Dr. Universe

Ask Dr. Universe – Feelings

Why do we have different feelings?  – Charan and Aishwarya V., 10 & 8, Rutherford, New Jersey
Dear Charan and Aishwarya,

Imagine you are playing a game of soccer and your best friend is on the opposing team. The sun is out, you are having a great time, and you score the winning goal. You’d probably feel pretty happy and so would your team.

But if you stepped in your best friend’s shoes, the emotion might be really different. Think of the players on the other team, too. Even if they had fun and played their hardest, they may be a little disappointed.

Humans feel all kinds of different emotions. They use them to react to different situations, whether that’s playing a game or maybe coming face-to-face with a saber-toothed tiger.

For your ancestors, an emotion such as fear could help increase the chance of survival if they did run into this ferocious feline. When people are faced with a potentially dangerous situation, changes in the body happen automatically.

A fear signal from the brain makes the heart race, muscles tighten, and the mouth gets dry. The body gets ready to fight or run away. You may express this fear on your face. That’s a signal to people around you that they’ve got to get ready to act.

My friend Sara Waters, a psychologist and researcher at Washington State University, is really curious about human emotions. She asks big questions about how and why we develop them and how we share them.

When you were a baby, you probably couldn’t express your emotions very well. You had to cry a lot to express yourself and get what you needed. Maybe you threw tantrums. But you soon discovered they didn’t work very well.

You may not have had the right words for your emotions yet. When you learned to talk, you started to give your emotions names, Waters explained. The grown-ups in your life probably helped you figure out what those names were. Sad. Happy. Mad. Then, you could start figuring out your feelings on your own and express them to others.

Waters’ research actually looks at how some mothers and their babies sort of catch one another’s emotions. When moms look at their babies with a certain emotion, the babies will also show those emotions. They’re kind of like copy cats.

Maybe after winning the soccer game your friend gives you a high five. Your friend tells you that it was a little disappointing to lose. Maybe your own team has lost in the past and you remember how it feels. You have a whole range of different emotions you can use to navigate the world, better understand people, and make good decisions.

What kinds of things do you do to bring others happiness? How do you show kindness? What makes you happiest? Make a list or tell us about it sometime at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at http://askDrUniverse.wsu.edu/ask

Ask Dr. Universe – Animals on Islands

How do animals get to islands? –Jax, 8, WA

Dear Jax,

Animals make their journeys to islands in different ways. Some float. Some fly. Others will swim.

My friend Jonah Piovia-Scott is a scientist at Washington State University. He studies how different living things interact with each other, especially in island habitats. He is really curious about predatory lizards that live on a chain of islands called the Bahamas.

“These lizards can get to islands,” he said. “They can swim, but not very well. They keep themselves afloat.”

Floating is one way animals get to islands. They may float on their own or they may take a kind of raft. This raft is often made up of plants, branches, or other things that blow out into the sea during a storm and are swept together in the ocean.

Flying helps animals like bats and bugs get to islands. Piovia-Scott reminded me that some animals fly for just a small part of their lives, too. Before some ants are fully grown, they go through a stage where they have wings. An ant might find it hard to swim in the ocean. But while it has wings, it can make a flight to a new place.

If animals are light enough, they may get picked up in the wind and sort of drift along. For example, spiders use their silk to catch the wind and move to new locations. Also, a lot of plants get to islands because of the wind. Plant seeds often catch a ride in the air. When they reach the island, they get buried in soil and start to sprout. These plants provide food for many animals.

Finally, there are animals that are just good swimmers, such as seals. They can paddle long distances to an island and some also find a home on the land.

Piovia-Scott explained that animals often take advantage of their new island life. We see these changes in animals such as the marine iguana. Most iguanas we know about only live on the land. But iguanas on the Galapagos Islands dive into water to look for food. They have developed ways to use the resources in and around their island environment.

Another place we see this is in the Pacific Northwest on the San Juan Islands. On these islands, we find raccoons that eat shellfish.

Piovia-Scott said you could probably say the same is true of people who live on islands—they tend to eat a lot of fish. That sounds like my kind of place. I might have to go and explore an island one of these days.

In the meantime, I’m going to see if I can make a flying device and floatation device to learn more about how things travel on water and in the air. You can try it out, too. Find this article and the instructions at askDrUniverse.wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at http://askDrUniverse.wsu.edu/ask

Ask Dr. Universe – Blood

Why do we have blood? Where does it come from? –Norelle, Olympia, Wash.

Dear Norelle,

Our bodies have many living parts, like skin, muscle, brain and bones. Blood helps keep these parts alive and healthy. The system that moves our blood around the body is sort of like a city’s postal service, said my friend Astrid Suchy-Dicey.

Suchy-Dicey is a scientist at Washington State University who is really curious about blood. Her research helps people at risk for diseases.

She said it first helps to know that blood is actually made up of different things: red blood cells, white blood cells, platelets, and plasma.

If you think of your circulatory system like the postal service, mail carriers are the red blood cells. They transport important packages and letters (oxygen) over a vast network of streets and highways (blood vessels).

About a gallon and a half of blood circulates through the human body, dropping off these deliveries, 24 hours a day. The strong heart muscle pumps blood out into the body. It’s working hard, too. The force needed to squeeze a tennis ball is similar to what you need to squeeze blood out of the heart.

White blood cells help your body fight off infections. There are lots of different types of white blood cells with different jobs. Some of them fight off tiny bacteria and fungi. Some of them fight off viruses or other invaders.

All of the white blood cells’ jobs have one common mission: keeping you healthy.

Platelets help keep you healthy, too. Whenever you get a cut or scrape, these disc-shaped parts come to the rescue. Platelets help stop blood from flowing. They also help prevent you from losing blood and keep out invaders.
Plasma is a watery solution with a few other things floating in it, like salt and proteins. It flows, carrying other cells freely along those streets and highways we know as blood vessels.
As for your second question, Suchy-Dicey said that blood cells are produced in your bones. Specifically, they are produced in the soft fatty part inside your bones called bone marrow.

Your plasma is formed mostly using water you drink. That’s why it’s really important to drink enough water each day, Suchy-Dicey adds. While on the issue of water, here’s a quick activity you can try to find out about how much blood your heart pumps in a minute.

You’ll need a bucket of water, an empty bucket, and a small Dixie cup. Fill a bucket with about a gallon of water. Have a friend set a timer for one minute and see how many little cups of water you can move to the empty bucket.

Each time your heart beats it moves about a small Dixie cup’s worth of blood. It takes our heart about one minute to pump about a gallon of blood. Can you move the liquid faster than a heart? Try it out sometime and let me know how it works.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at askDrUniverse.wsu.edu/ask

Follow-up video about why red blood cells look like donuts available at: https://askdruniverse.wsu.edu/2017/04/17/why-do-we-have-blood-where-does-it-come-from/

Ask Dr. Universe – Meat

Why does meat get brown on the grill? –Christina, 9, Seattle, Wash.

Dear Christina,

You know summer is just around the corner when the smell of barbecue is in the air. It’s a great question you ask and it leads us to the Meats Lab at Washington State University. That’s where I met up with my friend and animal scientist, Jan Busboom.

He’s really curious about animal nutrition and the meat we eat. Busboom explained that meat is muscle. It has a lot of different proteins. These proteins have different jobs. One of them delivers oxygen to the cells that make up muscles. It’s a protein called myoglobin.

Believe it or not, the red liquid we see in a package of meat comes primarily from myoglobin. The more myoglobin there is in a muscle cell, the redder the meat will look. Myoglobin is a big part of why meat is red in the first place—but it’s also part of the reason it turns brown on the grill, too.

Like almost everything on our planet, a hamburger is made up of atoms. As you may know, atoms get together to form molecules. These parts are arranged in ways that give things certain colors, tastes, and smells.

As is often the case when we heat up something, its atoms and molecules often start to move, or vibrate faster and faster. Then they transform.

When we heat up the hamburger meat, the myoglobin structure begins to change. Myoglobin loses its ability to bind onto oxygen. There’s also a change in one of the iron atoms at the center of the myoglobin.

These changes are happening on very small scale. But we can actually see the changes as the red meat transforms into a juicy brown hamburger patty.

It turns out color isn’t always the best sign that a burger is ready to eat. Busboom said sometimes a burger won’t brown on the grill. Even if it’s fully cooked, it will stay red.

On the flip side, sometimes a burger that is brown isn’t actually cooked. This is because there may be some other chemical factors going on here that influence color. That’s why it’s really important to use a thermometer and make sure your meat is safe to eat.

Not only does a burger’s chemistry influence color, but also its taste and smell. When we heat it up, proteins and sugars in the meat start to break down.

It was the French chemist Louis Camille Maillard (my-YAR) who discovered the way this works. When the Maillard reaction happens, it creates thousands of new chemical compounds that give meat flavor.

Yes, there’s a whole bunch of science happening right there on the grill. I suppose you might even say the grill master is a bit of a scientist.

Can you think of other kinds of science that go into building the perfect burger? Tell me about it sometime at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at http://askDrUniverse.wsu.edu/ask

Ask Dr. Universe – Turtles

How do turtles live so much longer than other animals? – 8th grader, Lewiston, Idaho

Dear Reader,

You’re right, turtles and tortoises live a lot longer than most other animals. If you were a turtle, you might live for more than 150 years. One giant Galápagos tortoise named Harriet even lived to be more than 170 years old, said my friend Donna Holmes.

Holmes is a professor and a member of the Center for Reproductive Biology, where scientists at University of Idaho and Washington State University work to tackle big questions about aging and animal lifespans.

Holmes explained that biologists have come up with several ideas, or theories, for how turtles can live for so long.

One theory has to do with the fact that turtles are cold-blooded and have what scientists call a slow metabolism. They don’t have to eat as much food to survive, since they use energy they get from food very, very slowly. Since they are cold-blooded, they also don’t need to use a lot of energy to keep themselves warm.

Our bodies need energy to keep us going. When we eat food, our body uses chemical reactions to turn it into energy we can use. But sometimes this chemical process also produces other products that end up damaging our tissues and cells over long periods of time. When this happens, we see signs of aging, such as wrinkles.

When we study animals with a slow metabolism, we observe that there isn’t as much damage to their tissues and cells as expected for their age and size.

A second idea about why turtles live so long is also related to that low metabolism. Turtles often hibernate. They sink down into the mud at the bottom of a lake or pond, going dormant for the season (kind of like hibernation), and use even less energy.

A third idea about why turtles seem to outlive so many other animals is one that Holmes likes best. She said it holds true for animals that have evolved special defenses against predators.

“You can see how animals that have hard shells would be protected against being eaten by another animal,” she said.

The harder the shell, the less likely you are to become someone else’s dinner. This is a benefit for each individual turtle. Lots of years to live also means that there is more time to breed and produce baby turtles who also have hard shells for defense.

The turtles that survive and breed in a particular environment will pass along to their offspring traits that are best suited for that environment—including tough shells.

“Animals with longer lifespans such as turtles, porcupines, mole-rats, bats and birds all have evolved defenses against predators in the form of shells, sharp quills, underground burrows,  or the ability to fly away,” Holmes said.

It seems that using energy slowly and having good defenses may be two key things that help turtles live slow and die old. But there are still many exciting questions left when it comes to aging and lifespan. Who knows? Maybe one day you can help us discover more about the different lives of animals on our planet.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at http://askDrUniverse.wsu.edu/ask

Ask Dr. Universe – Ladybugs

How do ladybugs survive the winter? Are ladybugs we see in spring several years old or did they just hatch? Are they worms before they are beetles? – Tanya, Pullman, WA 

Dear Tanya,

You know it’s springtime when animals start coming out of hibernation. That includes ladybugs that crawl out from their cozy winter hiding places.

As you pointed out, ladybugs are actually a kind of beetle called the ladybird beetle. They go through a life cycle of four stages: egg, larva, pupa, and adult.

When these young larvae hatch from their yellowish eggs, they don’t look like worms or even beetles.

They look more like tiny alligators with six legs and tiny spikes on their backs, said my friend Laura Lavine. She’s a scientist at Washington State University who studies insects and was happy to help out with your questions.

In the summer, these young alligator-looking larvae can be found searching for their favorite food. They feast on tiny insects called aphids that live on plants.

Young larvae are hungry predators. In fact, ladybird beetle larvae will even eat each other, spikes and all, if they get hungry enough. But more often, the larvae will feast on aphids.

These larvae shed their outer skeleton throughout this stage of life. They’ll use some of this shedding to attach themselves to a plant or sometimes the side of a building for their third stage of life. In this stage, they’re called a pupa and they build a cocoon to go through a transformation.

You may have heard about how a caterpillar changes into a butterfly. A caterpillar is also a kind of larva. It changes into an adult in a process we call metamorphosis. Ladybird beetle larvae go through metamorphosis to become adults, too.

After spending about two weeks inside their cocoon, or sometimes less, the adult beetle comes out into the world. Adult beetles will live for around three years or so. During that time, they will lay eggs and create several new generations. So the beetles you see in a group could be different ages.

When fall rolls around, adult beetles leave their feeding sites in yards, fields, and forests to hide out for the winter. They need a place where they can huddle together with hundreds or thousands of other beetles. This helps them stay protected from weather and keep from freezing.

They’ll find places in cracks, crevices, tree bark, and even your house or roof to spend the winter. On the Palouse where we live, we can find them in cracks of pine trees or logs. I might just have to take my magnifying glass outside and see if I can spot some ladybugs waking up from their hibernation.

Sometimes they land right on you and start crawling. But other times they can really zip around. Believe it or not, scientists have clocked ladybird beetles flying at 37 m.p.h.

Have you seen ladybugs or other insects in your neighborhood? Were they nesting together? Have you ever spotted a ladybird beetle larva? Take a look in your neighborhood and tell me about it at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a question of your own at askDrUniverse.wsu.edu/ask

Slow-motion ladybug lift off: https://www.youtube.com/watch?v=87iV4ISAY5U

Ask Dr. Universe – Stars

Hello! My name is Daiwik and my question is “Why are stars in space? Why are they needed? Can they be made on Earth?” No one I know knows the answer to this. Can you find out for me? Thanks, Daiwik 
P.S. You’re awesome!! 

Dear Daiwik,

If you are anything like me, you like watching the night sky. The stars we see are a lot like our nearest star, the sun. They are just much farther away. That makes stars look like small twinkly things instead of a big, furious thing like our sun.

We can’t make a star on Earth simply because it would be just so large. That’s what I found out when I visited the planetarium here at Washington State University. I met up with my friend and astronomer Guy Worthey.

Even the smallest stars are pretty big compared to Earth, he said. Maybe you’ve heard of stars like Trappist-1 or Proxima Centauri. These stars are ten times the size, or diameter, of earth. The sun is nearly 100 times larger. And the largest stars, hold on to your hat if you have one, are 150,000 times the diameter of earth, Worthey said.

It’s an interesting question you ask about we why need stars. It got me wondering what life would be like or if there could be life at all without stars. For one, it would be a pretty cold, dark place if the sun didn’t exist.

While some living things exist in dark places on our planet, almost all life as we know it depends on the sun. Plants use energy from sunlight to fuel the process that makes their food. In this process, they also make the oxygen that we breathe. Animals eat plants. Some animals eat other animals. When animals eat plants and other animals, they in effect get energy that started with the sun. You know, we are all pretty connected. And we can trace a lot of these connections back to stars.

When a star is born, it forms from a cloud of collapsed gas that pulls itself together with the help of gravity. Scientists estimate more than 100 billion stars are born and die each year. That’s more than 275 million stars per day in the observable universe.

Stars keep themselves fueled. They fuse elements together to make new elements. While we can’t make an actual star on Earth, some scientists are curious about creating this kind of reaction in the lab.

In stars, hydrogen atoms fuse together to make helium. Once the star runs out of hydrogen, the helium atoms fuse together to make carbon. Eventually, stars uses all their energy and die. Sometimes the huge stars will explode. The star stuff spews out into space. When conditions are just right, gravity helps pull this space stuff together to form new planets and stars.

We might not be able to make a star on Earth, but I must admit the view of the stars from our planet can be spectacular. Tonight, I’ll be taking an extra a moment to look up. Maybe you will, too. Who knows, the view might inspire a whole bunch new questions–and it will be quite pretty.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in a question of your own at askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Plants

Why are plants green? –Nadia, 8, Australia

Dear Nadia,

A lush tropical rainforest, a field of sunflowers, a garden in your neighborhood. Our Earth is home to all kinds of plant life. From trees to catnip, there are thousands of different species of plants. Most of these plants are green, but not all of them.


That’s what I found out from my friend Linda Chalker-Scott. She’s a professor of horticulture at Washington State University who knows a lot about how plants work.

Chalker-Scott said plants are green because they have chlorophyll, a natural pigment that gives them their color. A plant is made up of millions of cells. Inside some of these cells we find chlorophyll.

If you remember our question about why the sky is blue, you know that sunlight is a combination of all the colors of the rainbow. This light bounces, reflects, and gets absorbed in ways that lets us see a ton of different colors.

Chlorophyll is really good at absorbing red and blue light. But it doesn’t absorb the green light. Instead, the green light is reflected back to us, so that’s what our eyes see.

If you are anything like me, you might be looking for the first signs of spring. It’s still a little snowy here where I live, but when we look close we can find some green popping out of the ground.

These plants are taking in the sunshine. As plants suck water up through their roots, they are also grabbing stuff from the air called carbon dioxide. They use these ingredients to make special sugars to survive. This process also ends up making oxygen for us to breathe. Sunlight drives this whole reaction, called photosynthesis.

It doesn’t just happen on land. Photosynthesis is going on in our oceans, too. Little algae and plant-like organisms known as phytoplankton also use chlorophyll to make their own fuel. They produce about half of our planet’s oxygen, too.

But, I wondered, what about those plants that don’t have chlorophyll? How could they survive if they couldn’t capture sunlight? Chalker-Scott told me about plants like Indian pipe, which are white and pine drops, which are brown.

They don’t have the tools needed to capture energy from the sun and make their own food. Instead, they feed on the roots of surrounding trees. They are plant parasites.

We also find plants with red, purple and yellow leaves. They still have chlorophyll, Chalker-Scott said, but other colors mask the green.

What plants, flowers, and trees are in your backyard or neighborhood? Send in a drawing or picture of your own plant collection to Dr.Universe@wsu.edu.

Dr. Universe
Here’s a chance to get your very own Dr. Universe sticker! Take the survey and enter to win at askDrUniverse.wsu.edu/survey.
Ask Dr. Universe is a science-education project from Washington State University. Submit a science question of your own at http://askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Bumble Bees

Dear Dr. Universe: We have a lawn full of clovers that the bumble bees love. Where do bumble bees live? Do they have hives or live underground? I love watching them. Do they live through the winter? –Karen, Arizona

Here’s a chance to get your very own Dr. Universe sticker! Take the survey and enter to win at askDrUniverse.wsu.edu/survey.

Dear Karen,

When it comes time for bumble bees to find a home, it’s pretty much up to the queen bee.

That’s what I found out from my friends Rachel Olsson and Elias Bloom. They are graduate student researchers here at Washington State University and really curious about bees, too.

Like you, we enjoy watching bees in their natural habitat. They buzz and zip from flower to flower, sipping nectar with their hairy tongues. Bloom said bumble bees are actually pretty social. They live in colonies with dozens to hundreds of fellow bumble bees.

As part of their research, Bloom and Olsson are helping citizen scientists collect information about these important pollinators and other kinds of bees.

While some bees live in hives, a lot of queen bees will find a place to live underground, Bloom said. They’ll use burrows that mice or other rodents have abandoned. Other queens will find a clump of grass at the surface to call home. These kinds of houses help protect them from predators and extreme temperatures.

Before winter comes around, the bumble bee colonies will rear new queens. Meanwhile, the worker bees will die off. The new queens will mate and find a place to live for the winter.

To answer your second question, only the queens live through the winter. When their eggs hatch later in the spring, the cycle begins all over.

Bloom and Olsson like to remind people that flowers like dandelions and buttercups, which we might call weeds and want to get rid of, are actually really important.

Since bees come out early in the year, before other flowers are blooming, it’s important to let these flowers grow. The plant produces nectar and pollen that attracts bees, and while collecting pollen for food, the bee helps the plant reproduce. Bumble bees continue to surprise us with the kinds of work that they can do.

Scientists recently studied how bumble bees can use tools. They showed bumble bees how to put a yellow ball into a little goal.

When the bumble bees scored, they were rewarded with sugar. They got better and better at getting the ball in the goal.

You can get involved with bee research of your own. The Bumble Bee Watch project invites citizen scientists to help conserve North America’s top pollinators.

And if any readers happen to live in the Pacific Northwest, you can get involved with a research project from WSU. You’ll help us learn more about the role pollinators play in helping us produce food and you’ll learn to identify bees in the wild. You can get started at nwpollinators.org.

Your friend,
Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit a science question of your own at http://askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Water In Our Bodies

Why do we have water in our bodies? –Angelika, 12, Cathedral City, CA

Dear Angelika,

Believe it or not, we are mostly water. Of course, you may have noticed we aren’t sloshing around and spilling everywhere.

That’s because a lot of water in our bodies is found inside the cells that make us up. In fact, about 60 percent of our body is water, said my friend Yonas Demissie, a civil engineer and professor at Washington State University. He’s engineering ways to make sure people have good water resources for the future.

Every day, water is flowing in and out of our bodies. When we drink, water can do all kinds of good things for us.

Water in our blood helps carry nutrients, the important things we get from food, around the body. These nutrients take a ride in the blood and are delivered to your cells to help give you energy and keep your body fueled. That’s what I found out from my friend April Davis, an assistant professor of nutrition and exercise physiology at WSU.

One big reason we have water in our bodies is that it helps gives cells their structure, she said. It keeps cells a little plump. It also helps make different chemical reactions cells need to do their jobs.

Water is also in charge of moving things around the cell to keep it working. These cells make up our organs—like bones, lungs, and kidneys.

Water is a key ingredient for helping our organs stay healthy. In fact, our brain is about 70 percent water. Our lungs are about 90 percent water. The kidneys process about 50 gallons of blood each day. They process extra water your body doesn’t really need. Pretty soon, you’re running to the bathroom.

Another way water leaves the body is through sweating. If you’ve ever played soccer or just sat outside on a super hot day, you know you can sweat quite a bit. Water helps the body release heat. We do it through sweat. As the sweat evaporates from your skin, it also helps cool you down.

If we have too much water in our cells, our body has ways to get rid of it. But sometimes our cells actually don’t have enough water. We start to get thirsty and that signals our brains to find something to slurp up. There’s nothing like lapping up a cool, refreshing drink of water.

Water is so important to living things. But in some places, it is really hard for people to get clean water. Just here in the U.S. we use 10 times more than a person in countries where access to clean water is limited, said Demissie.

In Ethiopia, where he grew up, less than half the residents can get clean drinking water. Now, he’s using engineering to create water resources in our world, looking at how we can share them, and making sure that water is clean for people to drink. After all, water is important for every body, everywhere.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in a question of your own at http://askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Ears

How do our ears work? – Aryana, 11, Ohio

Dear Aryana,

The chirps of birds. The squeaks of mice. The barks of dogs. In a world full of different sounds, our ears take in almost everything. But it takes more than just our ears to hear.

My friend Gail Chermak told me all about it. As an expert in speech and hearing sciences at Washington State University, she offered to give us a little tour of the ear.

She said animals with two ears have what scientists call binaural hearing. Binaural hearing helps us pick up sounds that might otherwise be hard to hear with all the noise in the world. Sound that comes at you from two sides is also an advantage when you need to figure out the source of a sound, particularly one that might be a sign of danger.

Let’s say you hear a kitten meow. Probably not too dangerous. But before your brain knows that you even heard a meow, the sound travels through the air as vibrations. The vibrations enter through the bendy part of your ear made of cartilage and skin.

The vibrations make their way through the waxy ear canal. That is, until they hit a roadblock: the eardrum. It’s a good kind of roadblock, though. The sound strikes the eardrum and it vibrates.

When the eardrum vibrates, it actually moves three tiny bones. One of them looks like a stirrup on a horse saddle. The stirrup rocks in and out of a tiny opening that leads into the inner ear.

This motion creates vibrations that move along a snail-shaped part of your ear called the cochlea. This is where you start to process things like the high pitch tweet of a bird or the loud barking dog.

The signal that came into your ears now moves into your nervous system to translate the sound. Different parts of your brain help you make meaning out of sound. Believe it or not, you are actually using the part of your brain involved in hearing as you read this right now. The part of your brain that helps make meaning out of sound also helps you read.

The meow that came into your ear is no longer just a bunch of vibrations. You can understand that it is a meow and where it is coming from. Maybe the cat needs help. Maybe she’s hungry. Or maybe she’s meowing at something that you can’t hear. We cats are pretty good at picking up sounds outside the range of human hearing.

The animal kingdom is full of interesting ears. For example, jack rabbits in the desert use special circulation in their tall, thin ears to help them stay cool. Elephants can also use their big, floppy ears to scare away any potential predators. Ears can come in handy for hearing, staying cool, and keeping safe. They also help us with balance. But that’s a question for another time.

Keep sending in great science questions. As always, my friends at WSU and I are all ears.

Dr. Universe


Ask Dr. Universe is a science-education project from Washington State University. Send in your own question at askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Cow Burps

Why do cows burp methane?  -Silas, 10, Seattle, WA

Dear Silas,

There are more than a billion cows on our planet and they all need to burp. Just like us, they burp to get rid of extra gas in their stomachs.

We can’t see this gas. But we can often hear it escape our stomachs and vibrate part of our throats. And sometimes we can smell it.

We usually burp out extra air we’ve swallowed and the gas from our fizzy drinks. But for cows, it’s a little different. As you’ve pointed out, they belch a gas called methane.

I met up with my friend Joe Harrison to find out more about cow burps. He’s an animal scientist at Washington State University.

Harrison explained that a big part of the reason cows burp methane is because of their special stomachs. Humans have just one stomach compartment, he explained, but cows have four.

The first compartment in the stomach is the rumen. Cows love to eat grass and other plants. They use it to make energy. But they can’t do it alone.

Something else is moving around in their rumen: microbes. You’d need a microscope to see these tiny creatures, but they do a lot of work in the cow’s stomach. Microbes and cows are like best buddies when it comes to digesting food.

In fact, cows can’t digest some parts of plants on their own. They need help from the microbes that live in their stomach.

Inside the rumen, microbes help break down small parts of the plant into even smaller parts the cow can use for energy. As they do this, the microbes also make different gases.

Sometimes the microbes make hydrogen. Sometimes they make carbon dioxide. Some microbes make methane.

As the gas builds up, the cows have to get rid of it. Out comes a stinky burp.

Methane is not just the stuff of cow burps. It is also a greenhouse gas. Scientists are asking big questions about how this gas traps heat in the atmosphere, warming the planet and creating challenges for our environment.

Buffaloes, goats, and other ruminants burp methane, too. They all have special stomachs with four compartments. While stomachs may be different, burping is one way animals, including humans, take care of themselves. It keeps gas from building up in our bodies.

One really easy way to make up some gas of your own is to use a balloon, baking soda, and vinegar. Pour a little vinegar into a plastic bottle. Put a little baking soda inside a balloon. Stretch the balloon over the top of the bottle, then tap in the baking soda.

What do you think will happen? What kind of gas is in the balloon? Try it out sometime and let me know what you think at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in a question of your own at askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Slime

Dear Dr. Universe: What is slime? How can I make it?  -Nina, 10, Richmond, VA

Dear Nina,

Our world is full of slime makers. Slugs and snails leave behind gooey trails. Bacteria can create layers of slippery slime in water pipes. Even your body makes its own kind of slime. In our joints, we have slime that helps protect our bones.

My friend Nehal Abu-Lail is very curious about slime, too. She’s a researcher and professor in chemical engineering and bioengineering here at Washington State University. Part of her work is asking big questions about ways we can get rid of harmful slimes in pipes. She’s also interested in how we make slime so our joints move better.

Slime can behave in very interesting ways, she said. Depending on what kind of slime you are working with, it might flow between your fingers. But it also might behave more like a solid. You might even be able to roll it into a ball and bounce it.

Slime is in between a liquid and a solid. We call these kinds of fluids non-Newtonian fluids. When Sir Isaac Newton was studying liquids, he found that many flowed like oil and water. But we find things like slime flow a little slower.

Abu-Lail said the first thing you’ll want to do when making your own slime is decide what properties you want. Maybe it will be stretchy, gooey, slimy, or more solid. One way to get started is to use some Elmer’s School Glue, water, and borax detergent.

Dissolve about a teaspoon of borax in a cup of water. In another bowl, mix together about a half cup of glue and half cup of water. Then mix the two solutions together. You’ll notice slime starts to form in just a matter of seconds.

Abu-Lail explained that a very special chemical reaction is happening. The glue contains long chains of molecules. We call these polymers. And we can think of them like cooked spaghetti noodles, Abu-Lail said. They are pretty tangled up.

But if we dried the noodles a bit, and lined them up in a row, they would start sticking to each other pretty well. We could line them up next to each other in a repeating pattern. That’s kind of what happens when you add Borax to the glue. The Borax is a cross-linker. It takes those noodle-like polymers and links them together. What was once a free-flowing liquid is now thickened by polymers. Then things get slimy.

You can play with polymers and add different amounts of ingredients to see if you can change the properties of your slime. Twist it, mold it, stretch it. Try it out and see how two different things made up of different chemicals can create something totally new. Tell me about your slime science sometime at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in a question of your own at askDrUniverse.wsu.edu/ask.

Ask Dr. Universe – Animal Hibernation

Dear Dr. Universe: Why do animals hibernate?
Jarrett T., 10, Edinburgh, Indiana

Dear Jarrett,

Animals can get through winter in all kinds of ways. Us cats like to curl up on a cozy couch. Some penguins huddle in groups to create heat. A lot of birds fly south to warmer weather. Perhaps you put on mittens and a coat.

Then there are the hibernators. Some of these animals are bears, skunks, bats, frogs, and salamanders. Hibernation is like a deep, long winter’s sleep. But it isn’t exactly the same kind of sleep these animals would normally have at night.

Hibernation means big changes for these animals and their bodies. The reason they hibernate is to survive chilly winters, said my friend Nina Woodford. She’s the campus veterinarian here at Washington State University.

When scientists study hibernating animals, they find that these creatures have slower heartbeats than normal. A lot of animals can go without food for months at a time. Many don’t even have to wake up to go to the bathroom. The hibernating grizzly bears here at WSU wake up for about 15 minutes each day. They go for a quick stretch, paw their straw bedding, and rest again.

A lot of bears will spend months preparing for hibernation. While we were getting ready to go back to school, some animals were already stocking their food supply. Some animals stored their food in trees or burrows. Bears store food in their own bodies.

Researchers at WSU are learning a lot about bear behavior, including how they can survive with such a slow beating heart and so many extra pounds of fat. This year’s biggest bear, John, weighed in at 620 pounds. As he hibernates, he will lose fat. In spring, after he uses that stored up energy, he’ll be about 500 pounds. Researchers are using what they learn about bears to help us understand more about heart diseases and obesity in humans, too.

“It’s amazing how they can undergo this process and yet they are perfectly healthy,” Woodford said. “If we tried to do it, we’d become quite ill.”

Grizzly bears are big hibernators. But other kinds of bears have different techniques to survive chilly temperatures. Some panda bears migrate to warmer conditions.

Some polar bears can hibernate for about 8 months. They build dens and have other adaptations like thick blubbery fat and extra fur to help them survive in the cold, too.

And while some animals have adapted to survive chilly winters, other animals need to survive hot summers. This is called estivation. Instead of storing up food and staying warm, these animals save up water and try to escape the heat.

As as a cat that likes to snooze, I’d have to say taking a big old nap seems like quite a great way to get through the season.

Dr. Universe

Activity: Animals have all kinds of ways to stay warm in winter. Many animals that live in cold places year round have a layer of blubber that helps keep them warm. Make your own blubber!

Ask Dr. Universe is a science-education project from Washington State University. Send in your own science question at http://askDrUniverse.wsu.edu.

Ask Dr. Universe – Growing

Is it possible that we are growing every second?  – David, 9, Camas, Wash.

Dear David,

When I was a kitten, I used to keep track of my growth. Every now and then, I’d make a little pencil mark on the wall right above my ears.

We might not be growing taller every second, but parts of us do grow all the time. We grow new hair. We grow new fingernails. We grow new bone. We even grow new skin.

My friend Jonathan Jones, a scientist and professor here at Washington State University, is really curious about skin. His research helps us learn more about how our body helps heal wounds.

Skin is our body’s biggest organ, he said. It helps protect us. While you can’t see your individual cells without a microscope, your body is actually growing new ones at this very moment. And at this moment, too.

“As long as we are alive, our cells turn over,” Jones said. “I guess you could say that you turn over, or at least replace, what cells you have already.”

Every 40 days or so you’ll get a new layer of skin. Babies only take about 15 days to grow a new layer skin. I asked Jones why babies can grow new skin cells so much faster.

“We don’t know,” he said. “We would love to know why. As cells age, they get more problems. They don’t turn over as fast.”

Our bone cells have also been growing since we were babies. Our bone-building cells and bone-eating cells work away on our skeleton. In a way, our skeletal system is always remaking itself.

When you were about two years old, your brain nearly reached the size it would be for the rest of your life. We are born with tons of brain cells that will communicate with the rest of our body. For a while, scientists weren’t sure grown-ups could grow new brain cells. But it turns out they actually can grow new brain cells.

Meanwhile, other kinds of cells in our body grow pretty quickly, too. The ones in our stomach lining, for example. Our stomachs have a protective lining that we replace every five days or so. It helps keep our stomach from digesting itself.

Come to think of it, we would take up a lot of space if all our parts were literally getting bigger and growing every second. It might be a little awkward if we never stopped growing physically—if our body kept taking on new cells without getting rid of old ones.

But even if we stop growing taller, our bodies are still growing in all kinds of other ways. After all, a little more than a month from now, you’ll be in a whole new skin.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in your own science question at askDrUniverse.wsu.edu

Ask Dr. Universe – How Vaccines Work

Hi Doc Universe, I was wondering how vaccines work because I would really like to make a better way to get a shot that doesn’t hurt so much. Thanks.
–Jacob, 10, Cayman Islands 

Dear Jacob,

The quick, little sting of a vaccine shot can provide us with some big protection from germs that cause disease.

One kind of germ is a virus. Viruses are so small that you can’t see them even with a normal microscope. But if you use a more powerful electron microscope, you’d see each one wears a kind of coat with bits and knobs that stick out in different directions.

“Just like every person’s face looks different, every virus coat looks different,” said my friend Felix Lankester, a veterinarian at Washington State University.

He knows a lot about viruses, especially one that causes a serious disease called rabies. His team helps set up clinics in Africa to deliver life-saving rabies vaccines to animals. He offered to help us investigate how vaccines work.

Vaccines help kick your body’s big defense network, or immune system, into gear. When you get a flu vaccine, for example, you get a little bit of the flu virus. The virus doesn’t hurt you, though.

It’s in a really weak form but your white blood cells still notice something unusual is going on. They react by making Y-shaped parts called antibodies that attach to the virus’s coat.

“The bits that stick out of the coat of the virus are what antibodies recognize,” Lankester said. “It stimulates an immune response.”

The antibodies attack and tag the invading germs so your body knows to recognize and destroy them.

Your immune system doesn’t just fight off the germ, though. It actually memorizes it.

Particular kinds of cells in your body remember the different viruses that enter your system. It helps you build up what we call immunity. That way, if the virus returns, your body knows how to respond. It can fight off the invader before it makes you sick.

Memory cells are part of the reason we only get sick from some viruses once. When you get the chicken pox virus, your cells are able to remember. Then, if you get exposed to chicken pox virus again, your body knows to get rid of it quick and how.

Vaccines have helped eliminate serious diseases like smallpox and polio in many parts of the world. Rabies is a horrible disease that still affects people and our fellow animal friends. There is a vaccine for it, but some people live too far from hospitals and veterinary clinics to get it.

So delivering rabies vaccines to people who need it is really important. Lankester and friends at WSU are working toward a vision of a world without rabies, saving the lives of both people and their pets.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in your own science question at AskDrUniverse.wsu.edu

Ask Dr. Universe – Color of Stars

What color are our stars?
-Mira, 8, Ontario 

Dear Mira,

Just the other night, I grabbed my binoculars and looked up to the starry sky. At first the stars looked white, but when I looked closer I noticed some appeared more blue and red.

I was curious to find out exactly what color they were, so I visited my friend George Newman. He’s a physics and astronomy instructor at Washington State University.

He said that a star mostly emits the kinds of light that our eyes see as red or blue.

“The thing that determines which color they give off most is their temperature,” he said.

You may have seen the connection between color and temperature if you’ve ever made toast. The little wires inside the toaster glow red and you can feel the heat coming off them.

“We think of red as hot, but blue is actually hotter,” Newman adds.

Look closely at a flame and you’ll notice it’s made up of different colors, too. The bluish part is hotter than the reddish-orange part of the flame. It’s similar with stars.

The hottest stars are bluer. The cooler ones are redder. Of course, the cooler ones are still super hot.

And while stars may be hot at their surface, they are even hotter in their middles. Stars burn because of nuclear reactions that are continuously happening at their core. The reactions create a lot of heat and pressure.

Stars actually maintain their heat for most of their lives. But sometimes their temperatures change, as do their colors.

Young clusters of stars in the galaxy contain some of the most massive stars, which are super bright and very blue.

“There are plenty of these big hot blue stars being born in the galaxy and universe, but they burn out a lot faster, so there are a lot less of them around,” Newman said.

Stars gradually grow brighter over most of their lives. Then most puff up and cool off right near the end. They become even brighter, but redder. Older clusters will contain more stars like red giants.

One blue supergiant in our galaxy is called Rigel. While Rigel is a blue star now, it will likely puff up and get redder like another star in our galaxy, Betelgeuse.

Betelgeuse is an old, red giant. It will eventually explode in an event we call a nova, and probably become a black hole.

In fact, our sun will also become a red giant one day, too. But probably not for 5 billion years or so. The life of a star is really long and it can involve lots of different changes. The next time you look up to the night sky, remember that there’s more there than at first meets the eye.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your own question to Dr. Universe at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Trees

How long can trees live? – Jessy, 8, Seattle, WA

Dear Jessy,

As I was hiking through the bristlecone pine forests of the Sierra Nevada recently, I stumbled upon a tree barely six inches tall.

It was growing—slowly, but surely. I was surprised to find this tiny pine tree was already about 40 years old.

Some trees will stop growing once they reach that age. But others live much longer. In fact bristlecone pine trees aren’t just the oldest trees, they are some of the oldest living things on our planet. They can live for about 5,000 years.

“These trees were growing when the Egyptians were building the pyramids,” said my friend Kevin Zobrist, a forester at Washington State University.

Zobrist knows a lot about different trees and told me a bit about bristlecone pine trees.

By the time the pines are about 5,000 years old, they will stand 60 feet tall with a trunk that is nearly five feet around. If we were to cut into the trunk, we could look at its growth rings. Each ring would signify a year of its life. We would have a lot of counting to do.

On my hike, I noticed some of the trees’ young pinecones were purplish-pink. Eventually they would turn brown and fall to the ground. I spotted a few old cones by the tree. They had that fresh pine scent.

I looked up at the branches that twisted and stretched like arms up to the sky. I wondered how on earth these trees were able to live such long lives.

Zobrist explained that bristlecone pine trees are tough and have adapted to their environment. They are equipped to deal with drought, extreme climates, and insects that might cause serious damage if they attack.

For example, the tree can actually shut down or go dormant for a while, if conditions are too harsh. This helps the tree survive for thousands of years.

“They teach us that nature is resilient,” Zobrist said. “They teach us that nature can carry on.”

Of course, not all trees live quite as long as these pines. But many live longer than humans and us cats.

The redwood trees of California are about six times taller than the bristlecone pines. Some of them have been around for nearly 2,000 years.

Even when a tree dies, it finds a new life. Creatures and plants on the forest floor are counting on the trees to get old, die, and fall. They can use the fallen trees as their home or for food.

It’s been said that trees are our planet’s lungs. They help make the oxygen we breathe and keep life thriving on our planet. I took a deep breath of the mountain air and said a quick thank you to the trees before heading down the trail, on to the next adventure.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in your own question at AskDrUniverse.wsu.edu

Ask Dr. Universe – Space Volcanoes

Dear Dr. Universe: I was just wondering if there are any volcanoes on any other planets? -Danny, 10, Kenmore, WA

Dear Danny,

The answer to your question takes us out into our solar system and deep below the surfaces of other moons and planets.

It also takes us to the tallest building here at Washington State University. That’s where I met up with my friend Katie Cooper, a geologist who studies Earth and objects beyond its atmosphere.

“The largest volcano in our solar system we’ve found so far is actually not on Earth. It’s on Mars,” she said. “It’s called Olympus Mons and it’s much, much larger than any volcano we have on the Earth.”

We tend to think of the tallest feature on Earth as Mt. Everest. But it’s actually Mauna Kea, one of the five volcanoes that make up the Big Island of Hawaii. If you measure from its base on the seafloor to the peak, it’s actually taller than Mt. Everest.

“But on Mars, the Olympus Mons is almost three times as high as Mt. Everest,” Cooper said. “So, it’s a whopping large volcano.”

Olympus Mons and volcanoes here on Earth erupt molten rock, or lava. But there are also volcanoes in the solar system that erupt ice.

As a scientist, Katie is sometimes a kind of ice detective. She’s helping the people at NASA study frozen water on one of the moons of Jupiter, a big gas planet.

“Well you know, NASA is like the head of curious people, I would say and so they have sent tons of satellites out circling these planetary bodies,” Cooper said.

In fact, we’ve found that Venus has more than a thousand volcanoes. Neptune and Jupiter’s moons eject water and other gases like geysers do. On one of Jupiter’s moons, large plumes of gas can eject so high that spacecraft can see them as they pass by.

“We look for things that are tell-tale similar to what we see on Earth or might be incredibly different from what’s here on Earth, like ice volcanoes, which we don’t have necessarily here on the Earth,” Cooper adds.

Some of the ice volcanoes are on moons of giant gas planets. But it looks like Pluto has a volcano that might be erupting ice, too.

We still have lots more to explore when it comes to volcanoes on other planets. In the future, we will need scientists to help us understand more about the planets and our Earth.

Cooper explained that when looking for volcanoes on other planets, it’s almost like you have to use your imagination – a very well informed imagination.

“Always continue to remain curious,” Cooper said. “That’s what drives science. It can even be very simple questions, how do we even have volcanoes? How big can they get? Those questions aren’t completely answered yet.”

So keep asking smart and baffling questions about our universe. Maybe one day you can even help us find some more answers about volcanoes on other planets.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in your own question at askDrUniverse.wsu.edu.

Ask Dr. Universe – Digestion

Dear Dr. Universe: How does digestion work? –Abi, 12, U.S.; Megha R., 11, Dubai

Dear Abi and Megha,

All around the world, animals are eating all kinds of different foods. Our foods might be different, but one thing is true for all of us: We have to digest.

I decided to visit my friend Bob Ritter to find out how this works. He’s a researcher here at Washington State University who is really curious about the connections between our brain and stomach.

“What we eat at lunch is almost completely digested by the time we are ready to eat dinner,” he said. “It is digested, absorbed, and the food has totally changed.”

The molecules that make up a piece of meat or a vegetable on your plate are too big for your body to use, at least at first. The body breaks down the food using a nearly 30-foot-long digestive tract that runs from your head to your rear end.

And while we may all digest, different animals have different kinds of tracts. Ritter explained that a python could go for about six months without food. When it comes time to eat a meal, usually in a single gulp, the python’s digestive system will suddenly grow bigger.

Unlike pythons, humans need to eat much more often. The human digestive system can help you digest a meal in just a few hours or less.

Muscles in your stomach squeeze and occasionally grumble to tell your brain that you’re hungry. When you smell or even see food, your mouth starts to water. Even the sound of food going into my bowl makes my mouth water. This saliva helps us soften and break down food so we can swallow it.

The muscles in the esophagus, a long tube in your throat, help push food down into your stomach. There, your stomach acids and enzymes help you break down the food. Most of the food is now about the size of a grain of salt.

These little pieces move onto the small intestine, which is pretty big, despite it’s name. It’s here where the big chemicals in food are broken down to small ones that the body can absorb into your blood, like sugars, amino acids, and fatty acids.

There is a lot of surface area that makes it possible for your body to absorb these helpful nutrients, too. If you unfolded your small intestine on a flat surface, it would likely cover a tennis court, Ritter said.

Once the nutrients are absorbed, the large intestine absorbs water from the digested mix and helps give it back to your body. Some harder parts are left behind and get ready to leave the body. Pretty soon, nature calls.

Whether you are a cat, a python, or a human, the digestive system not only fuels your body, but also protects it. Humans even have a special lining in their stomach that gets replaced every few days to protect them from invaders like toxins or bacteria. It’s something to chew on the next time you sit down for dinner.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your own question to Dr. Universe at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Cats

Hi Dr. Universe! I’m Bree and I just wanted to ask, how do cats land on their feet?  -Bree, 10, Williamsburg, VA 

Dear Bree,

Curiosity can lead us cats to some pretty great heights. We like to climb trees and sneak along tall bookshelves. Sometimes we might have a bumpy landing, but more often our amazing cat reflexes help us land on our feet.

Like my fellow felines, I’ve been using my reflexes to fall on my feet ever since I was about three weeks old. But even I wasn’t sure exactly how this worked or why it doesn’t work all the time. I decided to visit my friend Matt McCluskey, a physicist at Washington State University, to find out more about it.

At first I thought the answer to your question might have to do with our tail. I suspected that as cats fall through the air, the tail helps us find balance. But it turns out cats without tails can land on their feet, too. There’s a little more to it.

McCluskey and I came across this fact in a study from a scientist in London who investigated your very question more than half a century ago. The scientist slowed down pictures of falling cats and observed their movements. He found that the cats landed in a very particular way. He published an article about it in New Scientist called, “How does a cat fall on its feet?”

Looking at the pictures of falling cats, he found that we first use our sharp ears and eyes to help us figure out which way is up. Our head, the lighter end of our body, twists one way. Then the heavier end of our body, the rear, follows. We use this movement to try to maneuver our bodies back to normal and brace for landing. Scientists call it the air-righting reflex. It’s what helps us go from free falling to feet on the floor, often in less than a second.

Our flexible spine and lack of a collarbone also make it possible for us to arch our backs in mid-air. We can arch our backs when we feel threatened, when we stretch, or to help us land after our body twists. Our arched backs help stabilize our bodies, preventing them from rotating, just before landing. McCluskey explained that even though our tails aren’t fully responsible for helping us land on our feet, they do help us be more stable upon landing.

There are actually so many cases of cats falling out of windows that veterinarians have a name for it: high-rise syndrome. Some researchers have found that cats who fall from greater heights have a better chance of landing on their feet than cats who fall shorter distances. It might be because they don’t have enough time to go through all the different movements that help them stick the landing. Sometimes we stumble. Sometimes we land in style. It’s all feline physics.

Dr. Universe

Ask Dr. Universe is a science education project from Washington State University. Send your own question in at askDrUniverse.wsu.edu

Ask Dr. Universe – Planet Earth

Why does the Earth spin?
–Morven, 8, Dundee, Scotland; Judith, 9, Sabah, Malaysia; Mara, 11, USA

Dear Morven, Judith, and Mara:

No matter how still we stand, or if we’re in Scotland, Malaysia, or the United States, we are always spinning. Our Earth spins at a constant, very fast speed as we make a trip around the sun.

But it’s not just the Earth that spins, said my friend Guy Worthey, an astronomy professor at Washington State University. The moon, the sun, and almost all the other planets spin, too.

Your question actually has a lot to do with our early solar system. Scientists think the solar system started out as a kind of giant pancake, Worthey said.

Not like a pancake you’d eat for breakfast, of course. It was more like a giant pancake-shaped cloud of gas and dust. The pancake was a unit, with all parts of it spinning in the same direction, Worthey explained.

“When the planets started to form out of this big mass of gas, they shared not only the same mix of material, but also a sense of spin,” he said. “Like little whirlpools in a bigger whirlpool.”

The Earth has been spinning for billions of years, but it’s also been slowing down ever so slightly. Some scientists are interested in tracking this, too. They’ve found that the spin slows just a fraction of a second each year. If the Earth keeps this up, it would take trillions of years before it ever stopped spinning,

The length of a year, 365.24219 days, which is how long it takes the earth to travel in a huge circle around the sun, is not changing very much. The length of a year is different depending on how a planet orbits in a huge circle around the sun.

Our Earth spins around on its axis, a kind of imaginary pole that runs through the planet from north to south. The Earth spins all the way around its pole to make one complete turn each day, or 24 hours.

But if you were to visit Venus, one day would last as long as 243 Earth days. Venus spins much slower than Earth. Scientists think that an object might have hit Venus and knocked it around a bit after the solar system formed, slowing its rotation. Uranus is another planet that spins in its own unique way. It’s got an unusual tilt that makes it spin on its side.

Our Earth also has a tilt. As it spins, it doesn’t sit upright on its axis. The imaginary pole that runs through the middle sits at an angle of 23.5 degrees compared to solar system north. This tilt makes it so that some parts of the planet get different seasons.

It’s exciting to know curious cats from all around our world are stopping to wonder about our Earth’s spin. Now, let me spin a question back to you. No matter how still we stand, we are spinning. But perhaps you’ve noticed you aren’t getting dizzy or flying off the planet. Why might that be? Send me your thoughts at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Submit your own question at http://askDrUniverse.wsu.edu.

Dr. Universe – Memories

How do we remember stuff?
– Aidan, 11, Franklin, Indiana

Dear Aidan,

Our brains have an incredible ability to help us remember all kinds of stuff. Of course, memory isn’t perfect. Sometimes we forget our homework or where we left our favorite cat toy.

My friend Maureen Schmitter-Edgecombe, a scientist at Washington State University, is also very curious about memory. Her research focuses on using creative technology to help people who have serious memory loss.

She explained that an important part of how we remember has to do with our hippocampus. It’s a seahorse-shaped part near the middle of our brain that plays a role in forming new memories.

Humans who have a missing or damaged hippocampus, like those in the late stages of Alzheimer’s disease, can’t form new memories, but they can still retrieve some of their old memories.

If you are anything like me, you know that a single smell, song, or picture can take you on a trip down memory lane.

In fact, your question reminded me of when I was first learning about our solar system.

I was having a tricky time remembering the order of the planets. Until I found out about this: “My Very Educated Mother Just Served Us Nachos.”

The first letter in each word helps you remember the names and order of the planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. I repeated this phrase over and over again to help the new information stick.

Strategies like this can help us remember big chunks of information and lay them down as new memories.

Another important part of remembering is being really attentive to information as we learn it, Schmitter-Edgecombe said. A good night’s rest can help us stay alert during the day. Some scientists are even investigating questions about how sleep triggers changes in your brain that help memories solidify.

Schmitter-Edgecombe explained that once we attend to the information, we have to help get it into long-term memory.

One way to do this is to connect new information with something you already know. As you read, your brain may be making connections with other things that you’ve learned before. The connections between your brain cells strengthen and may make it easier to remember what you have read.

And we have quite a bit of space for our memories, too. According to the magazine Scientific American, if your brain worked like a TV’s digital video recorder, it would likely hold three million hours of TV shows. And it would need to be running for nearly 300 years to fill up all the storage space.

That makes strategies for remembering the important things even more useful. Creating songs, poems, or drawings can also help our brains create stronger connections to the new information. You could even try out a few of these memory devices and see what works best for you or your friends. Let me know what you discover at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University.

Ask Dr. Universe – Fears

Dear Dr. Universe: Why do we find some things scary? -Jack H., 8, UK 

Dear Jack,

While our fears might be different, we all get scared sometimes. Vacuums, dogs, and even cucumbers make my hair stand on end. Perhaps for you it’s spiders, the dark, or the thought of monsters under your bed.

My friend Michael Delahoyde is really curious about what freaks us out. As an English professor at Washington State University, he’s even taught a course about monsters.

Delahoyde explained that our brains like to categorize information to help us make sense of our world. But monsters sort of live between different categories.

“We are comfortable with animals. We are comfortable with humans. We’ve got the distinctions down,” Delahoyde said. “But when you have a monster, like a werewolf who is somewhere in the middle, then it freaks us out.”

We can’t quite put our finger on what is happening, so we feel a sense of uncertainty. Zombies also break categories and laws of nature, as they are both living and dead.

Every culture has its own monsters, too. One in Japan is the bakeneko, a supernatural, shape-shifting cat creature whose presence in stories is often seen as a sign that a strange event is about to occur.

Our hearts start pumping. Our pupils get bigger. Our hands get sweaty. We might even get goose bumps or chills. The fear center of our brain, a little almond-shaped part called the amygdala, gets to work.

Our brain and body are getting ready to make a decision about what to do in the scary situation. We have to decide whether to face it or run away.

In some situations, our response to this fight-or-flight situation can be thrilling. That’s why some people actually enjoy watching scary movies. They know they are safe, even if they occasionally have to cover their eyes with their paws.

My friend Jaak Panksepp, a researcher in the WSU College of Veterinary Medicine, is also curious about emotions, like fear, in animals.

All of our brains contain a fear system, he explained, which is designed to protect us from harm. When this system is at work, we have a feeling that can be described as scary.

While our ancestors may not have come face-to-face with werewolves, they may have encountered a saber-toothed cat. They would have to make a decision to fight it or run. The fear system automatically tells us to avoid such situations. It also helps us figure out, often in an instant, how to deal with similar frightening events in the future. Fear helps us survive.

Our personal fears can actually change, as we grow older, too. We might become fearful of new things or learn to become less afraid of the things we once feared, like dogs or monsters under the bed.

Do you have an idea for a monster of your own or a scary story to share? Send in your drawings or stories to Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send in a question of your own at askDrUniverse.wsu.edu.

Ask Dr. Universe – Spiders

Dear Dr. Universe: How do spiders make silk? Also, sometimes spiders hang down from the ceiling, when they climb back up, where does the silk go? –Johnny, 8, Pullman, WA

Dear Johnny,

Spiders can do some amazing things with their sticky, stretchy, and super-strong silk. Us cats are pretty curious about these little silk-spinning machines, too.

Besides chasing spiders around, I’ve watched them use silk to build webs, catch bugs, and protect their young spiderlings.

Some spiders will even eat their own web. Imagine if you could build your own house and eat it, too.

Spiders have lots of jobs to do and eating their web is one way they can get a bit of energy. It’s also a good back-up meal in case they don’t catch any bugs. After all, their silk is made up of protein.

Inside their rear-ends, or abdomens, spiders have a liquid made of watery proteins. They also have special, nozzle-like organs called spinnerets. Along with some chemical reactions in the abdomen, spinnerets help spiders transform those watery proteins into silky strands.

That’s what I found out from my friend Beverly Gerdeman, an entomologist at Washington State University. Like you, she’s also very curious about bugs and spiders.

Gerdeman explained that spiders have two or more spinnerets. The exact number depends on the kind of spider you are.

While it might look like spiders make just one strand of silk, they actually make a whole bunch of strands spun together like a rope.

The silk is extremely flexible and can stretch up to four times its original length. And even though it’s lightweight, it’s really strong. In fact, spider silk is stronger than a piece of steel the same size. It’s a great material for building things.

Not all spiders build webs, but a lot of them do. Different spiders can also spin out silk in different thicknesses for different jobs.

Some spiders will use the silk to go “fishing” for bugs, wrap cocoons around their young, and even travel long distances.

A lot of young spiders, for example, can throw up a line of silk and wait for a draft of air to carry it away. Then they can control their movement using their legs and silk—much like your friendly neighborhood Spiderman.

It helps them move their population around. Some pilots have reported seeing spiders drifting along more than 10,000 feet up in the air.

Spiders may throw up a line of silk to help them travel, but as you observed, they also drop their lines down.

I’m not a scaredy cat, but I admit I get a little surprised to see a spider in front of my nose.

Sometimes, the spiders will climb back up their line really fast. The silk doesn’t go back into the spinneret, though. It likely just gets knocked away in the breeze or the spider pulls it back up for a snack. Mm, protein.

Once they eat their web, some spiders will recycle it back into their abdomen, so they can keep on spinning.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your science question to Dr. Universe at askDrUniverse.wsu.edu.

Ask Dr. Universe – Dr. Universe’s Favorite Experiment

What is Dr. Universe’s favorite experiment? -Garrett, 8th grade, Eastern Washington

Dear Garrett,
You know, your question reminds me of a couple other science questions from curious readers. Evangeline, age 7, wants to know why her hair is black. Sureya, age 8, wants to know why some people have curly hair.
It just so happens that one of my favorite science projects explores our questions about what makes us unique. It has to do with our DNA, or the blueprint for life.
Not too long ago, some of my friends at Washington State University showed me how to extract DNA—from a strawberry.
You can try it at home, too. You’ll need simple ingredients, including dish soap, meat tenderizer, rubbing alcohol, and strawberries. Find all the details at AskDrUniverse.wsu.edu/strawberry_dna.
Just like humans, strawberries and other plant life are made up of cells. Inside cells, you’ll find their DNA.
Your DNA contains the instructions for your eye color, hair color, and if that hair is straight or curly. These traits can be passed down through generations.
A strawberry’s DNA also holds information about the fruit’s color, size, and shape, and that it has seeds growing on the outside.
When we extract DNA from a strawberry, we have to bust through a few parts of the cell to get to the DNA. We start out mashing up the strawberries with a little water and pouring the smoothie-like liquid into a test tube.
Then we add a little dish soap to help dissolve a layer around the DNA called a membrane. Next, we add a bit of meat tenderizer to break up proteins that help hold different parts of the DNA together. But the DNA can’t separate from the rest of the ingredients without one final step.  
Add some cold rubbing alcohol to the mix and it will pull DNA up to the top of your test tube. When you try this out, ask yourself—does it look a bit like a booger floating in your tube? If so, you’ll know you’ve got the strands of DNA.
While living things carry around DNA in their cells all the time, it’s not every day people actually get to see it up close. That’s what my friends and I like most about showing people how to extract it.
If you want to turn this project into an actual experiment, you’ll need to test an idea or question about the extraction, too. What happens when you add more or less of an ingredient? Can you extract DNA from all vegetables and fruits? I’m sure you can think up even more questions to test out.
Give it a try one day and let me know how it goes. In the meantime, tell me about the latest science project you tried at home or school. Email 
Dr.Universe@wsu.edu or write to Dr. Universe, PO Box 641227, Pullman, Washington, 99164-1227.  
Dr. Universe
Got a science question? Email Dr. Wendy Sue Universe at Dr.Universe@wsu.edu. Ask Dr. Universe is a science-education project from Washington State University.

Ask Dr. Universe – Volcanoes

Why do volcanoes “die”? – Loretta, 11, Mexico

Dear Loretta,

Each volcano’s life is a little different. Many of them are born when big chunks of the Earth’s crust, or tectonic plates, collide or move away from eachother. The moving plates force hot, liquid rock, or magma, to rise up from deep within the Earth.

When things get super hot and lot of pressure builds up in the magma chambers, volcanoes can erupt. Some volcanoes can spew ash and lava several miles into the sky. Others will slowly ooze out lava.

Just as each volcano is unique, so are the reasons they go extinct. Generally, though, if a volcano doesn’t have a source of magma, it won’t erupt.

That’s what I found out from my friend John Wolff, a geologist at Washington State University. To explore more about how volcanoes lose their magma, Wolff and I headed to the plains of southeast Idaho. There, the remains of really old volcanoes are buried underground.

Millions of years ago, we would have been able to see these volcanoes at the surface. They might have been spewing out lava and ash. But now, they no longer have their source of life.

If you are anything like me, you might be wondering what on Earth happens to the magma. Wolff is really curious about this, too.

He explained that volcanoes, and all of us, are riding on pieces of the Earth’s crust.

These pieces of crust move very slowly—just about as fast as our fingernails grow. They move over heat sources, zones of hot, upwelling rock from deep in the Earth’s interior. It melts the crust when it gets near the surface to fuel the volcano.

“It’s burning a hole in the plate,” he said. “Just like if you passed a plastic sheet over a candle flame.”

Eventually, when volcanoes have rafted away from the heat source, they falter and die.

As the Earth’s crust moved, slowly but surely, over millions of years, the magma that was under old volcanoes in southeast Idaho ended up in Wyoming—under a big super volcano.

Never having seen a super volcano before, I imagined a huge mountain erupting tons of lava. You can imagine my surprise when Wolff explained that this super volcano was actually Yellowstone National Park.

Millions of years ago, the Yellowstone super volcano erupted and collapsed. There is still magma under Yellowstone, but we don’t expect it to erupt anytime soon.

While a volcano may need to have magma to stay alive, there are still volcanoes that have a magma supply and can sleep for millions of years—and you thought us cats slept a lot.

Some scientists are really curious about how the landscape changes, both above the ground and below it. In fact, they ask questions that are a lot like yours, Loretta. Who knows, maybe one day you could help us investigate the lives of volcanoes.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question in at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Cheetahs

Why do cheetahs run fast? –Shanyu, 9, London, UK

Dear Shanyu,

Cheetahs are in really good shape. Not only are they good runners, but the actual shape of their body helps them move at incredible speeds.

As the fastest cats on the planet, they can reach 75 mph. Whenever I lace up my shoes and run, I can only reach about 30 mph. Us tabby cats are pretty quick, but not quick enough to outrun a cheetah.

The difference has to do with a cheetah’s amazing anatomy—everything from its head and skeleton to its muscles and feet.

That’s what I found out from my friend Bethany Richards. She studies veterinary medicine here at Washington State University and is president of the Zoo, Exotics and Wildlife Club.

“Cheetahs are so lean and just cool,” she said, recalling a recent safari in Africa, where she saw them running around.

She explained that a cheetah’s spine is very flexible. It’s more flexible than other cat spines. The spine is so flexible that it allows the cheetah to quickly move its two back feet ahead of its two front feet. Along with some unique hips, this movement helps the cheetah get more distance per stride.

This allows the cheetah to take four long strides each second. In fact, if you slow down video of a sprinting cheetah you see it spends more time in the air than on the ground.

A cheetah also has strong muscles to help the spine move. They are made of special fibers that are ideal for sprinting short distances. Their small skulls and narrow bodies keep the big cats aerodynamic as they zip through the air. They also use their big nostrils and big lungs to breathe as they run.

Richards explained that another important tool that cheetahs use for speed is their claws. Unlike the rest of us cats, cheetahs can’t retract their claws into their paws. This lets their paws work more like cleats. They can dig into the ground and not have to worry about swerving out of control at high speeds.

Cheetah populations are actually pretty small. They are an endangered species—they are at risk of extinction—and the mothers don’t have too many cubs. They need their speed to survive, Richards explained.

“It made sense that the fastest cats would be able to get to the best food to provide for their limited number of young,” she adds.

Of course, speed can be very useful when looking for dinner. But once the cheetahs catch their prey, they have to rest before eating. Scientists have also found that a cheetah’s agility—its ability to turn quickly and sharply while running—may be just as important to the hunt as speed. Put the two remarkable abilities together and you’ve got one cool cat.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your science question to Dr. Universe at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Cheese

What is cheese exactly? –Mark, 11

Dear friends,

Cheese is delicious. At least, that’s this cat’s professional opinion. For the more scientific answer, I visited the cheese makers here at Washington State University.

Cheese is the fat and protein from milk, said my friend John Haugen who runs the WSU Creamery where they make Cougar Gold Cheese.

At the creamery, students test milk from the dairy to make sure its fat and protein ratio is just right for cheese. They also heat up the milk to get rid of any bad bacteria—it’s a process called pasteurization. Not all bacteria are bad, though. In fact, some bacteria are really helpful for making foods, including yogurt, pickles, and cheese.

All cheese is made with a kind of lactic acid bacteria. These tiny little organisms are so small you would need to use a microscope to see them. They eat the sugar in the milk and make acid. The acid gives the cheese its tangy flavor.

There are even certain kinds of bacteria that are in charge of making the holes in Swiss cheese.

As Haugen explained how they add bacteria into the milk, I wondered how the liquid mix becomes a solid.

Haugen said that we need an enzyme, a protein that has a very special job to do. In cheese, enzymes work on protein in milk to break the bonds that keep it together. The protein opens up and sticks to other proteins around it to create a solid. If the enzyme does its job, the liquid will thicken, or coagulate.

“It’s almost looks like thick yogurt,” he said.

After that, the cheese makers will cut up the coagulated milk. When it starts looking a bit like cottage cheese, a machine pumps the mix onto a metal table.

This mix is partly made up of whey, which is mostly water. The other part of the mix is the soft, fresh curds. You can eat the cheese curds. They are tasty. Trust me. But they aren’t quite officially cheese yet.

First, the student cheese makers will pack the curds together into big loaves. They will flip the loaves over several times in a process called “cheddaring.”

If you wanted your cheese to be stringier, softer, crumblier, or harder, you might treat it a little differently. But at the creamery, Cougar Gold gets cheddared, chopped up, and salted to kill off some of the remaining bacteria and to keep it from liquefying.

The cheddaring process is actually named after the place where cheddar was first invented—Cheddar Gorge in England.

During the 12th century, people kept their cheese in caves. The temperature and humidity was just right for storing cheese.

At the WSU Creamery, cheese is also stored at just the right temperature, but inside tin cans.

“It’s almost like its own little cheese cave,” said Haugen. The cheese will stay in the can one full year before we eat it. Aging the cheese helps bring out the flavors.

After my visit to the creamery, I learned cheese is not just delicious. It’s milk, bacteria, enzymes, and salt. It’s science.

Dr. Universe

Ask Dr. Universe – Leaves Changing Color

Why do leaves change color? –Lucy, 5, Seattle, WA
Dear Lucy,
Ever since I was a kitten, I’ve loved picking up big maple leaves in the fall. I’d take them home, put them under a piece of paper, and rub the side of a crayon over the top. It makes a great print of the leaf.
Leaves actually get their color from things called pigments. While scientists can use chemicals to make different crayon colors, nature can use pigments to create its own colors.
When leaves are green, they have a pigment called chlorophyll. Chlorophyll is not just important for color, though. Plants also need chlorophyll to collect energy from the sun to make their own food. Imagine if you could soak up sunshine, water, and stuff from the air to make your own food. That’s what plants do. They make their own food in a process we call photosynthesis.
My friend Asaph Cousins is a scientist at Washington State University who knows a lot about how plants function. He’s really curious about photosynthesis, too.
“It’s a remarkable process that helps convert energy from the sun into food for plants,” he said. “It’s a key part of life on our planet.”
Cousins explained that chlorophyll has the job of soaking in the sunlight and using energy to convert some gas from the air into sugars. In the spring and summer, when the sun is out, a plant needs to make a lot of chlorophyll to help create food. But in some places of the world, like here in the Pacific Northwest, the sun starts to set earlier and it gets colder in fall.   
As we pull out our scarves and mittens, trees get ready for the changing season in their own way. Their growth decreases and they start to store up some of that energy they made earlier in the year. This means photosynthesis slows down and they don’t need as much chlorophyll to make food. Photosynthesis slows and the chlorophyll inside the leaves breaks down—so we see less green before the leaves fall off.
Chlorophyll isn’t the only pigment in a leaf. There are also carotenoids, which are pigments that give fall leaves the yellow and orange colors we see. It’s the same pigment we find in sunflowers and carrots, too. You may remember from our question about apples, that the pigment called anthocyanin is responsible for the red color in the fruit. The same is true with red leaves.
Because there is so much chlorophyll in the leaf, it isn’t until the chlorophyll breaks down that the fall colors really start to pop out. Of course, not all trees lose their leaves in fall and grow new ones back in the spring. But the ones that do lose their leaves—the ones we call deciduous trees—can transform their colors in just a matter of weeks.
Once the leaves finally fall to the ground they make for some great piles to jump in, inspiration for art projects, and beautiful autumn scenes.
Dr. Universe 

Try it out! What can you create with leaves? Send a pic of your own fall leaf project to Dr.Universe@wsu.edu. Ask Dr. Universe is a science-education project from Washington State University.

Ask Dr. Universe – Lunar Rovers

How do lunar rovers work? -Pedro, 10

Dear Pedro,

When I got your question, I started to imagine what it would be like to drive a rover on the moon. As we bounced along craters, we could kick up moon dust and stop to gather samples of moon rock.

Rovers on the moon, and other kinds of exploration vehicles, have helped us learn about places that are hard for humans to reach on their own. Each rover has a mission and they need a few key things to work.

First, a rover vehicle needs a power source. Some rovers are battery-powered, like the lunar roving vehicle. Other rovers use solar panels to harness energy from the Sun. These solar panels are usually on top of the rover. The electricity they produce powers the wheels and the sensors the rover uses to conduct science experiments.

Scientists and engineers ask questions about what job they want a rover to do, and the environment where the rover will be working. The moon, for example, has no air. The tires we Earthlings have on our bikes and cars wouldn’t work on the moon. In fact, these kinds of tires would explode there. On lunar roving vehicles, tires are made up of a steel wire mesh. They support the rover’s weight, and astronauts don’t have to worry about getting a flat tire.

While lunar roving vehicles required astronauts to drive them, some rovers go on solo missions. Well, they aren’t totally alone. As they dig in the extraterrestrial soil and take pictures of these distant places, they communicate what they learn back to Earth.

Scientists send out computer commands that tell the rover what to do using super-powerful radio transmitters. The rover’s antenna helps send and receive the messages. It takes about a one second delay to command a rover on the moon and up to 22.5 minutes to communicate with one on Mars.

I decided to meet up with my friend Phil Engel to learn more about Mars rovers. He and a team of fellow student engineers from Washington State University recently brought back their award-winning rover from a global competition at the Mars Desert Research Station in Utah.

Their rover has an arm, or excavator, to dig for samples of dirt. The rover also uses sensors—like those you can buy to test your garden’s soil—to get the scoop on what’s in the dirt, including its temperature, humidity, and saltiness.

“What a rover vehicle does on Mars is pretty simple,” Engel said. “But what we are doing here on Earth with that rover is pretty extraordinary.”

While it might not sound exciting to look for dirt, these samples can tell us a lot about the planet or moon. The elements in these samples can help us find answers to some of our big questions about life on Mars—if there used to be life there, if there’s life now, or if life could be there in the future.

Whether on Mars, the moon, or even remote places on our own planet, rovers roam around to help us explore and discover. Who knows—maybe one day you’ll help find new ways to make them work and build rovers that are out of this world.

Dr. Universe
Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr.Universe@wsu.edu

Watch the WSU team’s rover here: https://askdruniverse.wsu.edu/2016/06/23/lunar-rovers-work/ 

Ask Dr. Universe – Apples

Why are apples red? -Emily, 5, Seattle, WA

Dear Emily,

Just the other day I was biting into a crunchy, delicious red apple when I was reminded of your question. I started wondering why apples are red, too.

I called up my friend and apple expert Kate Evans, a scientist here at Washington State University. Her research helps us develop new kinds of apples.

Before she answered your question, she had a question for us to wonder about, too.

“What might the benefit be for a tree to have red fruit?” she asked. I thought about it for a moment. Then I remembered that in nature, colors could sometimes help send a message to plants and animals.

The message might be “Don’t eat me,” as is the case of some brightly colored poisonous frogs. Other times it might be a chameleon using its colors to attract a mate, like saying “Look over here!”

Evans explained that the apple’s red color might just be a way of telling hungry animals, “We are delicious.”

Long before humans were shopping for apples at the supermarket, bears were scavenging for the fruit in forests. Bears have a good sense of smell and pretty good vision that helps them look for food. One idea is that bears are particularly attracted to red, a color that really pops.

“A red apple is kind of a pretty, attractive, easy-to-see piece of fruit, especially against the green leaves,” Evans said.

When bears see the red fruit, they eat it, digest it, and poop out the seeds. In fact, Evans said, the point of the tree having fruit at all is to help the tree spread its seeds. That way new generations of trees can grow.

Of course, you may have noticed that not all apples are red. Some are yellow, pink, or green. Red apples get their color from anthocyanins. These are pigments, or natural colorings, that develop as the apple grows. We also find these pigments in cranberries, raspberries, cherries, cabbage, and other red or purple foods.

Whether you are on four legs or two, the red color can be really appealing, Evans said. A lot of humans like to eat red apples, too. Here in Washington State, we produce more than 2 million tons of apples each year, far more than any other state.

Another way to think about the answer to your question may be to look at how we see different colors. When we look at a red apple, it’s absorbing colors from the sunlight. It absorbs all the colors of the rainbow—except for red. The red light reflects off the apple and our brain and eyes work together to let us know what color we are seeing.

Red is a color that can be appealing to both humans and other animals. It’s also one of my favorite fall colors. To celebrate the season, I’m off to pick some red apples and press them into delicious cider.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr. Universe at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Suns

How many suns are in the universe? -Kristen, 8, Pullman, WA

Dear Kristen,

Our sun is really one big star. And there are billions and billions of stars in our universe.

“More than we can even count,” added my friend Phil Lou. He’s an expert on solar energy here at Washington State University. He’s really curious about finding ways to power homes and schools using energy from the sun.

“Most of the energy and life around us that we know is linked to the sun,” he explained. Then we put on our sunglasses, slathered on some sunscreen, and headed out to explore.

As we walked along, we spotted some grass and plants. Lou pointed out that plants use energy from the sun to help make their own food. A leftover from this process is the oxygen that we breathe.

Humans can also get energy when they eat plants—or eat the animals that once ate the plants. The sun also puts energy into the oceans and evaporates water, which helps keep water moving through the planet. The sun heats land and air which causes wind and weather. All this energy from the sun is really important to support life on Earth, Lou explained.

“It also makes Hawaii and Fiji great places to go,” he added. It sometimes makes for nice sunny catnaps here where I live in Washington state, too.

Even the oil, coal, and gas we get from the ground and use to power cars and make electricity started with energy from the sun. These kinds of fuels came from old decomposing animals and plants—animals and plants that got their energy from the sun’s rays.

Stars, like the sun, can come in all kinds of colors, shapes, and sizes, too. Scientists put them in different categories depending on their size, brightness, and other characteristics. According to these rules, the sun falls into the category of a yellow star.

Scientists have also calculated that it’s about 27 million degrees Fahrenheit inside the sun’s core and more than 9,000 degrees Fahrenheit on its surface. Thankfully, we are 93 million miles away, so we get just the right amount of warmth and energy from it.

Although our sun might be the closest star to us on Earth, it certainly is not the biggest or brightest star in the universe.

“Our sun is fairly puny compared to some other stars,” Lou said.

In fact, if you put our sun next to the giant star VY Canis Majoris, you could barely see it. It’s a speck, like a grain of sand next to a basketball. Consider the fact that you could fit a million Earths in our sun and you can start to realize just how big some stars can get. We are still learning about different stars and if there might be more sun-like stars out in our universe.

“It gives us something to really ponder,” Lou said. “Isn’t that great?”

We would love to hear more questions from you about solar energy and how it works, too. Or send us your own ideas about how to use energy from the sun to power our world. Write to Dr. Universe at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr.Universe@wsu.edu or read more at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Colors

How many colors can we see? –Andrew P., 12

Dear Andrew,

The human eye can see millions and millions of colors. But believe it or not, some colors exist in our world that the human eye can’t see.

That’s what I found out when I went to visit my friend Rachna Narula, an optometrist at the Washington State University Vision Clinic. Using a special camera in her office, she took a picture of my retina, the part in the back of the eye that helps us see color.

Seeing color requires light, she said. When light comes into the eye, it travels to the retina, bounces around, and triggers certain nerves. This sends a signal to your brain. The brain helps translate this signal into an image. In fact, the brain actually plays a big part in how we see color. When you were a baby, your brain was still developing and so was your color vision, Narula said.

Narula explained that humans don’t typically develop full color vision until they are about half a year or so old. Scientists generally agree that babies can only see about eight inches in front of their faces. It’s a pretty blurry view, too. Babies’ eyes are more likely to pick up on black, white, and shades of grey, rather than colors.

But as the brain and eyes develop, they start to pick up on more color differences. The retina in the back of your eye has millions of tiny parts called cones. There are three kinds of cones typically found in the human eye: red, blue, and green.

It’s these three kinds of cones that work together and allow you to see millions of colors. If a person is missing one kind of cone or all of these kinds, they might have a kind of colorblindness. Scientists also think there might be a fourth kind of cone, Narula added. But they are still investigating to find out for sure.

Of course, we can’t know exactly what colors babies or other animals see because they can’t tell us. Instead, we can use what we know about the eye and cones to put together an idea of how it all works.

We cats have red, blue, and green kinds of cones, too. Dogs have only two kinds: one for blue and one for yellow. The mantis shrimp, with their rainbow-patterned exoskeletons, have 16 kinds of cones. This particular shrimp can even see certain kinds of ultraviolet light that humans can’t see. Different kinds and numbers of cones can give animals vastly different experiences of how they see the world.

After all, even a single color can change depending on the lighting, shadows, or environment. Who knows—maybe one day you’ll invent a color counting machine and we’ll be able to get an even better estimate of how many colors exist. In the meantime, pull out the crayons or mix some paint. Dr. Narula and I would love to see what colorful things you can create. Send a picture to Dr.Universe@wsu.edu for a chance to have it featured with this column on AskDrUniverse.wsu.edu.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr.Universe@wsu.edu.

Ask Dr. Universe – Seashells

Why do we hear the sea in a seashell? -Steve, Minnewaska School, Minnesota

Dear Steve,

Whenever us cats go to the beach, we tend to keep a safe distance from the water and like to explore the shore. I once stumbled upon a big, beautiful pink and white seashell.

When I put my ear up to it, I heard the familiar sound of whooshing waves. While there wasn’t actually an ocean inside, I figured the sound had to be coming from somewhere. So, I decided to investigate. You can try it out, too.

First, close your eyes and listen without a shell. Well, I suppose you are interested in reading this so you may not want to close your eyes, but definitely take a listen.

Perhaps you hear people talking, music playing, or a cat meowing. These sounds travel as waves from their sources at 761 miles per hour. When the waves reach your ears, they make your eardrums vibrate, and you can hear the sounds.

Just like a ball, these sound waves can bounce. A shell has a hard and curved surface. It is pretty good at reflecting, or bouncing the sounds around.

That’s what I found out from my friend Allison Coffin, a scientist at Washington State University. Her research helps people who experience hearing loss.

“When we hold a seashell up to our ear, we don’t actually hear the sea,” she said. “What we hear is normal sound from the environment we are in at the time—whether that’s your bedroom or the beach.”

As the sound waves bounce around inside the shell, they get a bit distorted, Coffin adds. A shell is a good kind of resonating device as air vibrates through it’s hollow inside.

It’s similar to the phenomenon of blowing across an empty glass bottle to make a whirring sound. Scientists can use their knowledge of how sounds move through different spaces as they engineer car engines, create musical instruments, and even reduce noise in planes.

You can find out more about how this distorted sound works by playing with some sound waves. Grab a shell, a cup, a mug, or even a toilet paper tube. You can also just place your hand around your ear and cup the end with your other hand.

Put one of these listening devices up to your ear and walk into rooms with different sounds. Listen to how the sounds in the shell change as you move from room to room. You might even try it out in a quiet room to hear what happens.

If you already happen to be standing on the beach, then you might just pick up on the sounds of the actual sea. After all, when you hear the sound of the sea in a shell, you are really hearing a combination of all the sounds around you at that very moment.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr. Universe at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Roots

How do plants hold dirt? –Gordon, Pullman, WA

Dear Gordon,

The other day, I wandered into a Washington State University greenhouse and ran into my friend Mechthild Tegeder, a professor and expert on plants.

She gently dug a small plant out of a pot so we could take a closer look. When she lifted it up, I pawed at the clumpy soil hanging from the bottom to reveal some stringy roots.

“They’re amazing, aren’t they?” Tegeder said. “The root system functions like a web, anchoring the plant and the soil.”

The plant had lots of short, fine roots growing near the surface. Tegeder explained that another kind of root is a taproot and it tends to grow straight down. You have eaten one of these before if you’ve ever had a carrot.

While some roots grow near the surface, other roots make a journey deeper into the Earth. In fact, scientists have found roots nearly 200 feet below the surface of huge trees.

These roots can grow wide, too. Like the underwater part of an iceberg, a plant’s underground web of roots can take up to about four times as much space as the plant itself.

Whether you look at the roots of a giant tree, a little dandelion, or a carrot, they each have a couple things in common. As you know, they anchor plants to the soil. But they also deliver water and nutrients, or food, to the above-ground part of the plant.

Plants actually do this using really tiny hairs that sprout out of their roots. These little root hairs absorb the water and nutrients from the dirt. They deliver them up the roots, to the stem, and the rest of the plant or tree.

And roots look for these important resources anywhere they can. That’s part of the reason they will grow out in different directions.

In fact, there is even a special part of these hairs that scientists believe helps the roots sense where they are going in the soil. It’s a bit like an obstacle course, or like using your hands to navigate through a dark room.

These roots will grow in any space they can find. For small plants, this might mean empty space between clumps of soil. For big trees, it might mean roots that start to grow up and over sidewalks or walls.

Not all roots grow down or underground, though. Roots can grow up and out of the soil to reach into the air for nutrients and water. Then there are plants that don’t have roots at all.

But roots are really helpful to plants that do use them. As the roots and soil hang onto each other, they keep the important top layer of soil—the part we use to grow food—from washing away in the rain or blowing away in strong winds. Roots don’t just help the plant, but also the soil itself.

As you can see, it really just takes a bit of digging to get to the bottom of it. Keep asking great science questions.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your own question to Dr.Universe@wsu.edu or vote in this week’s reader poll at askDrUniverse.wsu.edu.

Ask Dr. Universe – Smallest Insect

What is the smallest insect on Earth? –Laurenz, 8, Molino, Philippines

Dear Laurenz,

When I saw your question, I set out to explore with my bug net and a magnifying glass. I was searching all around for tiny insects when I ran into my friend Laura Lavine, a Washington State University scientist who studies bugs.

She said there are nearly a million different kinds of insects on Earth. The smallest of all the known ones are called fairyflies.

Like all insects, fairyflies have six legs. And like most insects, they also have wings. Some swim under water and use their wings as paddles. Their wings are also a bit hairy. It also turns out the fairyfly isn’t truly a fly. It’s a kind of wasp.

“They are almost impossible to spot with the naked eye,” Lavine said.

In fact, fairy flies are nearly 400 times smaller than the typical ant. And they are about two or three times the width of a human hair.

I imagine finding a fairyfly would be like finding a needle in a haystack. You’d have to keep a sharp eye out.

I started to wonder how exactly entomologists could spot such fairyflies or other kinds of small insects in the wild. For example, a couple years ago scientists discovered a new kind of fairyfly in Costa Rica. It was named Tinkerbella nana after the fairy from Peter Pan.

Lavine explained that scientists often use nets or traps to catch the insects. Sometimes they have to sift through dirt and litter, or decaying leaf matter, a teaspoon at a time to see what they can find.

Scientists can also use what they know about the insect’s behavior and habitat to help track them down. Fairyflies, despite their cute name, are killer insects. They lay eggs inside a host insect’s egg. When the fairyfly’s egg hatches, it eats the host egg. If we keep our eyes out for their host bugs and their eggs, we might also find the fairyfly.

Fairyflies are important for the environment, Lavine added. Farmers and scientists can use fairyflies to help get rid of bigger insects that damage grape vines, blackberries and sugar cane. These tiny creatures help us do a big job.

The insect world is filled with interesting critters. Thinking about the smallest insect also made me wonder about the biggest one on our planet. The biggest bug is a giant walking stick. It’s almost 2 feet long. But who knows? There might be even bigger insects or even smaller insects we haven’t discovered yet crawling around on our planet.

Thanks for your question, Laurenz. It reminds me that even the small things can inspire us to wonder big.

Dr. Universe
Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr.Universe@wsu.edu

Ask Dr. Universe – Why We Feel Pain

Why do we feel pain? -Sara, 11, Moscow, Idaho
Dear Sara,

Pain is unpleasant, but we need it for survival. Just the other day I was out exploring when I stubbed my paw and let out a big meow. My nervous system was doing its job.

Part of the reason we feel pain is because our bodies have tons of nerves that help us move, think, and feel in all kinds of ways.

When you stub your paw or toe, for example, the nerves in the skin of your toe will send a message to your brain that you are in pain. These messages are what scientists call impulses. They start in your toe, move to your spinal cord, then your brainstem, and onto your brain.

It’s actually your brain that tells you that you’re in pain. And if you’ve ever stubbed your toe, you know this message gets delivered pretty fast. In fact, when you feel pain, sometimes the impulse, or message, will travel at 250 mph. That’s the speed of a very fast racecar.

It’s important for the message to move fast because you have to make a quick decision about what to do. Sometimes your decision might be a matter of survival—but other times it might be as simple as deciding if you need a bandage, ice pack, or even a trip to the doctor.

Pain is actually the number one reason people see a doctor, said my friend Raymond Quock. He’s a scientist here at Washington State University who is really curious about pain.

“Pain in many aspects is good,” Quock said. “It’s a warning that your body is in danger.”
Most humans can feel pain, but not all humans, he said. Because of genetics or nerve injury, some people can’t feel pain.

Imagine touching a hot pan and not realizing it just came out of the oven. Or imagine if you broke your leg, but didn’t know it. And while that might sound pretty nice, it can also be quite dangerous.

If you didn’t feel pain, you might end up with even more damage to your body. Pain helps tell us when to take extra care of ourselves.
People have different kinds of pain, too. There’s physical pain, emotional pain—even growing pains. The kind of pain Quock studies is called chronic pain. Unlike acute pain, like stubbing your toe, chronic pain is pain that hurts and aches for months or longer.

This kind of pain doesn’t appear to have a very useful purpose. It doesn’t help much with survival. Quock and his team of WSU researchers are investigating why it happens and how to treat it. They are working on some great ideas about how to help patients feel better.

While some pain doesn’t seem to have a purpose, pain definitely does keep us safe in a lot of other potentially dangerous situations. Our nerves help us sense the world around us so we can explore. They can also help remind us to watch where we step next time.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr. Universe at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Plant Sunburns

Why don’t plants get sunburns? – Elijah, 5, Seattle, Wash.

Dear Elijah,

That’s a great observation. For as much time as plants spend outside in the sun, we really don’t see too many with a sunburn.

I decided to take your burning question to my friend Cynthia Gleason. She’s a plant scientist at Washington State University and knows a lot about plant defense.

Plants actually make their own kind of sun block, she said. It helps protect them from the sun’s intense ultraviolet rays.

We can’t see ultraviolet light, but we think bees can see it. This light helps bees find flowers so they can pollinate the plants and drink their nectar. Ultraviolet light might be useful for buzzing bees, but too much ultraviolet light can do some serious damage to plants.

“Unlike humans, plants can’t just move into the shade or put on a hat when the sun gets too intense,” Gleason explained. “Of course, plants also can’t slather on sunscreen.”

As you may remember from last week’s question, plants need sun to make their own food, as well as the oxygen we all breathe.

Plants face an interesting challenge because they need sun, Gleason said, but not too much sun. Otherwise, they might shrivel up, turn yellow, or even die.

For a long time, scientists weren’t really sure how plants avoided getting burnt to a crisp. But a few years ago, a group of researchers investigated a science question very similar to yours.

They found that when plants get too stressed out from the sun, they start to make their own kind of sun block. It isn’t like the sunscreen that humans squeeze out of a bottle or spray on. But like sunscreen humans use, it blocks the ultraviolet light.

The plant’s sun block is actually a combination of special molecules that form in the plant’s tissue. These molecules join together to create a compound that blocks the ultraviolet light. But at the same time, these compounds still allow other kinds of sunlight to pass through. That way, the plant can still make its own food—without turning into a lobster.

Plants aren’t the only living things that make their own concoction of chemicals to stay safe in the sun either. Some zebra fish create a compound that protects them from the sun, too. Even hippos make a kind of orange sweat that helps protect them from ultraviolet rays.

The sun is not only good for plants, but also for us. It gives us Vitamin D that our bodies use to help our bones stay strong. Thankfully for humans, chemists have invented sunscreen to keep you safe from the sun’s rays while exploring outside. And luckily for us cats and other critters, we can usually find a nice shady tree.

Dr. Universe
Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr.Universe@wsu.edu or read more at AskDrUniverse.wsu.edu.

Ask Dr. Universe – Why Onions Cause Us to Cry

Why does onion cause you to cry? –Kera, 5, Lawrenceville, GA

Dear Kera,

Try as we might, it’s hard to hold back tears while chopping up onions.

My friend Lindsey du Toit knows the feeling. She’s a scientist at Washington State University and works with lots of onions. Her research helps farmers grow good vegetables for us to eat.

“It’s not the onion itself that makes us cry,” she explained, “but a chemical reaction that starts when you cut into it.”

I wondered how exactly this chemical reaction worked. To find out, we set up a microscope in her lab and chopped up a Walla Walla sweet onion. I wiped a few tears from my cheek and slid a tiny piece of onion under the lens.

Under the microscope’s light, we could see rows of onion cells next to each other. Just like you and me, onions are made up of cells.

An onion sitting on the kitchen counter is pretty harmless because its cells are still together. But when we cut up an onion, we also cut up a bunch of the cells. This is where the chemical reaction begins.

Cutting the onion breaks open different parts in the cell and releases chemicals into the air. Some of these important chemicals contain sulfur.

“As the plants grow, they take up sulfur from the soil,” du Toit said. “It’s good for growing onions.”

This sulfur is important for the flavor, too. But some of the chemicals in onions that contain the sulfur also have the side effect of making us cry.

“It’s a sacrifice we pay for good-flavored onions,” du Toit adds.

The onion cells also contain parts called enzymes. It is the job of these enzymes to help chemical reactions happen. In the onion, the enzymes help convert the sulfur into a kind of acid.

This acid rearranges itself to form a new kind of chemical: syn-propanethial-S-oxide. It’s a bit of a tongue twister. It’s also a tearjerker.

When the chemical drifts up and meets the moisture in our eyeballs, it turns to sulfuric acid. Our eyes have many nerves and can sense that something unusual is happening—and that something is stinging.

Tear-producing glands in our eyes, called lachrymal glands, receive the message.

du Toit explained that an onion with more sulfur is often likely to produce more tears. For example, Walla Walla sweets are sweeter and don’t take up as much sulfur from the soil. They likely won’t provoke as many tears as some other onions might.

People have tried quite a few techniques to try to avoid crying when they chop onions. Some put onions in the fridge before cutting them to slow the chemical reaction. Others cut their onions under cold water to slow the chemical reactions with the sulfur compounds.

Chemical reactions often happen more slowly in cold conditions. So the idea is that cooling onions in the fridge before cutting them means that the sulfur chemicals are converted more slowly into the acid that reacts with your eyes —helping you chop more onions and slowing the waterworks.

Dr. Universe

Ask Dr. Universe is a science-education project from Washington State University. Send your question to Dr. Universe at askDrUniverse.wsu.edu.