During the Second World War, soldiers found a clever way to listen to the news. Foxhole radios were built by GI’s in World War II from materials they had easy access to in the field, such as razor blades and safety pins.
A foxhole radio basically consists of only a coil and a detector. You don’t need a crystal diode or batteries to make it work as it is powered only by the radio waves present in the air. In the following science experiment, build a working tuneable foxhole radio using only a few simple household supplies: