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Speaker 1: Welcome to brain stuff from how stuff Works High brain Stuff,

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Speaker 1: Lauren bulk bomb here, whether it's dry shampoo or paint,

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Speaker 1: or accustomed to shaking aerosol canisters before we spray them.

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Speaker 1: So it's only natural that when we pick up a

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Speaker 1: canister of compressed air to clean a keyboard, we also

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Speaker 1: want to shake the can even if it's label clearly

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Speaker 1: says do not shake. But is this force of habit

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Speaker 1: potentially harmful? In a word, yeah, compressed air canisters are

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Speaker 1: not really canned air. Rather, these canisters contain a compressed

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Speaker 1: liquefied gas that propels its own vapors through a nozzle.

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Speaker 1: Most of the time, the liquefied gas is one of

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Speaker 1: two types. One is die fluoro ethane or HFC one

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Speaker 1: two A, which is found in canisters marketed for computers

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Speaker 1: and electronic equipment, and incidentally is also known as free

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Speaker 1: on that same gas that helps make refrigerators and car

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Speaker 1: air conditioners cool. The other type of gas is tetrafluoro

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Speaker 1: ethane or HFC one D four A, which is recommended

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Speaker 1: for use when flammability might be an issue, such as

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Speaker 1: with hot surfaces or spark producing equipment. However, some types

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Speaker 1: of canned air may also contain butane, the same liquefied

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Speaker 1: gas found in cigarette lighters. According to three M, which

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Speaker 1: manufactures and cells compressed air canisters for dust removal, shaking

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Speaker 1: or tilting the can it may result in propelled liquid

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Speaker 1: instead of vapor. If this happens, the liquid may come

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Speaker 1: into contact with skinner eyes and cause frost bite because

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Speaker 1: the chemical will freeze your skin at room temperature. If

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Speaker 1: this happens, medical attention may be warranted. But first three

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Speaker 1: M recommends washing affected areas of skinless soap and water,

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Speaker 1: or flushing eyes with copious amounts of water. But what

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Speaker 1: about all those other air sel canisters that do recommend

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Speaker 1: shaking before use. Unlike the liquefied gas and canned air

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Speaker 1: that propels itself out through the nozzle, everything from dry

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Speaker 1: shampoo to spray paint requires a little mixing. The product

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Speaker 1: inside the can separates into layers and must be shaken

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Speaker 1: to mix with the propellant before use, otherwise the propellant

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Speaker 1: would come out. Today's episode was written by Laurie L.

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Speaker 1: Dove and produced by Tyler Clang. For more on this

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Speaker 1: and lots of other expansive topics, visit our home planet,

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Speaker 1: how stuff Works dot com,