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Cloud Chamber: Radioactivity in a cosmic setting

Cloud chambers are boxes specially made to detect charged particles and radiation. In this activity, a cloud chamber is used to observe alpha and beta particles, the charged products of the radioactive decay of thorium-232. Students should already have been introduced to the concept of radioactive decay and the differences between alpha and beta radiation. This experiment will assist students in their understanding by providing a physical demonstration of radioactive decay. Students will observe the condensation trails that charged particles leave in their wake in a cloud chamber, and learn to identify particles based on the trail properties. Trails made by cosmic rays can be seen in the cloud chamber, which could provide a starting point for introducing cosmic rays and their deflection by the Earth’s magnetic field. Students will practice calculating and writing radioactive decay equations. Implications of radiation for ESA are discussed, including the negative effects of radiation on circuits, and the use of radioactive decay as a power source.