This simple device regulates its own temperature. Currently, it does nothing more than that. Still, it’s the kind of ridiculously clever machine that will brighten your day, provided you’re a Wallace & Gromit fan.
This is a Leidenfrost Thermostat. The Leidenfrost Effect is a phenomenon that happens when a relatively cool liquid meets a much, much hotter solid. The bottom of the drop of liquid evaporates, and provides a little cushion of vapor for the rest of the drop to skitter around on.
Scientists at the University of Bath discovered a quirk of the Leidenfrost Effect a few years ago. Put the drops on a ratcheted surface, at a certain temperature, and they will move in specific directions. They’ll even climb hills. Now the researchers have come up with this neat little contraption. Drops fall down onto the ratcheted surface. When the surface is too hot, they move one direction, and get steered down below the ratcheted surface. There they evaporate and cool the system down. When the system gets too cool, the drops get steered in the other direction, and fall off and away from the ratcheted surface, allowing it to heat up.
The researchers are hoping that eventually this will lead to a thermostat with no moving parts. In the meantime, neat, right?
[Source: A Leidenfrost Thermostat]