On this day in 1877, French scientist Louis-Paul Cailletet became the first to liquefy oxygen. He was also the first to liquefy nitrogen, hydrogen, nitrogen, carbon monoxide, and acetylene. He was able to change these gasses into liquids, not just through simple cooling, but through cooling and compression. When the volume of a gas is reduced by so much that its molecules collapse upon each other, the substance becomes a liquid.
On this day in 1895, British scientist James Dewar exhibited his new apparatus for the production of liquid air at the Royal Institution in London.
This is liquid oxygen in a dewar flask
Liquefaction of gases is important for medical, scientific, industrial, and even commercial purposes. It is used to study properties of gas molecules, to store gases, and in refrigeration and air conditioning. When a gas is liquefied in a condenser, the heat of vaporization is released; when it is evaporated in an evaporator, the heat of vaporization is absorbed. Liquefied petroleum gases, such as propane or butane, are used for fuel or heating.
Find out more
...about how refrigerators work.
...about liquids, solids, and gases.
Do an activity on the states of matter.
…at Science Kids.
...at Galaxy Net.