Short Wave - 5-Year-Olds Asked Us Science Questions. We Answer

Episode Date: October 15, 2024

In honor of our show turning 5 (!!) today... 5 Short Wave staffersanswer 5(x2) questionsfrom some of our 5-year-old listenersand explain the science ... like they're 5. SPOILER ALERT: The questions are brilliant, delightful and span everything from how colors work to insects, the formation of Earth and space.Want to know more about the science of the world? Email us at [e-mail] — we might cover it on a future episode!See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Hey, Shortwavers. It's Emily Kwong and Regina Barber. And today's Shortwave's fifth birthday. Our show was born five years ago. And we love making this show for you all. Yes. That's true. And some of our most dedicated shortwavers were born five years ago, too, like this listener in Hawaii. My name is Willie, and my Christian is Magic Rio. I don't want to mess this up like I messed this question up for my own kid. Let's do it. So today on the show, we're handing over our programming to five-year-olds. Yeah, M and I and basically our whole team, we'll answer as many of your questions as we can

and tackle Lily's ultimate ask at the end, is Magic Real? You're listening to Shortwave, the science podcast from NPR. So the five-year-olds of Shortwave have spoken, and they have submitted questions in six categories. chemistry, biology, earth science, ocean science, and physics and space. We tried to cover as much ground as possible in this episode, and you'll hear from every shortwave staffer except our editor and our producer, Burley McCoy, as she's on maternity leave, spending time with her kiddo. We love you, Burley. In Burley's honor, we're going to start with chemistry. And this question, recorded by a short waver in Colorado.

Hi, I'm Paxton. How is yellow plus blue equal green? Paxton, I love how you turned your question into a math equation as well. It's so good. Paxton, the reason you can see color is because of light. Imagine sunlight like a big rainbow wave containing all the colors. That's why when the sunlight, which is white, hits the raindrops, it breaks up the white light into a rainbow.

And that white light, Light contains all of those colors. And it's actually because those different colors travel through water at different speeds that it makes this rainbow. And you can see it. Red, orange, yellow, green, blue, violet, and indigo shining through that raindrop. Papaxon, paint is different. Paint contains pigment. When light hits the blob of paint, some light gets absorbed, like sucked into the paint.

So you can't see it. It doesn't reflect off the surface of that paint. But other parts of the rainbow bounce off the paint. That reflected light is what you see as color. So, for example, blue paint appears blue because it reflects the blue parts of the light spectrum and absorbs the red and green parts. Yellow paint absorbs the blue light and reflects more of the red and green parts. And this balances out to create yellow. Now, when you mix blue and yellow paint, chemistry happens.

All those colors get absorbed together and appear to our eyes to reflect something new. Green. Okay, for this next lesson, we're switching to a biology lesson from producer Hannah Chin. Hey, Anna. Hey, Emily. Hi, Gina. Hi, Hannah. Okay, so Lionel from Los Angeles asked us,

Why do you like humans? I have to have what. And Anson, Aliikoa, from Hawaii, asked, do cockroaches have blood? And I think those questions are pretty closely related to each other. So I'm answering both today. I've never thought about it honestly So yeah first

Like what is the purpose of blood Okay so humans And this is true of basically all mammals too Use our blood as a great big Transportation and Delivery System As your blood circulates It delivers oxygen It delivers hormones

It helps regulate heat and hydration And you might remember this from like schoolhouse rock Succulation takes nutrition To yourself Gets rid of Common Diles What a bob. It's very upbeat. I'm kind of like catchy. I was in Schoolhouse Rock Live twice as a child. Anyway.

So circulation, it's out of sight, but it's like really important nonetheless. Absolutely. And the thing about the human circulatory system, part of the reason that it can do this so quickly and effectively, is because it's a closed and pressurized system, right? All that blood movement is being powered by your heart. Okay. Well, insects too or no? No. Because insects, their circulatory systems are open. With insects is different. Their heart is a long tube that goes the length of the body.

It goes from one extreme to the other, all the way from the head to the very tip of the abdomen. That's Julian Hillier from Vanderbilt University. He's a biological scientist who researches mosquitoes and other insects. And it is their only primary vessel. It's an open body cavity. It's an open system where the fluid is just kind of sloshing around until it can make its way back into the heart. So that's true of cockroaches, too.

The fluid's just like sloshing around. Yep. Just like, just like whoosh. And it's true of basically all insects. Okay. Hulian says the other big difference between insects and humans is the actual liquid that's circulating. That's because humans, we have three main types of liquid in our bodies.

We have blood, we have interstitial fluid, and we have lymph. Insects don't have those three this. Insects only have one kind of fluid in their body. This multipurpose fluid in insect's bodies is called hemolymph. Their hemolymph is usually yellowish. However, if hemolymph becomes exposed to air, it oxidizes, and you have a chemical reaction called melanization, and it starts turning black. Which is why when you squish a cockroach, it sometimes looks like it's bleeding yellow,

And sometimes looks like it's bleeding black. Yeah, that's great. Yeah, shout out to five-year-olds for asking the real questions. Yeah? Hannah Chin, the one and only. Thank you, Hannah. Okay, keeping on the biology theme, we've got producer Jessica Young here to answer more questions. Hi, guys.

Hey, Jess. Hey. Okay, so the questions I tackled all had to do with plant science. And a good number, I would say, really focused on plant growth. Excellent. My name is Gila. I live in California. How do branches get bigger?

How do plants grow? My name is Nick and I live in the reading, Anna. How do limbs on trees pop up in the first place? That was how do limbs on trees pop up in the first place, which, you know, such a valid question. I agree. I have no idea. I mean, so I talked to a few botanists around the world about this, and I think we can really answer these questions. together, starting with how they grow, which is basically mostly other tips.

They're not like adding from the bottom or anything like that. This is Alika Borsick, an assistant curator of eco-physiology at the New York Botanical Garden. If you were to write your initials or a love note in the bark of a tree, it wouldn't move up through the years. It would still be in the exact location relative to the ground. Oh, that's true. I've never thought about it. How does that happen, though? Yeah. So at the tips of plants, there are a lot of what are called merestimatic cells that remain undifferentiated, which means basically that they can become anything that the plant needs. So like merestimatic is like stem cells in humans, but like for plants. Exactly.

Okay. Cool. I talked to Alina Ferri Fierro about this. She's a botanist in Amazonian Ecuador, and she explained to me how as the plant ages, these cells at the tips, divide into two more cells. This tissue, it divides into undifferentiated tissue and into a tissue that would become later a leaf, a flower. A branch? Yes, exactly. So whatever it needs to thrive to take up more space, to get more sunlight, while also making more undifferentiated tissue to continue the growth process. This sounds really, really cool. I'm learning so much about plants.

No, totally. Me too. Like another really cool thing that they were telling me about is that at the very tip of these plants, they produce a lot of this hormone called oxen. Plants basically produce oxen to control growth so they don't just branch nonstop. So when you're like pruning a plant, you're cutting the tip and getting rid of that hormone maximum of oxen so that the plant is then free to branch out. Cool. Which is why if you think about how a tree grows, it grows up vertically towards the sky first. And on its sides, there are these little buds ready to turn into branches.

And initially, they're being stopped by the oxen at the very tip top of the tree. But as the tree grows taller and taller, then these branches are free to emerge because they're further away from the hormone. That's so cool. Totally. And another cool branching thing is that, like, Alica was telling me that branching also happens in a very specific pattern to prevent upper branches from stealing sunlight from lower branches. So plants are actually surprisingly good at math, if you will. And so the location of each leaf or branch or petal that develops will be offset just a little bit by the golden ratio. So that when you have the full organism, all of the things that need sunlight are like optimally arranged. I'll tell you what. Trees out here being the best mathematicians among them all.

I know. I think it's so amazing. Yeah. Thank you, Jess. Plants are amazing. Okay, so next up is Rachel Carlson, our West Coast producer. Rachel, you looked into some questions about the Earth itself. Hi, guys. Hi, Rachel. Okay, so one of our ocean questions was from a listener named Fiona. My question is, how were the oceans made?

Wow, I have no idea. How are they made? There's kind of some debate about it. So to help answer, I called up Ruth Blake, a professor of Earth and Planetary Sciences at Yale University. She told me, The first oceans were actually not water oceans. They were lava oceans. Because early in Earth's history, it was completely molten.

So picture the Earth covered in magma about four and a half billion years ago, ish. Yeah, the moon, too, was covered in this, like, magma ocean. Gina loves magma, just so everyone knows. But to answer Fiona's question, and scientists aren't actually really sure yet. But they do have some theories. Some think that volcanoes may have expelled gases from the inside of the earth, so it's like water vapor.

And eventually, they think that vapor condensed and rained back down as water forming our oceans. So cool. So cool. Others think maybe water came to Earth as ice and things like comets and meteorites. I mean, there is that big debate. Like, where did our water come from?

It could have come from space. Exactly, Gina. Which brings me to another listener's question. Lionel, who we heard from before, asked... How did the earth become alive? I talked to a couple different scientists, and they told me, again, the very fast answer is, we don't know.

Yeah, we don't. So, Lionel, it turns out this is a really, really good question. And like Fiona's, it's actually a really hard one to answer. I've run into this in my reporting, too. It's one of the hardest questions. But we know. We know that living things need some. basic ingredients. Water,

carbon, nitrogen, some kind of energy, like lightning or heat, or sunlight. Yeah, I mean, the light that we know on Earth, that's what they need. I know from, like, you know, my astronomy days that, like, comets and asteroids hitting the earth, like those impacts probably kept large amount of water and some of those molecules from forming, actually, in the beginning. Exactly. But a little less than $4 billion or so years ago, something happened that helped all of these ingredients start to combine into the recipe for these building blocks of life that we know today. Some scientists think this had to do with these really big collisions from comets and asteroids like we talked about before that basically

delivered these water and carbon molecules to Earth. Other scientists think these reactions happened in hydrothermal vents deep in the oceans. Yes, I also believe that. Or maybe even on the surface of rocks. But again, a lot of this we really just don't know. So Lionel and Theona, maybe you two can become scientists and then come back on shortwave and help us figure it out one day. Please, please do that. Thanks, Rachel. I'm glad you brought up space because we got so many space questions.

I'm going to give them all to Gina. Yeah. Our resident astrophysicist, Hamza in Michigan, had a question for you, Gina. What will happen if I've done from a billion? feet. Okay, to answer Homs's question, what would happen if I jumped from a billion feet? I called it my friend from grad school, James Davenport, because after doing a little bit of math, I realized that the moon is just a little over a billion feet away from Earth. And James is an astronomy research professor at the University of Washington in Seattle, so he studies space. So if you're on the moon, a billion feet from Earth and you jumped toward the Earth, would you just fall back to the moon?

Yeah, I asked him that, right? And he said... You would just land back down on the moon. Because the gravity, yeah. Even though the moon's gravity is really low, there's no way you could actually jump off the moon. You know, you would have to use a small rocket. But M, the thing I love about this question is that there's not just, like, one answer, right? So, like, say you're, like, far from Earth, like, not on the moon, but just, like, floating in space, and you perfectly jumped in the same direction the moon is going, you'd go.

to orbit around Earth. And so if you were able to jump in just the right direction, you actually might be temporarily a little mini moon. Okay. Our last space question is from Gavin in Ontario, Canada. Here's my question. And what happens at the end of space? What happens at the end of space?

Okay. I love this question. I was asked this all the time when I was teaching astronomy. And it's a trickier one. So first of all, most scientists think that there is no physical end of space. If you go a billion light years away, you'll just see more and more universe. You'll never reach the end. But?

There is definitely an edge that we can see. And that's determined by how old the universe is. Okay, so the further we see out in space, the further back in time we're seeing. Yes. So, like, think about the nearest star to our sun. That's Proxima Centauri. It's just over four light years away. So that means to travel from there to here, it took light four years.

And that means we're seeing what Proxima Centauri looked like four years ago. Yeah. And so what's even cooler is when I studied astronomy, I looked at galaxies that are hundreds of millions of light years away. Wow. So I'm not looking at what those galaxies look like now. Oh, right. It's like a time machine. You're seeing how those galaxies looked hundreds of millions of years ago.

Right. Because the universe is over 13 billion years old, right? So that's the time the images the new James Webb Space Telescope is taking pictures of. So to answer Gavin's question, what happens at the end of space? The beginning of time. Well, we have ended at the beginning of time. And we have to answer the question from the beginning of our episode from Lily in Hawaii is Magic Real. We've all the producers back.

What do we think? Hannah? Rachel, Jess. I mean, there was a time when a lot of this stuff out in the world making slime or trees growing, basically everything in outer space, all that seemed like magic. Truly. But because of science, we know how a lot of this stuff actually works. And there's still a lot more mysteries out there that scientists are trying to figure out. So, like, if magic was science in the past and science is real, then it's kind of like magic is real.

Special thanks to everyone who has ever helped create shortwave. This includes past shortwave staff members, interns, and fact checkers, everyone on the science and climate desks. And PR audio engineers who have helped us fix everything. our families, all of our brilliant guests, you are listeners. It's all for you, our listeners. You are the reason we make this show. Your curiosity inspires us. And we hope you'll join us for another five years of new discoveries, everyday mysteries,

and the science behind the headlines. I'm Emily Kwong. And I'm Regina Barber. Thank you, as always, for listening to Surewave from NPR.