The design and use of a Peltier-powered cloud chamber for outreach and classroom laboratory measurements

A challenge facing the scientist who studies anything at the subatomic level is convincing the general public and students that what they are studying is real. Astronomers can show beautiful images of stars and galaxies, geologists let you hold a 3 billion year-old rock in your hand, but the nuclear physicist must come up with other methods to demonstrate the equally fascinating science that they engage with. At Siena College, we have an ongoing 10 year project to improve a design for a Peltier-powered cloud chamber that is portable and does not require dry ice. This makes it ideal for both outreach activities and in-classroom demonstrations. Recently, we have developed a lab in which students use the device to extract scientific data. This involves a video analysis of a radioactive sample placed in the cloud chamber and the lengths of tracks are measured from a video analysis program. These lengths are used as an analog of the energy of the emitted particles and a spectrum is produced and compared to literature. A similar study can be done with cosmic rays where the lengths of the tracks map onto the angle of entry. We have successfully hosted a lab session where a group of students worked on a version of the lab. As a result, we have uncovered various opportunities to improve on some challenges with the lab structure and analysis. The current status of both the cloud chamber design and the efforts to turn this into a classroom lab will be presented.