With a boiling point of -196 °C (-321 °F), liquid nitrogen is cool enough to display some remarkable properties when exposed at room temperature. But what happens when the already-supercooled gas is placed in a vacuum to boil even faster?  The nitrogen reaches -210 °C (-346 °F) in the low-pressure chamber. That's just 63 °C above absolute zero, and at that temperature a rarely-seen chain reaction occurs, resulting in what I can only describe as exploding snow.