Cryogenic fluids are liquids that exist at extremely low temperatures, typically below -150 degrees Celsius (-238 degrees Fahrenheit). These fluids are used in various applications, including scientific research, medical technology, and aerospace engineering. Common cryogenic fluids include liquid nitrogen, liquid helium, and liquid oxygen, each with unique properties that make them suitable for specific uses. The primary characteristic of cryogenic fluids is their ability to remain in a liquid state at very low temperatures. When these fluids are exposed to higher temperatures, they rapidly vaporize, creating a gas. This property is utilized in processes like cryopreservation, where biological samples are stored at low temperatures to preserve their integrity.