Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff. Lauren bocal Bam here with another classic episode from our erstwhile host, Christian Sagar. Today he's talking about one of my favorite bits of everyday science, those little packets of silica gel that you find in everything from vitamin containers to the new bags that you buy, and why you
should not eat them. Hi, I'm Christian Sagar. This is brain Stuff, and today's question is what is silica gel and why do I find little packets of it in so many things? I mean, that's weird, right, Why would my new boots and my beef jerky be packed with the same stuff. Silica, or more precisely, silicon dioxide is the same stuff that quartz in sand are made of. It's a descant, meaning it adds orbs and holds water vapor,
and that's ads orbs with an ad, not absorbs. When we say that something adds orbs moisture, we mean that water molecules adhere to the surface of the material. Think of the way that sand can seem to soak up water. The water is really just adhering to each grain. Basically, silica gel does the same thing. It's covered in millions
of tiny pores that can retain moisture. It can actually adds orb about forty of its weight in moisture and can thus reduce the relative humidity in a closed container down to around so you'll find silica gel packs and anything that would be affected by excess moisture. It's in with leather products where it can limit the growth of mold. You'll see it packaged with electronics to reduce condensation, and because silica gel is nearly harmless, you'll find it preventing
spoilage and foods like pepperoni. You still don't want to eat it, though. If you emptied out a packet and ate the beads, they would begin adsorbing moisture from your tongue, gums, and the rest of your mouth. Your first instinct would probably be to spit it out. But if you did swallow it, well, okay, probably you'd be fine. But not all silica jel is the same. Some has a toxic
coating of cobalt chloride. Swallowing this stuff probably won't kill you, but it might cause nausea, vomiting, and a few other less than awesome symptoms. And when it comes to keeping things dry. Silica gel works pretty well, which is why it's so widespread. It's also found in vitamin containers, industrial air systems, and oddly enough, containers of cat litter. And this stuff is reusable. You can dry it out by heating it in an oven at about three hundred degrees
fahrenheit that's about one and fifty degrees celsius. And people have found all sorts of ways to reuse it. There might be too many to list. I mean, all right, I guess I can try here. It goes protecting papers from humidity, drying flowers, preventing rust on tools, preventing condensation on windows and inside picture frames, preserving art in display cases, mitigating small spills in luggage, slowing silver tarnishing, stopping seed mold,
and preventing camera lens from fog. Today's episode was written by me and produced by Tyler Clang. For more on this and lots of other reusable topics, visit our home planet, how stuff Works dot com