Mental Floss

Watch Liquid Boiling and Freezing at the Same Time

Erin McCarthy

In this video, you can watch an unknown liquid freeze and boil simultaneously. No, it's not magic. It's science!

What you're seeing here is a liquid reaching its "triple point"—the temperature and pressure at which the three phases of a substance (gas, liquid, and solid) co-exist in equilibrium. In this experiment, the scientists are changing the pressure in the beaker. When the liquid is at a certain temperature, it will do what you're seeing here.