Here is another awesome STEAM toy from Northern Circuits: String of Pisces is a kinetic lamp that uses a string to put on a mesmerizing light show. It demonstrates the standing waves phenomenon. It consists of a string bound by 2 motors rotating in opposite directions and illuminated by RGB LEDs.
As the string rotates 90 times per second, the lamp generates a white noise. String of Pisces measures 16x6x6 inches. You can use the 2 aluminum dials to change color patterns and motor speeds.