The picture shows the interactions in a particle stream in a bubble chamber filled with liquid hydrogen. Bubble chambers help to detect weakly ionised particles. // © CERN
Bubble chamber photographs provide an insightful introduction to the exotic short-lived particles that emerge from all high energy accelerator experiments.
Since they show actual trails of bubbles that are formed as charged particles force their way through an unstable liquid, bubble chamber pictures are perceived by non-particle physicists as real, and therefore a good way to introduce particle physics. The pictures themselves are quite often easy to understand in an intuitive, qualitative way.
The pictures, moreover, possess a mysterious, cosmic beauty that is particularly appealing to the non-scientist. -- Teacher's Web, CERN