In the Leidenfrost Effect, a water droplet will float on a layer of its own vapor if heated to a certain temperature.
The Leidenfrost effect is named for Johann Gottlob Leidenfrost, who described the phenomenon in A Tract About Some Qualities of Common Water in 1796. In the Leidenfrost effect, a liquid in proximity to a surface much hotter than the liquid's boiling point will produce a layer of vapor that insulates the liquid and physically separates it from the surface. Essentially, even though the surface is much hotter than the boiling point of the liquid, it vaporizes more slowly than if the surface was near the boiling point. The vapor between the liquid and the surface prevents the two from coming into direct contact.