Cloud Chambers, or Wilson Chambers, were devices created to view the ionisation trail of radiation. They are largely superseded by (rough chronological order) Bubble Chambers, Spark Chambers, Wire Chambers and Semi Conductor Particle Detectors. However these later devices are harder to construct, where as the Cloud Chamber has an elegant simplicity, and are visually very compelling.
As a child I was entranced by the continuous operation cloud chambers at the Science Museum in London. The museum were good enough to answer an enquiry on the device which was an elegant and entertaining (if a little noisy) cloud chamber.
“Complete diffusion cloud chamber, for making visible the tracks of cosmic ray particles (Inventory number 1968-758). This object entered the Museum’s collection in 1968 and was acquired from a company called De La Rue Frigistor Ltd. The object was on display until the early 1990′s. It is now being held by the Science Museum’s Small to Medium Object Store Blythe House.” – Enquiries Officer
A temporary device can be constructed in the class room quite easily. The trick is to supersaturate alcohol vapour, and the usual method is with dry ice which can be made with a cylinder of Carbon dioxide (although probably better to buy a suitable attachment rather than emulate the method my physics teacher use to use with an old bit of towel).
I have below some of the more interesting links I found on the topic.
Rather elaborate construction compared to some of the classroom methods, but a good explanation of what they are trying to achieve.
The videos whilst not great quality capture the magic I recall from the science museum as a child, with the perpetual swirl of particles.
Include a discussion of the particles that can be seen.
PHYWE are a commercial vendor, offering large and small cloud chambers intended for public viewing, and smaller Peltier cooled chambers.