A tank of liquid nitrogen, used to supply a cryogenic freezer (for storing laboratory samples at a temperature of about -150 Celsius).

Liquid nitrogen may be used to prepare "home-made" ice cream, as these students are doing.

Liquid nitrogen (liquid density at the triple point is 0.807 g/mL) is the liquid produced industrially in large quantities by fractional distillation of liquid air and is often referred to by the abbreviation, LN₂. It is pure nitrogen, in a liquid state. Image File history File linksMetadata Download high resolution version (1040x1983, 476 KB) File links The following pages link to this file: Nitrogen Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Image File history File linksMetadata Download high resolution version (1040x1983, 476 KB) File links The following pages link to this file: Nitrogen Metadata This file contains additional information, probably added from the digital camera or scanner used to create or digitize it. ... Cryopreservation of plant shoots. ... Image File history File links Download high-resolution version (788x678, 56 KB) photos by Nicolas George File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Nitrogen ... Image File history File links Download high-resolution version (788x678, 56 KB) photos by Nicolas George File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Nitrogen ... Missing image Ice cream is often served on a stick Boxes of ice cream are often found in stores in a display freezer. ... In physics, the triple point of a substance is the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium. ... Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. ... Liquid air is air that has been liquified by compression and cooled to very low temperatures. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...

Liquid nitrogen boils at -196 °C, and is a cryogenic fluid which is potentially capable of causing rapid frostbite on contact with living tissue. When appropriately insulated from ambient heat, liquid nitrogen can be stored and transported, for example in vacuum flasks, in which the very low temperature is held constant at -196 by slow boiling of the liquid, resulting in the evolution of nitrogen gas. Depending on the size and design the holding time of vacuum flasks ranges from a few hours to a few weeks. Cryogenics is a branch of physics (or engineering) that studies the production of very low temperatures (below –150 °C, –238 °F or 123 K) and the behavior of materials at those temperatures. ... This article is about a medical condition. ... Thermal insulation on the Huygens probe The term thermal insulation can refer to materials used to reduce the rate of heat transfer, or the methods and processes used to reduce heat transfer. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... This article is about the vacuum-insulated flask. ...

Liquid nitrogen can easily be converted to the solid by placing it in a vacuum chamber pumped by a rotary vacuum pump. Liquid nitrogen freezes at -210 °C. Despite its reputation, liquid nitrogen's efficiency as a coolant is reduced by the fact that it boils immediately on contact with warmer object, enveloping it in insulating nitrogen gas. This effect is known as the Leidenfrost effect applies to any liquid in contact with an object significantly hotter than its boiling point. More rapid cooling may be obtained by plunging an object into slush of liquid and solid nitrogen, than into liquid nitrogen alone. The Leidenfrost effect is the phenomenon in which a liquid in near contact with a mass hotter than the liquids Leidenfrost point, which is higher than its boiling point, produces an insulating vapor layer which keeps it from boiling rapidly. ...

Applications

Liquid nitrogen is a compact and readily transported source of nitrogen gas without pressurization. Further, its ability to maintain temperatures far below the freezing point of water (it boils at 77 K, −196 °C, −320 °F) makes it extremely useful in a wide range of applications, primarily as an open-cycle refrigerant, including: Freezing point can refer to several things: For the chemistry term, see Melting point. ... For other uses, see Kelvin (disambiguation). ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... For other uses, see Fahrenheit (disambiguation). ... A refrigerant is a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back. ...

• in the study of cryogenics
• as a source of very dry nitrogen gas
• the immersion freezing and transportation of food products
• the cryopreservation of blood, reproductive cells (sperm and egg), and other biological samples and materials
• the cryonic preservation of humans and pets in the hope of future reanimation.
• as a coolant for highly sensitive sensors and low-noise amplifiers^{[citation needed]}
• as a cooling supplement for overclocking a central processing unit, a graphics processing unit, or another type of computer hardware^[1]
• as a cooling medium during machining of high strength materials.^{[citation needed]}
• as a method of freezing water pipes in order to work on them in situations where a tap is not available to block water flow to the work area.
• in cryotherapy for removing unsightly or potentially malignant skin lesions such as warts and actinic keratosis.
• in the process of promession, a way to dispose of the dead.
• as the working fluid in a binary engine.^{[citation needed]}

Cryogenics is a branch of physics (or engineering) that studies the production of very low temperatures (below –150 °C, –238 °F or 123 K) and the behavior of materials at those temperatures. ... Cryopreservation of plant shoots. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... For other uses, see Sperm (disambiguation). ... A human ovum Sperm cells attempting to fertilize an ovum An ovum (plural ova) is a haploid female reproductive cell or gamete. ... Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: βίος, bio, life; and λόγος, logos, knowledge), also referred to as the biological sciences, is the study of living organisms utilizing the scientific method. ... Not to be confused with cryogenics. ... A coolant, or heat transfer fluid, is a fluid which flows through a device in order to prevent its overheating, transferring the heat produced by the device to other devices that utilize or dissipate it. ... Not to be confused with censure, censer, or censor. ... For the British rock band of the same name, see Amplifier (band). ... AMD Athlon XP Overclocking BIOS Setup on ABIT NF7-S. FSB frequency (External clock) has increased from 133 MHz to 148 MHz, and clock multiplier factor has changed from 13. ... CPU redirects here. ... “GPU” redirects here. ... Computer hardware is the physical part of a computer, including the digital circuitry, as distinguished from the computer software that executes within the hardware. ... Cryotherapy is used to define several techniques and procedures in the medical community. ... Skin cancer is a malignant growth on the skin which can have many causes. ... A wart is generally a small, rough tumor, typically on hands and feet, that can resemble a cauliflower or a solid blister. ... Actinic keratosis (also called solar keratosis, senile keratosis, or AK) is a premalignant condition of thick, scaly, or crusty patches of skin. ... An ecological funeral, also known as promession, is a method for allowing the body of the deceased to decompose in an environmentally-friendly way. ...

Safety

Since the liquid to gas expansion ratio of this substance is 1:694,^[2] a tremendous amount of force can be generated when liquid nitrogen boils off for whatever reasons. In a well-known accident in 2006 at Texas A&M University, the pressure-relief devices of a tank of liquid nitrogen were sealed with brass plugs. As a result, the tank failed catastrophically, and exploded. The force of the explosion was sufficient to propel the tank through the floor/ceiling immediately above it.^[3] Texas A&M University redirects here. ...

See also

• Computer cooling
• Liquid nitrogen economy

Computer cooling is the process of removing heat from computer components. ... A liquid nitrogen (LN2) economy is a hypothetical proposal for a future economy in which the primary form of energy storage and transport is liquid nitrogen. ...

References

1. ^ Wainner, Scott; Robert Richmond (2003). The Book of Overclocking: Tweak Your PC to Unleash Its Power. No Starch Press, p. 44. ISBN 188641176X. 
2. ^ Information Specific to Liquid Nitrogen. Harvard University (30 Jul 03).
3. ^ Brent S. Mattox. Investigative Report on Chemistry 301A Cylinder Explosion (reprint). Texas A&M University.