The Radioactivity Lab examines the intensity of radiation over distance, demonstrating the effects of the inverse square law. Students investigate the intensity of radiation being emitted from a radioactive Strontium-90 source, by setting distances at which a Geiger counter measures radiation, and collecting radioactive particle counts at each of these distances. A table holding the radioactive source is rotated until the source is aligned with a hole in a thick lead plate. The head holding the Geiger-Muller tube is moved to these distances from the radioactive source. Students receive data in the form of a .csv file to be analyzed in Microsoft Excel, or a similar data analysis tool.