Wilson's Cloud Chamber is the classical pattern where alcohol saturates a pad in the chamber and a vacuum pump (reversed tyre pump) is used to draw a partial vacuum to super saturate the remaining air with alcohol vapour.

A small alpha source in the chamber emanates particles that ionise the air particles along the path. The alcohol vapour condenses on these ionised paths to display miniature foggy tracks inside the chamber. These tracks can be called the path of the radiated particles.

A light source is required (microscope lamp or similar) to illuminate the cell. Made in Australia. Instructions included.