The study of radiation at the introductory college level usually includes experiments to determine the half-life of a radioactive isotope and also a study of the absorption of nuclear radiation by metal foils. These experiments are straightforward to do using a Geiger-Müller tube and scaler, and allow for the determination of well-known constants. The underlying theory behind these experiments is also easy to understand, but fails to take into account background radiation that will be present, regardless of the source being used. The purpose of this article is to show how students can measure the effect of background radiation on these experiments by modifying the standard textbook theory.