|MLA Citation:||Bloomfield, Louis A. "Question 551"|
How Everything Works 18 Jan 2018. 18 Jan 2018 <http://howeverythingworks.org/print1.php?QNum=551>.
Water boils not because it's hot but because any evaporation bubble that forms inside it is able to survive and grow despite the surrounding atmospheric pressure. At normal atmospheric pressure, the water does have to be hot for this to happen. But if you remove the atmospheric pressure, the water can boil at much lower temperatures. In fact, at sufficiently low pressures, even ice water will boil! It's funny to see ice cubes floating in a container of boiling water, but it happens when you remove the air from around the ice water.