If you’ve been watching Oppenheimer and it’s gotten you all excited about the idea of radioactive decay, you might want to visualize it. A cloud chamber is the perfect way to do that, and [NuclearPhoenix] is here to show us just how to build one.
The build relies on a Peltier device to cool a 10 cm square copper plate down to temperatures as low as -30 °C (-22 °F). Isopropyl alcohol is evaporated via warming resistors within the cloud chamber, and then condenses in the cooled area, creating a thin layer of fog. Ionizing radiation that passes through the chamber can then be spotted by the the trails it leaves through the fog. It’s even possible to identify the type of radiation passing through by the type of trail it leaves. Alpha particles leave shorter traces, while more energetic beta particles which are difficult to stop tend to streak further.
It bears noting that if you see a ton of activity in your cloud chamber at home, it might be worth making some enquiries. Some cloud chambers you’ll see in museums and the like use a small radioactive source to generate some excitement for viewers, though. Video after the break.