A Cloud Chamber is an instrument showing natural radiation. It works by showing the trails that charged particles leave behind them when they travel through the chamber.
Here are the steps to operate it:
- A sponge soaked in isopropyl alcohol is placed high inside the chamber. At room temperature, the alcohol will soon start to evaporate, saturating the chamber in alcohol vapor.
- The bottom of the chamber is cooled down to -45C creating a cold layer (1/4 inch) where alcohol vapor condensate to form a thin layer of liquid alcohol.
In that particular instrument, we are using 2 stacked peltier modules to reach that temperature.
- Once the temperature is low enough, any charged particle travelling in that supersaturated layer will ionize the surrounding alcohol molecules. The charged particles will adhere to other alcohol molecules to finally form tiny droplets. The combination of these droplets along the path of the particle form a line that resemble a spider silk thread. The droplets go to the bottom of the chamber after a fraction of a second because of gravity and merge with the pool of alcohol which starts to evaporate again on its side where the temperature is higher.
The particles we can see with this device are: electrons (-1 charge), protons (+1), alpha particles (+2), delta particles (slow -1).