A cloud chamber is a sealed chamber that uses cold temperatures and an environment of supersaturated alcohol vapor to visualize streaks of ionizing radiation.

Its theory relates to fog formation on earth, thermodynamics, and radioactive decay.

How are we able to visualize radiations with this?

As radiation emits from a source within the chamber, ionized particles are left behind by the radiation particle interacting with the air. This is known as ionizing radiation.

These ionized particles act as an anchor for the supersaturated alcohol vapor near the fog to attach and condense onto. This condensation is what we see as streaks in the chamber. This is similar to condensation trails left behind airplanes!

An interesting characteristic of these streaks is that their shape gives as hint towards the type of particle that created it. For example, alpha particles create straight streaks, whereas beta particles create more wispy or curved streaks. Also, the greater the condensation and thickness of the streak, the higher the energy of the radiation particle.