Dr. Universe

Ask Dr. Universe – Pulling Muscles

Dear Dr. Universe: Why does it hurt when we pull a muscle? -Dakota, 12

Dear Dakota,

Our big, strong, stretchy muscles can help us run, jump, and play. But sometimes these muscles stretch a little too far and it can really hurt.

Before we get into the part about pain, it helps to know what makes up a muscle: fibers. You can imagine these fibers kind of like a handful of uncooked spaghetti noodles.

Of course, muscle fibers are much thinner than noodles. You can have millions of fibers in a muscle. That’s what I found out from my friend Bert Tanner, a researcher at Washington State University who knows a lot about both engineering and muscle biology.

You also have muscle tissue, Tanner said. You can think of the tissue kind of like play-dough that holds together all the fibers, or noodles. Altogether, you have about 600 different muscles in your body.

It turns out these fibers are also what we call muscle cells. Cells are like building blocks. The whole human body is made up of lots of different cells including hair cells, eye cells, and skin cells.

When you pull a muscle, you are actually tearing some of the muscle cells. That’s what I found out from my friend David Lin, a researcher at WSU who is curious about engineering and biology, too.

Lin told me that when the cell tears, the cell signals some pain sensors in your body to start firing away. These nociceptors send a message to your spinal cord and the brain. They help you know that you are in pain and that you should avoid any more damage.

Even though these muscle cells can rip, tear, and pull, they also do a pretty good job at repairing themselves, said Lin. And while too much stretch may cause a muscle strain, a healthy amount of stretching can sometimes do the body good.

When we stretch our muscles, it can help clear our mind and let us focus on our body. I also like to stretch out my muscles when I wake up from a nap. Maybe you do this when you wake up, too.

Humans can stretch out their muscles during yoga or after playing sports. When they do this, it can release some chemicals called endorphins to the brain, which can make them feel happy. You could even take a quick stretch break right now.

Everyone’s muscles are a little different so you want to do the stretches that are best for you. Maybe you’ll reach up to the sky, make your arms wide, or touch your toes.

While humans have some pretty strong muscles, there are actually animals in our world that have some super strong muscles. If you were a Kangaroo rat, your muscles could help jump ten times your own hip height.

You could also jump and land on really rocky surfaces without pulling a muscle. My friend Lin is studying the behaviors of these animals to inspire new ideas for design and engineering. It turns out we can learn a lot from nature, and even our own muscles, when we ask big questions.

Sincerely, Dr. Universe


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Ask Dr. Universe – Lasers

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

Dear Manna,

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

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

First, we have to know a bit about light. Whether it’s light from our sun or your flashlight, light travels in tiny bundles called photons. It normally radiates out in all directions from its source, like the Sun, for example.

It turns out we can also find light energy stored in the atoms, or building blocks, that make up materials inside a laser pointer. There are different materials we can use in lasers, but some popular ones are gases like neon and helium. You may have seen neon atoms at work in a bright, glowing sign. You may also have filled up a balloon with helium atoms to make it float.

Atoms like these are sometimes really excited and other times they are at rest, or at their ground state. One way we can make some of these atoms really excited is to give them a source of energy, something like really strong flash of light or a jolt of electricity from the battery in a laser pointer.

Keane explained that under just the right conditions, you can get more excited atoms than resting atoms inside the tube of your laser pointer. When scientists were experimenting with different kinds of laser materials, they made excited helium atoms collide with resting neon atoms.

Atoms will normally emit photons when they transition from a particular excited state to a resting state. When there are more excited atoms than resting atoms, the first atom to emit light will trigger a kind of chain reaction and a lot of light will build up inside the pointer.

There are also two mirrors in a laser pointer that help keep our chain reaction going. It’s a different process, but in a way it reminds me of how we plug a guitar into an amplifier to increase its volume. But with lasers, instead of amplifying sound, we amplify light. LASER actually stands for Light Amplification by Stimulated Emission of Radiation.

The opening on one end of the laser is the light’s way out. It doesn’t radiate in all directions, but builds up in one very straight, focused point that we usually see as a bright red dot.

We don’t find lasers in nature. We have to make them in factories or labs. But there are naturally occurring “light amplifiers” in our universe. These are similar to our lasers on earth, except they don’t have any mirrors. We usually find them out in big clouds of gas where there are more excited atoms than resting atoms, which results in some brilliant light.

Dr. Universe


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Ask Dr. Universe – When It’s Spring

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

Dear Hannah,

When we see little green plants sprouting up from the soil, it is indeed a sign that spring has arrived. To find out how they know to grow, or germinate, I asked my friend Camille Steber.

In her U.S. Department of Agriculture lab at Washington State University, she studies the source of almost all plants: seeds.

A seed holds pretty much all the information a plant needs to know how to grow. The shell that holds all the seed parts inside even contains food for the plant. But the seed is very dry and needs to sense clues from outside to know when to germinate at the right time.

You may have heard that some living things go dormant or hibernate in the winter. Grizzly bears and some kinds of frogs, for example. They stay dormant to save energy and survive the season.

Seeds can go dormant, too—and they can’t germinate until spring. For a seed to know when it’s the right time, it first has to experience a cold and wet season.

In the winter and fall, rain and snow provide a lot of water for the seed. Maple tree seeds, for example, need to experience a couple of months of cold weather before they are ready to germinate. A change in temperature is one signal that helps plants know when to grow.

As plants sense temperatures rising, they release a combination of chemicals called hormones. They help tell the seed to start producing different parts, like roots, stems and leaves.

The length of the day is another way a plant knows when to grow. Just like your eyes have receptors that can sense light and help you see, plants can also sense light.

As Earth travels around the sun in its orbit, the length of days and nights changes from season to season. Plants can sense when the days are shorter in the winter. They can also sense when days are longer in the spring and many begin to grow.

There are some exceptions, though. The Christmas cactus, a plant that comes from rainforests in Brazil, flowers when days are short and nights are long. The ability to bloom in winter when days are shorter helps them keep from flowering when it is too hot. You can persuade the cactus grow by putting it in a dark closet.

A plant’s ability to sense these changes in temperature and daylight has to do with its genetic code, or DNA. DNA tells your hair and eyes to be a certain color—or when to have a growth spurt. Just as your genetic code is different from your friends’, a daffodil, a tulip, or a daisy are also different.

One of the first flowers to bloom in the spring where I live is the crocus. It’s a bell-shaped flower that comes in blues and purples. What flowers are popping up in your neighborhood? Tell us about it at Dr.Universe@wsu.edu.

Dr. Universe


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Ask Dr. Universe – Dizzy on the Road

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

Dear Rebecca,

Without even thinking about it, humans can use their eyes, ears, sense of touch, and brain to keep their balance. But sometimes these senses get a little mixed up.

Imagine you are in the car reading your favorite book. All of a sudden the road starts winding. As you look down at your book, your eyes focus on the pages. The book doesn’t appear to be moving, so the eyes send a signal to your brain that you could be sitting still.

At the same time, something is stirring in your inner ears. Lots of tiny little hairs called cilium are inside your ears doing an important job. They help you sense how your head is moving in the world.

You also have some fluid that moves around these tiny hairs to help you with your sense of balance. The way this fluid passes over the hairs can send different messages to your brain.

It might let you know if you are upside down, right-side up, spinning, falling, or perhaps, on a winding road. It’s part of a network you use to sense your movement in the world that scientists call the vestibular system.

That’s what I found out from my friend Robert Catena, a Washington State University researcher who studies all the ways the body maintains balance. When you are reading in the car, he told me, sometimes the vestibular system and the visual system are sending different messages.

“That’s what makes us dizzy,” said Catena when I visited him at the Gait and Posture Biomechanics Lab. “We have two bits of information that are in conflict with each other.”

Catena added that it’s also easier to get dizzy if you aren’t the one driving. That’s because it’s harder for a passenger to predict the twists and turns of the road.

You may have noticed you can also get dizzy just from spinning yourself around. If you were on a merry-go-round at a playground, the fluid inside your ears would also be circulating around and around.

The fluid in your ears has inertia, so it keeps moving inside your ears for a short period of time after you get off the merry-go-round. The eyes say you are on the ground, but the fluid in your inner ear keeps moving and you feel dizzy.

I also found out that if you traveled to space, the vestibular system would work a bit differently. It is actually kind of hard to get dizzy in a place where there is very little gravity.

After a couple days of floating around the International Space Station, that fluid would also start floating around inside your ears. The brain would adapt to this new environment, and you wouldn’t feel too dizzy or sick. I don’t know about you, but I think space sounds like a great place to read a book.

Sincerely, Dr. Universe

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Ask Dr. Universe – How to Help Stop Ocean Pollution

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

Dear Hailey,

It’s great to hear you want to help our oceans. After all, they do a lot for us. Life in the ocean provides much of the oxygen we breathe and is also a source of food for many animals, including humans.

One of the most important things we can do to prevent more pollution is to keep our garbage, especially plastic, out of the ocean. That’s what I found out from my friend Richelle Tanner, a marine biologist and researcher at Washington State University.

While a lot of plastic ends up in the ocean, it actually started under the Earth’s surface in the form of oil, leftovers of plants and animals that died long ago. Humans can take oil and combine it with other chemical ingredients to make plastics.

We can shape plastic into most anything, from caps to straws to bottles to bags. Let’s follow the trail of a plastic bag.

After a bag is made in a factory, it is shipped out to stores. Humans use the bag to carry different things that they buy. Afterwards, they might throw it in the trash. They might take it back to the store to be recycled with other bags or they might re-use it. They might even just toss it on the ground.

When this plastic bag gets loose in the environment, it might blow to a stream or river and flow to the ocean. That’s why it is important to keep all our waterways clean, even if we don’t live close to a beach.

If this plastic bag gets into the ocean, an animal like a turtle or shark might mistake it for a jellyfish they want to eat and the bag will get tangled in their stomachs.

Plastic has a really strong structure, which makes it a useful material, but it takes time to break down. A plastic bag can take about 20 years to break down. A plastic bottle takes about 400 years.

Tanner said it’s a lot easier to keep plastic out of the ocean than to get it out of the water. The National Oceanic and Atmospheric Administration estimates the amount of garbage humans put into the ocean every year is equal to about 90 aircraft carriers, those big ships at sea where planes take off and land.

Tanner said you might work with your class to pick up trash near waterways in your community. You might also share what you’ve learned and talk about it with family and friends.

One other thing you can do is try to reduce your own plastic use. For a week, keep track of all the plastic you use. Then, track another week and see if you’ve improved. Ocean pollution is a big problem, but we can all take small steps to help make a big difference.

Dr. Universe

Sidebar: What are microplastics? Microplastics are the tiny particles leftover from plastic breaking down. They are so small, we might even need a microscope to see them. Fish might mistake these pieces for food like plankton and end up swallowing them. Scientists have even found that when people eat these fish, the plastic ends up in their bodies, too.

Ask Dr. Universe – Plankton

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

Dear Arielle,

We can find millions and millions of plankton in bodies of water all over the world—from oceans, rivers, and lakes to ponds and mud puddles.

That’s what I found out from my friend Julie Zimmerman, a scientist with the Aquatic Ecology Lab at Washington State University. In the lab, researchers can use powerful microscopes to get an up-close look at these tiny creatures.

There are three main types of plankton, said Zimmerman. One of the groups is phytoplankton. They convert sunlight into energy through a process called photosynthesis, which helps them grow. Phytoplankton are actually quite similar to land plants, but are much smaller, and are the main producers of the oxygen we all breathe.

In fact, scientists estimate phytoplankton produce more oxygen than all the land plants, including the big oxygen producers in the rainforests. They come in lots of shapes and sizes, Zimmerman said. Under a microscope, we can see how some look like the Eiffel tower, a string of pearls, railroad tracks, zig-zags, corkscrews, and stars.

Zimmerman also told me about another group called zooplankton. These animal plankton eat the phytoplankton and other animal plankton. Copepods, a cousin of crabs and the most abundant zooplankton, may be one of the most abundant animals on Earth.

Daphnia are Zimmerman’s favorite plankton. They are related to copepods and are found in freshwater lakes and rivers.  They have the amazing ability to grow large, pointy helmets, tail spines, and even neck teeth if they sense predators. She says they are adaptable and also pretty cute.

The third group of plankton are bacterioplankton. These are the recyclers, said Zimmerman. They break down organisms and other animal waste to make nutrients, or food, for some of the plant plankton.

While the plankton within each of these groups have their differences, they also have some similarities. Zimmerman explained that plankton can’t swim against the current like fish do. Instead these organisms drift wherever the current takes them.

“Plant or animal, single celled or multi-celled, big or small, plankton all have one thing in common,” Zimmerman said. “They go with the flow.”

In fact, the world plankton actually comes from the Greek word “planktos,” which means to wander or drift.

When Zimmerman dips her plankton net from a research boat into Willapa Bay, she is curious to learn more about the plankton communities. Back at the lab, the team can look at what the plankton eat, how they grow, and see what species might be moving around to new places.

Zimmerman also studies plankton that live in the Columbia River and Vancouver Lake. She reminded me that the amount of plankton we find can change depending on the season or the place. When she goes out to the lake in summer, she can sometimes find a million tiny plankton in just a single teaspoon of water.

Dr. Universe

Ask Dr. Universe – How Many Peas Would Fit in the Sun?

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

Dear Keegan,

Our sun is so massive, you could fit more than one million earths inside of it. To find out how many peas would fit inside the biggest object in our solar system, I decided to ask my friend and mathematician Kimberly Vincent at Washington State University.

Vincent and her students said that to figure out how much of something can fit inside the sun, we need to know the volume of the sun. The volume is how much space something takes up.

One group of Vincent’s students worked to solve your question by estimating the volume of a pea is about 1 cubic centimeter. That’s the volume of a cube measuring 1 centimeter on each side.

We also need to know the volume of the sun. We can calculate this in kilometers. The Pacific Ocean, for example, has a volume of about 700,000,000 cubic kilometers.

The volume of the sun is about 1,410,000,000,000,000 cubic kilometers, or more than 2 million Pacific Oceans.

It’s also important to know there are 100,000 centimeters in a kilometer, and 1,000,000,000,000,000 cubic centimeters in a cubic kilometer. That means we can also say the volume of the sun is about 141,000,000,000,000,000,000,000 cubic centimeters.

To find out how many times a pea can fit in the sun, we divide the volume of the sun by the volume of a pea.

Here’s a quick challenge on a smaller scale. If the volume of a tennis ball is 148 cubic centimeters and a pea is 1 cubic centimeters, how many peas could fit inside a tennis ball? Hint: You can use a calculator to type in 148 ÷ 1.

Using a similar calculation, students estimated you could fit about 141,000,000,000,000,000,000,000 peas in the sun. To me, it sounded close to a zillion peas. But it turns out a zillion isn’t a real number.

A number with two groups of three zeroes is a million. A number with three groups of three zeroes is what we call a billion. Then there’s trillion, quadrillion, quintillion, and finally sextillion (seven groups of three zeroes). We could estimate 141 sextillion peas could fit in the sun.

After sextillion comes septillion, octillion, nonillion, decillion, and it goes on and on. These big numbers are useful when we want to make estimates or measure the size of the universe, the space between stars, or finding out how much water fills up a lake or ocean.

Vincent’s students also reminded me that sometimes we can approach an answer to a question in different ways. Maybe you have a different sized pea or you want to use inches or feet in your calculations. A few of the students were also thinking outside the box with your question. One of the students said that no peas would fit in the sun because the sun is a nuclear reactor and would make the peas disintegrate. Another student said it depends on how you hold the pea—if you hold it close to your eye, it might just take one to fill up, or cover, the whole sun.

Dr. Universe

Ask Dr. Universe – Why Flowers Smell Nice

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


Photo by Rachael Bonoan of a Puget Blue butterfly on a daisy. Some insects can pick up a scent with receptors in their feet.

Dear Miles,

Flowers not only smell nice to humans, but also to many insects and birds who help the flowers do a really important job. Let’s imagine that you are a bee or a butterfly. You don’t have a nose on your face, but instead use your two antennae to smell things.

As you fly around, you catch a whiff of chemicals floating in the air. Down below, you see a field of daisies. The flowers are releasing some chemicals, which are the building blocks of a smell.

You fly down to the field and land on a daisy’s petal. It’s just what the flower wanted you to do.

Not only can you drink nectar from the flower to get some energy, but you can help the flower get ready to produce even more flowers.

As you sip on the daisy’s sweet, liquid nectar, the hairs on your body start picking up pollen, sticky grains on the flower. If you are imagining yourself as a bee, you might also use your front legs to put the grains into your pollen baskets, or pollen pants, near your back legs.

That’s what I found out from my friend Rachael Bonoan, a scientist with the Conservation Biology Laboratory at Washington State University.

She told me that bugs, birds, bats, and a few other animals make up a group called pollinators. They carry pollen around from flower to flower. The process is called pollination and it is kind of like a matching game.

Different flowers will send out their own unique smells to attract the right kind of pollinators. Not all of these smells are sweet, though. Even stinky flowers need pollinators to survive.

Flies like flowers that smell like rotting garbage or poop, such as the corpse flower. Beetles like spicy, musky smelling flowers. Bees and butterflies like sweeter smelling flowers.

Flowers send out their chemical messages, or smells, at different times of the day. Jasmine and Honeysuckle are a few of the flowers that release their smells at night. They do this to attract insects like moths that are awake when it is dark out.

Insects also pick up smells from a flower’s leaves. And in addition to their antennae, some insects that walk around on plants can even pick up a scent with receptors in their feet.

Bonoan studies one of these insects in the Pacific Northwest. It’s called the Puget blue butterfly. She told me that a leaf’s smell is likely one way these butterflies decided where to lay their eggs. Smell plays a big part in how pollinators and plants can help each other survive.

Humans also really like the way flowers look and smell. We plant gardens, which are great places for pollinators to do their work. Do you have a favorite flower? What kinds of pollinators can you spot in your neighborhood? Tell us about it sometime at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Phobias

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

Dear Ryan,

We all experience fear in our lives. It is a useful tool that helps humans and other animals survive. I happen to be afraid of dogs, thunderstorms, and water. But fears are quite different from phobias.

A phobia is an intense fear of an object or situation, often one that you actually don’t need to fear. It can create a lot of anxiety. It can cause your heart rate to speed up, make it hard to breathe, and trigger nervousness, vomiting, sweating, or dizziness.

Phobias usually fall into four groups. That’s what I found out from my friend Jake Zimmerman, who teaches abnormal psychology and is getting his Ph.D. at Washington State University.

One of the groups is animal phobias. This includes things like dogs, insects, and spiders. Another group is environmental phobias, like fear of heights, storms, and water. Body phobias include fear of things like getting shots or seeing blood. Finally, there are phobias related to situations like flying in an airplane, riding an elevator, or going to the dentist.

Just as there are many kinds of phobias, there are many reasons why someone might develop one. Zimmerman explained that a person’s chance of developing a phobia can sometimes be passed down from previous generations. Just as we get our hair color and eye color from information that’s passed down to us through our parents’ genetic code, we can also get a code that makes us more likely to develop intense anxiety or phobias.

Zimmerman added that phobias might develop from a person’s negative experience with an object or situation. For example, if you were bit by a dog, it could lead to a phobia. But a phobia may also come from observation—seeing something bad or scary happen to someone else or maybe even on the television.

A lot of people tend to have phobias about animals or nature. Your human ancestors really did have to watch out for poisonous snakes, spiders, and big animals with sharp teeth. An authentic sense of fear helped them survive.

“We are descendants of people who didn’t get too close to the edge,” Zimmerman says.

While some phobias are really intense, they can often be treated by slowly and repeatedly exposing people to the object they fear. Zimmerman said that for most people a phobia will develop pretty early in life—before age 15. It’s common to fear something when you are young and then eventually stop fearing it as you get older.

We‘ve come up with quite a long list of names for phobias. Basophobia is a fear of falling, mysophobia is the fear of germs, thalassophobia is fear of the ocean, cynophobia is the fear of dogs, and coulrophobia is the fear of clowns—just to name a few. Oh, and ailurophobia? That’s a fear of cats.

Dr. Universe

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Ask Dr. Universe – Morning Breath

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

Dear Stephanie,

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

“They like to eat what you eat,” said my friend Claire Burbick, a veterinarian and microbiologist at Washington State University.

The microbes feed on leftover bits of food in your mouth. They not only help break down your food, but they also get energy from it. As they eat, grow, and multiply, they also release some smelly gases that might remind you of rotten eggs.

When microbes eat foods rich in protein, such as meat or dairy, they tend to grow and multiply pretty fast, Burbick said. In fact, sometimes meat eaters get more stinky breath than plant eaters. Something else that adds to the stink is leftover food. If large pieces or food are stuck between teeth or in your gums, it becomes a kind of playground where microbes can grow.

The mouth can get kind of gross, but it also has a way to clean itself out. One way it does this is with saliva, or your spit. It’s mostly made out of water and contains a few chemicals that help fight off bad bacteria. Saliva is kind of like a built-in cleaning system. Of course, it isn’t perfect, so brushing your teeth also helps. Not to mention, your family and friends will thank you for it.

Whether snoring or just breathing deeply, animals and humans sometimes sleep with their mouths open. When air moves in, it can dry out the saliva in your mouth and create an environment that makes the stinky bacteria go wild.

In the morning, you might wake up with particularly bad breath. You’ll probably want to brush your teeth again, sending those stinky microbes down the drain and leaving your breath fresh.

Bad breath isn’t just a people problem either. Cats, horses, cows, and of course dogs, get bad breath for many of the same reasons. Brushing teeth is also recommended for your pets, and they even have their own special toothpaste, said Burbick.

It turns out humans have been battling bad breath for thousands of years—and they’ve come up with some creative ideas. Some researchers have found evidence that Ancient Egyptians mixed together spices and honey to create a kind of breath freshener. They also used thin twigs with frayed edges to scrub their teeth.

One of the first toothbrushes in human history was made in China. It had bristles made of hog hair and inspired the plastic toothbrushes humans use today. Humans will also use floss, which helps get rid of bacteria in places where a toothbrush might not be able to reach. There’s also gum and mouthwash to help mask morning breath—or garlic breath, or onion breath, or whatever kind of stinky breath might come your way.

Dr. Universe

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Ask Dr. Universe – Sheep’s Brains

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

Dear Aiden,

A sheep brain is about the size of a human fist and is squishy like Jell-O. In some ways, a sheep brain is very similar to a human brain. In other ways, it is quite different.

I learned about sheep brains from my friend Craig McConnel, a researcher at Washington State University who is very curious about ruminants, a group of animals that includes cattle, giraffes, deer, antelopes, and of course, sheep.

Like a lot of mammal brains, a sheep brain is made up of grey and white matter. It has folds and grooves, but not quite as many as a human brain. It’s also a little smoother.

A human brain is about ten times as heavy as a sheep brain. Of course, just because an animal has a bigger brain doesn’t mean it is necessarily smarter. A sperm whale, for example, has a brain that is about five times heavier than a human brain.

Just like you and many other mammals, sheep have a part of the brain called the cerebrum. It is important for controlling movement, the senses, and thinking. Even though sheep might seem like they just stare off into space and chew grass all day, they do use their brains to think, just not on the same level as humans, McConnel said.

You and a sheep also have a brain stem which helps control the flow of messages between the brain and the rest of the body. There is also a cerebellum, which mainly helps with muscle functions and more movement—including the ability to move around with your flock.

Like us, sheep are social animals. When they graze together, they often eat in groups of five or so and keep an eye on each other. One sheep usually leads the way and the rest follow. It’s an instinct or a behavior that an animal has from birth.

One major difference between sheep and human brains has to do with the sense of smell. In sheep, the brain’s olfactory bulb is two or three times the size of the human olfactory bulb. It provides the sheep with a strong sense of smell which is key for survival.

A mother can use her sense of smell to find her baby in a flock. A baby can smell its way back to its mother if it gets lost. The leader of the herd can sniff out a predator like a wolf and that sense of smell will allow it to warn the other sheep.

Some sheep, like bighorn sheep, even have strong horns and thick skulls that help protect their heads and soft brains. Some scientists are studying them to learn about concussions. While a lot of mammals have similar things going on in their brains, each brain is little different, and sometimes it’s those differences that can help an animal survive, whether they are out on a farm or out in the wild.

Dr. Universe

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Ask Dr. Universe – Fish Pee

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

Dear J.P.,

Not only do fish pee, but their pee gives other animals in the ocean what they need to survive.

That’s what I found out from my friend, Cori Kane, a marine biologist at Oregon State University who got her Ph.D. at Washington State University. She knows a lot about coral reefs in our oceans. Coral reefs look like a ridge made of rock, but they are actually made up of living things.

Corals need a few things to survive. They need clear, warm water, sunlight, and nutrients, a kind of food that helps them grow. There aren’t usually a lot of nutrients in water near coral reefs. Luckily, there are a lot of nutrients in fish pee—and a lot of fish in the reef.

Like you, fish have kidneys. Kidneys help the body make urine. The shape and size of kidneys can be different depending on the species. Some kidneys are really long, like those in eels. Others are shorter and closer together like in an anglerfish.

A lot of fish get rid of the pee through an tiny opening, called a pore, that’s near their rear ends—and in some fish, waste also goes out through the skin or the gills.

When a fish pees in a coral reef, the corals wave their tentacles around like tiny arms to grab nutrients from the pee and absorb them.

Pretty much all living things—from plants to mushrooms to humans to cats—need nutrients to grow and survive. Humans get a lot of nutrients like minerals, fats, vitamins and carbohydrates from their food.

Corals get nutrients like nitrogen and phosphorus from the pee. It turns out, fish pee is pretty important to some marine ecosystems.

The nutrients will help the coral grow— slowly, but surely. In a year, the reef will grow anywhere from less than an inch to 8 inches. It will bloom in beautiful colors like red, purple, and blue.

Scientists have discovered thousands of fish that live in coral reefs. One of them is the clownfish. When clownfish pee, they can also help anemones— which look kind of like flowers but are actually animals closely related to jellyfish— grow.

Another organism called algae also lives in anemones. The algae take in nutrients from clownfish pee. The algae can then make sugars that feed the anemone. They are pretty good at helping each other out.

While we’re on the subject, fish also poop. Believe it or not, some of the corals will even grab onto fish poop to get some nutrients.

Kane also told me about the neon-colored parrotfish. It’s a fish that lives in tropical reefs around the world and has a mouth that looks like a parrot’s beak.

“Parrotfish are really famous for their pooping abilities because they eat dead coral and other things,” she said. “When they munch it up, they poop out sand.”

>From sardines to sharks, pretty much all of the animals in the ocean have to go to the bathroom.

Dr. Universe

Ask Dr. Universe – Volcanic Eruptions

Dr. Universe: How do volcanoes erupt? –Miles, 10, Tampa, FL

Dear Miles,

Wherever we find a volcano on the surface of our planet, we can find the source of an eruption beneath it. That’s what I found out from my friend John Wolff, a volcanologist at Washington State University.

Our planet is home to all kinds of volcanoes that erupt in different ways. Some eruptions are quiet and continuous, with a slow flow of lava. Other volcanoes erupt explosively and can spew ash and lava hundreds of feet up into the sky. All of this lava has its start underground in the form of something called magma.

Wolff said that scientists used to think there were large pools of hot liquid beneath volcanoes. Now we know it isn’t quite that simple. Magma is not really a liquid, but rather a kind of sludge or slurry. It helps to think of it kind of like honey.

“If you put honey in the cupboard for a long time it will solidify,” Wolff said. “But if you set it in a pan of hot water, you can return that honey to a more liquid state.”

Wolff is very curious about volcanoes and told me about super volcanoes like the Yellowstone Caldera in Wyoming. The pools of magma under the Yellowstone super volcano are anywhere from three to 12 miles deep.

When a volcanic eruption is about to happen, magma near the surface of the earth gets heated up by even hotter magma from below. The hot magma deep in the earth starts to melt the crystals in that magma above and the magma becomes more liquid-like. When this happens, the system is in a dangerous state, said Wolff. The volcano could erupt at any time.

The eruption also has something to do with density. When we talk about density we are talking about how tightly packed together the particles are in an object. For example, if you put an object in water and that object floats, the object is less dense than the water.

Magma from the earth is actually lighter, or less dense, than the rock around it. As the magma starts to rise, bubbles of gas start to form inside the magma and they can’t escape. That also makes the pressure build up in the volcano, makes the magma rise even more, and eventually erupt.

In fact this pressure is one of the things that is a major difference between volcanoes on land and volcanos under the sea. Yep, there are also submarine volcanoes deep in the ocean. In fact, about 75 to 80 percent of volcanic eruptions on our planet occur underwater.

Water pressure can prevent those gassy bubbles from forming in lava, so the explosions under the sea aren’t quite as huge as eruptions on land. Because it is so dark on the ocean floor, it’s harder to see these eruptions. But whether at land or at sea, there’s likely some volcanic activity happening somewhere on our planet at this very moment.

Dr. Universe

Ask Dr. Universe – Molecules

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

Dear Jolin,

A glass of water has more molecules than there are stars in the night sky. That’s what I found out from my friend Jack (Qiang) Zhang, an assistant professor of chemistry at Washington State University.

“Everything around us is made up of molecules,” he said. “And while these molecules may be different, they are all made of the same things.”

Those things are called atoms. Zhang told me we can think about atoms kind of like Lego blocks. Imagine that you have a pile of red Legos, yellow Legos, and blue Legos. Maybe you use them to build a tiny house, or you can use this same set of Legos to build something else like an airplane or a robot.

Just as you can arrange blocks in different ways, atoms arranged in different ways can make up different objects. There are a lot of atoms, but let’s talk about three of them. We can find their names on a big chart called the Periodic Table of Elements.

First, there is hydrogen, the smallest atom and the most abundant element in the universe. Then there’s carbon. Animals, like us, get carbon by eating plants or meat. And then there’s oxygen, which you might be familiar with because we all breathe oxygen molecules.

These atoms can do things individually, but when we combine them in different ways, they form all kinds of things.

You could make sugar, a sweet molecule that gives plants and animals energy. You could also use those same building blocks to make vinegar, a sour molecule and type of acid that we use in cooking.

One of the most abundant molecules on our planet is water. It can make trees grow tall, but through a process called erosion it can also break down the biggest mountains. It is made up of two hydrogen atoms and one oxygen atom, which is why some people will call it

Water and other molecules will undergo changes under different temperatures. When water gets cold it becomes a solid, called ice, but those very basic molecules still keep the same shape. Molecules are also always moving, said Zhang. Even in the wood that makes up your school desk, the wood molecules are vibrating ever so slightly.

Zhang said different molecules will sometimes interact with each other, too. For example, if you mix vinegar and baking soda together you are bound to see some bubbles start spouting. Here, the molecules that make up baking soda and vinegar start to re-arrange in a chemical reaction. In a way, it’s kind of like breaking apart your Lego creation to make something else. You can learn more about chemical reactions in this activity from the American Museum of Science and Energy. Tell me how it goes at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Clouds

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

Dear Desi,

If you’re anything like me, you like to watch the clouds go by in the sky. Even though some clouds might look like they are just floating around up there, they can do quite a lot for our planet.

The first thing to know about clouds is they are made up of tiny water droplets, ice crystals, or a mix of both—and there are many different kinds of clouds.

There are white and puffy cumulus clouds, thin and wispy cirrus clouds, and tall nimbostratus clouds that stretch high up in to the sky. Believe it or not, when you walk through fog, you are walking through a kind of cloud that’s touching the ground.
I learned about clouds from my friend Von P. Walden, an atmospheric researcher at Washington State University.

One thing clouds can do is move, Walden said. Some clouds move slow, while others— like the clouds of a spinning hurricane—can move about 100 mph. As clouds move, they transport water around our planet.

The clouds above North America are usually moving from the west to the east, Walden said. A lot of the water that makes up clouds comes from the Pacific Ocean.

As the water on the surface of the ocean warms up, tiny water molecules rise into the atmosphere to help form clouds. When the water particles that make up clouds get heavy enough, they will sometimes fall down to earth in the form of rain or snow. When that water falls, we can use it for various things.

We might use it to water plants for food. We can also use water to generate energy from dams for our homes and schools. We sometimes drink it or swim in it. Clouds can also cool us by reflecting sunlight back to space.

It had been raining the morning I went to visit Walden, but the sun was finally starting to shine. He noticed a small rainbow out the window.

We see rainbows when light moves through water droplets and the rays of light scatter around. It’s pretty rare, but sometimes we can spot a phenomenon called a rainbow cloud. These clouds occur very high in the atmosphere. Instead of being white or gray, the cloud is all the colors of the rainbow, or iridescent.

If you ever have a chance to visit the Palouse in Washington state, we have some great clouds. But really, you can watch clouds from anywhere on our planet.

What clouds do you see in your neighborhood? Can you draw their shapes? While investigating your question, I also learned that nephelococcygia is the act of seeking and finding shapes in the clouds. You can keep track of your observations with a pen and paper. Do you notice any patterns about the clouds? How fast do they move? Keep your eye to the sky and share what you discover at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Earthquakes

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

We’ve had a lot of earthquakes on our planet this year. Maybe you’ve learned about them from the news or felt one shaking up your own neighborhood. Earthquakes can happen in a few different ways.

First, it is important to know a bit about the Earth’s outer layer, or crust. The crust is made of seven big pieces called “plates.” They are about 60 miles thick and sort of float on the molten rock beneath them. That’s what I found out from my friend Sean Long, a geology professor at Washington State University who knows a lot about earthquakes.

These massive plates move very, very slowly—about one or two inches a year. But when plates slip over or under each other, collide or break away, an earthquake happens. Usually, they last just a few seconds but really big quakes can often last anywhere from 10 to 30 seconds.

After a big earthquake, we often feel a bunch of small earthquakes, or aftershocks. They happen as the crust adjusts to its new location, or settles into its new spot on the Earth’s surface. If one of the plates is under the ocean, sometimes an earthquake will trigger a wave called a tsunami. Depending on the earthquake strength, the wave can be massive or even just a few centimeters high.

According to the National Earthquake Information Center, more than a million large and small earthquakes shake the planet’s surface each year. We measure the strength and size of an earthquake on the Richter Scale, which goes from one to ten. Each number on the scale is 10 times as powerful as the number before it. The really destructive earthquakes are usually measured at a strength of around 5.5 and higher.

In the last year, more than 13,000 earthquakes above a 4.0 shook our planet. When a recent earthquake shook Anchorage, Alaska, it registered as a 7.0 on the Richter Scale. The big Pacific plate at the ocean floor slid under the North American plate that Alaska sits on. By the way, if you’re curious about where some of the recent earthquakes have happened, you can check out this cool map from the USGS

While earthquakes can cause a lot of damage, they can also help build up the face of our planet. My friend Sean Long studies the plates near places like the Andes Mountain Range in South America, which are about five miles tall, and the snowy Himalayas in Asia, which reach even higher.

Over millions of years, as the Earth’s plates collide again and again, long chains of mountains slowly but surely emerge on the surface. It often happens along fault lines, which are breaks in the Earth’s surface.  How many earthquakes do you think had to happen to create the tall mountains in the Himalayas and the Andes? Send us your ideas sometime at Dr.Unvierse@wsu.edu.

Dr. Universe

Ask Dr. Universe – Belly Buttons

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

Dear Jane,

Whether you have an innie or an outie, pretty much all us mammals have a belly button. But before you had a belly button, there was actually a different bit of anatomy in its place.

While you were still growing inside of your mother, a small, bendy tube on your tummy connected the two of you. This tube is how you got pretty much everything you needed to grow before you were born into the world.

When a mother eats something—maybe it’s salad or ice cream—she gets different nutrients like proteins, fats, and vitamins from the food. The tube, or umbilical cord, helps her pass along the different nutrients so the baby can grow.

That’s what I found out from my friend Gina Cronrath, a nursing instructor at Washington State University. She also told me the umbilical cord helps remove waste from the baby, as well.

“After the baby is born, it can drink on its own and go to the bathroom into a diaper,” she said. “So the umbilical cord isn’t needed.”

It actually isn’t until about five weeks into a mother’s pregnancy that the umbilical cord starts to grow—and it will keep growing until the cord is about two feet long. A pregnant mother’s belly can really stretch out. Sometimes a mother will even get a temporary outie belly button. Then it will return to an innie.

After a baby is born, a doctor, midwife or birth partner will help cut the umbilical cord. Don’t worry, though—it doesn’t hurt the mother or the baby. Unlike, say, your skin, the cord doesn’t have nerves that would help you sense pain. It actually has a kind of jelly-like texture and this substance helps protect the blood vessels inside of the cord.

A small part of the cord will stay attached to the baby’s belly for a couple of days before it falls off. What’s left is a brand new belly button. Or if you want to use the more scientific name, it’s a brand new navel.

It turns out that a lot more humans have innies than outies. It all depends on how the muscles and skin heal up after the cord is cut. In a way, the belly button is the body’s first scar.

>From big blue whales bellies to furry cat bellies to human bellies, mammals share a connection to their mothers through the umbilical cord. After you are born, what was once a big part of your survival doesn’t serve much purpose anymore—except for maybe collecting a bit of lint.

One thing is for sure, your question really got me contemplating my navel in a whole new way. And as Cronrath put it, our belly buttons are a kind of reminder that our mothers took care of us right from the beginning.

Dr. Universe

Ask Dr. Universe – The First Chocolate Bar

Dr. Universe: Who created the very first chocolate bar? – Emma, 11, USA

Dear Emma,

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

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

If we cut open the fruit, we would find about 20 to 60 seeds on the inside. In ancient times, people would grind up the seeds and use them in a drink.

“When Europeans arrived to the Americas they found the indigenous people who were drinking this delicious thing,” Cornejo said. “It was bitter and interesting. They didn’t use sugar.”

It wasn’t until Europeans returned home that they added sugar to make it more drinkable. The drink was very popular among royalty. But engineers and scientists who lived during the Industrial Revolution in the late 1700s and early 1800s helped find new ways to produce it so it could be enjoyed by everyone.

A cacao seed can give us a few things. One of them is cocoa powder, which is the dry part of the seed. Then there is the cocoa butter, which is the wet part of the seed.

The chemist Coenraad van Houten had the idea to make a cocoa press. His press took a lot of fat out of cocoa beans and created a paste like cake batter that could then be made into cocoa powder.

This press also made it possible to remix the powder with cocoa butter. When the powder is processed, heat and friction can activate the cocoa butter and help produce chocolate liquor, a thick, chocolatey liquid.

In 1847, Joseph Fry figured out how to use these different ingredients to create a chocolate paste that he could mold into a rectangle. He produced the world’s first chocolate bar.

After Fry figured out how to make a chocolate bar, he made a treat called Fry’s chocolate cream. You can still buy it today. It is a dark chocolate candy bar with a creamy mint filling.

Now we have all kinds of solid chocolate. We have chocolate chips for our cookies. We can make delicious truffles. We can also make chocolate bonbons with different fillings like nuts, caramel and even more chocolate. One of Cornejo’s favorite chocolates is a black pepper bonbon.

Just as the first chocolate bar came from Britain, so did the world’s biggest chocolate bar. It weighed 12,000 pounds—that’s more than twice as heavy as a rhino. The chocolate bar was 13-by-13 feet.

Just imagine what it would have been like to create the first chocolate bar. People are coming up with new ideas all the time—who knows, maybe you, yes, you reading this very sentence, will come up a great invention for our future.

Dr. Universe

Ask Dr. Universe – Smelliest Fruit in the World

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

Dear Tiana,

Our world is full of fruits that have all kinds of delightful smells. Maybe you’ve smelled the sweetness of watermelon, pineapple, peach, papaya, or mango. But you might also be wondering about the most stinky fruit in the world.

When I got your question, I asked my friend Lydia Tymon, a plant scientist at Washington State University. The first stinky fruit she thought of was the durian, a large, round fruit that grows mostly in Southeast Asia. The fruit is about a foot wide with a greenish-brown husk that has lots of spikes on the outside.

Some people have compared the smell of a durian fruit to rotting onions or sewage. In some countries in Southeast Asia, there are even signs that say not to bring durians on buses and trains.

Earlier this year, a college in Australia even evacuated a library when someone reported the smell of dangerous chemicals or a gas leak. The culprit was just a durian fruit someone left behind.

Even though durian has an unusual smell, it’s sometimes used in recipes from Southeast Asia. When the fruit ripens up, it has a custardy texture. In small amounts, it can add just the right flavor to rice dishes and sweet treats like cakes, crepes and candies. In China, it’s even a popular pizza topping.

Pretty much all fruits will eventually rot and get smelly. Tymon studies how tiny living things like microorganisms can make plants sick. Yep, plants can get sick, just like us.

Some microorganisms also depend on different fruits to get the fuel they need to survive. But as they eat them, the fruits start to go bad, or spoil. When the microorganisms eat, they also start to produce gases which can smell pretty rotten.

Whether it’s the sweet smell of ripe fruit, the stench of a durian, or the stinky smell of a rotting fruit, we can trace all scents back to molecules. A molecule is a group of atoms, the building blocks that make up pretty much everything.

When atoms bond together, we get a molecule. When those molecules come in contact with the receptors in your nose, they send a message to the brain to help determine what exactly you are smelling. Some scientists can use what they know about atoms and molecules to create artificial fruity smells—like cherry or grape— in the lab.

The part of your brain that processes messages from smelly molecules is actually the same part responsible for memories. That’s why when we smell something, it can often bring up different memories and emotions.

I don’t know about you, but one of my most favorite smelliest smells might just be fruit baked into a pie. Do you have a favorite fruit smell? Have you ever smelled a durian or another kind of stinky fruit? Tell us about it sometime at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Bunnies

Dear Dr. Universe. My favorite animal is a bunny. I want to know more about it. How fast does a bunny hop? How long does a bunny live? Can a bunny swim? How many babies does a bunny have? -Rueben, 7, Pennsylvania

Dear Rueben,

Bunnies are hopping all over our planet. Some hop through snow and deserts while others hop through wetlands and woods. There are lots of different kinds of rabbits and they are all a little different. For the most part, a bunny hops, or actually runs, anywhere between 25 and 45 mph That’s even faster than most housecats can run.

Rabbits are related to another group of animals called hares. Actually, rabbits and hares are in the same family, Leporidae. Hares look a lot like rabbits, but they have much bigger ears and bigger feet. European hares and jack rabbits, which are also hares, can run upwards of 45 mph. They have long, strong legs that help give them hopping power.

That’s what I found out from my friend Paul Jensen, a graduate student researcher at Washington State University. He studies snowshoe hares in northcentral Washington state to learn more about populations in the wild. While rabbits and hares have their differences, they do have a few things in common.

Both hares and rabbits have quite a few babies in their lifetimes. Hares are born in nests above ground. They are born with their eyes open and a body that’s totally covered in hair. They don’t require a lot of supervision from their parents. Hares have about 1 to 8 babies in each litter and sometimes they can produce four litters in one year. That’s a lot of baby hares, or as biologists call them, “leverets.”

Rabbits are born with their eyes closed, no fur, and no ability to manage their own temperature. They need more parental supervision to survive in the wild and especially to stay warm in the burrows where they live. While bunnies can hop around, some can also swim in water. They don’t always seem to like the water very much, though—not too unlike us cats.

Rabbits also have a lot of babies—anywhere from one to 14 in a litter. A baby rabbit is called a kit, which is short for kitten, which is also what they called me when I was young. In the company of humans who keep them as pets, some rabbits will grow to be about 8 years old. Rabbits can live for one or two years in the wild. Meanwhile, some hares, like the Arctic hare, can live to be about 3 to 5 years old.

The American Rabbit Breeders Association recognizes 49 different breeds of rabbits. On the  organization’s website, you can learn about all kinds of rabbits from the American fuzzylop and the lionhead to the crème d’ argent and cinnamon. Have you seen any bunnies hopping around your neighborhood lately? Tell us about it sometime at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Owls’ Heads

Dr. Universe: Why do owls rotate their heads? -Kaitlyn, 8th grade

Dear Kaitlyn,

Take a look around. Maybe you can turn your head to the left and right and move it up and down. You can move your eyes around in a bunch of different directions, and perhaps you can even cross them.

In the animal kingdom, there are lots of different kinds of eyes that see the world in different ways. Owls can’t move their eyeballs around in their eye sockets very well, but they do have pretty good night vision. They also have eyes that are positioned on the front of their heads like a lot of their fellow predators.

That’s what I found out from my friend Letty Reichart, who knows a lot about the study of birds, or ornithology. She earned her Ph.D. at Washington State University and now teaches biology at the University of Nebraska Kearney.

While owls might not be able to move their eyeballs around like you can, they more than make up for this by turning their heads, which gives them a really good view of their environment.

“It’s a unique adaptation for owls to be able to do that,” Reichart said. “It’s part of their predatory lifestyle, but we actually know relatively little about it.”

In fact, a lot of predators with eyes that face forward have what we call binocular vision. In the wild, owls use their vision to look for animals like raccoons, squirrels, mice, and lizards that they can eat for dinner.

Reichart said an owl’s bone structure is part of what helps with the head rotation. Owls have a part of their skeletal system, called a pivot joint, that helps give them a broad range of movement.

If humans turn their necks too far, that movement can cause some serious damage. That’s because turning the head too far can lead to pinching off vessels that run down the backbone. These vessels help carry blood around the body, so when the vessels get pinched it can cause blood to stop flowing through our body. But owls have necks that are a little different.

Not all the blood vessels run through their bones. The vessels that do run through bone have much more wiggle room. The opening a vessel flows through is about ten times the size of the vessel itself. When owls turn their heads, even though their necks are twisting, the bone is not likely to hit those vessels and arteries. That way, they can avoid major injuries to their necks.

In turns out that some owls can turn their heads in a half circle, about 180 degrees, to the left or the right. There’s another critter that can also rotate it’s head in this way. The praying mantis is a predator and also uses a rotating head to look for prey in the environment.

Meanwhile, some owls can actually turn their heads 270 degrees to the left of the right. That’s more than twice what a human can do.

Dr. Universe

Ask Dr. Universe – Caffeine

Dr. Universe: Why does caffeine make us stay up longer? – Cooper, 12

Dear Cooper,

You’re right, caffeine can help us stay awake—but only for so long. To understand exactly why it works, it helps to know about one of my favorite things: sleep. All animals need rest to stay healthy. But sometimes humans don’t get quite as much sleep as they need.

They might be tired during the day or have a lot of work to do. To feel more alert, they might drink a cup of coffee, tea, or soda. These kinds of drinks contain caffeine, a chemical and stimulant that can trigger changes in the body.

Caffeine can make people feel excited and happy or even a little sick and jittery. We can trace all of these reactions back to our central nervous system where our nerve cells regularly interact with different chemicals, or molecules, in our body to help us think, feel, and sense our world.

Each day, your body produces a chemical called adenosine (ah-den-o-seen). It can slow down activity in the brain and is part of what makes us sleepy. The chemical helps send a signal to the body when we need sleep, which helps the body recharge.

Part of the reason you feel tired is because the adenosine molecules you made have actually reached parts of your nerve cells called receptors. A receptor is kind of like a keyhole. The adenosine is kind of like a key and it can unlock your sleepiness. But sometimes an imposter molecule comes along.

To your neurons, the caffeine molecule looks a lot like the adenosine molecule. That’s what I found out from my friend John White, a pharmacy professor at Washington State University who knows a lot about how caffeine works in the body.

The reason we don’t feel tired when we have caffeine is because caffeine literally blocks the adenosine from reaching our cells and doing the job of making us sleepy. Caffeine may give us a temporary feeling of being awake, but it also has some other side effects. We might feel more nervous, have difficulties breathing, or a faster heart rate.

It turns out, humans aren’t the only ones that can feel the effects of caffeine. A few scientists have studied how some bees get caffeine from the nectar in flowers. In nature, we find caffeine in plants, but we can also make it in a lab.

Humans have used caffeine throughout history, but it wasn’t until about 200 years ago that a chemist named Friedlieb Ferdinand Runge took a much closer look at the chemical. Caffeine is a molecule made up of building blocks, or atoms, like carbon, hydrogen, nitrogen, and oxygen.

When these elements are arranged into the molecule caffeine, they have the unique ability to kind of trick our bodies. Even if we are craving sleep, we still feel wide awake. Speaking of sleep, I think it’s prime time for a catnap.

Dr. Universe

Ask Dr. Universe – New Taste Buds

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

Dear Tyra,

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

First, if you stick out your tongue, you will see a bunch of little bumps. They are not taste buds, but parts called papillae. The taste buds are hidden inside the papillae. Second, he explained, taste buds are actually bundles of taste cells which are like “a gateway to the taste centers in the brain.”

We rely on taste to figure out different traits in foods, like the sweetness of a marshmallow, the sour of a lemon, bitter dark chocolate, salty crackers, or the savory, meaty umami of ripe tomatoes.

Every time we eat or drink something, we are faced with a decision of whether to actually eat it or spit it out, Diako said. Our sense of taste helps us decide if what we eat is delightful or dangerous. In a way, it helps with our survival.

We grow new taste buds for a couple of reasons. The first reason is that taste cells die off after they’ve finished their job. The taste cells, like many cells, can age and when they lose their sensitivity, the body grows new ones.

The second reason we grow new taste buds is sometimes we burn them off with things like hot foods and beverages. The heat can kill our taste buds. If we don’t grow new ones, we would have problems detecting the tastes of food and probably wouldn’t enjoy a meal very much.

Taste buds grow from a class of cells called basal cells, Diako explained. The cells go through a process in which they divide and enter the taste buds. They then develop into one of at least five different taste cell types that help us detect sweet, sour, salty, bitter, and umami.

We are growing new taste buds pretty much all the time. Recent studies estimate that we lose about 10 percent of our taste cells every day. Around 20 to 30 percent of them are developing today and about 60 percent are in full use.

“When you sit at the Thanksgiving table and get ready to bite into that turkey, remember what an amazing job your taste buds and brain are doing to help you enjoy every bit of that occasion,” Diako said.

Do you have a favorite food? Does it fall under the category of sweet, sour, salty, bitter or umami? Send your answer to Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Hot Peppers

Dear Dr. Universe: What makes a pepper hot? -Christian, 12

Dear Christian,

If you’ve ever eaten a chili pepper, you know it can make you feel really hot. You might start sweating, get a runny nose, or even cry.
Like you, my friend Courtney Schlossareck is also very curious about spicy foods. She is a graduate student at Washington State University and part of her research involves finding out how well people can taste chili peppers in cheese.

When I told her about your question, she said that chili peppers are hot because they contain a particular molecule that brings the heat. Molecules are made up of building blocks called atoms. The molecule in spicy peppers is called capsaicin (kap-SAY-sen). It can add different sensations to the foods we eat.

Peppers come in colors like orange, green, yellow, and red, and have different amounts of spiciness. They can be dried into flakes, ground into powder, or made into a fiery hot sauce.

At the WSU Creamery, cheesemakers have come up with a few cheeses that have a spicy kick. My friend John Haugen, the creamery manager, said some of these cheese recipes include jalapeno peppers, cayenne peppers, and even spicier ghost peppers.

He explained that we can measure how intense a chili pepper’s heat is by using the Scoville Scale. A jalapeno pepper is only 2,000 to 5,000 Scoville units—about the same as tabasco sauce. Capsaicin in its raw form is about 16 million Scoville units. The ghost pepper is about one million Scoville units.

Haugen and Schlossareck said that when we eat a chili pepper, capsaicin molecules land on the receptors in our mouth. Our receptors are little bundles of fibers that transmit different sensations to the brain and around the body.

Our nerves help us feel all kinds of things, including a bit of pain from chili peppers. They can also trigger our eyes to water or make us sweat. Some people really enjoy eating chili peppers, while other people think they are just too hot.

Some scientists think the spiciness of chili peppers might be a defense mechanism to keep too many animals from eating them. Most mammals do stay away from spicy peppers. But in a recent study, researchers found that, in addition to some humans, the tree shrew seems to like hot peppers, too. Some kinds of birds will also eat chili peppers and help spread the seeds.

Schlossareck reminded me that there are lots of compounds that can add different traits to our food. While chili peppers are hot, other compounds can make our mouth feel cool. One of these compounds is called menthol. It comes from the peppermint plant.
Do you prefer peppermint or chili pepper? What about your family and friends? Why do you think people have different tastes? Send us your ideas at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Wasabi

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

Dear Christian,

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

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

The part of the wasabi plant we eat comes from the stem, or the rhizome, which can be up to about 4 inches wide and 12 inches long. The plant comes in different shades of green, leaf sizes, and shapes, and in more than 20 different varieties.

Wasabi is one of the hardest plants to grow, which also makes it pretty valuable. If you wanted to buy real wasabi at a store, it would probably be about $95 a pound, Lumpkin said.

In nature, wasabi requires just the right environment to grow. It needs a cool climate, but not too cool in the winter. It also needs freshwater all year long and grows best in a bed of gravel. The Pacific Northwest can provide a lot of these conditions, along with some good shade. Lumpkin and some of his students actually helped people in the Northwest learn how to grow wasabi.

Now there are wasabi farms up and running on the coast of Oregon and Canada’s Vancouver Island. Growing wasabi takes a lot of patience. Only a few farms in the U.S. grow wasabi and only a few fine-dining sushi restaurants serve it.

When cooks prepare the wasabi, they shave off a bit of the stem to clean it up. They sometimes use very fine grating tools, called orsoshigane, which are used in Japanese cooking. These tools can grate up stuff a lot finer than the kind of cheese graters we usually find in the kitchen. Finally, they gather these tiny pieces of wasabi stem together. We might eat it with sushi, sashimi, or noodles. The leaves and the part that connects the leaf to the stem, called petioles, can be pickled or dried.

When we grate the wasabi stem, it breaks the plant’s cells and triggers a chemical reaction that gives the vegetable a very powerful flavor. It’s so strong that sometimes vapors will travel into the back of your mouth and up into the nasal cavity. It hits the sinuses and can easily make your eyes water.

Even though we might not be eating real wasabi when we go to a restaurant, the horseradish in the paste can still add extra spice to your meal. And now you know that wasabi is made by grinding up the root of a pretty interesting plant. It probably came from Japan—but there’s also a chance it was grown in the Pacific Northwest.

Dr. Universe

Ask Dr. Universe – Venom

Dear Dr. Universe: What is venom? -Callum, 9

Dear Callum,

A lot of different animals, like wasps, spiders, snakes, jellyfish, and scorpions, make venom. Animals like the cone snail, the blue-ringed octopus, and centipedes do, too.

Venom is a mixture of different proteins that can be very toxic to animals. While humans don’t make venom, they do carry around proteins. Proteins called keratin are the building blocks of your hair and nails. The red protein hemoglobin in your blood helps deliver oxygen around your body.

Venom tries to disrupt the systems in our body that help keep us alive, said my friend Mark Margres. He’s a venom researcher who studied at Washington State University and now works at Clemson University.

In his work as a scientist, he’s also studied the venomous eastern diamondback rattlesnake. It is the largest of the 32 species in the rattlesnake family. It’s about four or five feet long. Snake venom is one of the kinds of venom scientists know the most about. Margres has collected thousands of samples of rattlesnake venom and he said proteins in the venom can do different things.

The proteins might prevent blood from clotting. They might create a drop in blood pressure. They might even stop the heart.

In the eastern diamondback rattlesnakes, some toxins can actually paralyze a mouse’s legs. But these toxins only paralyze the legs for about 30 minutes, then the mice can move around again. Some of the rattlesnake’s toxins will actually kill the prey. Then there are other toxins that help the snake digest its food.

Margres said that when an animal gets bit and venom enters the body, a lot of people think the venom travels through the blood. But it actually takes a different path.

The venom travels through a network of organs and tissues that are usually supposed to help an animal get rid of toxins and other unwanted invaders. It’s called the lymphatic system. When venom enters this system, it can spread all around the body.

It’s also a myth that you can suck out venom to keep it from spreading. Once the venom is in the body we can’t stop it without something like a medication called anti-venom.

Margres said that snakes can control how much venom they inject into an animal and sometimes make a “dry bite” using just their teeth— no venom.

“We are not exactly sure how or why they choose to do what they do,” Margres said.

Who knows? Maybe one day you can study venomous animals on our planet to help us learn more about these creatures, their defense mechanisms, and even how we can use venom to help make medications.

Margres adds that snake bites are often a sign that an animal was feeling threatened and needed to take action to protect itself. It turns out, rattlesnakes actually can’t eat without using their venom—they need it to kill their prey. Otherwise, they go hungry. They only bite as a last resort and don’t want to waste their venom.

Dr. Universe

Ask Dr. Universe – Allergies

Dear Dr. Universe: How did we discover allergies? -Zion, 8, Australia

Dear Zion,

Before humans even came up with the word “allergy,” they observed how some people would get rashes, sneezes or become really, really sick from different things in their environment. Historians even noted how people in ancient civilizations talked about something called “plant fever,” which gave people runny noses.

On the way to discovering allergies, scientists first had to learn about the immune system, which helps protect the body from invaders, or things like bacteria and viruses. These invaders are called antigens and when they get into your system, your body gets ready to react, releasing something called antibodies to help defend you. The antibodies will also recognize if they’ve come across an invader before. That way they know what to attack in the future. Allergens include things like shellfish, dust, eggs, pollen and insect venom.

Early in the last century, the Austrian scientist Clemens von Pirquet realized that the immune system isn’t there to just protect us. This was actually a very big and new idea at the time, which was about a hundred years ago. Pirquet helped us understand that while antibodies are on the lookout for invaders like bacteria, sometimes they mistake an allergen as something that is harmful.

The immune system is just trying to do its job, but it isn’t perfect. It can sometimes bring on serious reactions in the body. When people are having an allergic reaction, they will often get a runny nose, itchy eyes, sneeze a lot, but they have more serious reactions like trouble breathing and throwing up.

Pirquet was actually the scientist who helped coin the term “allergy” and he used it to talk about how our immune system can react and respond to invaders in different ways. He helped us understand that the immune system can sometimes set off false alarms.

As is often the case with curious science questions, we can also look at this one from another angle. Doctors are discovering different allergies in different people all the time. I talked to my friend Jennifer Robinson about it. She’s a clinical associate professor of pharmacy at Washington State University.

Today we can discover what a person is allergic to with a simple test. Robinson said doctors will often make a tiny scratch on the surface of the person’s skin and inject a little bit of the allergen. Then, they will look for a little redness or swelling near the injection site to see how the body reacts. They are also prepared to respond, just in case the patient gets really sick.

If you do have allergies, doctors may prescribe medicine, have you use a device called an EpiPen, or have you avoid the allergens entirely. We can help make sure our friends with allergies stay safe by keeping allergens away from them, too.

Dr. Universe

Ask Dr. Universe – Funny Bones

Dear Dr. Universe: Why do we have funny bones and why does it hurt so much when we hit that spot on our elbows? -Ms. Hundley and students

Dear Ms. Hundley and Students,

The human body is made up of 206 bones with different names. There’s your skull, or cranium. There’s your finger and toe bones, or phalanges. There’s also your kneecap, or patella. But it turns out, the bone we call the funny bone isn’t really a bone at all.

That’s what I found out from my friend Janessa Graves. She’s a researcher at Washington State University who knows a lot about the human body and studies injuries, like concussions in children.

When you hit your funny bone, you are actually hitting part of a whitish bundle of fibers called a nerve. Your nerves help send messages from different parts of your body to the brain. Just as bones have different names, so do nerves. The one we feel when we hit our “funny bone” is the “ulnar nerve.”

Most nerves in the body usually have some kind of protection. Often they are cushioned by muscle or bone. But the ulnar nerve is a little different. Part of your ulnar nerve travels through a channel in your arm called the cubital tunnel. This leaves part of the nerve around your elbow a bit more exposed. It’s only protected by a bit of skin and fat.

When we hit our elbow just right on a corner or hard surface, that nerve gets squished, or compressed.

“This compression creates a painful, shocking, burning or tingling sensation that is pretty unique,” Graves said. “It shoots all the way down to the tips of our fingers, which is where the nerve ends.”

If you do hit your ulnar nerve, you’ll probably only feel those sensations for about 30 seconds or so. Even though it can be a bit painful, it doesn’t usually do much damage to the nerve. Graves adds that sometimes people do hit their funny bone and that feeling doesn’t go away, so they have to see a doctor to figure out exactly what might be going on.

Either way, it doesn’t seem like much of a laughing matter when you hit your funny bone. That made me wonder where it got its name. Graves said there are a few ideas about it.

One idea is that it’s because the ulnar nerve is next to a bone called the humerus bone, which runs from your shoulder to the elbow. Some people think the funny bone got its name because humerus sounds like humorous—it’s a homonym, or a word that sounds like another word but has a different spelling.

Another idea is that the sensation of hitting the nerve creates a funny or unusual feeling in our arm, hand, and fingers. I don’t know about you, but even though it is technically a nerve, I think I’ll stick to the tradition of calling it the funny bone.

Dr. Universe

Ask Dr. Universe – Octopus Hearts

Dr. Universe: What would happen if we had three hearts and one of them stopped? From, Marko, 8, Melbourne, Australia

Dear Marko,

It’s hard to say exactly what would happen if you had three hearts and one of them stopped. Humans, and cats, have just one heart, so we have no experience with this. Octopuses, on the other hand, do have three hearts.

When I called my friend Kirt Onthank, a professor at Walla Walla University who studies how octopus bodies work, he told me all about the three hearts. Before becoming a professor, he also studied biology here at Washington State University.

Onthank says the answer to your question depends on which of an octopus’s three hearts stops working. Octopuses have two types of hearts. Two of them are called branchial hearts and one is called a systemic heart.

Each branchial heart sits right next to each of the octopus’s gills. The branchial heart pumps blood through the gills and after the blood leaves the gills, the single systemic heart pumps it to the rest of the body.

“The branchial hearts kind of work like the right side of your heart, pumping blood to the lungs, and the systemic heart works like the left side of your heart, pumping blood to the rest of the body,” Onthank says.

If one of the branchial hearts failed, the octopus would probably be okay. Of course, it wouldn’t be able to use the gill next to it anymore. Just as humans can live with one lung, octopuses can live with one gill.

“In fact, an octopus with one gill is likely better off than a human with one lung,” Onthank said,

That’s because, unlike humans, octopuses can also breathe through their skin. They don’t have to depend on just their gills to breathe. This ability to breathe through their skin is why they can move around on land for short periods of time.

But if the octopus’s systemic heart failed, it would be bad news. The octopus would not be able to survive because that is the heart that provides the whole body with blood, which also helps deliver important oxygen around the body.

If you thought three hearts was a lot, you might be even more surprised to learn about the hagfish, which looks kind of like a slimy, sticky eel. It actually has four hearts. One is the main heart, while the other three support it. The supporting hearts are what scientists have named auxiliary hearts.

Of course, humans only need one heart. Put your hand on your chest and you’ll feel it beating. At this very moment, the right side of your heart is receiving blood from your veins and is pumping it into to your lungs, which pick up oxygen and get rid of carbon dioxide. The left side of your heart is receiving blood from your lungs and pumping it through to the rest of your body. It pumps with a strong force—about the same force it takes for your hand to squeeze a tennis ball— and helps keep you going each day.

Dr. Universe

Ask Dr. Universe – Why We Have Eyelashes

Dr. Universe: Why do we have eyelashes? -Rebekah W., 12

Dear Rebekah,

Across the animal kingdom, we see all kinds of eyelashes. They come in different sizes, shapes and textures. They also come in different colors, though most fall somewhere between black, brown, and blonde. All of them are actually hairs and the scientific term is “cilia.”

When humans look in the mirror, they usually see eyelashes lining both their upper and lower eyelids. Sometimes lashes fall out, but humans can grow them back. The lashes are just thick enough to keep things like small particles of dust away from their eyeballs. But there are some animals with even thicker lashes.

If you were a camel or a llama, you would have a lot more eyelashes. Camels actually have three eyelids protecting each eye. Two of those eyelids have bushy eyelashes. They help keep the sun and sand out of the camel’s eyes.

Giraffes also have some pretty full eyelashes. Giraffes like to eat from big prickly trees called acacias. One of the challenges of eating from a tree with thorns is that you might get your eye poked. Eyelashes help the giraffes sense if they are getting too close to the thorny branches.

While eyelashes come in different shapes and sizes, they all have a sense of touch. It makes them what scientists call tactile organs, said my friend and veterinarian Kevin Kaiser. He studied at Washington State University and now helps animals at the Animal Eye Clinic of Spokane.

Kaiser said eyelashes help the body recognize when something might cause harm to the eyes and tell the eyelids to shut. While a lot of animals have eyelashes, some animals also have other kinds of hairs on their face to help them sense the world. Some of these animals include cats, like me.

Horses have something similar. In addition to upper eyelid lashes, they have very long hairs around their eyes called vibrissa. Meanwhile, dogs have two to four rows of eyelashes along the upper eyelid and none along the lower eyelid.

Hair is unique to mammals. In fact, some animals don’t have eyelids at all. For example, some kinds of fish don’t have eyelids or lashes. They live in an environment that keeps their eyes wet. Water gets in their eyes, but it doesn’t seem to bother them. They even sleep with their eyes wide open.

Animals that do have eyelashes also have something in common when it comes to the size of their lashes. A few years ago, scientists studied about 20 animal specimens at the American Museum of Natural History in New York. They took a close look at the eyelashes. They found that most eyelashes in the animals were about one third the width of the animal’s eyeball. It’s an eyelash length that appears to be just the right size to protect an animal’s eyes.

Dr. Universe

Ask Dr. Universe – French Fries

Dr. Universe: Why are French fries so good? – Emma, 8, Alaska

Dear Emma,

A good French fry starts with the right potato. My friend Rick Knowles is a potato researcher at Washington State University and told me all about the spuds.

It turns out there are certain kinds of potatoes that make the best fries. Two of them are the Clearwater Russet and Blazer Russet potatoes. These potatoes have a good texture and their long shape makes them great for cutting into fries.

If you took a bite of a raw potato, it probably wouldn’t taste very good. But when we cook a potato at just the right temperature, something called the Maillard reaction happens.

The Maillard reaction is a reaction in potatoes that happens between glucose, a kind of sugar, and amino acids, the building blocks of protein. Knowles explained that the Maillard reaction changes the flavors and odors of some foods that we cook.

“In the case of potatoes, we want a certain amount of Maillard reaction to give us the golden brown color and characteristic cooked flavor of the chips and fries, but not too much Maillard reaction,” Knowles said. “Otherwise we get dark colored fries that have a bitter, burnt flavor.”

You may have noticed the Maillard reaction doesn’t happen when we cook up mashed potatoes. That’s because we only boil the potatoes to around 212 degrees Fahrenheit. The Maillard reaction happens when foods like potatoes have just the right amount of glucose and amino acids and are heated to above 302 degrees Fahrenheit.

A big part of the flavor in fries also comes from the oil we use to fry them. A little salt also adds to the taste.

A lot of people in the food industry are very curious about flavor. In the lab here at WSU, Knowles and his team invite people to taste test French fries each year.

“We make them up right here,” Knowles said, when I visited him in the research building where he works.

Researchers in the Knowles lab study new potato varieties that they are growing in Oregon, Washington, and Idaho. They developed potatoes like the Clearwater Russet and Blazer Russet through a process called plant breeding. Plant breeding helps the researchers select the traits they want in a plant, like a certain shape, size, or a high amount of protein.

The team is helping farmers learn which potatoes people will buy and want to eat. In Washington state, we grow more than 9 billion pounds of potatoes every year and most of them will go on to become French fries.

You can also whip up some fries right at home with the help of a grown-up. My friends at WSU Extension even have a recipe for you to try: crispy potato wedges. Try out the science of cooking in your kitchen sometime, check out that Maillard reaction, and let us know how your potatoes turn out at Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – Sleep and Sounds

Dr. Universe: Can the sound of rain help us sleep? – A reader

Dear Friends,

All around the world, people fall asleep to different sounds. Maybe you hear a snoring dog, whooshing waves, noisy traffic, chirping crickets, a soft lullaby, or raindrops.

These kinds of sounds can actually help different parts of our body kick into gear, said my friend Devon Hansen. She’s a sleep researcher at Washington State University.

Her lab often investigates two of our body’s systems by hooking people up to a heart monitor. Monitoring a person’s heartbeat can help her see which of these two systems are active.

One system is the sympathetic nervous system. If you ever feel threatened, this system helps you decide whether to run away or confront the situation.

Another system is the parasympathetic nervous system. This one helps you stay calm, rested, and also digest your food–without even having to think about it. When you are in “fight or flight” your heartbeat speeds up. When the parasympathetic nervous system is active, your heartbeat is slower.

A fire alarm going off, a lion roaring nearby, or someone screaming might startle you and kick in that “fight or flight” system. You’re suddenly alert and awake to respond to danger. But the sounds of rain or ocean waves aren’t usually very threatening noises. They activate the parasympathetic nervous system and your body relaxes.

These kinds of soothing sounds can also muffle noises that might keep you awake or distract you, such as a howling dog or loud traffic.

Hansen said it’s important to remember that sound itself doesn’t make you fall asleep. It’s really that your parasympathetic nervous system is activated, which is what relaxes the body. Once the body is relaxed, it will naturally fall asleep.

You can try a sleep experiment of your own at home. Find a metal spoon or fork. Write down the time you go to bed. Then grab a metal tray and put it on the ground next to your bed. Once you are ready for bed, hold the utensil in your hand over the tray.

When your body and hand relax, you will drop the fork or spoon. The clatter will probably wake you up. Then write down the time you woke up. Subtract the time difference and you’ll see how long it takes you to fall asleep. You can try this while listening to different sounds, like the sounds of a forest, rain, or the ocean.

Hansen adds that putting on soothing background sounds can be helpful when falling asleep, but it’s not as helpful for staying asleep. If your speakers are on all night, they could be waking you up a lot without you realizing it. But it could explain why you might be tired the next morning. A good night’s sleep is important for humans, especially if you want to stay sharp and keep thinking up great science questions.

Dr. Universe

Ask Dr. Universe – Why Cats Like Lasers

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

Dear Izzy,

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

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

A zipping red light that quickly switches directions might have a similar motion to a mouse or other critter. The light sort of mimics an animal scurrying around to escape its prey. Even though we cats know the laser is not an actual mouse, it triggers our predatory instinct.

An instinct is something hard-wired into animals—they don’t have to learn it, they just naturally know how to do it. For example, dogs drool when they see food. Birds build nests. These are all instincts and some can help animals survive.

As predators, cats also have a few other tools that are useful for survival: claws and sharp teeth. We also have good eyesight and hearing. Plus, we are pretty fast.

The house cat is actually descended from a wild species of cat, including the European and African Wild Cat. These cats were big hunters. While house cats are more domesticated, we still share that instinct to hunt.

Meanwhile, big cats like lions, tigers, and cheetahs have even bigger claws, teeth, and speed. Some of these animals show at least a bit of interest in laser pointers, too.

It turns out cats big and small aren’t the only ones who like to chase lasers. Other animals seem to be very curious about them. Dogs will chase lasers. Some insects go a little wild when they notice a laser moving. People have even recorded fish following the light in aquariums.

Biologists might call the laser a kind of superstimuli. It really draws in the animal’s attention because it’s so different from anything else going on in its environment. Unlike smart prey in nature who camouflage, the red laser point stands out.

While investigating all kinds of things about cats and lasers, I discovered that house cats haven’t been playing with lasers very long. The first cats were domesticated about 4,000 years ago in ancient Egypt. Some researchers think we might have been domesticated even earlier.

Lasers were only invented about sixty years ago. That might seem like a long time at first, but when you consider how long cats have been domesticated, only a small number of cats throughout history have ever played with a laser. That got me wondering how lasers work in the first place. We’ll save that question for another time.

Dr. Universe

Ask Dr. Universe – Ancient Rain Filtering

Dr. Universe: How did people in ancient times filter water from rain? – Richard A., 11

Dear Richard,

Every day people around the world get their water in different ways. Some get water from a well, others turn on a tap, go to the store, and some walk many miles to a river. But no matter how we get our drinking water, it almost always starts with rain.

Rainwater is really clean, said my friend Julie Padowski. She’s a scientist at the State of Washington Water Research Center at Washington State University.

In ancient times, some people harvested rain in big containers, but many more people used water that had collected naturally in streams, rivers, and in the ground.

They could find groundwater rushing by in rivers, or bubbling up from underground through a spring. They could also dig deep into the earth to find water.

“What people did way back in ancient times is they looked for water that was flowing or they used groundwater,” Padowski said. “Groundwater from deep down in the earth is often safer to drink because it’s more protected from contamination.”

As cities grew up around the world, people had some new ideas for getting water. The Romans built big, bridge-like structures called aqueducts, which helped bring water from distant springs or mountains into the city. They also had different ways to filter the water. Padowski said we still use some of these ancient techniques.

For example, we let water sit, or settle, so particles fall to the bottom. Then we can strain off the particle-free water. We boil water to kill any bacteria. We also filter water through soil or sand. In ancient times, people actually built sand filtration columns. As the water slowly trickled through the column, it cleaned the water.

When using soil or sand as a filter, particles that might be bad for you get stuck in the little gaps, or pores. This small stuff gets trapped as the water continues to flow down. Tiny bacteria in the soil also eat up some of the particles. By the time the water moves through the soil, we have some very clean water.

We live on a wet planet—about 70 percent of the surface is covered in water. But only about one to two percent of that is water we can actually drink.

These days we have new technology and creative ways to filter some of the dirtiest water on our planet and transform it into clean drinking water. It allows us to tap into new techniques people in ancient times may not have been able to use, Padowski said.

Who knows, maybe one day you will also help us come up with innovative ways to make sure everyone has clean drinking water and that no one goes thirsty. Water is a precious resource and we can all do our part to take care of it.

Dr. Universe

Ask Dr. Universe – How Land Affects the Weather

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

Dear Isaac,

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

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

If you are out on the ocean, you might not feel a big temperature difference between night and day. But we do feel a bigger difference in temperature on land. Especially when conditions are clear and calm, the weather can be very warm in the afternoon and chilly by the morning. Loyd explains that land normally warms up and cools down more quickly than water.

You can test this out at home. Fill up one plastic tub with sand or dirt and fill up another plastic tub with water. Put them out in the sunshine. Using a thermometer, take the temperatures of the two tubs every ten minutes for thirty minutes. Record your results to find out which one heated up faster. You may want to try this a few times just to make sure your results are accurate. Water actually absorbs at least as much energy from the sun as the land does—but water just isn’t capable of warming up as fast as land, or in your case, sand or dirt.

The different types of land around the planet also impact the weather. One good example is mountains, Loyd said. The air is usually much colder if you are up high in the mountains. That’s also where we see a lot of glaciers, ice, and snow all year long. In the mountains, the air is thinner and it doesn’t trap in the heat very well.

Exactly what covers that land also influences the weather. Forests, cities, plains, or deserts can absorb a lot of the sunlight that reaches them, warming the air above the land. But when land is covered in snow, much of the sunlight is reflected away instead of being absorbed into the land. This also helps keep snowy areas colder.

So yes, the land, as well as the water, affects the kind of weather we experience on our planet. But the weather can also affect the land. Just think of the rain that helps plants grow on farms. Or the sun that gives plants energy they need to grow. Can you think of other ways the weather might change the land? Can you think of how these changes might shape the land over a long period of time? Send your ideas to Dr.Universe@wsu.edu.

Dr. Universe

Ask Dr. Universe – How Trees Survive After a Wildfire

Dear Dr. Universe: How do some trees survive after being burned in a wildfire?
-S.P., Quilcene, WA

Dear S.P.,

While it might seem like wildfires only cause destruction, they are actually a natural and important part of keeping forests healthy. After many years, trees have adapted to their homes. Some are pretty invincible when it comes to surviving a wildfire.

There are a few ways they can survive, says my friend Andy Perleberg. He’s a forestry expert at Washington State University.

One thing that protects trees from wildfire is thick bark. In Washington state, the most common trees with really thick bark are the western larch and ponderosa pine. Ponderosa pine actually has jigsaw-puzzle shaped pieces of bark. Maybe you have seen these in your neighborhood. Some people call the pieces “scales,” Perleberg said. When on fire, these scales peel back and fall to the floor, taking the fire back to the ground.

The tree makes sugar—its food– through a process called photosynthesis. Under the bark is a very important part of the tree that helps the tree mobilize sugar called the phloem.

It helps move sugars around the tree and to the roots. The thick layer of bark also helps protect the tree’s food-processing system from fire and other damage so it can get the energy it needs to survive.

When a fire happens, some trees will release a kind of sticky, honey-like substance called sap, or pitch. The pitch will flow into cracks where fire could reach that very fragile phloem. It’s kind of like smearing putty over a crack in a wall, Perleberg adds. This leaves the tree with a fire scar, he says, but the tree survives and keeps growing.

Fire ecologists can use these fire scars to trace the patterns of historic fires and how often they happened. Sometimes, fires occur naturally through lightning strikes. Sometimes, fires are man-made, and Native Americans traditionally burned areas to help people survive, encourage certain plants and keep ecosystems healthy.

Some trees have also adapted to shed their lower limbs. As the tree grows higher and higher, some limbs don’t grow anymore. The fire can’t climb up the tree as quickly without the source of fuel to help it along.

After a fire, the trees left standing likely had thick bark or another one of these adaptations. Meanwhile, the rest of the dead trees will also have a new purpose in life.

Dead trees and old plants that turn into ash return important things, called nutrients, to the soil. The old trees also become habitats to some kinds of wildlife that live in the forest. Bark beetles like the weak trees and go in to eat the sugary layer beneath the bark. Other critters, like flying squirrels or tree frogs, might turn a dead tree into their new home in the forest.

Dr. Universe

Ask Dr. Universe – Where Bees Sleep

Dr. Universe: Where do bees sleep? – Annalisa, 10, Middletown, NJ

Dear Annalisa,

Sleep is important for lots of the animals on our planet. Just like you need a good rest, so do bees. But, bee sleep is different than human sleep.

That’s what I found out from my friend Brandon Hopkins, a bee researcher at Washington State University. I asked him how you can tell if a bee is asleep.

“They don’t have eyelids, so you can’t just look for bees with their eyes closed,” he said. “By carefully watching bees, scientists have found that honey bees stop moving their antennae and in some cases fall over sideways.”

Sometimes other bees will try to help keep a bee from falling over. They actually hang onto the fellow bee’s legs so it won’t fall off the honeycomb. That’s some serious team work. The sleeping honey bee also relaxes its muscles so the upper body and rear-end droop a little. It’s wings may also rest on its body.

Exactly where a bee sleeps depends on where it lives. More than 20,000 known species of bees live on our planet and we find them in different places.

Honey bees work day and night and take shifts sleeping inside the hive. Their sleep patterns change as they grow up. Younger bees sleep a lot less than the older bees. The older foraging bees that collect pollen and bring it back to the hive have more of a regular sleeping pattern.

It’s a little hard to say how long they sleep, but these older bees catch between 30 minutes and an hour and a half each night. To get all that rest, they take little sleeps, or catnaps, of about 15 to 30 seconds at a time.

It’s very important that honey bees sleep, Hopkins explains. Researchers have found that older honey bees need sleep because it helps their memory. Yes, bees can learn and remember things, too. They need to have good memory to remember where they find pollen and nectar.

In studies where bees stayed awake for long periods of time, scientists also found that bees were poor dancers.

It’s ok if a human is a poor dancer, but honey bees dance to communicate with other bees and tell each other where they might find flowers.

“If they are sloppy dancers, the hive becomes less efficient and won’t be able to collect as much nectar and pollen,” Hopkins says.

Then again, not all bees live in live in hives or have a colony. Some are solitary bees, like the teddy bear bee. The teddy bear bee often bites into small branches and hangs there for the night. Other solitary bees will sleep in their nests or on plants.

Now that you know bees sleep, maybe you’ll spot one taking a snooze in your neighborhood. Just be sure and let it rest. In meantime, you can watch this short video of a sleepy bee catching some z’s.

Dr. Universe

Ask Dr. Universe – Sticky Sand

Dr. Universe: How does sand stick together?– Kamrin, USA

Dear Kamrin,

Sand is actually made up of lots of different things. When we look at it under the microscope, we can see cooled lava, coral, seashells, and other kinds of wonderful, colorful rocks.

If you add just the right amount of water to sand, it transforms into a pretty good material for shaping towers, walls, and spires for a sandcastle. At first, I thought the wet sand stuck together because of a chemical reaction. But it turns out this interplay of sand and water creates what scientists call a physical reaction.

That’s what I found out from my friend and physicist Lauren Barmore, a graduate researcher at Washington State University who is very curious about matter and how things work on our planet.

She explained that if you had two rocks and put a bit of water in the middle, the water would be attracted to the rocks and form a kind of liquid bridge between them. One property of water is that it doesn’t like to touch the air. It has to do with its chemical make-up. Water would rather hang onto something else.

Sand is really just a lot of little rocks and some of those other solids. There are a lot of these tiny liquid bridges in a handful of wet sand. The sand particles aren’t sticking to each other, but are being held together by water.

A lot of these little bridges can make the sand stick together better. The water bridges are actually shaped like hourglasses, thin in the middle and thick at each end, Barmore explains. But as you add more water, the bridge gets weaker and that bond breaks. Then you end up with a soupier sand. On the other hand, if the sand dries out, the water bridges start to disappear and the sandcastle crumbles.

The force behind this is called surface tension. We see it when we fill a water glass to the top and it forms a curved edge. It’s also how some bugs can walk on water and why a bit of water forms into a droplet instead of spreading out.

Perhaps you can try some sandcastle investigations of your own at home or the next time you’re at a beach. Can you find the best recipe for sandcastle sand? Is it one part sand to a half cup water? One cup sand to one cup of water? A different combination? What happens if you use a different kind of liquid instead of water? Tell us what you discover or create at Dr.Universe@wsu.edu.

Dr. Universe

3 sandy facts from physicist Lauren Barmore and Dr. Universe

• Some engineers have found a way to make strong building material out of sand. They can layer up two materials that are not very strong on their own—sand and paper towel—to hold up a car. Watch a video about the engineering process.

• The water bridges that connect sand actually have a scientific name: interstitial water bridges.

• The Guinness World Record for the tallest sandcastle is 54 feet.

Ask Dr. Universe – Why Music Gives Us Chills – Part 2

Part 2: Dr. Universe: Why does music give us chills? -Nicole, 11, Spokane, Wash.

Dear Nicole,

It turns out that the experience of getting chills when we listen to music actually has a scientific name: frisson. That’s what I found out when I met up with Washington State University brain scientist Steve Simasko.

Simasko said he also experienced frisson last year when the moon passed in front of the sun and he saw the total solar eclipse. That made me realize we not only get the chills when we experience music, but also when we experience other kinds of art or wonders in nature.

It isn’t exactly easy to measure frisson, but Simasko said we can still make a few speculations about it based on what we know about the brain.

When we take in music we are using our limbic system. This is a system which helps us process emotions and memories. In the middle of the brain is the amygdala, which also plays a big part in processing emotions.

This emotional system helps us navigate the world. When you experience different emotions, sometimes a physical sensation comes along with it. Fear might give you sweaty palms, a racing heart, and desire to run away from something. This kind of response is helpful for survival.

We also have other kinds of responses. When you get nervous maybe you experience the sensation of butterflies in your stomach. This triggers a release of adrenaline in the body. That left me wondering: Why is frisson tied to this emotional system in our brain?

Simasko explained that human emotions are closely tied to the social part of people’s lives. Sound can actually be an important part of our social life from a very young age. Mothers often sing to their babies, and the babies often coo back. It is part of human bonding.

Emotions are not just important for survival, but also understanding norms, or the way things usually work in a group. Music is also tied closely to our culture—it’s something that we can use to connect and we can share with each other.

If someone grew up listening to opera in China, maybe they get goosebumps when they hear it as an adult. Maybe you live in another part of the world and don’t listen to Chinese opera. It might not have as strong as a connection to you and those around you. But maybe there is a different kind of music that reminds you of memories with your family and friends. Can you think of a kind of music that gives you the chills?

While music is an important part of people’s lives, the truth is, we still don’t know everything about why it gives us the chills. But we do know that a lot of people experience frisson. Perhaps we will learn more about it one day, but until then, keep asking great questions– and turn up the music.

Dr. Universe

Ask Dr. Universe – Why Music Gives Us Chills – Part 1

Part 1: Dr. Universe: Why does music give us chills? -Nicole, 11, Spokane, Wash.

Dear Friends,

If you are anything like me, maybe you’ve suddenly felt a chill while listening to music. Perhaps, you got goosebumps and saw your arm hairs stand on end. Maybe you even teared up.

The truth is I really wasn’t sure why music gives us chills, but I was determined to find out. My first stop was the Washington State University School of Music. That’s where I met up with my friend and music professor Greg Yasinitsky.

He played a few different notes on the piano in his office. He told me that if you play three or more notes at once, it’s called a chord.

Major chords tend to make us happy,” he said. “Minor chords are more ominous or sad.”

However, when the music tends to be sad people don’t always describe it as unpleasant, he adds. Just think of an emotional or dramatic part of a movie. Even if the music has more of a sad sound, sometimes it brings about a positive emotion.

Composers will sometimes mix around major and minor chords to play with a listener’s emotions. They also play with things like rhythm, the strong regular repetition of sound, and melody, or the sequence of notes that helps a song sound just right.

Yasinitsky said there seem to be two situations in which people will report feeling the chills. The first is when a listener hears something that is a surprise. Maybe a song has a pretty repetitive pattern, but then something happens that they weren’t expecting.

“That one little change suddenly has this immense importance and for a lot of people could send a chill up their spine,” Yasinitsky said.

Another situation where people might get the chills is when they hear something that is not a surprise. When they finally hear what they’ve been expecting, they might get goosebumps.

Of course, not everyone gets the chills—and different kinds of music may bring out the chills in different people. Either way, most people have an emotional connection to music.

“Pretty much every culture on the planet has music,” Yasinitsky said. “Even those that have outlawed music, they chant, they are still singing. We all need music.”

After chatting with Yasinitsky, I headed across campus to visit the WSU neuroscience department. That’s where I met up with our friend Steve Simasko. He told me more about music, emotions, and the brain. But we’ll explore that next week.

In the meantime, you can try making your own instruments at home. Collect different supplies like rubber bands, popsicle sticks, toilet paper tubes, or other kinds of materials to create your own sounds. Try making a coffee can drum or some maracas. If you are feeling really ambitious, try out a shoebox guitar. Maybe you can play a tune along with your friends. Let me know how it goes at Dr.Universe@wsu.edu.

Dr. Universe