Liquid nitrogen being poured into a flask. Nitrogen is liquid at temperatures below 77.4 Kelvin (-198 Celsius). The vapour seen streaming down is composed of water droplets condensed from the air by the extremely low temperature. Note the frost that has formed on the sides of both containers seen here. Nitrogen is the largest constituent of Earth's atmosphere, and is relatively inert under normal conditions. It is extracted from the air by fractional distillation. In the liquid state it is used as a refridgerant in cryogenics, and in low-temperature research.