system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how does a Geiger Counter work?
gpt
A Geiger counter is made with a large tube filled with a noble gas like helium or neon, and it's charged with a high voltage.

When incoming radioactive particles hit the gas, it briefly becomes conductive because the gas is briefly *ionized.* The tube conducts an electrical pulse, and that pulse is sent to the processing electronics, which usually results in the audible clicking you associate with radiation.