This large cloud chamber allows the visualization of atomic particles as they pass through a super saturated Isopropanol vapour, cooled by dry ice. Energetic charged particles collide with the gas molecules causing a trail of ionized particles. These ionized gas particles act as nucleation sites on which the super saturated alcohol vapour condenses, leaving a cloud like trail that lasts for a few seconds. The built in LED lighting is collimated to produce less glare, making the traces highly visible. The foam inserts housed in a Gratnells tray, provide excellent insulation giving run times of over one hour, as well as convenient storage. The large tank size means the cloud chamber is even capable of detecting background radiation. Supplied with a thoriated welding rod to use as a source and full instructions. Requires Isopropanol, 12V d.c. power supply and dry ice to function (not supplied)