Electricity & Magnetism

Cloud Chamber

Visitors watch the paths of high speed charged particles as they are revealed by condensing clouds in this cloud chamber.
The main bulk of the exhibit is a refrigeration unit which keeps the air in the chamber supersaturated with alcohol. High speed charged particles are produced by cosmic rays. These high speed charges ionize the air along their tracks. The ions in the air then act as condensation nuclei for the alcohol. so droplets of alcohol form clouds along the tracks of the charged particles. As the droplets grow they settle out of the chamber, which is then ready for more particles.
Some of the charged tracks are produced by particles of anti-matter.
The exhibit shows that we are bombarded by particles all the time.
The charged particles tracing out the cloud paths are the basic building blocks of the universe.