Although autoclaves have many important scientific and industrial uses, which we'll cover later, the main focus of this article is going to be on how these handy machines are used in sterilization.
You've probably heard of pressure cookers? They were all the rage until microwave ovens became popular in the 1980s. They're like over-sized saucepans with lids that seal on tightly and, when you fill them with water, they produce lots of high-pressure steam that cooks your food more quickly (if you want to know more, please see the box at the bottom of this page).
Autoclaves work in a similar way, but they're typically used in a more extreme form of cooking: to blast the bugs and germs on things with steam long enough to sterilize them. The extra pressure in an autoclave means that water boils at a temperature higher than its normal boiling point—roughly 20°C hotter—so it holds and carries more heat and kills microbes more effectively. A lengthy blast of high-pressure steam is much more effective at penetrating and sterilizing things than a quick wipe in ordinary hot water!