The cloud chamber, first demonstrated in 1911, is a device for visualising the tracks of subatomic particles. The tracks are seen as trails of liquid droplets, formed as charged particles cross the chamber's supersaturated environment.
Cloud chambers based on a simple, but effective, design, have been built by members of the Elementary ParticlePhysics Group at the University of Birmingham, and are available for demonstrations at schools. A cloud chamber can be loaned for up to two weeks at a time, for a nominal hire cost of £10.00 per week (longer hires are more expensive). For operation, the chambers require a small amount of isopropyl alcohol and some dry ice. Full details, and general suggestions for experiments and measurements linked to the school curriculum, are given in the Cloud-Chamber Manual. An example of a full successful experiment, tested at a School event happened at the University of Birmingham in 2012, can be found in the Example Experiment here. The experiment consists in measuring the rate of alpha particles emitted from 2 different rods, calculate a prediction for it and compare the result wth the prediction, including estimating uncertainties. At the end, the students were askedto summarise their results and produced beautiful posters !
Teachers may also ask for a researcher from the Elementary Particle Physics Group to come to their school to give a demonstration of the cloud chamber, and answer questions from students. In this case the school would need to cover the cost of the isopropyl alcohol and dry ice for operation, and the researcher's travel expenses.
For more details about the loan scheme, or to request a demonstration, please contact Dr Cristina Lazzeroni (cl@hep.ph.bham.ac.uk).