20. Geiger Counter

Small "license free" sources of activity < 0.1 microcurie can be taken into the class to activate a small hand held counter. Cloud chamber alpha sources of lead 210, beta souse of strontium 90, and an old Coleman gas mantle which contains thorium 232 are available.

A Gieger-Mueller tube simultaneously connected to a counter, an analog meter, and an amplifier and speaker will show the activity of the sources in three different ways.

Experiments 8 and 9 in the 8E lab are concerned with absorption of radiation, half-lives, etc.