What is silica gel and why shouldn’t you eat it?
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From the brains behind Brains On, this is Moment of Um. Answering those questions that make you go... Moment of Um comes to you from APM Studios. I'm Rabbit De Niro, the Dust Bunny. Um.

You know, one of my favorite places to hang out is under your bed. Technically, I don't have a choice. I'm just a messy little ball of hair and dust that literally goes wherever the wind takes me. But I can't complain. There's lots of cool stuff under here to keep a dust bunny like me entertained. There's an old checker set. I'm a tough opponent. I've never won a match against myself.

There's a circa-1998 Furby. Best toy ever made, in my humble opinion. Oh, and of course, the old harmonica you dropped under your bed last summer. I'm getting really good. Check it out! There is one mystery item, though. It's a tiny little white paper packet that says, "Silica Gel. Do not eat." on it. I'm pretty sure it fell out of the box when you got a new pair of sneakers.

What is silica gel anyway? Why can't you eat it? Timmy asked about this too. So I found someone who knows a lot about it. The point of these things is they absorb water, keeping your products from getting damp. I'm Professor Mark Lorch. I work at the University of Hull in the UK.

You'll find these little packets and all sorts of things. We call them silica gel, but they're really silicon dioxide. So it's actually the same sort of stuff as sand and glass is made out of. And the reason they work is because they are crammed full of silicon.

millions and millions of tiny, tiny pools and networks. So it might look like a little bead if you open up one of the packets to look at it, but there's tiny channels running through that sort of thing. So amazingly, if you take about half quarter of a teaspoon of this stuff, yeah, weighs about a gram, that has a surface area about the same as three tennis courts.

And water sticks to it, literally sticks to it. So, you know, just like your sand at the beach or whatever, it gets wet and you can't really see the water in there. It's just gone somewhere. Well, it's gone into all these sort of pores and stuff. So that's how silica gel works. Super common and cheap. And you can dry it back out again. It gets damp. You can put it in the oven. It dries out again. Right. But the question is, why shouldn't you eat it? Well,

simply is not food it's just not food and it's a choking hazard and so just yeah don't swallow it for that reason but it's amazing stuff and you know if you want to hang on to the packets keep them in a jar if stuff gets damp you drop your phone in a puddle you want to dry it out stick it in a bag with your silica jelly um wow wow wow pretty incredible stuff

Silica gel isn't actually gel. It's tiny clear beads. But it's also so much more. Each bead has tons of tiny holes and tunnels in it that are too small to see with your eyes. If you look at a silica gel bead under a really powerful microscope, it actually looks like a sponge because of all the little holes in its surface.

And those are important because they help the silica gel beads suck up water and keep things dry. That's why so many different products have little packets of silica gel in them, like toys, shoes, and electronics. The gel beads keep all the stuff nice and dry.

Oh, and one more thing. There's a reason why little packets of silica gel say, do not eat, in big letters. They can make you feel sick and could even stick in your throat and cause choking. So don't eat them. Now, if you'll excuse me, I'm in the middle of a riveting game of checkers against myself. And if I lose, I'll never let myself forget it.

If you liked this episode, take a second to subscribe to Moment of Um. Wherever you listen to podcasts. And if dust bunnies like me make you sneeze, check out the Brains On episode where we have a whole episode all about sneezing. It's called Achoo! How fast do sneezes travel?

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