Vaporisation and Evaporation

Temperature and pressure determine the state of aggregation of a material, that is, whether it is solid, liquid or gaseous.

For example, water at normal pressure (1013 hectopascal, hPa) and at temperatures below 0 °C is solid (ice), between 0 °C and 100 °C it is liquid, and at boiling point, that is, at temperatures above 100 °C, it is gaseous (steam). The special case of boiling - evaporation occurs when particles with a high kinetic energy (e.g. through the influence of heat) are able to overcome the attractive forces of particles with lower kinetic energy in a fluid. If the particles remaining in the cooled down fluid continue to extract energy from their surroundings, the fluid will eventually evaporate entirely.

In a conventional temperature control chamber with natural convection or recirculating air, temperature distribution that is as even as possible (no formation of hot spots) reduces the risk of the evaporation of fluids in samples. For a chamber load that must not dry out under any circumstances, this is supported by the continued addition of humidity, e.g. using water trays or a controlled feed of humidity.

 

Overview Glossary Temperature control chamber

 


Picture credit: Memmert GmbH + Co. KG

Evaporation of fluid in a temperature control chamber