Sealed sources of alpha particles and beta particles are used with a small student cloud chamber to observe the paths of alphas and betas. The alpha paths are very distinct and clear, whereas the beta paths are more diffuse. Cosmic ray products or gamma rays are also visible, but less distinct. A TV camera views the "action," which is displayed on a monitor or on the rear projection system in the lecture halls (photograph at right).
The cloud chamber uses dry ice for cooling, and uses alcohol to remove heat from the chamber and to provide the atmosphere of supersaturated alcohol vapor which condenses along the path of the ionizing particles to make the path visible.