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Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures.Liquid helium may show superfluidity.. At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C (−452.20 °F; 4.15 K).
Solid helium requires a temperature of 1–1.5 K (about −272 °C or −457 °F) at about 25 bar (2.5 MPa) of pressure. [107] It is often hard to distinguish solid from liquid helium since the refractive index of the two phases are nearly the same.
The value of −240 °C, or "431 divisions [in Fahrenheit's thermometer] below the cold of freezing water" [18] was published by George Martine in 1740. This close approximation to the modern value of −273.15 °C [ 1 ] for the zero of the air thermometer was further improved upon in 1779 by Johann Heinrich Lambert , who observed that −270 ...
Helium also has a very low boiling point (-268.9°C or -452°F), allowing it to remain a gas even in super-cold environments, an important feature because many rocket fuels are stored in that ...
An MRI can’t function without some 2,000 liters of ultra-cold liquid helium keeping its magnets cool enough to work. ... With a boiling point of minus 452 degrees Fahrenheit, liquid helium is ...
2.5 mK, Fermi melting point of helium-3; 60 mK adiabatic demagnetization of paramagnetic molecules; 300 mK in evaporative cooling of helium-3; 700 mK, helium-3/helium-4 mixtures begin phase separation; 950 mK, melting point of helium at 2.5 megapascals of pressure. All 118 elements are solid at or below this temperature. microwave excitations
Nitrogen is a liquid under −195.8 °C (77.3 K).. In physics, cryogenics is the production and behaviour of materials at very low temperatures.. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington, DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (−153 °C) to ...
The combination of helium’s extremely low molecular weight and weak interatomic reactions yield interesting properties when helium is cooled below its critical temperature of 5.2 K to form a liquid. Even at absolute zero (0K), helium does not condense to form a solid under ambient pressure.