Stickers are everywhere. They label our groceries, cover our car bumpers, and decorate our notebooks. But how do they stick? We’ll zoom in on a sticker to see how a special glue helps a sticker cling to a surface. Plus, we’ll hear about stickers that can help people heal from surgeries. We’ll also find out what kind of stickers Bob collects, and guess a new Mystery Sound.

Guest: Phillip Messersmith, professor of material science and engineering at the University of California, Berkeley.

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There’s more to sloths than slowness. They’re great at saving energy, hanging upside down, and swimming! In this episode, Sloth Appreciation Society founder Lucy Cooke stops by to tell us all about these amazing animals. We also get into a sloth mystery: The Case of the Perilous Poop Journey. Luckily, there’s a sloth sleuth on the case. And sloths aren’t the only animals who aren’t in a hurry — a few others show off their slowest skills.

There’s also a Mystery Sound for you to guess. Stay sloooooooooow!

Guests

Lucy Cooke, zoologist and founder of the Sloth Appreciation Society

Jonathan Pauli, UW-Madison Forest and Wildlife Ecology

Dr. Sushma Reddy, Breckenridge Chair of Ornithology, Bell Museum

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Have you ever heard of Lake Natron? It’s located in Tanzania, Africa, and, if you believe the internet, it can instantly petrify anything that touches it. Lucky for us, we have a direct line to the Hoax Hunters (aka Sanden and Marc) - they love myths, and they hate getting tricked.

Along the way to saying yea or nay to this stoney phenomenon, the Hoax Hunters speak with Neovitus Sianga. Not only does he have firsthand knowledge of the lake, but he works for African People and Wildlife, where he helps protect the environment around Lake Natron.

We also have a brand new Mystery Sound… and Marc and Sanden start a cleaning service?!?

Guest: Neovitus Sianga

Want more Hoax Hunters? Here are a few more episodes featuring our hoax hunting pals:

Are UFOs real?
Lost Cities
Mermaids, Kraken and Loch Ness Monster
Bigfoot, Unicorns and Dragons

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Skunks can stink, no doubt about it. But that stink is actually a superpower! Join Molly and co-host Diya as they find out how these critters use their smell to scare away enemies, what the smell is made of, and how to make your own de-skunking potion. Plus, Wombat Pete drops by to promote his new music festival, we speak to some skunk experts, and we try our best to guess a new Mystery Sound.

Don't forget the de-skunking potion mnemonic:

4 Cats Had Problems

Queen Coughed Beside Suzie's Tenth Lasagna, Don't Sneeze

Translation:

4 Cups hydrogen peroxide

Quarter Cup baking soda

Teaspoon Liquid Dish Soap

Guest: Marie Tosa, Research Scientist with the Washington Department of Fish and Wildlife.

Guest: Ted Stankowich, Professor in the Department of Biological Sciences and CSU Long Beach.

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 We're on a little winter break and we're gonna be back with a new Brains On episode next week. This week we have an episode of our Sister show forever ago to share with you. If you're interested in origin stories or history, this is the show for you. You can subscribe wherever you listen to Brains On.

Get ready for an out-of-this-world episode! Joy and co-host Elsa are trapped in a black hole with a baby elephant and a mountain of old junk!

They’ll explore the history of a super secret astronaut testing program for women called the “Fellow Lady Astronaut Trainees.” This group of bold, highly-trained pilots spent years making a case for why women are just as qualified to become astronauts as men!

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 We're on a little winter break here, but we're gonna be back with a new episode of Brains On January 6th. Until then, we have an episode of our sister podcast, smash Boom. Best to share with you the episode. Features some familiar voices. Me, mark, and Sandon, enjoy the show!

Whether you like your wheels big or small, this debate is for you! It’s Monster Trucks vs Hot Wheels. It’s a battle between Brains On besties Marc Sanchez and Sanden Totten. Marc goes full throttle for Team Monster Trucks and Sanden speeds toward victory for Team Hot Wheels. Who will win? Head over to smashboom.org to vote and listen to see who our judge crowns the king of cars.

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The Brains On crew is hitting the road in 2026, and our first shows have just been announced. If you like fun, games, dancing, optical illusions and... Mystery Sounds, check out Your Brain is Magic.

Head to brainson.org/events to get tickets for the following shows:

1/17 Newark, NJ Victoria Theater

1/18 Red Bank, NJ The Vogel

1/23 San Diego, CA The Observitory

1/24 Aneheim, CA House of Blues

2/21 Vancouver, BC Playhouse Theater (JFL Festival)

2/22 Seattle, WA Neptune Theater

If you don't see your city listed, we're adding more dates, so keep checking back!

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In our final look at metal, we explore how metal wires changed the world. Once humans figured out how to send little blasts of electricity through metal, we quickly developed lots of uses for this. One was a new way of communicating called the telegraph. Join Molly and co-host Ava as they team up with Dylan Thuras, co-founder of Atlas Obscura to learn how people laid hundreds of miles of wire in hopes of sending messages across oceans. Plus, the new Brains On Headquarters is having an opening ceremony, and there’s a brand new Mystery Sound to guess!

Guest: Dylan Thuras, co-author of The Atlas Obscura Explorer's Guide to Inventing The World.

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