Watch a liquid boil and freeze at the same time

What exactly is going on here? In this amazing video, scientists have sucked the air out of the container and managed to find a pressure/temperature combination that's near the triple point of the fluid, which has been identified as cyclohexane - the triple point is the very precise temperature and pressure at which the three states of matter (solid, liquid and gas) exist in thermodynamic equilibrium.

Lauren Davis over at io9 explains: "As the liquid boils, high energy molecules leave the liquid as gas, lowering the temperature of the liquid left behind and causing it to freeze. This process of boiling and freezing continues while the substance remains at this pressure and temperature."

While some outlets are reporting that this is a case of cyclohexane reaching true triple point, Lauren Davis explains that instead we're seeing phase changes near the triple point as the three states aren't in perfect equilibrium.


Source: io9