Solenoid Magnetic Accelerator: six electromagnet coils push a steel ball to terminal velocity. Each coil is triggered to briefly energized only when an infrared led and sensor circuit detects the presence of the ball. The steel ball’s speed seems limited by the strength of the temporary magnetic field and the friction it encounters from the track. This ring configuration demonstrates proof of concept for a means of accelerating steel marbles and I hope to incorporate these coils in other marble

Rhythmic Ferrofluid: an iridescent magnetic fluid interacts with a variable strength electromagnet (like those found in speakers). A circuit supplies power to the electromagnet in proportion to the sound waves picked up by a microphone, the changing magnetic field- combined with the liquid surface tension of the colloidal ferromagnetic liquid- produces the captivating motion that keeps time with any music played. ➡️ Follow the link in my @physicsfun profile for info on where to get this device a

Magnetic switch circuit