Chemical Concepts Demonstrated
- Radiation damage
- Site imperfections in glass
|Observe a desiccator used to store radium compounds.|
The dessicator is stained purple. A Geiger counter reveals that the dessicator is radioactive.
The glass in the dessicator, like most glass, has site imperfections. These sites were damaged by the radiation given off by the radium compounds. The glass now bends light differently, making the dessicator appear violet.
The dessicator is radioactive simply because it was never decontaminated. There are trace amounts of radium still present inside of the piece of glassware, and these amounts are still undergoing radioactive decay, setting off the Geiger counter.
Purdue University also has, in its possession, a wine goblet and Florence flask that have obtained a brown color because of exposure to a cobalt-60 source. Although the glass is similar in all circumstances, the site imperfections in the dessicator and the other two pieces of glassware were damaged in two different ways. Radium's decay produces alpha radiation, while cobalt-60's decay series involves beta particles and gamma rays as more immediate products. This is why the glassware is stained two different colors.
- Dr. George Bodner (Perdue University)