Cryogenics is a branch of physics which is defined as the study of the production, physical interactions and storage of materials at very low temperatures. It is generally accepted, however, that cryogenics involves temperatures below -150 oC (approximately 123 K – do you still remember the Celsius-kelvin conversion taught during our Physics tuition classes?). Certain gases, such as oxygen, hydrogen, helium, and nitrogen, display irregular properties when nearing their boiling points – which are temperatures lower than -180 oC. For example, liquid helium shows nearly no resistance to flow (viscosity) and its ability to conduct heat increases to a few hundred times greater than that of copper. Hence, it is said that these gases become superconductive at such low temperatures.
Besides playing a role in stimulating superconductivity, cryogenics is also for several other fields. Cryogenics is often confused with cryonics; cryonics is a field that applies cryogenics. To understand the differences between cryonics, cryogenics and its sub-disciplines, we need to consider each term individually:
Cryogenics is the study of all processes, or activities, relating to the use, production, and storage of materials at temperatures below -150 oC. Cryogenics is a science that is applied to many other disciplines, such as the use of liquid oxygen as a fuel in the aeronautics industry or preserving organs for transplantation.
Cryonics makes use of cryogenics to preserve biological tissue, including corpses or organs, with the hope of advancing the field of medicine, or complete resuscitation when such technology is eventually developed. Currently, however, cryopreservation is not reversible – hence it is not possible to “freeze” someone and bring them back to life. Additionally, cryopreservation is commonly thought to make use of water for the freezing process, which is inaccurate since liquid nitrogen is often used to minimize tissue damage.
Cryobiology is the study and of cryogenics to preserve biological content, particularly embryos of endangered animals. In order to ensure the survival of species that are near extinct, the improvement of cryobiology as a field is paramount.
Cryotronics is industry that involves the manufacturing, research and study of electronic equipment that usually incorporates the concept of superconductivity. Such equipment is usually manufactured for cryopreservation purposes. Another use of this technology is for amplifiers in radio telescopes can be cooled to reduce the effects of thermal noise.
It is therefore apparent that various industries make use of cryogenic information to advance technology in contemporary society. It is also crucial to ensure that endangered organisms do not become extinct, and that the fields of medicine and science, in general, are constantly improved.