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Ask Dr. Universe rcwebber

Dr. Universe: What does it mean to go brain dead? – Noelle, 10, Sumner, WA

Let’s say we wanted to find out what kind of electrical activity was happening inside your brain at this very moment. Yep, you read that right: your brain is full of electricity. It actually generates enough electricity to power a lightbulb. In fact, the tiny cells in your body use electricity to send messages to each other. That’s part of what helps the brain and body communicate. I decided to visit my friend Samantha Gizerian, a neuroscientist at Washington State University, to find out more about our brains. She said if we wanted to observe activity in a human brain, we could do a test called an electroencephalogram (uh-lek-trow-uhn-seh-ful-luh-gram), or EEG for short. We’d attach some small discs with thin wires, or electrodes, to a person’s head. Read More ...

Dr. Universe: If snakes smell with their tongues, what do they do with their noses? – A.J., 5, Kennewick, WA

You’re right, snakes have an amazing sense of smell. They can use their tongues to pick up on all kinds of scents in the air. Whenever we smell something in the air, we are actually sniffing tiny building blocks called molecules. These molecules are what make up the scents of everything around us—things like baked bread, fresh-cut grass, and warm cookies. If you were a snake, you might sniff out the scent of a slug or mouse. You’d use your tongue to pull the molecules from the air into your mouth. Read More ...

Dr. Universe: Why do we have a tailbone? -Tyler, 15, East Liverpool, England

Dear Tyler,

At the very bottom of the human spine is a bone that sticks out a bit called the coccyx (cox-ix). We sometimes call it the “tailbone,” but it is actually made up of several different spinal bones.

In some animals that actually have tails, those different bones at the bottom of the spine help them move their tail around. But in humans, those bones partially fused together.

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Dr. Universe: Why do we have nightmares? -Kourtney, California,  10

You are running through the woods and a bear is chasing you, when all of a sudden you wake up in your bed and realize it was just a scary dream. Our nightmares can sometimes feel super scary, even if what’s happening isn’t real. Fear is a natural part of being a human. In fact, you may have even felt shaky or sweaty after waking up from a bad dream. It’s all part of something we call the fight or flight response. When humans are faced with something scary, this response helps them decide if they should face their fears and fight or run away by taking flight. This fight or flight response works even when you are asleep. Read More ...

Dr. Universe: Why do people like different kinds of music? – Skyler, 14, Michigan

Dear Skyler, When I got your question, it was music to my ears. Humans have been experimenting with all kinds of sounds, lyrics, and instruments for thousands of years. There are hundreds of genres of music, so while you might like one kind, a friend might like something completely different. Or maybe you became friends because of your similar taste in music. My friend Horace Alexander Young is a musician and professor at Washington State University. When I went to visit him, he had been practicing his saxophone and offered to help out with an answer to your question. Read More ...

Dr. Universe: How did the first horse change into the horses of today? -Ava, 7, Kennewick, Wash.

We can learn a lot about animals of the past from fossils, the imprints or remains we find in rocks. One fossil found in the Bighorn Basin, Wyoming helped us learn about the oldest known horses. These horses are called Sifrhippus (siff-RIP-us). They had four toes on each foot and were very small. Believe it or not, these tiny horses weighed only about ten pounds. That’s just a bit heavier than your average house cat. According to the fossil records, Sifrhippus lived somewhere between 54 and 30 million years ago. When I went to visit my friend Lane Wallett, she told me all about the history of horses. As a veterinarian and a paleontologist at Washington State University, she is very curious about both horses and fossils. Read More ...

Dr. Universe: Why do people have different accents? Why do we have them and need them? -Florrie P., 9, UK

Whether you say hello, ‘ello, hey ya’ll, toe-may-toe or toe-ma-toe, we all have a kind of accent that often comes from where we live or who lives around us. That’s what I found out from my friend Nancy Bell, a Washington State University professor who is really curious about the way language works. She told me more about why we have accents and why we need them. There are a lot of different accents. You might have friends who speak English but have a Scottish, Irish, Australian, or French accent. Even in the U.S., there are many accents from the east to the west to the mid-west to the south. In those regions, people also speak many types of English such as Chicano English, African American English, or Indian English. Read More ...

Dr. Universe: How do trees help the air? – Ella, 12

Take a big, deep breath. As you inhale and exhale, you can probably feel the air taking up space in your lungs. The air we breathe is made up of a few different things. It includes gases such as nitrogen, oxygen, and carbon dioxide—just to name a few. Animals breathe in oxygen and breathe out carbon dioxide. But in the plant world, it’s the opposite. Trees, plants, and even algae in the ocean, take in carbon dioxide from the air and, using the energy of the sun, transform it into the oxygen we all breathe. Read More ...

Dear Dr. Universe: How do we talk? – Emmy, 7, Wash. State

Dear Emmy, When you were a little kid, maybe you played Peek-a-Boo or sang “Itsy Bitsy Spider.” These kinds of games and songs have a lot of the different sounds we make when we are first developing speech. A lot of humans start out playing with speech through cooing and crying. At about six months old, this cooing and crying turns to babbling. A baby might make sounds such as ma-ma, pa-pa, or ba-ba. Read More ...

Dr. Universe: Why are dogs important to humans? Stephani R., 9, Washington State

Dear Stephani, Dogs are important to humans in all kinds of ways. The connection between the two goes back thousands of years. A long time ago, wolves would trail along after humans on hunting trips and eat any scraps they could find. Eventually these wolves evolved into dogs that helped protect the hunters and gatherers. Read More ...

Dr. Universe: How do bags form under your eyes? –Sophia Ivy, 7, New Providence, NJ

Dear Sophia Ivy, If you’ve ever stayed up late and woke up really early, you may have noticed a little puffiness or swelling under your eyes. When I asked my friend Devon Hansen about the answer to your question, she said that we first have to know a bit about how sleep works. Read More ...

Dr. Universe: What are shooting stars made of? – Erin, 11, Arkansas

If you are anything like me, you probably like watching for shooting stars in the night sky. A shooting star, or a meteor, is usually a small rock that falls into Earth’s atmosphere. When I went to visit my friend Michael Allen, a senior instructor of astronomy and physics at Washington State University, he told me a lot of shooting stars are no bigger than a pencil eraser. Read More ...

Dr. Universe: Why can’t sea turtles pull back into their shell? I was at the Saint Louis Zoo and they said tortoises and other turtles can pull back into their shells. – Tyler, 7, Missouri

There are more than 350 species of turtles that live on our planet. While many of these turtles live on land, others live in the sea. Depending on where a turtle lives, its body will be a little different. Turtles have adapted to live in different environments and they have traits that help them survive in those places. As you mentioned, a lot of turtles and tortoises on land have the ability to pull, or retract, their head into their body. Read More ...

Dr. Universe: Why do we sneeze? -Nyuma, 10, North Carolina

Imagine you are home sick from school or are just playing outside when all of a sudden—ah-ah-ah-choo! It might seem like that sneeze came out of nowhere, but a lot of things went on in the brain and body to make it happen. That’s what I found out from my friend Hans Haverkamp, a scientist at Washington State University who is really curious about the human body and how it works. Read More ...

Dr. Universe: How does the moon glow? -Reece, Pullman, Wash.

Our moon is one of the brightest objects in the night sky. But unlike a lamp or our sun, the moon doesn’t produce its own light. Light can travel in lots of different ways. Moonlight is actually sunlight that shines on the moon and bounces off. The light reflects off old volcanoes, craters, and lava flows on the moon’s surface. Read More ...

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: Why do people litter? – Jenny, 11, California

There is a lot of litter on our planet, but it hasn’t always been that way. For most of human history, people made stuff out of things they found in nature. They might make tools out of rocks or sticks. These things break down and become part of the soil again. It wasn’t until the invention of new materials, like plastic, that we started creating more litter. In fact, along with the rise of these new materials came the word “litterbug.” Read More ...

Dear Dr. Universe: Why do we dance? – Helen H., 11, California

If we traveled around the world, we would see all kinds of dancers. We might see classical ballerinas in Russia. We might see break dancers performing on the streets of New York. We might even see tango dancers in Argentina. While the exact reasons we dance remains a mystery, there are a few theories about it. That’s what I found out from my friend Ed Hagen, an anthropologist at Washington State University who has researched the roots of dance. Read More ...

Dr. Universe: How do you make mummies? -Michael, 7, Arizona

When we think of mummies, we might imagine the kind from ancient Egypt wrapped up in linen. But there are lots of ways to make mummies—and they can even form in nature. That’s what I found out from my friend Shannon Tushingham, an archaeologist at Washington State University and director of the WSU Museum of Anthropology. Read More ...

Hi Dr. Universe: Are whales smart? -Tishawnie P., 9, Massachusetts

Dear Tishawnie,

Whales can learn to do all kinds of amazing things. Humpback whales learn how to blow bubbles and work together to hunt for fish. Dolphins, a kind of toothed whale, teach their babies different sounds. It’s a kind of language the young dolphin will know for life.

But to find out just how smart whales really are, I asked my friend Enrico Pirotta, a Washington State University researcher who studies how blue whales make long journeys across the ocean.

Let’s talk intelligence

Before he revealed the answer to your question, he shared a bit more about intelligence. Usually people talk about intelligence … » More …

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Dr. Universe: How do plants know when it’s spring? -Hannah, 3

When we see little green plants sprouting up from the soil, it is indeed a sign that spring has arrived. To find out how they know to grow, or germinate, I asked my friend Camille Steber. In her U.S. Department of Agriculture lab at Washington State University, she studies the source of almost all plants: seeds. A seed holds pretty much all the information a plant needs to know how to grow. The shell that holds all the seed parts inside even contains food for the plant. But the seed is very dry and needs to sense clues from outside to know when to germinate at the right time. Read More ...

Dear Dr. Universe: How do lasers work? -Manna, 12, India

Dear Manna,

Humans use lasers for everything from scanning barcodes and putting on light shows to performing delicate eye surgery and measuring the distances between objects in space.

Cats also like to chase lasers, but I wasn’t sure how they worked. I asked my friend Chris Keane, a physics professor at Washington State University. Keane came to WSU from the National Ignition Facility at Lawrence Livermore National Laboratory where he helped work on a laser as big as a football stadium.

The light we see

First, we have to know a bit about light. Whether it’s light from our sun or your flashlight, … » More …

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Dear Dr. Universe: I have a question for you. Why do you get dizzy when you read on the road? -Rebecca, 10

Without even thinking about it, humans can use their eyes, ears, sense of touch, and brain to keep their balance. But sometimes these senses get a little mixed up. Imagine you are in the car reading your favorite book. All of a sudden the road starts winding. As you look down at your book, your eyes focus on the pages. The book doesn’t appear to be moving, so the eyes send a signal to your brain that you could be sitting still. At the same time, something is stirring in your inner ears. Lots of tiny little hairs called cilium are inside your ears doing an important job. They help you sense how your head is moving in the world. Read More ...

Dr. Universe: What can I do to help stop ocean pollution? -Hailey, 10

It’s great to hear you want to help our oceans. After all, they do a lot for us. Life in the ocean provides much of the oxygen we breathe and is also a source of food for many animals, including humans. One of the most important things we can do to prevent more pollution is to keep our garbage, especially plastic, out of the ocean. That’s what I found out from my friend Richelle Tanner, a marine biologist and researcher at Washington State University. While a lot of plastic ends up in the ocean, it actually started under the Earth’s surface in the form of oil, leftovers of plants and animals that died long ago. Read More ...

Dear Dr. Universe: How do houses get built? -OWL School Students, United Kingdom

Humans have built all kinds of houses throughout history. During the Ice Age, humans made their homes in big caves. A few thousand years later, people figured out how to fire up a hot oven and bake their own clay bricks. A lot of the first houses made of these bricks didn’t even have front doors. To get in the house, you climbed up a ladder to the roof and used another ladder to get down inside. “As soon as humans left their caves and started settling in cities, architecture has been with us,” said my friend Mona Ghandi. Read More ...

Dear Dr. Universe: Why do flowers smell so nice? – Miles, 5

Flowers not only smell nice to humans, but also to many insects and birds who help the flowers do a really important job. Let’s imagine that you are a bee or a butterfly. You don’t have a nose on your face, but instead use your two antennae to smell things. As you fly around, you catch a whiff of chemicals floating in the air. Down below, you see a field of daisies. The flowers are releasing some chemicals, which are the building blocks of a smell. 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 ...

Dear Dr. Universe: How many different types of plankton are there? Are there freshwater plankton? – Arielle, 11

We can find millions and millions of plankton in bodies of water all over the world—from oceans, rivers, and lakes to ponds and mud puddles. That’s what I found out from my friend Julie Zimmerman, a scientist with the Aquatic Ecology Lab at Washington State University. In the lab, researchers can use powerful microscopes to get an up-close look at these tiny creatures. 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 ...

Dr. Universe: Why do we get phobias? -Ryan, 13, Hillarys, Western Australia

We all experience fear in our lives. It is a useful tool that helps humans and other animals survive. I happen to be afraid of dogs, thunderstorms, and water. But fears are quite different from phobias. A phobia is an intense fear of an object or situation, often one that you actually don’t need to fear. It can create a lot of anxiety. It can cause your heart rate to speed up, make it hard to breathe, and trigger nervousness, vomiting, sweating, or dizziness. Read More ...

Dr. Universe: Why do we get morning breath? -Stephanie, 10

Dear Stephanie, If you’ve ever caught a whiff of someone’s stinky morning breath, or even your own, you know it can be pretty rotten. We can trace the smell back to tiny culprits that live in our mouths. They are called microbes and they live around your gums, between your teeth, and on your tongue. Read More ...

Dr. Universe: What’s inside a sheep’s brain? – Aiden, 11

A sheep brain is about the size of a human fist and is squishy like Jell-O. In some ways, a sheep brain is very similar to a human brain. In other ways, it is quite different. I learned about sheep brains from my friend Craig McConnel, a researcher at Washington State University who is very curious about ruminants, a group of animals that includes cattle, giraffes, deer, antelopes, and of course, sheep. Like a lot of mammal brains, a sheep brain is made up of grey and white matter. It has folds and grooves, but not quite as many as a human brain. It’s also a little smoother. Read More ...

How many bones did dinosaurs have? – Addison, 9

Before humans even had a word for dinosaur, they were digging up dinosaur bones. When one paleontologist dug up a big dinosaur leg bone, he wondered if it belonged to a giant human. A woman who dug up some large teeth wondered if they belonged to a huge iguana. Read More ...

Dr. Universe: Do fish pee? – J.P., 9 ½ , Texas

Not only do fish pee, but their pee gives other animals in the ocean what they need to survive. That’s what I found out from my friend, Cori Kane, a marine biologist at Oregon State University who got her Ph.D. at Washington State University. She knows a lot about coral reefs in our oceans. Coral reefs look like a ridge made of rock, but they are actually made up of living things. Corals need a few things to survive. They need clear, warm water, sunlight, and nutrients, a kind of food that helps them grow. There aren’t usually a lot of nutrients in water near coral reefs. Luckily, there are a lot of nutrients in fish pee—and a lot of fish in the reef. Read More ...

How do volcanoes erupt? –Miles, 10, Tampa, FL

Wherever we find a volcano on the surface of our planet, we can find the source of an eruption beneath it. That’s what I found out from my friend John Wolff, a volcanologist at Washington State University. Our planet is home to all kinds of volcanoes that erupt in different ways. Some eruptions are quiet and continuous, with a slow flow of lava. Other volcanoes erupt explosively and can spew ash and lava hundreds of feet up into the sky. All of this lava has its start underground in the form of something called magma. Wolff said that scientists used to think there were large pools of hot liquid beneath volcanoes. Now we know it isn’t quite that simple. Magma is not really a liquid, but rather a kind of sludge or slurry. It helps to think of it kind of like honey. Read More ...

Dr. Universe: What are molecules? - Jolin, 9, Maryland

A glass of water has more molecules than there are stars in the night sky. That’s what I found out from my friend Jack (Qiang) Zhang, an assistant professor of chemistry at Washington State University. “Everything around us is made up of molecules,” he said. “And while these molecules may be different, they are all made of the same things.” Those things are called atoms. Zhang told me we can think about atoms kind of like Lego blocks. Imagine that you have a pile of red Legos, yellow Legos, and blue Legos. Maybe you use them to build a tiny house, or you can use this same set of Legos to build something else like an airplane or a robot. Read More ...

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Questions? E-mail rcwebber@wsu.edu.

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Dr. Universe: What do clouds do? - Desi, 9, Maryland

If you’re anything like me, you like to watch the clouds go by in the sky. Even though some clouds might look like they are just floating around up there, they can do quite a lot for our planet. The first thing to know about clouds is they are made up of tiny water droplets, ice crystals, or a mix of both—and there are many different kinds of clouds. There are white and puffy cumulus clouds, thin and wispy cirrus clouds, and tall nimbostratus clouds that stretch high up in to the sky. Believe it or not, when you walk through fog, you are walking through a kind of cloud that’s touching the ground. Read More ...

Dr. Universe: Why do we have a belly button? – Jane, 9, Kennewick, WA

Whether you have an innie or an outie, pretty much all us mammals have a belly button. But before you had a belly button, there was actually a different bit of anatomy in its place. While you were still growing inside of your mother, a small, bendy tube on your tummy connected the two of you. This tube is how you got pretty much everything you needed to grow before you were born into the world. Read More ...

Dr. Universe: What is the most smelliest fruit in the world? -Tiana, 9

Our world is full of fruits that have all kinds of delightful smells. Maybe you’ve smelled the sweetness of watermelon, pineapple, peach, papaya, or mango. But you might also be wondering about the most stinky fruit in the world. When I got your question, I asked my friend Lydia Tymon, a plant scientist at Washington State University. The first stinky fruit she thought of was the durian, a large, round fruit that grows mostly in Southeast Asia. The fruit is about a foot wide with a greenish-brown husk that has lots of spikes on the outside. Read More ...

Dr. Universe: How fast does a bunny hop? How long does a bunny live? Can a bunny swim? How many babies does a bunny have? -Rueben, 7, Pennsylvania

Bunnies are hopping all over our planet. Some hop through snow and deserts while others hop through wetlands and woods. There are lots of different kinds of rabbits and they are all a little different. For the most part, a bunny hops, or actually runs, anywhere between 25 and 45 mph That’s even faster than most house cats can run. Rabbits are related to another group of animals called hares. Actually, rabbits and hares are in the same family, Leporidae. Hares look a lot like rabbits, but they have much bigger ears and bigger feet. Read More ...

Dr. Universe: How do earthquakes happen? -Aescli E., 10, Utah

We’ve had a lot of earthquakes on our planet this year. Maybe you’ve learned about them from the news or felt one shaking up your own neighborhood. First, it is important to know a bit about the Earth’s outer layer, or crust. The crust is made of seven big pieces called “plates.” They are about 60 miles thick and sort of float on the molten rock beneath them. That’s what I found out from my friend Sean Long, a geology professor at Washington State University who knows a lot about earthquakes. Read More ...

Dr. Universe: Why do we have five fingers and five toes? -Eli, 11, Edinburgh, Indiana

Dear Eli, While humans may be one of the few animals that can give a high five, they are one of many with five fingers and toes. Humans are part of the primate family, which also includes monkeys, apes, and even lemurs. As a member of the family, you also have fingernails instead of claws and pads on your fingertips that help with your sense of touch. Read More ...

Why does caffeine make us stay up longer? -Cooper, 12

Dear Cooper, You’re right, caffeine can help us stay awake—but only for so long. To understand exactly why it works, it helps to know about one of my favorite things: sleep. All animals need rest to stay healthy. But sometimes humans don’t get quite as much sleep as they need. They might be tired during the day or have a lot of work to do. To feel more alert, they might drink a cup of coffee, tea, or soda. These kinds of drinks contain caffeine, a chemical and stimulant that can trigger changes in the body. Read More ...

Who created the very first chocolate bar? – Emma, 11, USA

Dear Emma,

For most of human history, people have enjoyed chocolate in a spicy, bitter drink. But when people discovered how to turn chocolate into a solid, it opened up a whole new world of possibilities.

That’s what I found out from my friend Omar Cornejo, a scientist at Washington State University who is very curious about the history and life of the cacao tree. Chocolate comes from the seeds of leathery fruits that grow on the tree.

If we cut open the fruit, we would find about 20 to 60 seeds on the inside. In ancient times, people would grind up the seeds … » More …

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Why do you grow new taste buds? I read in a book once that you grow new taste buds every week. I started wondering how and why? I'm hoping you can help me with my question. -Tyra, 10, Jacksonville, NC

Dear Tyra,

You read it right— taste buds can have a lifespan of anywhere from one to two weeks. That’s what I found out from my friend Charles Diako who researched food science at Washington State University. Before he explained exactly how and why we grow our taste buds, he told me two important things about them.

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Dr. Universe: How is wasabi made and where does it come from? – Christian, 12

Dear Christian,

When you think of wasabi, you might think of that hot green paste people serve up with sushi. Some restaurants put a bit of wasabi on your plate, but it’s usually not real wasabi. It’s actually a mixture of horseradish, mustard, and green dye. Real wasabi is a lot different.

That’s what I found out from my friend Thomas Lumpkin, a plant scientist who studied wasabi as a researcher at Washington State University. Wasabi is a plant that mainly grows in Japan in the cool, running water of mountain streams and springs.

Illustrated, cartoon cat with labcoat» More …

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Dr. Universe: Why do cats like lasers? -Izzy, 10, MD

Not only do I enjoy answering science questions from kids, but I also like naps, tuna fish sandwiches, and chasing lasers. I wasn’t entirely sure why I like chasing those little red dots. I asked my friend Leticia Fanucchi, a veterinarian at Washington State University.

“Cats like lasers because they are predators and like to chase or hunt anything that moves fast around them,” Fanucchi said.

A zipping red light that quickly switches directions might have a similar motion to a mouse or other critter. The light sort of mimics an animal scurrying around to escape its prey. Even though we cats know the … » More …

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Dr. Universe: How does land affect the weather? – Isaac, 7, Baltimore, MD

The surface of the earth is covered in all kinds of landforms. We have tall mountains, deep valleys, wide canyons, and scenic shorelines—I bet you could think of a few others, too. A little less than a third of our planet is land and the rest is mostly ocean. Both affect the weather, said my friend Nic Loyd, a meteorologist at Washington State University.

We get different weather patterns depending on a few conditions, such as how much sun the land gets, if the land is near mountains or ocean, and how air circulates through the atmosphere.

alt» More …

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Why do lizards lose their tails? -Bailey, Inwood, Iowa

Dear Bailey,

Our planet is home to all kinds of lizards. Maybe you’ve seen one climbing up the wall, scurrying through the grass, or at the pet store. Just the other day I saw a big green iguana when I visited the Washington State University Veterinary Teaching Hospital in search of an answer to your question.

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Dr. Universe: How do cacti survive in such hot and dry environments?

-Ravin, 11, London, England

Dear Ravin,

All plants need water to survive. Those that live in places where water is scarce use some interesting strategies to stay alive.

That’s what I found out from my friend Charles Cody, who manages one of the greenhouses at Washington State University. When I went to visit the greenhouse, he pointed out a few different cacti.

One was tall and cylindrical with big spines. Another was small and round with what looked more like little hairs. A rainforest cactus hung on the wall like a vine.

Cody explained that if … » More …

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Dear Dr. Universe: What happens to the world’s garbage? -Presley, 8, Spokane, Wash. How do you recycle an object into another object? -Brianna, 12, New York

Dear Presley and Brianna,

So far, we’ve investigated how recyclables like plastic, aluminum, and paper can end up in the trash. If our clothes get damaged, or we simply outgrow them, we might toss them in the trash, too. Or send them to a thrift shop. Either way, they often end up buried in a landfill.

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Dear Dr. Universe: What happens to the world’s garbage? -Presley, 8, Spokane, Wash. How exactly do you recycle an object into another object? -Brianna, 12, New York

Dear Presley and Brianna,

While a lot of our trash goes in a landfill, we can also recycle all kinds of stuff on our planet. Depending on what the object is made of, we might grind it up, mix it up or melt it down before we turn it into something new.

Let’s start with paper. When you recycle paper, it usually ends up at a recycling center where it gets washed with soapy water and mixed into a huge, thick slurry.

Sometimes we add a few other ingredients if we want a specific kind of product, like cardboard or printer paper. The slurry is … » More …

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Dr. Universe: Do you have any experiments you can recommend? Thanks! -Etta, 7, Milwaukee

Dear Etta and Friends:

You can try all kinds of fun experiments at home. It really all depends on what you are curious about. Lately, I’ve seen some really great sunsets and started wondering what gives them their colors.

I decided to ask my friend Tom Johnson, who leads fun physics demonstrations for kids visiting Washington State University. I asked him if he had any simple ideas for an experiment I could try out in my lab, or even the kitchen. One idea he had was to create a sunset in a cup.

Maybe you can try it, too. You’ll need a flashlight, a … » More …

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Can video games help us learn? - Isaac, 12, Clyde, N.Y.

Dear Issac,

All kinds of games can help us learn, including some video games. They can be a fun and useful way to help you remember what you learn, too.

Our brains work hard each day to take in and process information. Ever since video games were invented, people have been asking if and how they might change our behavior and brains.

For example, people once thought that video games left players with poor eye-sight and poor attention. Some scientists decided to actually test out these ideas. Their studies have shown that some video game players … » More …

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Dear Dr. Universe: Why does hair turn gray? –Darae, 10

[caption id="attachment_2942" align="alignleft" width="592"] Dr. Universe examines a gray hair.[/caption]

Dear Darae,

Hair comes in lots of different colors. There’s black, medium brown, auburn, light brown, strawberry blonde, and copper, to name just a few. But in the end, almost everyone will have hair that’s gray or white.

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Dear Dr. Universe: How does a light bulb work? When one bulb in a string of lights goes out, why do they all go out? – Molly, 8

Dear Molly,

Just the other day I was taking down a string of lights from my lab, when I discovered the bulbs were burnt out. I visited my friend Aaron Crandall, an engineer at Washington State University, to see if I might get them working again.

Crandall explained when you plug in a string of lights to a power source, like an outlet, an electrical charge flows into the wires. A lightbulb works when an electrical current runs through thin metal wires in the bulb and electrical energy gets converted to heat and light. We can get this current of electricity to follow different paths, … » More …

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Dr. Universe: How is glass made? And, what is it made out of? What about thick glass like they are putting up on the Space Needle? – Tali, almost 8 years old, Seattle, Wash.

Dear Tali,

We can make glass in factories and we can find it in nature. Some volcanoes make glass. When they spew out lava, it often cools into obsidian, a black glass. Glass can also form on sandy beaches. Small tubes with smooth glass on the inside may appear after super-hot lightning strikes the sand.

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Dr. Universe: How do planes fly? -Tahira, 12, India

Dear Tahira,

Planes are very heavy, yet they stay up in the air kind of like a bird in the sky. They can get us across the world in less than a day. Humans went from learning how to fly a plane to putting a man on the moon in a little over 60 years.

But the answer to your question goes even further back. It goes all the way back to the 1700s and actually started not with air, but with water.

That’s what I found out from my friend Michael Allen, a physics and astronomy professor at Washington State University. He thought you … » More …

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