Speaker 1: Welcome to brain Stuff from how stuff Works dot com.
Speaker 1: We're smart Happens. Hi. I'm Marshall Brain with today's question,
Speaker 1: how does an oxygen canister on an airplane work? When
Speaker 1: we think of store to oxygen, we usually think about
Speaker 1: a large metal tank holding pressurized oxygen gas. This is
Speaker 1: the way we see oxygen in hospitals and on welding rigs.
Speaker 1: We also see scuba divers taking their oxygen with them
Speaker 1: in the form of compressed air and scuba tanks. Because
Speaker 1: these tanks are so common, we tend to think that
Speaker 1: they are the only way to store oxygen. It turns
Speaker 1: out that there's also a chemical way to store oxygen.
Speaker 1: Many chemicals, including potassium chlorate and sodium chlorate, are rich
Speaker 1: in oxygen, and they're willing to give it up as
Speaker 1: a nearly pure gas when they get heated. The scuba
Speaker 1: tanks that divers wear might weigh up to eighty pounds
Speaker 1: but can only store an hour or two of air.
Speaker 1: An oxygen canister weighing half that can provide about four
Speaker 1: days worth of oxygen. The sodium chlorate is acting something
Speaker 1: like an oxygen sponge, and you squeeze the oxygen out
Speaker 1: of that sponge with heat. Modern oxygen canisters are extremely
Speaker 1: lightweight and they store a lot of oxygen. You find
Speaker 1: oxygen canisters, also known as chemical oxygen generators, on airplanes, submarines,
Speaker 1: and space stations, places where oxygen can run out unexpectedly. Typically,
Speaker 1: an oxygen canister contains a sodium chlorate pellet and an igniter.
Speaker 1: The igniter can be triggered by friction or impact. It
Speaker 1: generates enough heat to start the sodium chlorate reaction, and
Speaker 1: then the heat of the reaction sustains itself. The sodium
Speaker 1: chlorate does not burn, its decomposition, just happens to give
Speaker 1: off lots of heat and lots of oxygen. The reason
Speaker 1: why oxygen canisters can cause fire is because they're hot
Speaker 1: and they generate oxygen. Anything nearby that happens to ignite
Speaker 1: will burn incredibly intensely because of that rich oxygen supply.
Speaker 1: Be sure to check out our new video podcast, Stuff
Speaker 1: from the Future. Join How Stuff Work staff as we
Speaker 1: explore the most promising and perplexing possibilities of tomorrow. The
Speaker 1: How Stuff Works iPhone app has arrived. Download it today
Speaker 1: on iTunes.