EXPERIMENT 4: Observing Radioactivity by Radiography

THINGS YOU NEED: Alpha ray source from Experiment 3. Photographic print paper and a “one shot” kit containing developer, stop-bath, and fixer (both paper and kit are available at photo supply shops). A 16-ounce measuring cup. Three small plastic trays. A photographic “safelight” (optional). A dark room to work in (a bathroom is ideal). Plastic tongs.

This is an optional experiment on radiography, which is the art of taking a picture with radiation other than light . . . X-rays, for example. In this case we’ll use alpha
rays. Here, photographic print paper exposed to alpharays will, when developed, show the radiation as. . . well, you’ll see.

If you do not have access to photographic lab equipment and decide to buy the materials needed, start by mixing the three chemical powders supplied in the kit. Follow directions, but don’t worry too much about water temperature; the quality of the developed print won’t matter. Wash your hands if you get any powder or solution on them; some people are sensitive to the chemicals and can develop minor skin rashes if exposed to them.