Step 1 : Introduction to the question "What musical instrument is played without touching it?"
...The theremin is an electronic musical instrument. It was invented in 1919 by a Russian physicist Leon Theremin. Besides its unusual appearance, the theremin is also unique in that it is played without being touched. The theremin consists of a box with two metal antennas which create an electromagnetic field. The musician stands in front of the instrument and moves his hands in the proximity of the two antennas, which forms a capacitor between his hands and the antennas. The electric signals from the theremin are amplified and sent to a speaker system. The sound of the instrument is often associated with eerie situations. Thus, the theremin has been used in many movie soundtracks.