Cryogenic freezing is a type of freezing which requires extremely low temperatures, generally below -238 Fahrenheit (-150 Celsius). This process is part of a branch of the sciences known as cryogenics, which focuses on the production of very cold temperatures and the study of what happens to objects subjected to these temperatures. Research in this field ranges from basic studies on severe cold to applied research in which cryogenics is applied to various issues confronted by humans.
Just generating the extremely cold temperatures required for cryogenic freezing requires a lot of work. It's not as simple as turning up the refrigerator, because refrigeration components can only get so cold. Typically, it relies on the use of liquified gases such as helium. These gases can only exist in a liquid state at extremely cold temperatures, which means that once the gas is in liquid form, it can be used to generate freezing temperatures.
Cryogenic freezing is utilized to temper high-end metal products and certain other industrial products. The use of cryogenics appears to improve the strength and performance of such products, and it can be used for tasks which vary from creating extra-strong knives to making baseball bats. Cryogenics is also utilized in the lab environment to create cold temperature for various experiments, and cryogenic freezing is one method for producing specialized fuels like rocket fuel.
The food industry utilizes this method to flash freeze fresh foods so that their nutrients and texture will be largely preserved. Flash freezing can be seen in use everyone from fishing boats to plants which prepare TV dinners. In the medical profession, cryogenic freezing is used to preserve vaccines so that they will remain stable and viable for administration. Once frozen at such low temperatures, objects can remain frozen with the use of special refrigeration units, including mobile units with liquefied gases which permit cryogenically frozen objects to be shipped.
People sometimes confuse cryogenic freezing with cryonics, the field of preserving human bodies in freezing conditions with the goal of reviving them at some point in the future. Cryonics relies on the idea that advances in the sciences are constantly occurring, and that while it may not be currently possible to bring someone back from the dead, this could happen in the future, so people who want another chance at life may opt for cryonic preservation so that their bodies will be available for reanimation.