Scientists Create “Liquid Gears” That Spin Without Touching

NYU researchers created “fluid gears” that transmit motion through liquid currents instead of meshing teeth.

One rotating cylinder can drive a second passive cylinder, with the rotation direction changing based on spacing and speed.

Experiments in a glycerol-water mixture showed the setup can spin the follower in the same or opposite direction.

The approach could offer a more durable, flexible alternative to conventional gears that wear, break, or need precise alignment.