynamics, denoted as QCD vacuum. QED vacuum is a state with no matter particles (hence the name), and also no photons. As described above, this state is impossible to achieve experimentally. (Even if every matter particle could somehow be removed from a volume, it would be impossible to eliminate all the blackbody photons.) Nonetheless, it provides a good model for realizable vacuum, and agrees with a number of experimental observations as described next.

Question: The state with the lowest possible energy in quantum mechanics defines what ?
Answer: vacuum

Question: A vacuum state with no matter particles or photons is called what?
Answer: QED

Question: why is a QED vacuum impossible to achieve ?
Answer: impossible to eliminate all the blackbody photons

Question: What is a QCD?
Answer: vacuum of quantum chromodynamics,
Title: Vacuum

QED vacuum has interesting and complex properties. In QED vacuum, the electric and magnetic fields have zero average values, but their variances are not zero. As a result, QED vacuum contains vacuum fluctuations (virtual particles that hop into and out of existence), and a finite energy called vacuum energy. Vacuum fluctuations are an essential and ubiquitous part of quantum field theory. Some experimentally verified effects of vacuum fluctuations include spontaneous emission and the Lamb shift. Coulomb's law and the electric potential in vacuum near an electric charge are modified.

Question: When are electric and magnetic fields with zero average values, but their variances are not at zero?
Answer: In QED vacuum

Question: What is a verified effect of vacuum fluctuation?
Answer: spontaneous emission

Question: what is  vacuum fluctuation?
Answer: virtual particles that hop into and out of existence

Question: Finite energy in a QED is called what?
Answer: vacuum energy

Question: What modifies can Coulomb's Law in a vacuum?
Answer: vacuum near an electric charge
Title: Vacuum

Stars, planets, and moons keep their atmospheres by gravitational attraction, and as such, atmospheres have no clearly delineated boundary: the density of atmospheric gas simply decreases with distance from the object. The Earth's atmospheric pressure drops to about 6998320000000000000♠3.2×10−2 Pa at 100 kilometres (62 mi) of altitude, the Kármán line, which is a common definition of the boundary with outer space. Beyond this line, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar winds, so the definition of pressure becomes difficult to interpret. The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather. Astrophysicists prefer to use number density to describe these environments, in units of particles per cubic centimetre.

Question: `Why does thermosphere past the Karman line vary so greatly?
Answer: due to space weather

Question: What is commonly known as the boundary of outer space?
Answer: the Kármán line

Question: What do Astrophysicists use to describe outer space beyond the karman line?
Answer: number density

Question: What is more significant than isotropic gas pressure past the Karman line?
Answer: radiation pressure from the Sun and the dynamic pressure of the solar winds
Title: Vacuum

Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges.

Question: What was the object to use first in widespread manner process of vacuum?
Answer: incandescent light bulb

Question: What is produced by a vacuum and used in electron beam welding and vacuum frying?
Answer: chemical inertness

Question: Hight to ultra-high vacuums removes what obstruction?
Answer: obstruction of air,

Question: How does freeze drying, distillation and metallurgy benefit from a deep vacuum?
Answer: Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing

Question: What are two things made possible by the electrical properties of vacuum?
Answer: electron microscopes and vacuum tubes
Title: Vacuum

Manifold vacuum can be used to drive accessories on automobiles. The best-known application is the vacuum servo, used to provide power assistance for the brakes. Obsolete applications include vacuum-driven windscreen wipers and Autovac fuel pumps. Some aircraft instruments (Attitude Indicator (AI) and the Heading Indicator (HI)) are typically vacuum-powered, as protection against loss of all (electrically powered) instruments, since early aircraft often did not have electrical systems, and since there are two readily available sources of vacuum on a moving aircraft—the engine and an external venturi. Vacuum induction melting uses electromagnetic induction within a vacuum.

Question: What provides power assistance for auto brakes?
Answer: vacuum servo

Question: What are two available sources of vacuum on a moving airplane?
Answer: engine and an external venturi

Question: Why are the Attitude indicator and heading indicator vacuum-powered?
Answer: protection against loss of all (electrically powered) instruments,

Question: What does a manifold vacuum do on a car?
Answer: drive accessories

Question: What no longer used accessories were powered by vacuum?
Answer: vacuum-driven windscreen wipers and Autovac fuel pumps
Title: Vacuum

Evaporation and sublimation into a vacuum is called outgassing. All materials, solid or liquid, have a small vapour pressure, and their outgassing becomes important when the vacuum pressure falls below this vapour pressure. In man-made systems, outgassing has the same effect as a leak and can limit the achievable vacuum. Outgassing products may condense on nearby colder surfaces, which can be troublesome if they obscure optical instruments or react with other materials. This is of great concern to space missions, where an obscured telescope or solar cell can ruin an expensive mission.

Question: what is evaporation and sublimation in a vacuum?
Answer: outgassing

Question: Why can outgassing products ruin a space mission?
Answer: obscure optical instruments

Question: When does outgassing become important in all solid or liquid materials?
Answer: vacuum pressure falls below this vapour pressure