Sand! We use it to make all kinds of things, from spectacular sandcastles to roads and bridges. But where does it come from? And why is the sand on so many beaches disappearing?

In this episode, Molly and co-host Leon head to the beach to explore the secrets of sand. They run into the ultimate sand STAN Sanden Totten and discover what it's made of. Then, they chat with producer Nico Gonzalez Wisler about why beaches are running out of sand. All that, plus a stumper of a new mystery sound!

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LEON: You're listening to Brains On, where we're serious about being curious.

CREW: Brains On is supported in part by a grant from the National Science Foundation.


MOLLY BLOOM: Leon! Over here!

LEON: Hi, Molly. Nice beach setup.

MOLLY BLOOM: Yes, I've got the lounge chairs, the umbrellas for shade, a cooler full of super exotic and/or made-up beverages.

LEON: Mango bean and lime berry spritz? Don't mind if I do.

MOLLY BLOOM: And I even set up a studio right over here. Come check it out. I figured, if we're going to do an episode all about sand, why not tape it at the sandiest place of all-- the beach? The studio is right over here. Marc, what are you doing in our studio?

MARC SANCHEZ: Shh! Molly, Molly, he's in the middle of saying something.


LEON: Are you using the studio to interview a seagull?

MARC SANCHEZ: Yeah, and he's been talking for over an hour now. He really has a lot to say.


MOLLY BLOOM: What is he saying?

MARC SANCHEZ: Honestly, I have no idea. And at this point, I'm a little too embarrassed to tell him that I don't speak seagull.


Uh-huh, uh-huh. Wow, oh, yeah. Fascinating!

MOLLY BLOOM: Well, we need him to stop talking so we can do our episode.

LEON: I have an idea. Oh, hey, look. Someone just dropped a plate of French fries over there.



MOLLY BLOOM: Great thinking, Leon. Now we can start the show.

MARC SANCHEZ: Yeah, uh, good work. Now, would you please move? I got to get those fries before that seagull hawks them all!


Hey! Save some for me!


MOLLY BLOOM: You're listening to Brains On from APM Studios. I'm Molly Bloom. And my co-host today is Leon from Ipswich, England. Hi, Leon.

LEON: Hi. I'm very excited to be doing this.

MOLLY BLOOM: Well, we are very excited that you're here today. Is there a beach near where you live in England?

LEON: Um, yes. The beach that I go to quite a lot is called Felixstowe.

MOLLY BLOOM: And what is your favorite thing to do at that beach?

LEON: Probably make sand castles.

MOLLY BLOOM: Do you do it-- like you put sand in a bucket and kind of like flip it over? Do you have another technique you use?

LEON: Sometimes I just almost make a pile of sand.

MOLLY BLOOM: Very fun. So when you make your sandcastle, do you imagine that there are people there or animals, or it's for crabs? Like, what is your imagination doing when you make a sandcastle?

LEON: Normally, I make it a castle, and then I put something inside of it. Then I have to try and protect it, almost.

MOLLY BLOOM: Fun. What are you protecting it from?

LEON: The water.

MOLLY BLOOM: Yes, that water always has a way of coming and wrecking our sand castles, doesn't it?

LEON: Yeah.

MOLLY BLOOM: Not very nice. So, as you've been on the beach, have you wondered about sand? What have you been curious about?

LEON: I've wondered how it's made and how it's got here.

MOLLY BLOOM: Excellent question. Well, we're not the only ones who love to think about the beach. Today, we're answering this awesome question.

SOPHIE: Hello, my name is Sophie. And my question is, How deep does the sand go on the beach?

MOLLY BLOOM: Great question. We know beaches have lots of sand but there must be something under all those little grains. What's holding it all up?

LEON: I know one way to find out. Got your shovel, Molly?

MOLLY BLOOM: Of course.

LEON: Well, let's start digging!

MOLLY BLOOM: While we dig, we do need to say that every beach is different.


LEON: Right. Some beaches may just have a few centimeters of sand.

MOLLY BLOOM: Picture a layer of sand as tall as a turkey, lettuce, tomato sandwich.

LEON: While others can have 40 to 50 meters of sand.

MOLLY BLOOM: That's like a 12-story-tall building's worth of sand.

LEON: So far, we've dug about 4 inches deep.

MOLLY BLOOM: Whoa. And now our beautiful hole is filling in with water at the bottom! Where is the water coming from?

LEON: I was expecting that. If you're very near to where water hits the beach, you'll get to water pretty fast.

MOLLY BLOOM: Oh, right! There is underground water in lots of places. And here at the beach, that underground water starts at the same level as the ocean.

LEON: If you're further away from the water, you'll be able to dig until you hit rock. That's the solid part of the Earth's crust.

MOLLY BLOOM: Yeah. Remember how our Earth has layers inside? Go check out our episode about what would happen if you dug a hole to the center of the Earth to learn all about those layers.

LEON: The top layer of the Earth is called the crust. So if you dig deep enough anywhere in the world, you will eventually get to the crust, which is made out of rock.

MOLLY BLOOM: So the short answer to Sophie's question, How deep does the sand go on the beach--

LEON: It depends.

MOLLY BLOOM: But no matter how deep the sand goes on your particular beach, we can all agree-- sand is super cool.

SANDEN TOTTEN: Yes! We can agree. Sanden is super cool.

MOLLY BLOOM: Well, hello there, Sanden Totten. And no, we didn't say Sanden is super cool.

LEON: We said sand is super cool.

SANDEN TOTTEN: Well, I agree with you on that, too. Sand is super cool. And because Sanden is also super cool, I'm proud to announce the grand opening of-- drumroll, please-- um, Molly, Leon, drumroll.

LEON: Oh, yeah, sorry about that.

MOLLY BLOOM: Yeah, sure, sorry.


SANDEN TOTTEN: Oh, much better. The grand opening of Sanden's Super Cool Sand Stand!

MOLLY BLOOM: You're selling sand?


LEON: At the beach?

SANDEN TOTTEN: Absolutely.

MOLLY BLOOM: But Sanden, we're surrounded by sand. Why would we want to buy yours?

SANDEN TOTTEN: Because no one knows sand like Sanden's Super Cool Sand Stand. Plus, it comes in a nifty glass bottle with my photo on it!

LEON: Well, you do have a winning smile.

SANDEN TOTTEN: Thank you, Leon.

MOLLY BLOOM: So where did you get all this sand?

SANDEN TOTTEN: Where anyone gets sand-- from a thousands or even millions years long process of rocks and minerals breaking down into tiny pieces.

MOLLY BLOOM: That wasn't what I meant, but--

SANDEN TOTTEN: You see, Molly and Leon, sand is made up of rocks and minerals, which includes stuff made from minerals like seashells. And there are different kinds of sand that are made from different kinds of rocks and minerals. Here, see this bottle?

LEON: Ooh, it's super dark, almost black.

SANDEN TOTTEN: That sand is made from tiny bits of stuff that came from volcanoes. Imagine this-- a volcano erupts-- [IMITATING EXPLOSION]. It spews lava-- [IMITATING LAVA]. The lava hardens and turns black once it starts cooling. Then, over many, many, many years, wind and rain and animals hoofing it across that hard black rock breaks it into tiny pieces. Those pieces break into even smaller bits and on and on until you have black--

LEON: Sand.

SANDEN TOTTEN: You got it, buddy. And this bottle of white sand comes from the famous white sand beaches in Hawaii. Any guesses what it's made out of?

LEON: Dried unicorn tears!

MOLLY BLOOM: Petrified marshmallows!

LEON: Heat resistant snow?

MOLLY BLOOM: The white t-shirt belly button fuzz of one million dads.

SANDEN TOTTEN: Well, I love the enthusiasm, but the answer is even more surprising. It's made out of parrotfish poop.

LEON: Honestly, surprised we didn't get fish poop.

SANDEN TOTTEN: Parrotfish love to snack on coral, and the parts they can't digest come out of their booties as this bootiful white sand. Ah, over here? Check this out. This bottle of beige sand looks kind of boring, right?

MOLLY BLOOM: Yeah, plain old sand.

SANDEN TOTTEN: But take a look now with my handy dandy sandy ray.

MOLLY BLOOM: Isn't that just the Zoom Ray from Brains On headquarters?

LEON: And you've just taped a photo of yourself on the side.

SANDEN TOTTEN: Sanden's Super Cool Sand Stand is an in-demand brand with a plan to expand to Zoom Rays.

MOLLY BLOOM: Hard to argue with that impish grin. OK, carry on.

SANDEN TOTTEN: Let's zoom in.

THEME: Zoom, zoom, zoom, zoom, zoom, zoom, zoom.

LEON: Whoa. Seeing the sun zoomed in like this is incredible. There's all kinds of cool stuff here and so many colors.

MOLLY BLOOM: I see orange seashells, pink translucent sea glass, dark, shiny rocks, and tiny bits of white coral.

LEON: It's gorgeous.

SANDEN TOTTEN: It is. And for the low price of whatever cash you have in your pockets, this bottle can be yours. So many different materials have been broken down to make sand. Some of those bits even made their way to the beach all the way from the mountains, traveling down rivers, breaking down more and more until they made their way here. Zoom out, handy dandy sandy ray.

THEME: Zoom, zoom, zoom.

MOLLY BLOOM: OK, you definitely know your sand.

SANDEN TOTTEN: Well, I should know my sand facts. After all, sand is named after me.

MOLLY BLOOM: I'm pretty sure sand has been around longer than you have.

SANDEN TOTTEN: So, can I interest you in Sanden's Hand-Bottled Sand? How about one bottle for 3 or two for 10?

LEON: Hmm, I think I'll pass for now. I'm literally sitting on a giant pile of sand.

SANDEN TOTTEN: Well, want to bottle some while you're just sitting there? I can always use a hand at the sand stand.

NICO WISLER: Hey, guys. Nice beach chairs.

LEON: Hey, it's producer Nico Gonzalez Wisler. What's up?

NICO WISLER: Oh, not much. Just trying to enjoy my beach day. [SIGHS]

MOLLY BLOOM: What's the matter? The sun is shining. The waves aren't too scary.

LEON: There's a gentle breeze.

SANDEN TOTTEN: Look. I'm drinking a pineapple freezie out of a pineapple! What more could you want?

NICO WISLER: Ugh, it's just-- I was at this beach a few years ago, and there's way less sand here now than there was back then.

SANDEN TOTTEN: Ha-ha, I mean, heh, I don't know what you're talking about. Looks like there's lots of sand still here. And not just in the many, many bottles I currently have for sale-- OK, I got to go. Bye.

MOLLY BLOOM: Wow, he packed that whole stand up very fast.

LEON: I've never seen someone exit like that. Wait, Nico. What were you saying about there being less sand?

NICO WISLER: Well, a lot of people think sand is always just here, and it'll always be here. Like, it's a resource that keeps getting replenished. More and more keeps coming. But turns out, sand isn't like that. In fact, we might be running out of beach sand.


NICO WISLER: Yeah, it's a major bummer.

MOLLY BLOOM: What about you tell us all about it in a minute? But first , would it cheer you up to listen to the--


THEME: Mystery Sound.

NICO WISLER: Oh, definitely.

MOLLY BLOOM: OK, Leon, are you ready for the mystery sound?

LEON: Yep.

MOLLY BLOOM: OK, here it is.


Hmm, I think we need to hear it again. It was kind of a short one.


OK, Leon, what is your guess?

LEON: I think it's someone like pouring a jug of ice and water into a cup.

MOLLY BLOOM: Oh, that is a very good guess. I love it. Well, we will hear it again, get another chance to guess, and hear the answer after the credits. So, stick around.


We are working on an episode all about matches, those incredible little wooden sticks that make fire when you strike them on a surface. And we want to hear from you. If you could come up with a new name for matches, what would it be? Maybe Sparkle Sticks or Fire Pixies? Leon, what do you think? What would you rename matches, if you could?

LEON: I would probably rename them Spark Scratchers.

MOLLY BLOOM: Oh, very nice. Why that name?

LEON: Because normally you scratch them against something, and they make sparks.

MOLLY BLOOM: Yes, I love that name, Spark Scratchers. And I love something that has two S's. Alliteration-- I love it. All right, Leon, I'm sold. Listeners, record yourself delivering your new name for matches. You can send them to us at And while you're there, you can send us mystery sounds, drawings, and questions.

LEON: Like this one--

CALLER: What happens if you take a party room into space?

MOLLY BLOOM: Again, that's

LEON: And keep listening. You're listening to Brains On. I'm Leon.

MOLLY BLOOM: And I'm Molly. And today, we're exploring sand while at the beach. And our pal, Nico, is here, too.


MOLLY BLOOM: OK, so Nico, you said we might be running out of beach sand. How can that be? We just learned that sand comes from natural materials breaking down into tiny pieces and washing ashore. Isn't new sand being created all the time?

NICO WISLER: Well, yes, but that process takes millions of years. And we're using up sand much faster than it can be replaced. We use sand to make building materials for stuff like roads, bridges, and houses.

LEON: Huh, that stuff is very important.

NICO WISLER: And you need sand to make glass for windows and mirrors.

MOLLY BLOOM: Oh, gotta have windows and mirrors.

NICO WISLER: And you need it for lots of metal products, like pots and pans, street lampposts, and even car parts, which are often shaped using sand.

MOLLY BLOOM: Wow. OK, sand is really important.

NICO WISLER: I'd say. Scientists think humans use about 50 billion tons of sand every year.


LEON: That is a lot of sand.

NICO WISLER: It's the same as if every single person on Earth used about 40 pounds of it every day. My dog is about 40 pounds.


So, imagine me and you two and every other person on Earth making an exact sand replica of my dog every single day of the year.


MOLLY BLOOM: So, is construction where the sand from the beach is going?

NICO WISLER: Some of it, but most of the sand used in building construction comes from rivers and lakes. So that's not the only thing to blame. Molly, Leon, sadly, there is another reason sand is disappearing. Picture a sandy beach. As the waves lap up onto the shore and slide back out to sea, they drag some of the sand with them. Sand might also be pushed further down the beach when there's a strong wind.

MOLLY BLOOM: But isn't it natural for sand to get washed out to sea by big waves or pushed farther down the beach by the currents and wind?

NICO WISLER: Yeah, these processes are totally natural, but they're getting more intense. Climate change is making storms like hurricanes stronger, which means bigger waves and more wind, which also means more sand getting swept away.

LEON: Oh, yeah, and glaciers and icebergs are melting into the ocean, causing sea levels to rise, which means even if the sand on our beaches isn't going anywhere, more of it is underwater.

NICO WISLER: Right, and even when the sand on the beach could be replenished by new sand, remember, we're taking a lot of sand out of rivers so we can use it to build things. So that sand never has a chance to make it to the beach. Plus, humans have also built roads and houses right along the beach and dams that stop rivers from flowing.

LEON: Huh. So all of that would block a new sand from making it all the way to the beach.


MOLLY BLOOM: You know, I hadn't thought about that, but my family used to go to Florida every year, and the sand would be less, basically, every time we went. It was pretty surprising. Leon, have you noticed any change in the sand where you go to the beach?

LEON: There's a lot less sand than there was before. It's a lot more rocky.

MOLLY BLOOM: Very interesting. Yeah, so sandy beaches are really important because they help protect the communities behind them from flooding during storms. That's because when storms send really big and intense waves crashing onto the beach, the sand absorbs some of their energy and slows them down so the waves don't rush up past the beach.

LEON: Sandy beaches are also home for countless creatures. You might see sea lions socializing or crabs scuttling back and forth to find food, or even baby sea turtles taking their very first steps towards the ocean.

MOLLY BLOOM: Dang. Is there anything humans can do to make the problem better?

NICO WISLER: Actually--

SANDEN TOTTEN: I've got it!

LEON: Sanden, there you are. Where did you go?

SANDEN TOTTEN: Well, after you guys accused me of taking all the sand off the beach--

MOLLY BLOOM: No one accused you of that, Sanden.

SANDEN TOTTEN: I decided to read more about the problem. At first, I just wanted to clear my good name. But it turns out, Nico was totally right. Beaches all over the world really are losing sand. So then, I had to do a dramatic wail, like so-- oh, no! I mean, sand is such an exquisite substance. Without it, a beach day would just be a day. Nobody wants to make grass castles or bury themselves in plain, old dirt. So, I started working on a prototype.

LEON: Prototype?

SANDEN TOTTEN: Ahem. [CLEARS THROAT] Did you know Mars is covered in sand? Here are the schematics for a big chute in space, a sand chute-- ha-ha, Sanden's Sand Chute-- to send all that sand down here to Earth.

(SINGING) It's raining sand

Hallelujah, it's raining sand

Huh? So? You guys like it?

NICO WISLER: That is not a realistic solution, Sanden. But I love your enthusiasm. And the good news is, there are some solutions with real potential. Like in Louisiana, which is a state that's seen a lot of beach erosion, there's a company that's recycling glass back into sand.

MOLLY BLOOM: Oh, we did a whole episode a few years ago about how glass is made. The main ingredient is silica sand.

NICO WISLER: Then it can be used for things like making concrete, filling in playgrounds or volleyball courts. You can even put some of it back in beaches and wetlands.

LEON: That's so cool.

NICO WISLER: It is, but recycled glass doesn't work for every beach, so scientists are trying other things, too. One of them is beach nourishment, which is just a fancy way of saying putting sand back on the beach. But instead of building a chute from Mars, this sand is usually pumped from the ocean floor and dumped onto the beach.

MOLLY BLOOM: Does it work?

NICO WISLER: Well, sometimes. But eventually, that sand usually gets washed out or pushed away, too. One of the best ways to keep sand on beaches is to make sure all the sand washing down from rivers makes it there in the first place. Some communities have done that by removing dams that blocked up rivers. And other communities are considering removing roads and buildings next to beaches.

LEON: Which would allow the beach to go back to its normal cycle of losing and gaining sand?

NICO WISLER: Yep, and of course, if we manage to slow down climate change, we'll have fewer intense storms and less sea level rise.

SANDEN TOTTEN: That's a tall order. But I know one place we can start. The sand from my sand stand should stay right here on the beach. Bye-bye, little bottled buddies. Now, if you'll excuse me, I need to go figure out my next big money making scheme. Ooh, maybe coconut freezies that you drink out of coconuts! Oh, great idea, Sanden.


LEON: Sand is made from rocks and minerals breaking down over millions of years.

MOLLY BLOOM: And how deep it goes depends on the beach and how close you are to the ocean.

LEON: And while it's great for making sandcastles, we use sand for all kinds of things.

MOLLY BLOOM: Like building roads and bridges, making glass and mirrors, and shaping things made of metal. But beaches and riverbeds are losing sand.

LEON: Luckily, some very smart people are thinking of ways to replenish it so that we can keep enjoying our beaches for many years to come.

MOLLY BLOOM: That's it for this episode of Brains On.

LEON: This episode was written by Molly Bloom and Nico Gonzalez Wisler. It was produced by Rosie DuPont, Anna Goldfield, Aron Woldeslassie, Anna Weggel, Ruby Guthrie, and Marc Sanchez.

MOLLY BLOOM: Our editors are Sanden Totten and Shahla Farzan. This episode was sound designed by Rachel Breeze. We had engineering help from Gareth [? Patch, ?] Jake [? Aylward, ?] and Jess Burg. Our executive producer is Beth Pearlman. And the executives in charge of APM Studios are Chandra Kavati, Alex Schaffert, and Joanne Griffith. Special thanks to Lanita Bishop.

LEON: Brains On is a non-profit Public Radio program.

MOLLY BLOOM: There are lots of ways to support the show. Subscribe to Brains On Universe on YouTube, where you can watch animated versions of some of your favorite episodes, or head to

LEON: While you're there, you can send us mystery sounds, drawings, and questions.

MOLLY BLOOM: OK, Leon, are you ready to hear the mystery sound again?

LEON: Yep.

MOLLY BLOOM: OK, here it is again.


All right. Any new thoughts? You're going to stick with your original answer? What do you think?

LEON: I think I'm going to stick with my original answer.

MOLLY BLOOM: OK, remind us what that was.

LEON: Someone with a jug of water and ice in it, pouring it into a cup.

MOLLY BLOOM: Very good guess. Are you ready for the answer?

LEON: Yes.

MOLLY BLOOM: OK, here it is.

MILES: Hi, I'm Miles, and I live in Pasadena, California. The sound that you just heard was me pouring water and ice.

MOLLY BLOOM: Oh, my goodness. Leon, holy cow. Excellent ears. How do you feel?

LEON: Very happy.

MOLLY BLOOM: [LAUGHS] Yeah, it was an excellent guess. So I'm guessing you have-- well, you must have poured water and ice at some point in your life, then.

LEON: [CHUCKLES] Yeah, I really like having ice and water, so I do it almost every day.

MOLLY BLOOM: Oh, my gosh. So good. Excellent work.


Now it's time for the Brains Honor Roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives.


We'll be back next week with a fire episode, all about the magic of matches.

LEON: Thanks for listening.

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