Leidenfrost Cart

Friction is a major inhibitor in almost every mechanical system. Enlightened by the Leidenfrost effect — a droplet can be levitated by a vapor layer on a hot surface — we demonstrate for the first time that a small cart also can be levitated by Leidenfrost vapor provided that the surface temperature is above the Leidenfrost point. The levitated cart can carry certain amount of load and move frictionless on the hot surface. The maximum load that the cart can carry is experimentally tested over a range of surface temperatures. We show that the Leidenfrost levitated cart can not only be propelled by gravitational force on a slanted flat surface, but also can be self-propelled on a ratchet shaped horizontal surface. In the end, we experimentally measured water consumption rate for the Leidenfrost levitated cart, and compared the results to theoretical calculations. If perfected, this frictionless Leidenfrost cart could be used in numerous applications.