Particles are identified in a bubble chamber by analyzing the tracks they leave in the chamber’s liquid.

A bubble chamber is a sophisticated device designed to detect and identify subatomic particles. It comprises a container filled with a superheated liquid, such as liquid hydrogen or helium. When a charged particle traverses the liquid, it ionizes the atoms and molecules along its path, leading to energy loss and the formation of a trail of bubbles.

The trajectory of the particle can be captured by photographing the bubbles as they form and expand. By examining the shape, size, and curvature of these bubbles, scientists can infer crucial properties of the particle, including its charge, mass, and momentum.

Different types of particles produce distinct tracks in the bubble chamber. For instance, an electron typically leaves a thin, straight track, while a proton generates a thicker, more curved track. By comparing the characteristics of the tracks produced by various particles, scientists can accurately identify the type of particle responsible for each track.

Although bubble chambers were widely used in particle physics experiments until the 1980s, they have since been largely supplanted by more advanced detectors, such as the multiwire proportional chamber and the silicon strip detector. Nevertheless, bubble chambers continue to serve as valuable educational tools for teaching and outreach, and they are still utilized in certain experiments today.