Last week I was watching History Detectives (I love that show) and they featured a Theremin. I had had a little exposure to the concept of a Theremin in the past when my husband explained that it is similar in sound to the saw (which he plays so very well). The sound is truly like a saw, but it is an electronic instrument.
I am not really the person to explain this instrument or its operation - check the information on Wikipedia for that. When I read the listing of movies that have made use of the Theremin in the background music, I wonder how many times I was hearing a Theremin when I thought I was listening to a saw. The sound is unique - check that out on YouTube, as played by its inventor, Leon Thermin. There's also a great version of "Over the Rainbow" on the Theremin, played by Peter Pringle . . . my husband loves to play that song on the saw and it sounds very much like the Theremin version. Wonder what they would sound like together? Well, maybe not.
It is a very visual instrument - the player with good technique appears to do a hand-ballet over the components to create the music. Impressive. Of course, now I think we should get a Theremin to make our instrument collection even more complete (no, it will never be finished!). Anyway, if you haven't seen one or heard one, check out those links and others they will take you to so you can add to your musical education!