Richard Sudney (Youtube user 2sudsy) has been building Crystal Sets since he was 9 years old. He is a bit older than that now and his passion hasn’t drifted, it has just been honed over the years.
Via: Make
“A crystal radio receiver, also called a crystal set, is a very simple radio receiver, popular in the early days of radio. It needs no battery or power source and runs on the power received from radio waves by a long wire antenna. It gets its name from its most important component, known as a crystal detector, originally made with a piece of crystalline mineral such as galena. This component is now called a diode.”