I finally got to putting up a page for my Peltier-cooled cloud chamber. You can see it in action here (YouTube video).

A cloud chamber is a basic ionizing radiation particle detector. It’s a container with supersaturated vapor. A charged particle passing through will produce ions that act as condensation nuclei, forming a visible trail of droplets. This virtual cloud chamber (click to see) gives you a rough idea of you what you can expect to see in a cloud chamber.