The theremin is an electronic musical instrument that is played using electrical fields. When it was first introduced, people were shocked to see this instrument that could be played without even touching it. The theremin unsually is tuned so that it has a range of three and a half octaves. The theremin's operation is based on the theory of beat frequencies. Two antennas stick out on each side. Usually a vertical antenna is located on the right which controls the pitch. The closer the players hand is, the higher the pitch. A horizontal loop antenna is located on the left and controls the volume. The closer the hand is, the louder the volume.
Patented in 1928 by Leon Theremin, the theremin has not escaped its original status as a novelty instrument. Most people have heard the theremin, even though they may not recognize it. The theremin is a staple of sci-fi films, particularly classic ones. It is not as prominent today but it has featured in recent movies such as Mars Attacks and Ed Wood.