Note Only Industry is available at the time of this post.. I just put them all in for when our population increases to the point where they become available.. and keep from having to edit this post to add them
He's playing music on a theremin, which is some instrument that uses electromagnetics or something like that to sense your hand positions and makes sounds based on that. It's a completely touchless instrument.
Go google it if you want the details. I'm just working off memory from looking it up once.
As an extra note to everyone: If there was a song you liked on my show but can't remember what it was, all my playlists are saved so feel free to ask away.. give me any part you remember (aproximate time played, series, artist...) and I'll try to figure out which track it was.