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Speaker 1: Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff.

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Speaker 1: Lauren bocal Bam here with another classic episode from our

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Speaker 1: erstwhile host, Christian Sagar. Today he's talking about one of

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Speaker 1: my favorite bits of everyday science, those little packets of

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Speaker 1: silica gel that you find in everything from vitamin containers

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Speaker 1: to the new bags that you buy, and why you

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Speaker 1: should not eat them. Hi, I'm Christian Sagar. This is

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Speaker 1: brain Stuff, and today's question is what is silica gel

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Speaker 1: and why do I find little packets of it in

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Speaker 1: so many things? I mean, that's weird, right, Why would

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Speaker 1: my new boots and my beef jerky be packed with

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Speaker 1: the same stuff. Silica, or more precisely, silicon dioxide is

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Speaker 1: the same stuff that quartz in sand are made of.

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Speaker 1: It's a descant, meaning it adds orbs and holds water vapor,

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Speaker 1: and that's ads orbs with an ad, not absorbs. When

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Speaker 1: we say that something adds orbs moisture, we mean that

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Speaker 1: water molecules adhere to the surface of the material. Think

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Speaker 1: of the way that sand can seem to soak up water.

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Speaker 1: The water is really just adhering to each grain. Basically,

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Speaker 1: silica gel does the same thing. It's covered in millions

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Speaker 1: of tiny pores that can retain moisture. It can actually

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Speaker 1: adds orb about forty of its weight in moisture and

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Speaker 1: can thus reduce the relative humidity in a closed container

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Speaker 1: down to around so you'll find silica gel packs and

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Speaker 1: anything that would be affected by excess moisture. It's in

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Speaker 1: with leather products where it can limit the growth of mold.

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Speaker 1: You'll see it packaged with electronics to reduce condensation, and

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Speaker 1: because silica gel is nearly harmless, you'll find it preventing

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Speaker 1: spoilage and foods like pepperoni. You still don't want to

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Speaker 1: eat it, though. If you emptied out a packet and

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Speaker 1: ate the beads, they would begin adsorbing moisture from your tongue, gums,

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Speaker 1: and the rest of your mouth. Your first instinct would

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Speaker 1: probably be to spit it out. But if you did

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Speaker 1: swallow it, well, okay, probably you'd be fine. But not

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Speaker 1: all silica jel is the same. Some has a toxic

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Speaker 1: coating of cobalt chloride. Swallowing this stuff probably won't kill you,

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Speaker 1: but it might cause nausea, vomiting, and a few other

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Speaker 1: less than awesome symptoms. And when it comes to keeping

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Speaker 1: things dry. Silica gel works pretty well, which is why

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Speaker 1: it's so widespread. It's also found in vitamin containers, industrial

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Speaker 1: air systems, and oddly enough, containers of cat litter. And

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Speaker 1: this stuff is reusable. You can dry it out by

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Speaker 1: heating it in an oven at about three hundred degrees

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Speaker 1: fahrenheit that's about one and fifty degrees celsius. And people

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Speaker 1: have found all sorts of ways to reuse it. There

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Speaker 1: might be too many to list. I mean, all right,

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Speaker 1: I guess I can try here. It goes protecting papers

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Speaker 1: from humidity, drying flowers, preventing rust on tools, preventing condensation

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Speaker 1: on windows and inside picture frames, preserving art in display cases,

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Speaker 1: mitigating small spills in luggage, slowing silver tarnishing, stopping seed mold,

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Speaker 1: and preventing camera lens from fog. Today's episode was written

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

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

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Speaker 1: how stuff Works dot com