Physics

The Leidenfrost Effect Can Make Water Flow Uphill

March 17, 2014 | by Justine Alford

Photo credit: Wikimedia Commons

Have you ever noticed whilst cooking that sometimes bead-like water droplets seem to dance around the bottom of the hot pan? Well, that's the Leidenfrost effect, and it only occurs above specific temperatures. If you place a liquid onto a hot surface that is below the boiling point of the liquid (100 degrees Celsius for water), the liquid will bubble away and slowly evaporate. If you increase the temperature to slightly above the boiling point, the liquid evaporates rapidly. However, if you increase the temperature even more, exceeding the Leidenfrost point, this cool phenomenon called the Leidenfrost effect comes into play. This occurs when the surface temperature is so hot that it generates a thin layer of vapor that lies between the surface itself and the liquid. This causes the liquid to become insulated, and slows down the evaporation. 

Scientists from the University of Bath, led by Dr. Takashina, have experimented with this effect, and documented some incredible footage including water flowing uphill. Check it out on this YouTube video: