
But Why: A Podcast for Curious Kids
But Why is a show led by kids. They ask the questions and we find the answers. It’s a big interesting world out there. On But Why, we tackle topics large and small, about nature, words, even the end of the world. Know a kid with a question? Record it with a smartphone. Be sure to include your kid's first name, age, and town and send the recording to questions@butwhykids.org!
Latest episodes

May 21, 2021 • 21min
How Are Words Added To The Dictionary?
Our guest this week is a lexicographer. That's someone who studies words and, in this case, edits dictionaries. Emily Brewster is a senior editor at Merriam-Webster and host of the podcast Word Matters.
Emily answers a question from 8-year-old Emma in Kentucky, who wants to know how words are added to the dictionary. But before we can answer that, we'll tackle 7-year-old Julia's question, "How are new words created?" Join us for an episode about how words are created, when they've reached a critical level of use to get their own dictionary entry, and when words are removed from the dictionary. Get ready for some word nerdery!
Download our learning guides: PDF | Google Slide | Transcript
More Word Episodes:
Who Invented Words?
But Why Live: Words and Language
Why Are Some Words ‘Bad’?
"How do words get added to the dictionary?" - Emma, 8, Kentucky
Lexicographers like Emily Brewster read and listen a lot and pay attention to the new words that people are using. They collect these examples and determine how many instances there are of the word and what different kinds of sources are using the word.
"If all the examples are only appearing on TikTok, then that tells us one thing about the word. But as soon as they're also appearing in, you know, a magazine that you would see at the dentist's office, then that tells us something else about the word's status," Emily explains. "So we are always looking for information, for evidence, of how words are being used by the people who speak the English language. And when we have enough evidence that the word is really part of the language, that it's a word that most people already will recognize when they hear it, that's when we know that it's ready to be added to the dictionary."
For example, the word COVID-19 was a word created by the World Health Organization about a year and a half ago. "It got into our dictionary faster than any other word in the history of the dictionary has ever been added. Because what we knew immediately was that this word was not going away, that everybody was talking about this word," Emily says.
Sometimes dictionary editors update the definition of words that were already included. For example, the definitions of "pod" and "bubble" were updated this past January to include a new meaning: people you might have grouped up with when you weren't seeing other people because of the pandemic.
Other new words recently added to the dictionary include: "makerspace," where people get together in a common area and often share tools to make their own projects; "BIPOC," an abbreviation for Black, Indigenous and People of Color; and "second gentleman," in reference to Vice President Kamala Harris's husband.
Once it's been established that a word is in widespread use, an editor will carefully read through evidence of the word in use and formulate a meaning in very careful language. Another editor will determine how old a word is and its earliest usage, another will look at the word's history, and the word will get a pronunciation. Then it's ready to be added to the dictionary.
Merriam-Webster updates their online dictionary with new words or new definitions of words a few times a year. Emily says words don't usually get taken out of dictionaries, but editors do make choices about which words appear in print dictionaries.
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May 7, 2021 • 28min
How Do You Whistle?
How do people whistle? How does whistling make a sound? Why does your tongue change a whistle higher or lower? Can you get a trophy for whistling? Can people with laryngitis whistle? Get ready, we learn all about whistling with musician and champion whistler Emily Eagen and musician Yuki Takeda. And who whistles our theme song? We'll hear from musician Luke Reynolds, and a kid whistling chorus from our listeners!
Download our learning guides: PDF | Google Slide | Transcript
How do you whistle? - Aurelia, 6, New York
Emily says the first thing you should do is lick your lips or use lip balm. "If your lips are dry when the air passes it doesn't feel good," she says. Then you'll make your lips kind of into a pucker, circle your lips tightly.
Next, stick your tongue touching your bottom teeth. Then you make kind of a yuh, yuh, yuh sound. "But instead of saying the words, make it with a little stream of air. You want to let air pass over the top of your tongue and out your lips. You're making a tiny little instrument by curling your tongue."
"I like to think about between your nose and your lips, that's a little body part called a philtrum. I like to pretend that my whistle is coming out of that. That helps me make the sound have a little focal point," she says.
Emily says it helps to make little sounds when you practice. "Pretend your sipping tea with that little tiny space there. You don't want to push too much. If you blow too much air it won't work. You have to be really gentle."
Once you find your first whistle, it's all about practice and playing around to see what sounds you can make.
"If you move your tongue forward, the notes go up, and if you move your tongue down, the notes go down," she says. If you can make a variety of notes, then you can start putting them together to make music!

Apr 23, 2021 • 36min
How Are Rocks Formed?
How are rocks made? Why are some rocks hard and others soft? How do rocks shine? How are geodes and crystals made? Why do some rocks have gems in them? Answers to your rock questions with Hendratta Ali, rock doctor! Ali is a geologist who studies and teaches at Fort Hays State University in Kansas.
Download our learning guides: PDF | Google Slide | Transcript

Apr 9, 2021 • 17min
Ethics: Is It OK To Break A Rule?
Is it OK to do something that you were told not to do and then never tell anybody? In this episode we tackle that thorny question from 10-year-old Finn from Seattle. We'll also wrestle with the question, "Why do people make really bad choices and want other people's lives to be harder?"
Download our learning guides: PDF | Google Slide | Transcript
We're tackling some ethical dilemmas in this episode and we're letting kids give the answers! We also get a response from ABC Radio's Short & Curly, a podcast devoted to ethics for kids.
Here's how some of our young listeners answer the question about whether it's ever okay to break a rule and lying about it:
"No, because it usually just means you get in trouble." - Juniper
"I think so. If you're protecting somebody or keeping a surprise." - Camille
"It depends who told you. Like if your parents told you, then you shouldn't do it. Or if you do it, you should tell them you did it. But if it's like a mean person you met on the street it's ok. And it depends what it is. Because if it's a bad question, you shouldn't do it either way if it's a bad thing. If it's a good deed you should do it. And if you did that, why wouldn't you tell anyone?" -Sylvie
"No, not really. If you don't tell anyone about it. It's mostly the doing it and then not telling anybody about it. Mostly what isn't the good thing about it. It's a little bit worse, if you don't tell someone you might get a feeling where you feel kind of embarrassed. And you don't tell anybody and it just sticks with you the rest of your life." - Piper

Mar 26, 2021 • 23min
Why Do We Compete?
Have you ever felt competitive with a friend or a sibling? Competition comes up in a lot of different ways in life. Maybe you're running a race with a friend and you want to beat them! Maybe you're trying to play a song without making a mistake and you're competing against yourself.
Sometimes competition feels good and fun. It can make you want to do better, and make a game more enjoyable. But not always. Sometimes competition feels bad. Like it's too much pressure, or takes away from the fun of being with your friends. Some people really don't like competition at all.
3-year-old Kai from Tokyo, Japan asks: "Why do we need to compete with other people, especially friends, for example on a sports day or at gym class?"
In this episode we discuss competition with anthropologist Niko Besnier. And we'll hear from 12-year-old Harini Logan, a competitive speller from San Antonio, Texas, and 10-year-old Del Guilmette, an athlete from Monkton, Vermont.
Download our learning guides: PDF | Google Slide | Transcript
We put Kai's question to Niko Besnier, anthropologist at the University of Amsterdam. One of his books is called The Anthropology of Sport, written with Susan Brownell and Thomas F. Carter. He says there are two reasons that people take part in competitions:
"One is that sports are fun. It's fun to play with your friends and classmates, to run, jump, play ball. We've all experienced this rush of pleasure and fun doing these things. But the other aspect that's contradictory to the fun part is that it enables us to measure our strength, our speed, our physical ability against those of other people. It's the competition part of sport, and competition can become extremely serious. Frequently, the fun part of sport gets lost."
Besnier says when competition gets out of hand it can lead to hurt feelings, and on a larger scale, competition can lead to things like war and inequality.
But with the right attitude, competition, especially when we compete against ourselves, can help us get better at sports and academics.
That's how it is for Harini Logan. She's a competitive speller who has made it to the Scripps National Spelling Bee twice!
"Competition teaches you a lot, whether it's the preparation leading up to that competition or the outcome," Logan says. "It can teach you a lot about not only your abilities, but also new things that can change the way you look at life. When you're preparing for a competition you can learn how to work hard, and how not to give up on something. And during the competition you learn teamwork. That's one thing you learn in spelling bees, because you want to be with your community, your friends. One thing to learn if you win: sportsmanship! You don't gloat about it, you still appreciate yourself but you don't overdo it so others don't feel bad. And if you don't win it doesn't matter. [You just say:] I'm going to try harder next time."
Competing also helps us get better. That's how 10-year-old Del Guilmette views it. He likes to play against tough teams when he plays sports, because that's how you get better.
"The best players at the game, whatever sport it is, they didn't get better because they played teams that they knew they were going to beat. They played those teams that were better than them. They got better and they practiced!"
Listen to the full episode to hear more about how these mature young competitors think about the value of competition.

Mar 12, 2021 • 27min
Why Are Mammoths Extinct?
In the ice age, megafauna roamed North America: mammoths, saber-toothed cats, even giant land sloths! What happened to them? In this episode we answer questions about the ice age: What was it? Did birds live during that time period? How about giraffes? Did people live with woolly mammoths? Why did mammoths go extinct? We'll answer your questions with Ross MacPhee, senior curator at the American Museum of Natural History and author of End of Megafauna: The Fate of the World's Hugest, Fiercest, and Strangest Animals. And we'll hear from Nathaniel Kitchel, a Dartmouth researcher who used carbon dating to discover the age of a mammoth rib. Plus, John Moody, of the Winter Center for Indigenous Traditions in Norwich, Vermont, on how mammoths appear in the oral history of the Abenaki people.
Download our learning guides: PDF | Google Slide | Transcript
"What was the ice age?" -Karen, 5, Wilmington, Delaware
In the Pleistocene era, which lasted from 120,000 years ago to 15,000 years ago, ice covered the landscape in much of the northern hemisphere. Ice covered all of Canada down into the Northern United States and all of northern Europe. And there were smaller ice sheets in Russia. How did this happen? Scientists think it was a buildup of ice over time.
"The theory is that the winter never ended," explained Ross MacPhee. "You would have snowfalls in the winter and it never really got warm enough to get rid of it completely. The next year that would be built on, built on and built on. And the thing about snow is that it kind of makes its own weather. If you have snow it gets very cold! And that preserves the snow pack for a very long time."
The weight of that snow would compact into ice, eventually covering parts of the world in great sheets of ice. It might help to think of the process as a little bit like what happens when you have a favorite sledding hill: the snow is light and fluffy when you start, but if you sled down it enough times (and walk up the hill, too), eventually the paths get icy from the footsteps and sleds continually packing the snow down.
It wasn't just ice sheets that were a feature of the ice age. All of that water caught up in the ice made sea level drop 300 feet lower than it is now. That exposed lots of land that is now covered in water, including a land bridge connecting Alaska and Russia!
This land bridge allowed a number of species to move into North America from Asia, like bison. And some North American animals went into Asia, like camels and horses! Bear species traveled in both directions. Humans also used the land bridge to migrate into North America, though scientists think some early humans probably used boats too.
Mammoths also migrated over that land bridge! They originated in Asia and came into North America. But there were other species of megafauna that roam the landscape as well, like giant condors, saber toothed cats and even giant sloths.
These species went extinct at the same time as mammoths, as the ice age was ending. Listen to the episode to learn more about the theories of why so many large animals went extinct around the same time.

Feb 26, 2021 • 18min
What’s Your Idea To Clean Up The Great Pacific Garbage Patch?
In 2019, we answered a question about the Great Pacific Garbage Patch, a huge mass of plastic and other trash swirling around in the Pacific Ocean. Mary James heard that episode and was so inspired, she created a device to help clean up the plastic in the ocean. In this episode of But Why, we learn about her invention, the mermicorn!
Download our learning guides: PDF | Google Slide | Transcript
Listen back to Why Is There A Big Patch Of Garbage In the Pacific Ocean?
Kids: we'd like to know what you think could be done about all the garbage in the ocean. Download our learning guide above to draw a picture or describe an invention you would make to help clean it all up.
Mary James sent her picture of the mermicorn to the Little Inventors competition, for Canadian children. See Mary's entry here. Her invention has been chosen from among hundreds of other submissions to be turned into a prototype, a model of what the real thing might look like. There are Little Inventors competitions in the UK as well, and lots of countries and organizations sponsor design challenges for kids. See if you can find one where you live!

Feb 17, 2021 • 25min
What Are Robots Doing On Mars?
On Thursday, February 18th, a robot called a rover is expected to land on the surface of Mars, and begin collecting information scientists hope will help us learn if life ever existed on that planet! We answer your Mars questions with Mitch Schulte, NASA program scientist for the Mars 2020 mission.
Download our learning guides: PDF | Google Slide | Transcript
NASA has a number of ways that you can watch the landing live on February 18th at 11:15 a.m. PST / 2:15 p.m. EST / 19:15 UTC.
The rover is called Perseverance, which means not giving up, continuing to work toward a difficult goal even when challenges are placed in your way.
And it is quite a challenge just to get to Mars! The rover was launched on a rocket from Cape Canaveral in Florida more than 6 months ago, by NASA, the U.S. Space Agency. And it has been traveling through space ever since, on a path to Mars. And now, people all over the world are eager to watch it land on Mars and get to work.
And it’s not just Perseverance that is going to land on Mars. There’s also a helicopter, called Ingenuity, which means cleverness, creativeness and resourcefulness all rolled into one. Ingenuity, the helicopter, is basically a drone—there’s no one inside driving it around, just as there are no people onboard the rover. But ingenuity is the first helicopter to ever test-fly on another planet!

Feb 12, 2021 • 27min
Cool Beans: How Chocolate And Coffee Get Made
How is chocolate made? Why can't we eat chocolate all the time? Why is chocolate dangerous for dogs? Why do adults like coffee? In this episode, we tour Taza Chocolate in Somerville, Massachusetts to learn how chocolate goes from bean to bar. Then we visit a coffee roaster in Maine to learn about this parent-fuel that so many kids find gross! And we'll learn a little about Valentine’s Day.
Download our learning guides: PDF | Google Slides | Transcript
"How is chocolate made?" - Samarah, 8, Johnson, VT
"Chocolate actually comes from cocoa beans--which is no bean at all--they are seeds of the cacao trees," says Ayala Ben-Chaim of Taza Chocolate. Taza is a "bean-to-bar" chocolate maker. That means starting with raw cocoa beans and going all the way through the process to turn those beans into a chocolate bar you can buy in a store. (Some chocolatiers get chocolate that's already mostly made and they just add stuff to it and shape it.)
The tree that those cocoa beans come from is called the Theobroma cacao tree, which grows in warm tropical parts of the world--within 20 degrees of the equator. Taza Chocolate sources (buys) cocoa beans from farmers in the Dominican Republic, Haiti, Belize and Bolivia.
It takes about five years from when it's planted for a cacao tree to produce cocoa pods. "Cocoa pods are a little bit funny to look at. They look like a gourd growing off of the tree, or like a lumpy tiny American football. The cocoa pods grow off of the branches of the tree like apples, but they also grow right off of the trunk of the tree," Ben-Chaim explains.
"The next step in the process is fermentation. Fermentation is so important in chocolate making. And this is one of the things that is so surprising about chocolate making.
After the beans ferment, they spend a week drying in the sun on wooden planks. At this point they look like almonds. Next, they are packaged and shipped to wherever they'll be made into chocolate.
The first thing the chocolate maker will do is roast the beans at 200 degrees for about an hour, which gives them a nice toasted flavor.
"We also start to separate the thin outer shell that surrounds the inner part of the cocoa bean. Our next step is to separate that shell from the inner part of the bean, called the nib. We do this by winnowing the cocoa beans, using a machine," says Ben-Chaim.
"At Taza Chocolates we use a traditional Mexican milling style using a molino - or mill - to grind the cocoa beans down," Ben-Chaim says, demonstrating. "Over time, those cocoa nibs will be turned into a cocoa liquor, which is smooth and chocolaty. Imagine a chocolate waterfall. It looks beautiful, it smells chocolaty and delicious and yet it is not very tasty because we're missing a really important ingredient, and that is sugar."
Sugar is added to the chocolate liquor, then the sweetened chocolate is ground again, and other ingredients are sometimes added, like spices or coffee or fruit.
At this point some chocolate makers will conche the chocolate, which blends and mixes the chocolate at a high temperature over many hours, which makes it smooth and creamy. Taza doesn’t conche their chocolate. The next step is tempering. Tempering the chocolate makes it glossy and brittle. Then the chocolate is poured into molds and cooled. Then it's wrapped up and ready to take home.
Also in this episode: we visit 44 North Coffee to learn more about the mysterious beverage that so many adults like to drink--coffee!

Jan 29, 2021 • 31min
Why Are Cactuses Spiky?
What makes a cactus a cactus? And what are you supposed to call a group of these plants--cacti, cactuses, or cactus?! We'll find out in today's episode, as we learn more about the cactus family with Kimberlie McCue of the Desert Botanical Garden in Phoenix, Arizona. She'll answer kid questions about why cactuses are spiky and how they got those spikes, as well as why teddy bear cactuses aren't actually cuddly!
Download our learning Guides: PDF | Google Slide | Transcript
Those prickly spines that are so characteristic of the cactus family are actually modified leaves! Cactuses don't have the kind of leaves like a maple or oak tree. But they might have had leaves that were at least a little more like that way way back in the past. Over time, those leaves evolved into the spiky spines we see on cactuses today because they help the plants survive in hot, dry environments.
Why are cactuses spiky? -Noah, Iowa
"They can be a defense mechanism to discourage herbivores - animals that eat plants - from eating the cactus. But, also, spines create shade!" explains Kimberlie McCue.
"When you're covered in spines, as the sun moves across the sky, those spines are casting shadows on the body of the cactus. They're little shade umbrellas!"
All cactuses are native to desert environments, and some live in places where it never rains at all. So how do they get water to survive? Well, Kimberlie tells us that these plants grow not too far from the ocean.
"Early in the morning, there will be fog that comes off the water. Those spines provide a place for the water to condense, form little droplets of water that run down the spine, to the body of the plant, down to the ground and to the roots."
Cactuses are also extremely important parts of their desert environments, as they hold soil in place and provide shelter for birds and other animals. Those insects and birds in turn help pollinate the cactus flowers. Cactuses are also an important local food source for humans.
Unfortunately, cactuses are in danger from people who poach (illegally take) wild plants from their environment. Kimberlie McCue says one way to help make sure cacti stay healthy and plentiful is to be careful when you buy cactus plants. Check to see where the plant seller got the cactus and make sure they're taking care to be ethical stewards of these plants before you buy.