The Spark Discharge Apparatus is an extremely visual and audible demonstration of the ionization of air caused by Alpha particles. As an Alpha source is moved along the brass mesh, Alpha particles ionize the air, causing a conductive path to form from the mesh to the conductor below, causing a shower of bright sparks and a crackling sound. Moving the source along the track clearly demonstrates that the sparks follow the source.

Requires an alpha source and EHT (5kV) power supply