Crystal radio technology has been around for many years. This "bottle radio" take on a crystal radio requires no power source, operates on the power from radio waves, and receives signal from a long wire antenna. As radio stations slowly move away from the AM band, the "window of opportunity" to experience this remarkable technology is dwindling. The "crystal" in question is contained inside a germanium diode, and is used to rectify the radio signal so that our ears can hear it.
The title says it all: this blog features physics videos found everywhere on the web: animations, demonstrations, lectures, documentaries.