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Ask Dr. Universe Technology, Engineering, Math
University Communications Network > Ask Dr. Universe > Technology, Engineering, Math

Why do glow-in-the-dark things light up when it’s dark? – Haygarth, 5, United Kingdom

Dear Haygarth,

I love glow-in-the-dark stickers. I leave them next to a sunny window for a little while. Then turn off the lights and watch them glow.

I asked my friend Hergen Eilers how those stickers work. He’s a physicist at Washington State University.

He told me that glow-in-the-dark things use a type of phosphorescence. That means they absorb energy—like light—and then glow. A material that can do that is called a phosphor.

Glowing in the dark works because of electrons.

Everything in the universe is made of atoms. That includes you, me, whatever you’re reading this note on—and glow-in-the-dark stickers.

All those … » More …

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How many atoms are in a leaf? – Lily, 8, Georgia

Dear Lily,

I love thinking about things I can’t see with just my eyes. Like the atoms that make up everything.

I asked my friend Fred Gittes how to figure out the number of atoms in a leaf. He’s a physicist at Washington State University.

He showed me a worksheet he gives his students. It included a question exactly like yours!

“It’s a question I assign college students for fun,” Gittes said.

So, you’re in great company when you ponder big questions like this.

We decided to use stoichiometry to find the answer. That’s a kind of math that scientists do to understand chemical reactions.

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How is ice cream made? - Israel, 7

Dear Israel,

It just so happens that July is National Ice Cream Month. To celebrate, I decided to whip up some homemade ice cream. You can try it at home, too.

Put milk, sugar and vanilla into a freezer bag and seal it up tight. Fill another gallon freezer bag with ice and rock salt. Place the liquid mix bag inside the bag of ice and give it a good long shake. Some scientists might call this part "agitating." After five minutes or so, you'll notice the liquid mix in your bag becomes solid. Then you can dig in with a spoon.

After making my own homemade tuna-flavored ice cream, I decided to take a trip to the Washington State University Creamery to see how the professionals make ice cream for Ferdinand's Ice Cream Shoppe.

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What is pi? – Johsan, 10, Alabama

Dear Johsan,

One of my favorite holidays is Pi Day. On March 14, people who love the math constant called pi celebrate by eating the other kind of pie. Like apple pie, pumpkin pie and even pizza pie.

I talked about the number pi with my friend Kristin Lesseig. She studies how kids learn math.

She told me pi is the ratio between the distance around a circle and the distance across a circle. A ratio is the relationship between two numbers. We usually think of pi as about 3.14—but there’s more to it than that.

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What do robots eat? Why do they have mouths if they don’t eat food? – Oliver, 4, Virginia

Dear Oliver,

I just scarfed down tuna with a side of kibble. That’s how I get the energy I need to investigate your questions.

To do that, I talked with Ming Luo. He’s a robotics scientist at Washington State University.

He told me that robots don’t eat like we do.

“A human has a digestive system,” Luo said. “That’s how food can be converted to energy. But a robot can’t do that. The robot can just take in energy directly.”

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Why don't birds get electrocuted when they sit on power lines? – Angel, 14, California

Dear Angel,

I’ve never sat on a power line. I like to keep my paws firmly on the ground. But birds love resting there, especially in winter. Power lines give off a little heat, so it’s a good spot for birds to snuggle together and stay warm.

I talked about how they do that safely with my friend Javier Guerrero. He’s a professor of electrical and computer engineering at Washington State University.

He told me birds do get electrocuted on power lines sometimes. But that won’t happen if the bird touches just the power line—and doesn’t touch other lines or the pole at the same time.

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How is inflation caused? – Raymond, 12, California

Dear Raymond,

When I reached out to my friend Christopher Clarke with your question, he said, “That’s so cool that a kid is asking about inflation!” I agree.

Clarke is an economics professor at Washington State University. He told me inflation is the average rise in prices for goods and services.

So, what are goods and services? Let’s say you go to a restaurant and order enchiladas. The enchiladas are goods. You can see them, touch them and taste them. Services are the other parts of your dining experience. The people who take your order, cook your food and wash your dishes are all providing services.

The price you pay for goods and services changes over time.

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Dr. Universe: How does electrical power travel through metal? - Gabriel, 4, Illinois

When you watch the zapping bolts during a lightning storm, you know how powerful electricity is. Humans have only been harnessing electricity to bring light and energy to our towns and homes for about 150 years—and metal is one of the main ways we get this powerful tool from place to place. To learn more, I talked to my friend Bob Olsen, a professor emeritus in the Washington State University School of Electrical Engineering and Computer Science. Olsen said it’s important to realize that we don’t need metal wires to move the waves that carry electricity, which are called electromagnetic waves. Some technologies, like cell phones, pick up waves that are sent through the air. Read More ...

Dr. Universe: Why does oil on the street look like a rainbow? -Jorgos, 10, Bothell, WA

When it rains, sometimes we can see oil on the street rise to the top of puddles and spread out into a rainbow of colors. One of the main reasons we see color is because of light, said my friend Cigdem Capan, a physics instructor at Washington State University. She reminded me that when our eyes sense colors, we can trace those colors back to different wavelengths of light. Perhaps you can make some waves in the air with your hand. Make small, tight waves. Now make a big, wide waves. Read More ...

Dr. Universe: Can a shadow make a shadow? – Aven, 7, Palouse, WA

Dear Aven, When we look around our world, we can find all kinds of shadows. One way we can explore the answer to your shadow question is with a little experiment. My friend Anya Rasmussen, a physics professor at Washington State University, told me all about it. First, you will need to cast your shadow on a wall. Rasmussen reminded me shadows form when an object—such as your body— blocks light and keeps the rays from reaching a surface—like a wall. Read More ...

Dr. Universe: How many black holes are in the galaxy and the universe? -Krisha, 9, New Jersey

Dear Krisha, While we can’t see black holes with our eyes, astronomers have figured out how to spot these objects in our universe. One astronomer who is really curious about understanding black holes is my friend Sukanta Bose, a researcher at Washington State University. First, he told me there are different kinds of black holes. Supermassive black holes can be millions to billions of times the mass of the Sun. We have a supermassive black hole in our own Milky Way galaxy called Sagittarius A*, which is pronounced as Sagittarius A-star. Read More ...

Dr. Universe: How do people stain glass to make it all the colors it can be? - Emily, 10, Edmonds, WA

Dear Emily, Ever since humans discovered they could use sand to make glass, they’ve been experimenting with it. They even learned how to control the colors. My friend Dustin Regul is a stained glass artist and painter who teaches fine arts at Washington State University. He told me more about where glass gets its color. “It’s actually metals that help change the color of the glass,” he said. Read More ...

Dr. Universe: Why does the internet go down? -Mia, 11, Sheridan, Wyoming

The internet has helped many people connect with classmates, friends and family during the pandemic. But you’re right, sometimes the connection gets lost. My friend Dingwen Tao, an assistant professor of computer science at Washington State University, said we can think about the internet like a highway of information. You may remember from our question about how the internet works that information, like the data that makes up your favorite cat video or science website, travels through electronic signals we cannot see with our eyes. Read More ...

Dr. Universe: Do robots have their own language? And is there a translator? - Hank, 8, Virginia

Robots do have their own language—and yes, there’s a translator. That’s what I found out from my friend Manoj Karkee, an engineer at Washington State University who is also really curious about robots. Karkee and his team work on lots of robots that help farmers do important jobs. They can program robots to do different tasks such as pick apples or pull weeds. Read More ...

Dr. Universe: How are coins made? -Dahlia, 10, Olympia, WA

In the United States, pennies, nickels, dimes, quarters, and other coins are made through the U.S. Mint. It turns out, they’ve been making a lot more coins than usual during the global pandemic. But more on that in a moment. It takes both science and art to make coins. Coins are made from metals that have been mixed together. We call these kinds of metals alloys. The very first coins in the world were made thousands of years ago in Turkey from electrum, an alloy of gold and silver. A penny is made from an alloy of copper and zinc. Read More ...

Dr. Universe: Why does soap get bubbly? Samuel, 9, East Peoria, IL

When you wash your hands with soap and water, a few different things happen to make bubbles. Just like you, water and soap are made up of parts called molecules. Water molecules really like to stick together. If you’ve ever jumped in a puddle or a pool, you may have even observed how water splashes in the shape of little drops. As water sticks together, it likes to form spheres. Read More ...

How does the Internet actually work? I know you can type in most anything and it just pops up and all that, but how? - Eden, 8, Oregon

Dear Eden,

If you wrote me a physical letter, it would take a few days to reach me. You put the letter in your mailbox. A postal worker picks it up. Then it travels between different post offices on its journey from you to me.

But within seconds of you sending this question over the Internet, it was sitting in my inbox. How can this be?

The whole Internet works like the mail system—but much faster. That’s what I learned from Adam Hahn, an Assistant Professor of Computer Science at Washington State University.

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How do you make submarines? - Luke, 5, Western Washington

Dear Luke,

The next time you’re in the bathtub, turn a cup upside down on the water. Push down on it as hard as you can. See if you can get it to sink below the water.

It’ll be difficult to do! The air inside the cup makes it lighter than the water. But what happens if you turn the cup on its side, allowing water to rush in? You’ll see it’s easier to push underwater.

Those same basic forces make a submarine work.

That’s what I learned from Ian Richardson, an engineer at Washington State University. He is very curious about how liquids and solids interact. He has even helped NASA work on a submarine to someday go to Titan, one of Saturn’s moons.

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Dr. Universe: Why does the wind blow? -Odin, 7, Mt. Vernon, Wash.

Dear Odin,

When the wind blows, it can do all kinds of things. It can help pick up tiny seeds and carry them away, so plants and flowers can grow in new places. It can push a big sailboat across an ocean. We can even harness the wind to make clean energy to power our homes and schools.

That’s what I found out from my friend Gordon Taub, an engineer at Washington State University. He is very curious about wind energy and told me more about why the wind blows.

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Dr. Universe: What’s the best story ever made in the world? – Jada, 13, New Jersey

Humans have been telling stories for thousands of years. At first, they told these stories out loud, then they started to write. There are more than a hundred million published books on our planet now and to find out which one is best, I visited my friend Matthew Jockers. He’s a professor at Washington State University who combines his love of stories with computer science to research what makes some books bestsellers. Read More ...

Dr. Universe: Back when cell phones weren’t a thing, how could you place a call from across the ocean? Were there wires under the ocean? -Tali, 9, Seattle, Wash.

Long before telephones, if you wanted to say “hi” to friend across the ocean you’d probably write them a letter and send it over on a ship. But in the last hundred years or so, we’ve been able to connect across the ocean much faster. And yes, it often required thousands of miles of wires, or cables, deep in the sea. That’s what I found out from my friend Bob Olsen, a professor of electrical engineering at Washington State University, who told me all about the telephone. Read More ...

Dr. Universe: How many peas would fit in the sun? -Keegan, 8

Our sun is so massive, you could fit more than one million earths inside of it. To find out how many peas would fit inside the biggest object in our solar system, I decided to ask my friend and mathematician Kimberly Vincent at Washington State University. Vincent and her students said that to figure out how much of something can fit inside the sun, we need to know the volume of the sun. The volume is how much space something takes up. Read More ...

Dr. Universe: Why do gadgets need batteries? How do they work? -Shereen and Jasmine, 8, Florida

Dear Shereen and Jasmine, Batteries can power up all kinds of gadgets. To find out how batteries work, I decided to visit my friend and materials engineer Min-Kyu Song. He makes batteries in his lab at Washington State University. As you might know, materials are made up of atoms—and atoms have tiny parts called electrons. If you’ve ever felt a spark when you touched a doorknob, you’ve felt electrons making the jump from your body to the door. Read More ...

Dear Dr. Universe: What do planets have inside? -Rhianna, 10, Calif.

Dear Rhianna,

Each planet is a little different on the inside. And what’s inside a planet can shape what’s on the outside, too. That’s what I found out from my friend Steve Reidel, a geologist at Washington State University.

“Well, there’s the rocky planets,” he said. “Then there are the big, gas giants.”

Rocky planets, like Earth, are wrapped in a thick crust. Beneath Earth’s crust is the mantle. The mantle is quite solid, but it actually behaves more like a fluid. It flows and deforms. It’s similar to Silly Putty, but a really strong version of Silly Putty. It’s about 1,800 miles thick. It is also the main source of Earth’s volcanoes.

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Dr. Universe: I have a ginormous question for you. How come non-biodegradables take like a million, billion, zillion years to decay? -Madeline C., age 8

Dear Madeline,

You’re right. It can take a really long time for some things to decay.

If we buried an apple peel in the backyard it might only take a few weeks to break down into the soil. But if we buried a plastic water bottle, it would probably still be there hundreds of years from now.

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What is the Kuiper Belt? -Zaara A., 7, Deep Bay, Australia 

Dear Zaara,

You might say the Kuiper Belt is the frozen frontier of our solar system. Out beyond Neptune’s chilly orbit, this saucer-shaped region is home to Pluto, billions of comets, and other icy worlds.

“The Kuiper Belt is really the edge of knowledge,” said my friend and astronomy professor Guy Worthey when we met up in the Washington State University planetarium.

“Out there it’s a little dim,” Worthey said. “We are pretty far from the Sun.”

In fact, it’s about 3 billion miles away. Even at the speed of a jet airplane, it would take more than 680 years to travel from Earth … » More …

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Why is Pi 3.1415...? What if it was just 3? -anonymous

Dear Curious Readers,

It’s almost March 14. You know what that means: Pi Day, as in 3/14, or 3.14159265359 and so on.

I met up with my friend Nathan Hamlin, a mathematician and instructor here at Washington State University, to explore your question about this never-ending number.

We calculated Pi with some of my favorite items: yarn and a tuna can. You can try it at home, too.

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Why do bees make hexagons in their hives? Why not any other shape? -Aditya, 10, New Delhi, India

Dear Aditya,

When bees make hexagons in their hives, the six-sided shapes fit together perfectly. In fact, we’ve actually never seen bees make any other shape. That’s what I found out when I visited my friend Sue Cobey, a bee researcher at Washington State University.

Cobey showed me some honeycombs where the female bees live and work. Hexagons are useful shapes. They can hold the queen bee’s eggs and store the pollen and honey the worker bees bring to the hive.

When you think about it, making circles wouldn’t work too well. It would leave gaps in the honeycomb. The worker bees could use triangles or squares for storage. Those wouldn’t leave gaps. But the hexagon is the strongest, most useful shape.

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Dear Dr. Universe, Please answer this question: Do animals dream? What dreams do they get? I humbly request you to answer these questions. BYE! Or should I say MEOWY! -Prahlad R.

Dear Prahlad,

After a quick catnap and a stretch, I went to visit my friend Marcos Frank, a scientist at Washington State University who studies animal sleep.

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Dear Dr. Universe: I want to know how my family car works. How does the gas reach the engine and go? How does the steering wheel make the car turn and how do the brakes help us to stop? -Jordan, 6, Queens, New York 

Dear Jordan,

As a cat, car rides can sometimes make me feisty. But as a scientist, it’s fascinating to learn about the mechanics, engineering, and chemistry fueling the cars humans drive every day.

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Dr. Universe, How are magnets made? -Andrea, 8, Berkeley, CA 

                                                                                   

Dear Andrea,

When I saw your question, I headed straight for the Magnetics Lab and met up with my friend John McCloy. I found out the word “magnet” comes from a Greek word for the region of modern-day Turkey we once called Magnesia. That’s where people found magnets in nature.

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Dr. Universe: Are aliens real? -Lily, 10, New York City, NY Is there life on other planets? -Heidi, Cincinnati, OH 

Dear Lily and Heidi,

Well, we don’t know for certain. Looking up to the stars at night, I’ve often wondered if alien cats are out chasing alien mice or taking naps on other planets.

My imagination aside, your questions are like those scientists are asking, too. And it’s no wonder we are so curious.

With billions of planets in our galaxy, including small Earth-like worlds, the possibility of life out there is an exciting thought to many people. So, humans have set out to look for planets that might support life.

In fact, this month scientists announced the Kepler spacecraft’s discovery of … » More …

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Dr. Universe: What materials would you use to make a rocket -Freya, Scotland

Dear Freya,

Whether it’s a model rocket you build in the backyard or one that launches a space shuttle, there are lots of materials you could use. So, when I saw your question I grabbed my lab coat and safety goggles, and zoomed over to my friend Jake Leachman’s lab. He’s a rocket scientist and engineer at Washington State University.

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How do I make a diary?  -Nimra, Kitchener, Ontario

Dear Diary,

Oh, I mean...Dear Nimra,

Making a diary is like creating your own top-secret book. So, I headed straight for a Washington State University library where there are more than a million books.

My friend Linnea Nelson was working with some of the books from the special collections when I went to visit her in the lab. She is a conservator, so part of her job is to repair and re-build old books. It preserves their history.

Some of the books had an old smell that wafted up into my little nose. The smell comes from different chemical compounds that escape into the air, including one similar to vanilla. The compounds are in the ink, paper, and other materials used to keep the pages together. And one way to keep the pages together is to bind them with thread. 

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Will electricity ever run out?  -Zoe, WA

Dear Zoe,

Scientists could see and feel electricity in nature long before they discovered how to make it. Maybe you’ve seen it during a powerful electrical storm or felt a little shock from static electricity.

It happens because of tiny parts of atoms. They’re called electrons and they are everywhere.

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Why are ripe fruits sweet and why is it so important?  -Alexa, Schenzhen, China

Dear Alexa,

My friend Kate Evans said the answer really depends on whether you want the perspective of a person, a plant, or even a cat. Evans is a plant scientist at Washington State University in Wenatchee, where she investigates fruit in the Apple Capital of the World.

She explained how long ago, wild apples actually grew in forests. Without farmers around to plant them in orchards, trees had to scatter their own seeds to survive.

For some trees, the key to survival is growing sweet, ripe fruit.

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Can you grow stuff like thread, cloth, silk, and most importantly, clothing? -Jay, Colorado

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Dear Jay,

We can use all kinds of animal, bug, and plant materials to make cloth. Even some of the tiniest living things on the planet can make cloth, too.

I heard about this from my friend Hang Liu, a Washington State University professor who studies the science of materials we use and wear every day.

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What if gravity pulled up, instead of down? -Kyle, Cedar Lake, IN

Our universe would look so different, Kyle. You might not recognize it even if you could be here to see it. Unfortunately, there probably wouldn’t be a whole lot to see. I learned about this from Washington State University professor and physicist Matthew McCluskey, who studies the material world. He explained how gravity pulls together dust, gas, and little particles floating around space to make massive clumps of matter that form stars and planets. For example: planet Earth. Every particle in the Earth is pulling on you at this very moment--every single one. Read More ...