Try putting a light ball (ping pong balls work well) into a stream of air blowing straight up from a hairdryer. (Make sure it’s on a cool setting!) Once the ball ‘balances’ try lowering the angle of the stream of air.
Connect a camera to a TV screen so that the screen shows the camera’s view. You could use a web-cam and computer screen instead. Point the camera at the screen. What sort of patterns can you make? Try playing with the lighting and film at different angles.