Triple punto

Science! - Cyclohexane at the Triple Point

A volumetric flask containing liquid cyclohexane is depressurised to a very low pressure by a turbomolecular vacuum pump. The rapid drop in pressure results in a rapid drop in temperature, causing the substance to temporarily freeze, but the system is unstable, flirting with the triple point (a point of pressure and temperature at which a substance is simultaneously solid, liquid, and gas).
The result is a fluctuation between all three states of matter, in a rather stunning display of chemistry and physics in action.