The Leidenfrost Effect (Chemistry Water) Frosted Glass Coffee Mug

The Leidenfrost effect is a phenomenon in which a liquid, in near contact with a mass significantly hotter than the liquid's boiling point, produces an insulating vapor layer which keeps that liquid from boiling rapidly. Specifically, the Leidenfrost point signifies the onset of stable film boiling, representing the point on the boiling curve where the heat flux is at the minimum and the surface is completely covered by a vapor blanket. Heat transfer from the surface to the liquid occurs by conduction and radiation through the vapor. In 1756, Johann Gottlob Leidenfrost observed that water droplets supported by the vapor film slowly evaporate as they move about on the hot surface. As the surface temperature is increased, radiation through the vapor film becomes more significant and the heat flux increases with increasing excess temperature. Educational, scientific attitude about the chemistry of water that you probably didn't know about are found on any of these gifts!