How does a bubble chamber work?
Imagine a tank of superheated liquid—just below its boiling point, like a soda can about to fizz. When a charged particle passes through, it deposits energy along its path, creating tiny ionization sites. Those sites act as nucleation points for bubbles to form. You time it so that just as the particle goes through, you expand the chamber with a piston, dropping the pressure and making the liquid superheated. Then, in a few microseconds, bubbles grow to a visible size—maybe a millimeter across. You trigger a flash and take a photograph. The tracks show up as dashed lines of bubbles, and their curvature in a magnetic field tells you the particle's momentum and charge. It's a beautiful, direct way to make physics visible. I built the first one from a glass flask and some rubber gaskets—pure tinkering.
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