A cloud chamber is a type of particle detector. The cloud chamber was invented by physicist C.T.R. Wilson in 1912, for which he was awarded a Nobel Prize for in 1927.

This design includes a sealed container that is cooled from the bottom and has an absorbent material that is soaked with highly concentrated alcohol. This allows the air to become supersaturated and when charged particles go through, the alcohol condenses which allows you to see the tracks. Another use of the cloud chamber is to detect secondary cosmic rays, in which there is no radioactive source in the sealed container. This design allows for easy transportation and use, instead of the traditional classroom design, which uses dry ice to cool the alcohol vapor.