Dr. Universe: How many beetles are there in the world? – Tu, 12, Utah

Dear Tu,

If beetles seem to be everywhere, that’s because they are. Some beetles stand out because they’re colorful. Think about jewel beetles and ladybugs. Others play useful and weird roles in the ecosystem—like the poop-rolling dung beetle. Their ancestors probably even ate dinosaur poop.

Nobody knows exactly how many beetles there are, but scientists have some ideas. I talked about it with my friend Joel Gardner. He’s the collection manager for the insect museum at Washington State University.

When scientists find a new species, they describe what it looks like. They give it a name. They publish that information so other people know about it. That’s called describing a species. Scientists describe new insect species all the time.

Gardner told me scientists have described about 400,000 species of beetles so far. There are many more beetles we don’t know about yet. Altogether, there are probably between 1 million and 2 million beetle species.

Right now, beetles make up 40% of all described insects. They’re 25% of all known life on Earth.

But another group of insects may have more species than beetles—parasitic wasps. These wasps lay eggs in or on other insects. When the eggs hatch, the baby wasps eat the host.

“For every insect there’s probably a wasp that parasitizes it. So, you can imagine there are millions out there,” Gardner said. “Parasitic wasps are generally very small. Different species look almost identical. So, you need to use advanced methods to tell them apart.”

If scientists described all those parasitic wasps, beetles might be closer to 5% of all insects.

Another way to look at your question is how many individual beetles are on Earth right now. Gardner did the math to figure that out.

He told me scientists think there are around 10 quintillion individual insects. That’s 10 followed by 18 zeroes. Like this: 10,000,000,000,000,000,000. If 5% of all those insects are beetles, there are probably around 500 quadrillion individual beetles.

Pretend you’re the beetle boss. You make those 500 quadrillion beetles line up. If they’re all half an inch long—about average size for beetles—that line of beetles would wrap around the Earth more than 150 million times. That’s a lot of beetles.

There are about 500,000 beetles in the collection at WSU. Gardner stores them in 917 wooden drawers. Some were collected by scientists. Others were donated by people who collect insects for fun.

Beetles belong to the order Coleoptera. You can often identify a beetle just by looking at its wings.

Like most insects, adult beetles have four wings. Scientists call their hind wings membranous. That means they’re thin, flexible and transparent. They flap these soft wings to fly. The front wings are hard coverings called elytra. They protect the hind wings. The red-and-black part of a ladybug is its elytra.

The only way to know for sure how many beetles are out there is to find and describe them. One of the best parts of entomology—the study of insects—is that it’s open to everyone. Getting to know the beetles that live near you is a great way to get started. Maybe one day you’ll find a new species of beetle!

Sincerely,
Dr. Universe

Dr. Universe: What is the difference between B cells and T cells in the immune system? – Tanveer, 11, California

Dear Tanveer,

Everyone who heard your question agreed that it’s a sophisticated one. To get my paws around the answer, I talked with my friend Phil Mixter. He’s an immunology professor at Washington State University.

He told me all living things need to protect themselves from microbes that could make them sick. These are called pathogens. They can be bacteria, viruses, fungi or parasites.

“Almost every organism I can think of—from plants to animals and beyond—has a defense system to handle the possibility that another organism might sneak in,” Mixter said.

Complex organisms need better defenses. That’s why animals like mammals have two-part immune systems.

The first part is called the innate immune system. It includes physical, chemical and cellular ways to keep pathogens out. It uses patterns to recognize something isn’t part of your body and eliminate it.

The second part is called the adaptive immune system. It includes those B cells and T cells you asked about. They’re both white blood cells called lymphocytes. They work as a team. B cells and T cells have different jobs on the protection team.

B cells produce and release proteins called antibodies. Their job is to grab onto pathogens and not let go. Sometimes the antibody blocks the part of the pathogen that interacts with your cells. These are called neutralizing antibodies.

Antibodies have another job, too. A pathogen with an antibody on it is marked for destruction. It’s like a giant neon X that tells your immune system to gobble up the pathogen or blast it with a chemical defense.

Mixter told me about two kinds of T cells: helper T cells and killer T cells. Helper T cells are in charge. They help B cells by telling them what to do—like what antibodies to make more of and where to send them. Killer T cells are like assassins. Their job is to look for pathogens hiding inside your cells. Then, they eliminate those unhealthy cells before they can spread.

Once the adaptive immune system encounters a pathogen, it’s primed to act if that pathogen shows up again.

“I like to think of it like a fire drill,” Mixter said. “The immune system is not the same after that first encounter.”

In real-life fire drills, you get faster every time you practice. The second time a pathogen shows up, the immune response is faster, too. Helper T cells can give the order to crank out B cells with the right antibodies. That’s called recall response. It’s more efficient to “recall” trained team members than to recruit and train new ones.

You’re a part of the team, too. The stuff you do to stay healthy—like washing your hands—supports your immune system so it can protect you.

Sincerely,
Dr. Universe

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Dr. Universe: Why do we get sleepy when we study? – Sadaf, 12, Pakistan

Dear Sadaf,

Like many good students, you’ve probably noticed that when you study, especially late in the day, you feel sleepy. Scientists don’t know exactly why, but they have a few clues.

The human brain is packed with tens of billions of cells called neurons, which process and store information that helps us observe, understand and make decisions about the world.

My friend Hans Van Dongen, director of the Sleep and Performance Research Center and a professor of medicine at Washington State University, said you might think about neurons as workers in a huge company. Each neuron is an expert in a piece of information, and neurons work together to share what they know and build new connections in the brain.

And just like workers in a company—or students like you—neurons need rest when they’ve been working hard. When you feel sleepy, that’s a sign that you (and your neurons) need to go to sleep.

Van Dongen said there are probably several reasons your brain needs sleep. The first is that thinking takes energy. Neurons processing information and making new connections may use up energy especially quickly.

“We know that one of the things that sleep can do for us is replenish the energy stores in the brain,” Van Dongen said.

Just a few years ago, sleep scientists discovered that your brain also pulses to flush out waste while you’re deeply asleep.

Imagine an office in that huge company where people have been piling up papers and coffee cups all day long. Pretty soon, it gets so cluttered there’s no room to work. The workers need to take a break and clean up.

Finally, your brain needs time to make sure the information it’s storing will last a long time. While you’re studying, your neurons are making new connections, and they might still be a little wobbly. While you’re sleeping, those connections get stronger.

Thinking back to your brain as a huge company, imagine the office needs some construction done to make room for new computer servers. It’s hard for the construction crew to work while everyone’s bustling around, so they come in and build things at night.

So, what should you do when you’re trying to focus on your homework, but you start to feel sleepy? Listen to your brain.

According to the American Academy of Sleep Medicine, kids ages 6 to 12 need nine to twelve hours of sleep every night. When you’re a teenager, you’ll need eight to ten hours—and Van Dongen said sleep scientists have learned teenagers’ brains usually like to fall asleep later at night and sleep in later in the morning.

If you were a cat like me, you’d need as much as 18 hours of a sleep every day. Even though you’re a kid, you can take cat naps to help your brain, too.

“Naps are awesome because naps are sleep,” Van Dongen said. “They pretty much count one hour for one hour. If you get two hours of napping in, that will count for two hours of sleep that you need in 24 hours.”

Next time you feel sleepy when you’re studying, head to bed or curl up for a nap. Who knows, maybe you’ll dream about being a scientist who discovers even more about sleep.

Sincerely,
Dr. Universe

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Dr. Universe: What are butterfly wings made of? Serenity, 12
 
Dear Serenity,
 
Butterfly wings may be quite thin, but they are also durable and strong. This strength comes from the material that makes up the wings: chitin (KITE-IN).
 
Chitin is a kind of building material we find in nature. Chitin makes up not only the wings of butterflies but also the outer skeletons—or exoskeletons—of crabs, shrimp and lots of other insects.
 
My friend David James, an entomologist at Washington State University, told me all about it.
 
He said that chitin is a bit like the strong keratin material that makes up your hair and fingernails. Of course, butterfly wings are much thinner than a fingernail. These thin, light wings help the butterflies float and fly through the air. 
 
“They’re wafer thin, and there’s not much to them, but they allow the butterfly to migrate sometimes thousands of miles,” James said.
 
A butterfly’s wings are also covered in lots of tiny scales. You read that right. Butterflies have scaly wings.
 
“The scales are overlapping like the tiles on a roof,” James said. “They can come in many colors.”
 
These scales are also made of chitin. In fact, the butterfly’s head and abdomen are made of chitin too. It’s one of the basic materials in the outer parts of most insect bodies.
 
James added that one misconception some people have about butterflies is that they can’t fly when the scales come off their wings. Of course, butterflies are delicate and should be treated gently, but they can also be pretty tough.
 
“Sometimes you see butterflies that are completely beat up, tattered and the colors have gone, but they’re still flying and able to move around,” James said.
 
The colorful scales don’t really help with flight, but they can help the butterflies survive in the wild in other ways.
 
Some wing colors can help butterflies blend into their environments and help them hide from predators. Bright colors on butterfly wings can send a signal to predators that the butterfly is poisonous and should not be eaten. The different colors and patterns may also help a butterfly attract a mate.
 
When a butterfly is forming in a chrysalis, its wings are usually one of the last things to develop. As a butterfly comes out of a chrysalis, its wings are wrinkly and wet. 
 
James said this is the most vulnerable time for the butterfly because its wings are not hardened yet. Usually, butterflies will emerge early in the morning to hopefully avoid any birds who might be looking for their next meal. 
 
It takes a few hours for the wings to dry and for the hemolymph—the insect’s blood—to pump through its veins. The veins help give the wings some shape and structure. Then, when the time is right, the wings expand, and the butterfly is ready to take flight.
 
The next time you see a butterfly fluttering past you, see if you can catch a glimpse of its wings. Who knows, maybe you will become a scientist one day and help us learn more about the amazing world of insects.
 
Sincerely,
Dr. Universe

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Dear Dr. Universe: Why do we get hiccups? – William, 9, Indiana
 
Dear William,
 
When you get hiccups, it might seem like they are coming out of nowhere—and before you know it, they’re gone.
 
To find out exactly why hiccups happen, I talked to my friend Dr. Luisita Francis, a professor of medicine at Washington State University.
 
She told me part of the reason humans get hiccups has to do with a very important muscle in the abdomen: the diaphragm (DYE-UH-FRAM).
 
This dome-shaped muscle sits near the top of your stomach and intestines, but underneath your lungs. When you breathe in, it contracts and flattens. This motion of contraction helps pull air into the lungs.
 
When you breathe out, the diaphragm returns to its usual shape and helps push air out of the lungs. This happens all day long and helps you keep breathing. But sometimes the diaphragm gets a little irritated.
 
“When you have hiccups, what happens is you get some irritation of that diaphragm,” Francis said. “The muscle just contracts, and you end up taking in a whole bunch of air very quickly.”   
 
The body gets a signal that all this air is coming in quickly, and that it needs to keep even more air from coming in, so the vocal cords close up.
 
“The vocal cords snap together really quickly and that makes the hiccup sound,” Francis said.  
 
I was curious to know what exactly can irritate the diaphragm and cause that squeaky hiccup sound. Francis said sometimes when a person eats or drinks too much, it can make the stomach extend, which can irritate the diaphragm.
 
Sometimes when the body experiences stress, the diaphragm will get tight and that can make it harder for someone to take a deep breath. Some people have noted that when they experience stress, along with irregular breathing that it can irritate the diagram, too.
 
You know, humans have come up with a bunch of different remedies to try and stop hiccups. Maybe you’ve heard of trying things like holding your breath, counting to ten, having someone scare you or other kinds of tricks. I was curious if any of them really work.
 
Francis said there aren’t exactly any research-based cures for hiccups. But some patients have reported that blowing into a paper bag helps them control their breath and decreases irritation. Other patients have reported that drinking a cold glass of water helps.
 
Hiccups can serve as a signal to be mindful of eating habits or to check in on our stress levels. While they don’t tend to stick around very long, there are some exceptions.
 
According to the Guinness World Records, the longest bout of hiccups on record lasted 68 years. If someone has hiccups for more than 48 hours, it’s best to talk to a doctor. But generally, hiccups are a normal part of life.
 
The next time you get a bout of hiccups, see how many you can count—and remember you can always blame them on your diaphragm.
 
Sincerely,
Dr. Universe

Dr. Universe: Why do numbers never end? – Louis, 11, Wenatchee
 
Dear Louis,
 
That’s a great observation about numbers. Whether you start counting backwards or forwards, numbers never seem to end.
 
To find out more about these mysterious numbers, I took your question to my friend Kevin Fiedler. He’s an assistant professor of mathematics at Washington State University.
 
He reminded me that there are a lot of different rules mathematicians follow. For instance, if you think of a number, you could always add one to it. 
 
Think of the highest number you can. Maybe you can even write it down on a piece of paper. Now, add one to it. Try it again and again. Perhaps the simplest answer to your question is you can always add one to a number.  
 
Fiedler reminded me that some numbers are whole numbers, such as 1, 2, 3, 4 and 5. But there are also numbers like 1.33333…, and the 3’s go on without end. A lot of the time mathematicians and engineers will round these numbers.
 
On your piece of paper, you can also try adding a decimal, like .3, to your number.  
 
The answer to your question might also depend on what set of numbers you are using in the first place. Fiedler told me about a kind of math called clock arithmetic that uses the set of numbers 1 through 12.
 
You might just think of those numbers 1 through 12 like the hours on a clock.
 
For instance, in normal arithmetic, 8 + 5 equals 13. But in clock arithmetic the math works out a bit differently. The answer to 8 + 5 is actually one.
 
Imagine you place your finger on the number eight of an analog clock, that is, a clock with hands and numbers 1 through 12. If you have a real clock, you can try this at home. Put your finger on the eight. Now count to one and put your finger on the nine.
 
On the second count, put your finger on the 10. On the third count, your finger goes to the 11. Perhaps, you are seeing a pattern. On the fourth count, your finger will be on the 12.
 
Finally, on the fifth count your finger will land on the one. In clock arithmetic, 8 + 5 equals one.  
 
Of course, even in clock arithmetic, the numbers don’t really end. Once you reach the number 12, you can go back to one and start again.  
 
If you’re curious about numbers, chances are you’ve also heard of infinity.
 
Infinity is a bit weird, Fiedler said. Infinity is something larger than any other number we know about, but we can’t put an exact value or counting number on it like we can with numbers such as 10, 100, or 1000. Perhaps as you continue on your learning journey, you’ll investigate more about infinity.  
 
You know, this wide range of numbers allows mathematicians, scientists and engineers to work on all kinds of different problems in our world. Who knows, maybe one day you will use your math skills to help change the world, too.
 
Sincerely,
Dr. Universe

Dr. Universe: How is DNA built? – Riot, 8, Everett, WA
 
Dear Riot,
 
Pretty much every living thing on our planet—from a blue whale to a tiny ant—has something in common. We all have cells, which are the building blocks of life, and inside of those cells we have DNA. 
 
My friend Gunjan Gakhar, a Teaching Assistant Professor at Washington State University, was happy to help with your question.
 
First, she reminded me that DNA contains the instructions for living things to grow, survive, and reproduce. DNA determines everything from our eye color to our hair color to our height.  
 
“DNA is built like a ladder,” she said. “And if you twist that ladder, that’s what DNA looks like.”
 
Let’s imagine we are building a DNA ladder. We will need a few simple ingredients. First, there are sugar and phosphate.
 
You probably know about sugar already, but phosphate is something present in your teeth and bones that helps make you strong.
 
The sugar and phosphate form a repeating pattern that makes up the side rails of the DNA ladder. Of course, every ladder needs steps, or rungs, too.
 
If we were building a real ladder, not a DNA ladder, we would probably use a single, solid piece of material to build each step.
 
But in our DNA ladder, the steps are actually made of two materials, called nitrogen bases, that are strongly bonded to each other. There are four varieties of nitrogen bases that we find in DNA. Scientists call these nitrogen bases A, C, T, and G. ‘A’ always binds with ‘T’ and ‘G’ always binds with ‘C’.
 
By following this rule, nitrogen bases can bond to each other and the side rails to form the entire DNA ladder.
 
It’s the differences in these combinations of bases that give us the different traits we see across species and even in individual human beings.  
 
Whether you are an ant, a human, or a blue whale, you get half of your DNA from one parent and the other half from your other parent.
 
Another interesting thing about DNA is that your body’s cells can use your existing DNA to make even more DNA—and they do it with the help of things called enzymes.  
 
You produce enzymes that do lots of different jobs. For instance, enzymes in your saliva help break down food. There are also enzymes in your body that help break apart DNA and make more DNA. Enzymes can open up the DNA ladder. They are like DNA scissors that can split the ladder in half.  
 
As long as ingredients like sugar, phosphate, and nitrogen bases are available in the cells, each side rail of the DNA can use those ingredients to make more DNA.
 
If you are curious how DNA looks, perhaps you can make your very own DNA model. I might use toothpicks as bases and paper to model the phosphate and sugar, as you can see here in this DNA model activity from our friends at the American Museum of Natural History. Tell us about your DNA model sometime at Dr.Universe@wsu.edu.
 
Sincerely,
Dr. Universe

Dr. Universe: Why do people have feelings like boredom, happiness, sadness and love? – Sophia, 11, Utah
 
Dear Sophia,
 
You’re stuck inside on a rainy day when all of a sudden you start to feel a bit bored. Maybe you aren’t sure what to do with the feeling. Maybe you decide to read a book or bake some cookies and the feeling starts to fade.
 
Perhaps you then start feeling happiness from doing an activity you love. You know, pretty much everyone experiences a variety of different feelings every day. 
 
My friend Elizabeth Weybright, an associate professor of human development at Washington State University, is really curious about emotions, especially boredom.
 
She said that while we may have all kinds of feelings, they serve a similar purpose.
 
“Feelings are really there to help us communicate to ourselves and to communicate things to others,” she said.
 
The feeling of fear can help signal when we might be in danger. We might even be able to communicate that feeling to those around us, so they can stay safe, too.
 
Weybright also reminded me that there aren’t exactly bad or good emotions. Even if something like fear or boredom might not feel very good, they can have some benefits.
 
Boredom might inspire you to use creativity, for example. Meanwhile, love is an emotion that can help us feel connected others. But even if you feel love, it can sometimes come with some sadness.
 
Imagine you live very far from your grandparents or other family that you love. You might miss them and feel sad if you don’t get to see them very often.
 
While we might have different emotions, you can see how they sometimes have strong connections to one another. It’s also a reminder you can have multiple feelings at a time.
 
Weybright also reminded me that some people might struggle with expressing feelings. They might also need some help understanding other people’s feelings. After all, humans aren’t just born knowing all these different emotions. They have to learn about these feelings as they grow up.
 
She also said sometimes parents, caregivers, teachers and coaches can work together with children to help them learn more about these big feelings. That way when a big feeling like boredom, sadness, love or happiness comes up, you can be prepared to observe it.
 
It’s also great to know there are scientists in our world who are studying more about how emotions work, which may also help people better understand their fellow human beings.
 
Finally, just remember that feelings are a big part of what helps people communicate. Feelings may come and go, but it’s okay to feel them all.
 
Oh, and if you’re ever feeling bored, you might just investigate a good science question. Chances are it will open up a whole new set of questions to explore.
 
Sincerely,
Dr. Universe

Dr. Universe: How come some people can’t see color? – Pearl, 8, South Dakota

Dear Pearl,

Our brains have the amazing ability to gather information and interpret it. This ability to gather and interpret—or perceive— is a big part of what helps humans see colors.

Our eyes have tiny cones that receive light, turn it into chemical energy and activate nerves that can send information to the brain. You might see an apple and think to yourself, “That’s the color red.”

My friend Rachna Narula, an optometrist at Washington State University, told me all about it.

You may remember that the colors people see correspond with different wavelengths of light. Part of the reason someone can see red is because they have a type of cone that picks up on certain long wavelengths of light.

While red cones pick up on long wavelengths of light, blue cones pick up on short wavelengths. Green cones pick up on middle wavelengths. A person with full-color vision typically has three kinds of cones: red, blue and green.

But sometimes a person’s cones might be a little different. They may not have some of those main three cones, which means they can’t pick up on certain wavelengths of light. Or the cones might not work very well.

Narula told me the most common color deficiency is red-green. That means that the cones aren’t able to pick up on long wavelengths and middle wavelengths of light. People with this kind of color deficiency may have trouble spotting the differences between colors, the brightness of colors or the shades of colors.

Narula also showed me a book that optometrists use to test how people see color. It’s called the “Ishihara Test for Color Blindness” and it was designed by a professor at the University of Tokyo in 1917. Each page features different colored dots that make up a background and a number.

For instance, someone with full-color vision might see a background of green dots and the number “5” made up of red dots. But someone who has red-green color deficiency would see a completely different number.

If you’re like me, you might be curious to find out not only how people can perceive different colors but why.

Narula told me color vision deficiency is a kind of hereditary trait. This means it is something that can be passed from parents to their offspring. Most people who experience color vision deficiency were born with it. It’s in their genes.

She also told me there are some people who can see many more colors than most of the population. Narula said these people have a fourth cone. Some scientists are studying genetics to learn more about this kind of fourth cone and find out exactly how this kind of vision works.

Like humans, most cats also have the three main kinds of cones: red, blue and green. Dogs have just two kinds of cones. You know, it sure is interesting to think about what it might be like to see the world through different types of cones than my own. I bet it would provide a whole new perspective.

Sincerely,
Dr. Universe

Dr. Universe: Why is too much salt bad for you? – Dot, 12, Palm Desert, CA
 
Dear Dot,
 
The human body uses salt in all kinds of different ways. Salt helps the cells in our bodies do their jobs, it helps the muscles contract and it plays a big part in keeping us hydrated.  
 
But as you’ve pointed out, too much salt can cause problems. My friend Catalina Aragon told me all about it. As an assistant professor at Washington State University Extension, she works with communities all across the state to share information about food and how it impacts our health.  
 
When humans eat food, they can get lots of nutrients such as calcium, potassium, iron and sodium. Sodium is the mineral our body gets when we consume salt. The sodium gets absorbed into the blood and gets delivered around the body through channels called blood vessels.
 
Eating too much salt can lead to high blood pressure, or hypertension. Over time, high blood pressure can make the blood vessels stiff and narrow. That makes it harder for blood to pump through the blood vessels and deliver all the important things the body needs. High blood pressure can lead to stroke and heart disease.
 
It’s important to be mindful of how much salt we eat, Aragon said. While it depends on the person and what their doctor recommends, the Dietary Guidelines for Americans generally recommends that people 14 years old and older limit sodium to 2,300 milligrams a day. That’s equal to about one teaspoon of salt.
 
“A lot of people think about the salt they can see and sprinkle on top of food,” Aragon said. “But 70 % of sodium in the American diet comes from prepackaged and prepared foods.”
 
She said one good rule of thumb is to read nutrition labels and look at the Daily Value (DV) percentages per serving. If the amount is below 5% of your Daily Value, that’s a low amount of sodium. If the Daily Value is above 20%, that’s a high amount of sodium. Maybe you can use these guidelines to check out some of the nutrition labels around your house to learn more about what’s in your food. 
 
Some of the top sources of sodium are bread, rolls, pizza and sandwiches. A lot of people really enjoy salt because it adds flavor to their food, but there are some other ways to make food taste good. 
 
Aragon said one thing that can be fun to try is experimenting with a variety of spices in the kitchen. Instead of going right for the salt, you might try something like garlic, sage, paprika, oregano or even cinnamon. Maybe even a little lemon juice, depending on your recipe.
 
With help from a grown-up, the kitchen can be a great place to learn more about different types of food and all kinds of science. You can practice your math skills when measuring, learn how different food ingredients interact with each other— and the best part is when you are all finished, you might even be able to eat your experiment.
 
Sincerely,
Dr. Universe

Dr. Universe: How do germs enter the body? -Amari, 8, Indiana
 
Dear Amari, 
 
There are many different ways germs can enter the body. Sometimes they find a way in through an opening like the mouth, nose, eyes or a cut in the skin.   
 
Most of these germs—what scientists call viruses and bacteria—are so small we’d need a microscope to see them. 
 
My friend Leigh Knodler is a researcher at Washington State University who works with a particular kind of bacteria called Salmonella.  
 
Salmonella can sometimes live on food, such as undercooked chicken or unwashed fruits and vegetables. It typically enters the body through the mouth when someone takes a bite of food.  
 
If we followed Salmonella through the body, it would pass through the esophagus, the stomach and finally into the intestines.  
 
It turns out that lots of germs have to cross a kind of membrane, or barrier, to get into the body’s system. For instance, Salmonella must cross a membrane that lines the intestines.  
 
When the bacteria pass through the membrane, they can get into the blood and circulate through the body.   
 
Sometimes germs will also pass through the thin membranes that cover the eyeballs when we touch our eyes and face. It’s rare, but even Salmonella can sometimes enter the body this way.  
 
Finally, some germs can enter through the nose as well. When germs in the air make it down into someone’s respiratory system, the germs can pass through the membranes of the lungs and into the blood. For instance, SARS-CoV-2, the virus that causes the novel coronavirus, often enters the body through the nose or mouth through tiny saliva droplets. The virus travels down into the airways and into the lungs.  
 
While some germs might enter the body through contaminated food or saliva, other germs might find a way into the body through the bites of mosquitos or ticks. The viruses and bacteria do what they can to survive and reproduce.  
 
But the good news is you have a system that is primed and ready to defend you when they arrive. The immune system, which is made up of different cells, tissues and organs, can recognize that the invaders might make you sick. The system kicks into gear and works to help protect you.  
 
You know, not all bacteria are bad, but there are things we can do to help keep the bad germs from spreading around. For instance, we can cover our mouths when we cough or sneeze. With the novel coronavirus, we can wear facemasks that help us keep our germs to ourselves and help stop SARS-COV-2 from spreading to others. We can also wash our hands frequently, especially before we eat, drink, prepare food or use the restroom.  
 
It’s also great to know that there are scientists who study viruses and bacteria, including Salmonella, to help us better understand these germs and how they work.  
 
Through research, people are developing vaccines and medications that can help us prevent the spread of viruses and bacteria— and help improve the health of humans all around the world.  
 
Sincerely,
Dr. Universe

Dr. Universe: Why do people like listening to music? – Bruce, 10, Tacoma, Wash.
 
Dear Bruce,
 
Think of your favorite song. Maybe it brings you happiness or joy. Maybe it makes you want to start dancing. Or maybe it’s a sad, melancholy song, but you still really like it.  
 
From the radio to concerts to our mobile devices, music is all around us. To find out exactly why people like listening to music, I talked to my friend Sophia Tegart.
 
Tegart is a flutist, musicologist and assistant professor at Washington State University. She said one of the reasons many people like listening to music is because it can affect emotions. 
 
“Music is emotion you can hear,” she said.
 
Humans have the ability experience dozens of emotions, ranging from happiness to sadness to fear. Perhaps you can think about a few of the different emotions you’ve felt while listening to music.
 
This idea that music can affect our emotions has been around for thousands of years, Tegart said. The ancient Greeks would even prescribe certain types of music to help improve people’s well-being or mood.
 
In modern times, research has shown us that the brain will release certain natural chemicals when listening to music. The body’s nervous system produces endorphins, which can help reduce pain and stress. They are also known as “feel-good” chemicals. When people feel sad, they may turn to music to help them feel better. 
 
You know listening to music involves more than just the sounds that come into your ears. Tegart told me a bit about a percussionist named Evelyn Glennie who started to lose her sense of hearing when she was 12 years old. But that didn’t stop Glennie from becoming an accomplished musician.
 
“She plays barefoot and feels the vibrations of the music through her feet,” Tegart said.
 
Maybe you’ve also experienced music with more than just your ears. Maybe you felt the vibrations of the bass speaker or felt chills in your body. Maybe the music got your toes tapping. 
 
Tegart said another reason people like music is it has the ability to get us moving. Whether it’s clapping our hands or dancing, music can make us want to move.
 
Movement can get our hearts beating and our blood flowing which is good for our health. Dancing can also help release some of those endorphins that make us feel good. 
 
The next time you turn on the tunes, or maybe even perform a song on stage yourself, take a moment to be curious about the emotions you experience.
 
“Music can change style depending on what’s popular or what’s being written,” Tegart said. “But I think the common thread is that it continues to speak to us emotionally.”
 
If you’re up for a challenge, maybe you can even dig into the music and see if there’s something in the composer’s toolbox—a chord, a lyric, a key change—that helps make your favorite song such a good one.
 
Sincerely,
Dr. Universe

Dr. Universe: How does hail form? -Emilio, 11, San Diego, California
 
Dear Emilio,
 
During a thunderstorm, there are often lots of tiny water droplets in the clouds that form precipitation like water, snow or hail. But that precipitation doesn’t always fall right to the ground. 
 
Sometimes a falling raindrop will get swept back up in a current of air. The air current can carry the raindrop to higher parts of the thunderstorm cloud where temperatures are below freezing.
 
Under these super cold temperatures, a raindrop will freeze. Then, other water droplets will start clinging to the frozen droplet. This is how hail, or a hailstone, begins to form.
 
That’s what I found out from my friend Jonathan Contezac, a field meteorologist with AgWeatherNet at Washington State University.
 
“As long as the updraft within the storm is strong enough to keep this hailstone suspended in the atmosphere, it’ll continue to grow. If it gets too heavy, it will fall to the earth, or if the updraft weakens, it will fall to the earth,” Contezac said.
 
While it may not hail very often in places like San Diego, there are some regions that experience really intense hailstorms.
 
According to the National Severe Storms Laboratory, Florida has the most thunderstorms, but Nebraska, Colorado and Wyoming get the most hailstorms.
 
In the summer, when humidity and warmth fuels thunderstorms, the region can experience anywhere from seven to nine days of hail. It’s no wonder this part of the country has even been given the name “hail alley.”
 
Often hailstones are about the size of a pea, but sometimes they can grow to the size of grapefruit. Contezac told me that the size of a hailstone depends on how long it stays up in the storm. As the hailstone gets tossed around, new layers of ice can form around it. 
 
In fact, if we look at a hailstone cut in half, we might just be able to observe some icy rings. They would look sort of similar to the rings you might find if you sawed open a tree trunk.   
 
The way the icy rings look can tell us a bit about the hailstone’s journey through the storm. A white, cloudy ring of ice means the water droplets froze very quickly as they met the hailstone. The water froze so fast, some air bubbles were even left in the water which made it appear cloudy.
 
When we see a ring of clear ice, it tells us that droplets were freezing more slowly onto the hailstone. There was enough time for the air bubbles to escape before the water froze, so the ice looks clear.   
 
While some hailstones make the journey to Earth’s surface, there are other hailstones that simply melt away on their journey down from the atmosphere.
 
Hail might make us take cover, but it sure makes me curious, too. Who knows, maybe one day you will become a meteorologist and help us learn more about our planet’s incredible weather.
 
Sincerely,
Dr. Universe

Dr. Universe: Why do things like rockets catch fire as they pass through Earth’s atmosphere? – Conner, 11, Dunn, North Carolina
 
Dear Conner,
 
When objects like spacecraft pass through Earth’s atmosphere, things can really heat up.
 
To investigate the answer to your question, I talked to my friend Von Walden. He’s a professor and researcher with Washington State University’s Laboratory for Atmospheric Research.  
 
First, he said it helps to know a bit about the differences between Earth’s atmosphere and space.
 
Our atmosphere is made up of stuff, or matter, called gas. These gases that make up our air include oxygen, nitrogen, carbon dioxide and other elements. But space is pretty empty. There isn’t much matter in-between the planets and stars.  
 
That means when any object travels to Earth from space, it’s going to run into a lot of air molecules. This can create a lot of friction, which is the force of two surfaces sliding against each other.
 
Maybe you can try to create some friction just by rubbing your hands together. You’ll notice how the motion produces heat, and you can feel some warmth.
 
As the air molecules in Earth’s atmosphere and the material that makes up the spacecraft push against each other they also create a lot of friction.
 
At the same time, the air molecules slow down the object such as a returning spacecraft as it passes through the atmosphere at high speeds. In the process, it creates a lot of heat.
 
There’s so much friction and heat that we can start to see a glow around the spacecraft. It isn’t exactly catching on fire, though.
 
“It’s like when someone is cooking and the pan turns red or orange. The fire from the stove is heating up that pan, but the pan itself isn’t on fire. It’s the same type of thing,” Walden said.
 
Astronauts have reported that upon re-entry the glow looks pink and orange from inside the spacecraft. The re-entry process only takes about 4 minutes. After re-entry, it’s about a 60-mile journey back to the surface of Earth.
 
You know, engineers and scientists at places like NASA have calculated just the right angle and speeds at which spacecraft need to enter the atmosphere to make it to space and return home safely. It’s also an important calculation for when we send experiments up to the space station, too.
 
As a student, Walden even had the chance to send up an experiment on NASA’s Space Shuttle to learn more about how different fluids behave in space.
 
Whether we send astronauts, experiments, or even everyday citizens to space, the question of what happens to objects when they pass through the Earth’s atmosphere is an important one to think about, especially as we set out to learn more about our solar system.
 
Who knows, maybe one day you’ll be an engineer or scientist who helps us learn more about space travel. Or maybe you’ll even have a chance to travel to space or another planet as a citizen of Earth.
 
Sincerely,
Dr. Universe

Dr. Universe: How are baseballs made? -Kaden, 11, Saratoga Springs, Utah
 
Dear Kaden,
 
There are a lot of steps that go into making a baseball. As we investigate this question, we’ll focus on the ones made for Major League Baseball.
 
My friend Lloyd Smith, a mechanical engineer and director of the Sports Science Laboratory at Washington State University, told me all about it.
 
A while back, he had a chance to visit a facility in Costa Rica where they make MLB baseballs. Smith said it begins with a small sphere called a pill, which has a cork center and a couple of rubber layers.
 
The pill helps with elasticity—that is, how the ball bounces back up after you bounce it on the ground. The pill gets put into a bin of adhesive, which is sort of like a tacky glue, before it gets wrapped in wool yarn.  
 
If you’ve ever tried to wind up some yarn into a ball, you know that it isn’t always easy to get it into a perfect sphere. The facility uses special winding equipment to wrap the wool yarn into a nice, spherical shape.
 
They wind it three different times with very particular kinds of yarns. The exact way they wind up the yarn is top-secret information, Smith said.
 
Next, the ball is wound in a layer of cotton and it gets another layer of tacky coating. This tacky coating will help attach the cotton to the outer layer of leather.
 
A machine cuts out white leather panels that will fit just right around the baseball. The panels are soaked in water to soften them up and make it easier for people to mold around the baseball. 
 
Finally, there is the sewing. This was one of the steps that amazed Smith the most on his tour. The workers stitch the balls by hand with long pieces of a red-dyed thread. Each baseball gets exactly 108 stitches.
 
At this point, the thread is still a bit raised on the surface of the baseball. To smooth out the surface, the ball goes into a wooden piece of equipment that flattens out the seams. Even a seam that is just a little too high can add to the drag, or slow down the speed of the ball. They’ve got to get everything just right.
 
“There’s so much interest in the ball and so many conspiracies that if anything changes in the game, they sometimes look at the equipment,” Smith said. “People will take these balls apart and look for any differences.”
 
Smith also adds that about 55% of the baseballs from the facility will end up in an MLB game. In a single game, players will use dozens of baseballs that came from the facility. The remaining baseballs are often sent out to shops where fans can buy one.
 
Now you know there’s a lot more that goes into making baseballs than meets the eye. It’s something to think about the next time you are watching—or maybe even playing— the beloved sport of baseball.  
 
Sincerely,
Dr. Universe

Dr. Universe: Why do bacteria in the Yellowstone hot springs make the water different colors? – Ava, 9, Kennewick, WA
 
Dear Ava,
 
One of the most eye-catching hot springs in Yellowstone National Park is the bright and colorful Grand Prismatic Spring. It’s blue in the middle with bands of colors ranging from green and yellow to orange and reddish-brown.
 
My friend Peter Larson is a geologist at Washington State University who is very curious about hot springs. He spent much of his research career in Yellowstone National Park.   
 
Larson said that when we look into the hot spring, we are seeing the colors of tiny living things called cyanobacteria.
 
In the middle of the hot spring, there aren’t any cyanobacteria. The water is nearly boiling, and they can’t survive the high temperatures.  
 
But as we move out from the middle of the hot spring, the water gets a bit cooler. We find a lot of cyanobacteria showing off their green and yellow colors.
 
These colors come from something called pigments. In fact, a lot of the colors we find in nature come from pigments. You even have pigments in your hair, eyes and skin. Pigments absorb certain waves of light from the sun and reflect others, which helps to give us the colors we see.
 
One very important pigment that cyanobacteria have is called chlorophyll. It not only gives them their yellow and green colors but also helps them survive.
 
Cyanobacteria can use their chlorophyll molecules to absorb energy from sunlight—an important ingredient they need to make their own food. When we see a lot of green or yellow in the hot spring, we know that the cyanobacteria are alive and well.
 
Some cyanobacteria also make pigments such as carotenoids, which help them use chlorophyll. Carotenoids can also provide them with some protection from the sun. When we see orangish parts of the hot springs, there are likely some carotenoid-making cyanobacteria in the water. 
 
At the very edge of some hot springs, we can also see some reddish-brown colors. This is the coolest part of the spring and home to a diverse community of cyanobacteria and other kinds of bacteria that give off red and brown colors. Even though this is the coolest part of the hot spring, it’s still really hot—around 131 degrees Fahrenheit.
 
Organisms that live in extreme environments, including some of the cyanobacteria in hot spring, are called extremophiles. Larson said hot springs and these extremophiles often get a lot of attention when scientists are wondering about the origins of life on Earth.
  
Larson and I want to thank you for your great science question. It’s a good reminder that a single question can take us into many different scientific fields. From geology to biology to astrophysics and beyond, it sure is an amazing world to explore.    
 
Sincerely,
Dr. Universe

Dear Dr. Universe: How does COVID-19 affect our household pets? – Kolton, 11, Michigan
 
Dear Kolton,
 
A lot of researchers around the world are investigating this very question. While we don’t know everything about how the SARS-CoV-2 virus affects household pets, there are some things we do know.
 
My friend Dr. Raelynn Farnsworth, a veterinarian at Washington State University, told me all about it.
 
The risk of household pets spreading the SARS-CoV-2 virus to humans currently seems to be very low, she said. But a human who has the virus could potentially spread it to an animal, like a cat or dog, if they’ve been in close contact.
 
At the beginning of the pandemic, scientists at WSU and the University of Washington wanted to investigate a similar question to the one you’ve asked. They visited with pets that were living in households where the owners had COVID-19, the disease caused by the SARS-CoV-2 virus.
 
They tested the cats and dogs for the virus by putting a little swab up the animals’ noses. Maybe you or someone you know has had a test like this, too. Farnsworth said it’s a bit harder to do a swab test in cats, just because they have such tiny nostrils. Veterinarians sometimes give the cats a little throat swab instead. 
 
In the communities they studied, none of the pets showed symptoms of COVID-19. Those symptoms can often include sneezing, a runny nose, watery eyes or fever.
 
Some cats and dogs didn’t show any symptoms, but they did have something else. The researchers found antibodies. Antibodies are a substance the body makes when it responds to a foreign substance in the body, like SARS-CoV-2. The antibodies develop to help fight off any future disease.
 
This was just one of many studies on pets and COVID-19 in our world. Scientists continue to look for cases of COVID-19 in animals. For example, in September 2021, the first U.S. case of a ferret with COVID-19 was reported in Florida.
 
Farnsworth told me that one animal related to the ferret is the mink. Early in the pandemic, researchers learned that humans can pass the virus onto mink and that mink can also pass it back to humans.
 
Scientists have also found COVID-19 in animals including tigers, lions, otters, non-human primates, hippos and white-tailed deer. We are still learning exactly how transmission between humans and other animals happens.
 
If you have more questions about COVID-19 in household pets or if you are curious about COVID-19 in other kinds of animals, you can visit the Centers for Disease Control and Prevention and their “Healthy Pets, Healthy People” website at cdc.gov/healthypets/covid-19. 
 
Thanks for your thoughtful question, Kolton. While there’s still a lot more research to do around COVID-19, including how it affects our pets, it’s great to know there are smart and caring researchers in our world who are helping us learn more about it. They work hard so people and their pets can be safe and healthy.
 
Sincerely,
Dr. Universe

Dear Dr. Universe: How did you get your name? – Byron, 13, Pennsylvania
 
Dear Byron,
 
It turns out a lot of kids around the world have been wondering about the answer to this very question—after all, you don’t hear the name “Dr. Universe” every day.
 
Believe it or not, I wasn’t entirely sure about the origin of my name. But my friends at the Washington State University Libraries had the answer in their historical archives. Yes, the local library is a great place to visit when you have a big question.
 
As I read through the archives, I learned that I wouldn’t have my name if it weren’t for two people who worked at the university.   
 
One of these people was Tim Steury, who at the time was writer and editor of WSU’s research magazine, “Universe.” The other person was Bob Smith who served as dean of the WSU Graduate School.
 
While most people call me Dr. Universe, my first name is Wendy, and my middle name is Sue. With the last name Universe, that makes my initials W.S.U. You couldn’t ask for a better set of initials, really.
 
You know, our names are an important part of our identity. Identity means the qualities, beliefs, personality and expressions that make up a person or a group of people. Maybe you even have a nickname that’s part of your identity. Sometimes my friends call me Dr. U for short.
 
While I was thinking about your question, it also reminded me how scientists often name things, too. For instance, when they discover a new planet, species or element—or come up with a new theory—they have to think of something to call it.
 
In biology, one of the terms for the system of names we use to describe something is called nomenclature. “Nomen” in Latin means “name.” The binominal, or two term, naming system is what biologists around the world use to describe different animals, insects, bacteria and other living things.
 
The naming system requires both a species name and the genus name. For example, I am a feline, or Felis catus. Some animals have a species name and genus that are the same. For instance, Pica pica is the magpie, a kind of bird. Mola mola is the ocean sunfish. Bison bison is, well, a bison. There’s even a name for these types of names: tautonyms.
 
You are a Homo sapiens, or human. Individual humans have a variety of different names. They come in all kinds of different languages. All right, here’s a question for you: How did you get your name? Perhaps you can do an investigation of your own.
 
Ask your family about the origin of your first and last name. Find out if it comes with an interesting story, holds a special meaning, was passed down from someone else or maybe even has a connection to the past. Ask your family and friends about the stories behind their names, too. When you ask a good question, you never know what you might discover.
 
Sincerely,
Dr. Universe
 
 Note: Bob Smith will publish a book about his career working in universities next year. Thanks for giving me a name and for sharing our story in your book.

~

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Dr. Universe: Why does the sky turn darker in winter? – Alex, 6, Cincinnati
 
Dear Alex,
 
As winter gets underway here in North America, you may notice we don’t feel the sun’s rays for quite as many hours as we did in fall and summer.  
 
To find out why this happens, I talked with my friend Vivienne Baldassare, an astronomer at Washington State University.
 
She said the reason we get fewer hours of daylight in the winter has to do with how Earth rotates. As our planet goes around the sun, it is always rotating. This rotation is also why we have day and night.
 
When the part of Earth you’re standing on faces the sun, it is daytime. When the part you’re standing on faces away from the sun, it is night.
 
But the reason the length of daylight changes throughout the year is because our planet is a little bit tilted.
 
“Earth isn’t perfectly straight up and down,” Baldassare said. “It’s a bit tilted on its axis, more like a spinning top.”
 
The top half of the planet, which is known as the Northern Hemisphere, is tilted more toward the sun when it is summertime. But when it’s wintertime, that means Earth’s Northern Hemisphere is tilted away from the sun. This can make the days feel shorter, and we have just passed the shortest day of the year.
 
In the Northern Hemisphere, we had 7 hours, 49 minutes and 42 seconds of daylight on Tuesday, Dec. 21. This is the day we mark as the winter solstice when the Earth’s northern pole reaches its maximum tilt away from the sun. You may also know it as the first day of winter.
 
After the winter solstice, the days start to get longer again in most places. But there are some places on our planet, like Tromsø, Norway, that will be completely dark for a few months. Antarctica will have six months of complete darkness.  
 
“The farther north you go, the earlier it gets darker in the winter. If you are all the way at the top of the world in the wintertime, you never feel the sun. It’s always dark,” Baldassare said.
 
Earth’s tilt is the reason why it gets dark so early in wintertime and the reason we have different seasons.
 
If you find yourself indoors for most of the winter season, you might try a new game, cozy up with a book, listen to your favorite music, do some stretches or keep a big list of all your science questions.
 
What kinds of activities do and your family like to do on winter days? Talk about it with your family or friends. Then, share your answer and ideas in an e-mail to Dr.Universe@wsu.edu. We might just feature your answers at AskDrUniverse.wsu.edu.   
 
Sincerely,
Dr. Universe

Dear Dr. Universe: How do scientists know how to predict a solar eclipse? -Beau, 11 ½
 
Dear Beau,
 
Before humans even knew how to predict solar eclipses, they were fascinated with the phenomenon. To figure out how to predict an eclipse, astronomers asked lots of questions and made observations about the motion of our moon, sun and Earth.
 
My friend Jose Vazquez, an astronomer at Washington State University, told me all about it.
 
“It took centuries to figure it out,” he said. “It was a journey.”
 
A total solar eclipse happens when the sun, moon and Earth are lined up just right and for a few minutes, the moon blocks the Earth’s view of the sun. During a total solar eclipse, the moon casts its shadow down to some places on Earth.
 
Vazquez told me about the Greek astronomer Hipparchus who was really curious about the moon. Using knowledge from early astronomers, he studied lunar eclipses—that is, when the moon passes into the Earth’s shadow. He watched the night sky and recorded his observations about the moon.
 
Maybe you can try this, too. Every day for a week, stand in the same spot outside your house. You may notice that the moon seems to move across the sky west to east.  
 
When Hipparchus was studying the moon, his models were based on an idea that the moon orbited Earth in a circle. About 400 years later, Claudius Ptolemy would use mathematics to show many objects in our solar system orbit in a circle. But today, we know that isn’t the case.
 
The astronomer Johannes Keppler created a more accurate model and showed us that the moon orbits Earth in a shape called an ellipse. You can imagine this shape by taking a hula hoop circle and squashing it on one side so it forms more of an oval.
 
Also, the moon doesn’t move in a perfectly straight path in its orbit. It sort of goes up and down as it moves along its path.
 
Through watching the sky and observing the patterns and orbits that the moon, sun and Earth follow, astronomers can help determine when the three objects will line up. They can make an educated guess about when the eclipse will happen. 
 
While many people, including in the ancient Mayan, Babylonian and Chinese civilizations, have observed solar eclipses and recorded their observations, it was the astronomer Edmond Halley who used mathematics to get some of the most accurate predictions in 1715. These days, we also use computers that make calculations to help predict eclipses.
 
Believe it or not, scientists at NASA are now able to predict eclipses for the next thousand years. We know that the last eclipse of 2021 will be on Dec. 4. While we won’t be able to see it in North America, it will be visible in places like South Africa, southern Australia, South America and Antarctica.
 
If you are curious about upcoming solar eclipses, you can also visit NASA’s database. They make it easy for anyone around the world to know when they can catch the next solar eclipse.  
 
Sincerely,
Dr. Universe

Dr. Universe: Why do we find bones in rock? – Wyatt, 9, Washington state
 
Dear Wyatt,
 
When humans want to look into the past, they often dig into the ground. Under the soil, archeologists can find all kinds of things that help us learn about life long ago. 
 
That’s what I found out from my friend Rachel Horowitz, an archaeologist at Washington State University who is very curious about the lives of our human ancestors.   
 
She said part of the answer to your question lies in some important processes that happen above and below Earth’s surface.  
 
Let’s say a human ancestor passed away and was buried at the edge of a lake. Layer after layer, the soil, pebbles, sand and other earth materials start piling up on top of the burial site. 

Over thousands of years, the layers create a lot of pressure and heat which can eventually turns all those different materials into rock.
 
All of these layers create a lot of pressure and heat which eventually turns all those different materials into rock. Meanwhile, there’s another process at work that helps transform the human ancestor’s bones.     
 
Inside of a bone, there is a soft material called marrow. Over thousands of years, the marrow gets replaced with minerals. Maybe you’ve heard of minerals like calcium, zinc or sodium.
 
As water moves through the soil, it brings some important minerals to the bone. The minerals replace the marrow. When this happens, we get a fossil. Fossils might look a lot like bones, but they are now rock—and we can learn a lot from them.

Horowitz told me that we can also find other things besides traces of bones. For instance, some archeologists have found fossils of poop, which are called coprolites. They have also found fossils of teeth. These kinds of fossils can help scientists learn more about what animals and humans used to eat.  
 
Archeologists have even found fossils of human footprints that have been preserved in stone. We can also find things in the earth that don’t fossilize, including stone tools, scrolls, coins and pottery.
 
All of these different fossils and remains can help scientists put together a better picture of history on our planet. Of course, you never know what someone might dig up next. It might add a new chapter to the story or change the way humans think about life long ago. Who knows, maybe one day you can be an archeologist or a historian and help us discover something new about the past.
 
Sincerely,
Dr. Universe

Dr. Universe: What bacteria make us get stomach bugs? – Austin, 9, Texas

Dear Austin, 
 
There are all kinds of tiny pathogens, including bacteria and viruses, in our world. Some of them are helpful and do things like keep the human gut healthy—but there are others that can make us quite sick.   
 
I talked to my friend Alan Goodman about it. He’s an associate professor at Washington State University who knows a lot about the pathogens that can cause illness in people and other animals.  
 
When we talk about stomach bugs, usually we think of pathogens that cause the stomach flu. If you wanted to call the infection by its official name, you could say “viral gastroenteritis.” But we’ll stick with stomach flu for now.   
 
The stomach flu isn’t influenza. Goodman said we might call influenza “the flu”, but influenza actually impacts the nose, throat and lungs. The stomach flu causes trouble in the stomach and intestines that make up the gastrointestinal system.   
 
The culprit behind the stomach flu is often norovirus. Norovirus is a sphere-shaped virus that is really good at spreading from person to person. 
 
This virus can sometimes spread through tiny particles of poop, which is part of the reason it’s really important to wash our hands after we go to the bathroom.  
 
When we wash our hands properly, it can help prevent all kinds of germs from getting into our bodies. It also keeps our germs from spreading to other people.   
 
If norovirus does get into the body, it can create some changes in the digestive system and intestines. It can make the body react in unpleasant ways, such as causing diarrhea or vomiting. Thankfully, that usually only lasts for a couple of days before a person starts feeling better. 
 
Meanwhile, there are also some bacteria called Salmonella and E. coli that can cause stomach troubles. These bacteria might be living on uncooked poultry, raw eggs or unwashed vegetables. That’s why it’s important to keep food safety in mind when cooking or eating certain foods.   
 
Unfortunately, there isn’t a perfect treatment for these kinds of “stomach bugs.” You just have to let your body’s immune system—which works to protect you— do its best to fight back.  
 
But the good news is there are also some things we can do to help illness from striking in the first place.  
 
If you haven’t already taken note by now, one thing we can do to avoid spreading around pathogens is to wash our hands after we use the bathroom, and before and after we prepare or eat food.   
 
A lot of pathogens can spread pretty quickly and easily, so if you are sick, it’s good to stay home from school if you can. That way the virus or bacteria doesn’t have as much of a chance to spread to other people.  
 
When we take these thoughtful measures, we can help ourselves, along with our family and friends, stay safe and healthy.  
 
Sincerely, 
Dr. Universe 

Dr. Universe: Why do animals have different hearing? – Dorothy, 9, Washington State

Dear Dorothy, 
 
You’re right—different animals can hear different types of sounds. To find out more about it, I talked to my friend Dr. Vishal Murthy, a veterinarian at Washington State University.
 
Murthy reminded me sound comes from vibrations that travel through the air. For instance, when you feed your pet, the kibbles that fall into the bowl send out vibrations to your pet’s ears.
 
Some animals, like cats, dogs, elephants and humans, have ears that stick out and can help funnel these vibrations into the inner ear.
 
But some animals don’t have outer ears—dolphins, for instance. Dolphins have some of the sharpest hearing of all the animals on our planet. Scientists think dolphins rely on a part of their jawbone to help send those vibrations to their inner ears.
 
In animals, the vibrations travel to a part of the inner ear called the cochlea, which looks like a snail’s shell. It has tiny parts called hair cells, which look like a little series of hairs in a line, that help animals sense a certain range of sound.
 
When we talk about a range of sound, we often talk about frequencies. A chirp or a whistle is a kind of high-frequency sound. A bass drum or thunder is a kind of low-frequency sound.
 
Some of the animal’s hair cells can pick up on lower frequencies while others pick up on higher frequencies. Murthy said the longer an animal’s cochlea, the more likely it is we will find a variety of hair-cell types. This wide variety is one factor that can give the animal a wider range of hearing abilities.
 
If you are like me, you might be wondering why some animals can hear certain frequencies, while other animals cannot.
 
Murthy said part of the answer to your question also has to do with the way hearing helps animals adapt and survive. Elephants are one great example. Elephants can hear lower frequencies than a lot of other animals can. It turns out low frequencies can travel farther than high frequencies.
 
“Elephants are migratory and travel long distances, so they need to be able to hear over longer distances,” Murthy said. “Elephants have evolved this ability, so they can communicate with each other.”
 
He also told me elephants will sometimes pick up on vibrations using their feet. The vibrations travel through their bones and to their ears where they can be turned into sound.
 
Meanwhile, cats can hear a lot of high-frequency sounds. Prey animals, like mice, often make higher frequency sounds, like a squeak. The ability to hear particular frequencies can help some animals find prey. Murthy also mentioned most cats have better hearing than dogs, especially when it comes to high-pitched sounds.
 
You heard it here, young scientists. From tiny hair cells to the structure and shape of the ear, there are a lot of factors that go into helping animals hear different types of sounds.
 
Sincerely,
Dr. Universe

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Dr. Universe: What makes leaves fall? – Kaitlyn, 13, Moncks Corner, SC;
Why do leaves fall in the fall? – Aiden, California, 11
 
Dear Kaitlyn and Aiden,
 
You’re right, each year during the fall, we often see a lot of trees dropping their leaves. To find out exactly what happens when leaves fall, I talked to my friend Henry Adams, a researcher at Washington State University.
 
Adams is very curious about the lives of trees and how they can survive harsh conditions. He reminded me that all year long trees make their own chemicals that help control how they grow.
 
It turns out there are two main chemicals that play a part in whether the leaves stay on the tree or fall to the ground. 
 
The chemical that helps a tree keep its leaves is called auxin. Meanwhile, a chemical called ethylene helps flowers open, fruit ripen and leaves fall.
 
“There are these two chemicals, and they are sort of fighting it out throughout the year,” Adams said.
 
In summer, the tree makes a lot of auxin. But when fall comes around, the tree starts making less auxin and more ethylene at the place on the plant where the stem attaches to the leaf. Scientists call this the abscission zone.
 
When there is too much ethylene in the tree, the building blocks that make up the leaf will start to die. The leaves detach from the tree and fall to the ground—with help from gravity and the wind, of course. 
 
I started to wonder why we see these kinds of changes in chemicals. Adams said one thing we know is that plants can respond to different kinds of signals from the environment. Some of these signals include the amount of daylight, temperature and overall climate where the plant lives.
 
When the days get shorter and colder as they do during fall in the Northern Hemisphere, that’s a signal to the plant to stop making the leaf-attaching chemical, auxin.  
 
It’s actually a good thing the tree doesn’t want to keep its leaves, though. Big flat leaves are a problem if they freeze and die, Adams said.
 
Plants put a lot of important stuff called nutrients, which is kind of like their food source, into their leaves. These nutrients include things like magnesium and nitrogen that help the trees grow.
 
“Those nutrients are hard to come by. It’s really valuable, and the plant would rather keep that stuff around,” Adams said.
 
Instead of continuing to make leaves that would otherwise just die during a frost, the trees store up some nutrients from their leaves in other parts of the tree before the winter. Then they drop their leaves. For some trees, it’s better just to have bare branches during the cold seasons. It will help them survive.
 
As fallen leaves break down, or decompose, they can also provide some nutrients to the soil and play a part in helping a new generation of trees to grow. That means more new tree leaves to watch bud in the spring and more leaves to jump in when fall comes around again.  
 
Sincerely,
Dr. Universe

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Dr. Universe: What’s the purpose of baking soda? What’s the purpose of baking powder? What’s the difference between the two? – Kyle, 9, Florida

Dear Kyle,

When I got your question, I headed straight to my kitchen cabinet. I grabbed some baking soda and baking powder from the shelf and made some observations.

Not only did the baking soda and baking powder look similar to one another but both contained an ingredient called sodium bicarbonate.

To find out more about this mysterious ingredient, I talked to my friend Stephanie Smith, a professor who teaches food science at Washington State University.

She reminded me sodium bicarbonate is a chemical compound. A compound is something made up of atoms or molecules. This particular chemical compound can react with certain ingredients to create tender and fluffy textures in our baked goods.

While baking powder and baking soda may have a similar purpose, they work in slightly different ways, Smith adds.

If you’ve ever mixed baking soda and vinegar together, you know that the mixture foams up quickly. As this happens, the mixture lets off a gas called carbon dioxide.

The carbon dioxide gas is actually what helps give everything from muffins to cookies to cakes their nice, fluffy textures. The gas creates small pockets of air in your cookie mix or cake batter. It ultimately helps the final product puff up.

Baking soda is just sodium bicarbonate. It needs a couple of things to help it react with other ingredients in our mixing bowls. First, it needs an acid. There are all kinds of acids in our world. When it comes to baking, some of the acids we use include buttermilk or lemon juice.

Once you have an acid, you’ll also need a liquid, such as water or milk. Finally, the carbon dioxide bubbles will be able to form.

Meanwhile, baking powder is actually just baking soda, plus some dry acid. Since it already has the acid, all you have to do is add water or another liquid to get those carbon dioxide bubbles.

There’s another ingredient we can sometimes use in the kitchen to create carbon dioxide gas, too. Perhaps you’ve heard of it before. Unlike baking soda and baking powder, this particular ingredient is a living organism.

It’s an ingredient that is also often used in making bread or pizza dough. If you are thinking of yeast, you are correct. Yeast is a kind of microbe that can eat the sugar in your dough and release carbon dioxide gas to help the bread rise.

Whether you are using yeast, baking soda or baking powder, there sure is a lot of science that goes into making baked goods rise and get fluffy. You know, the kitchen is a great place to ask big questions about how and why things work.

Maybe one day your questions will lead you even further into the fascinating worlds of baking, chemistry or even food science.

Sincerely,
Dr. Universe

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Dr. Universe: What are the strings inside a pumpkin? Some are attached to the seeds. – Maggie, Woodinville, WA
 
Dear Maggie,
 
If you open up a pumpkin, you would see all kinds of different things inside. Some people call all this gooey stuff the pumpkin’s “brains” or its “guts.”
 
There’s the meaty orange flesh, sticky pulp, lots of seeds, and, of course, all those little strings. The strings actually have a really big job.
 
My friend Lydia Tymon is a plant pathologist. That means she is like a doctor for plants—and she was happy to hear about your question.
 
The pumpkin’s strings, or fibrous strands, help the seeds get something important while the pumpkin is growing on the vine: nutrients.  
 
You might think of the nutrients as if they were the seeds’ food, and you might think of the strings as if they were the pumpkin’s own food delivery service.  
 
“In a lot of vegetables, there’s something that attaches the flesh to the seeds so that it can get the nutrients that it needs,” Tymon said.
 
Tymon said peas are another great example of a vegetable that has this kind of little system. If you pop open a pea pod, you may notice there is a little part that attaches the pea to the pod. It’s what plant scientists call the funiculus.
 
After learning about how nutrients can travel to the plant’s seeds through these fibrous strands, I asked Tymon exactly why these seeds need all of those important nutrients.
 
She reminded me that the seeds are how a plant reproduces, or makes future generations of plants. Those nutrients that pass through the fibrous strings of a pumpkin eventually get stored up in a part of the seed called the endosperm.
 
It’s this little part of the seed that stores up all the nutrients the seed will need to one day grow and develop into a plant. When the seed is exposed to water, soil and sun, new pumpkins can start growing on the vine.
 
You know, it sure is interesting to observe all the plants on our planet. Whether you are curious about pumpkins or other fruits and veggies, you never know when a great science question might strike.
 
With the help of an adult, maybe this year you can work together to do a pumpkin dissection of your own. Open up a pumpkin and see if you can identify all of its different parts.
 
If you are up for it, maybe you can even count all the seeds. Pumpkins have lots of seeds. You could even do some research to find out what the flesh is made up of or exactly what’s inside the seed.
 
After all that pumpkin exploration, you might feel a bit famished. When you are done, think about the different ways humans can use pumpkins for food.
 
You might even consider baking something like chocolate chip pumpkin muffins or a pumpkin pie. Or if you’re like me, you might just bake the seeds and enjoy a healthy pumpkin snack. 

Sincerely,
Dr. Universe

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Dr. Universe: Why does sleep feel so short? – Brooklyn, 12
 
Dear Brooklyn,
 
That’s a great observation. When my friend Ashley Ingiosi was a kid, she remembers how napping in the car during a four-hour drive to her grandparents’ house seemed to make the time fly by. Maybe you’ve had a similar experience.
 
As a researcher at Washington State University, Ingiosi is really curious about what goes on within the human brain during sleep. She was happy to help with your question.
 
“Sometimes sleep feels so short because we become less aware of our surroundings,” she said.
 
As you go about your day, you rely on certain signals from your senses—or stimuli— to know if you are awake and aware. This awareness is what sleep scientists call consciousness.  
 
But when you are sleeping, you don’t really sense the world in the same way. You can’t use your sense of touch to feel your bedsheets. You often can’t use your sense of hearing to pick up on the sounds around you. You might not feel it, but during certain stages of sleep, your eyes are darting around under your eyelids.
 
Even though you have a lower level of awareness, your brain and body are still very active. 
 
“Brains are still very busy during sleep and doing a lot of different things,” Ingiosi said. “But the reason why we can stay asleep is that we are less aware of what’s going on around us.”
 
When you are awake and aware, you can use clues from your environment to sense all kinds of things, including how time is passing. But when you sleep, it makes it harder to track all those seconds, minutes and hours ticking by.  
 
“If we were aware of things in the way that we are when we are awake, we’d have a really hard time staying asleep,” Ingiosi said.
 
The amount of time humans spend sleeping is also important, she adds. As children and teenagers grow up, they need to sleep even longer than adults need to sleep.
 
According to our friends at the National Institutes of Health, school-age children and teenagers need about 9 hours of sleep each day. After the teenage years, you can do with a little less sleep. Most adults need about 7 to 8 hours of sleep each day.
 
While scientists are still unraveling many of the mysteries around how and why humans sleep, we do know sleep gives the body and mind a chance to recharge. It helps you stay healthy.
 
Sleep can also help strengthen the memories that you form throughout the day. It helps keep your brain working well, so you can do everything from finishing your homework to playing sports to asking big questions about our world.
 
Who knows, maybe one day you’ll be a scientist who helps us understand more about the fascinating experience of sleep. As for me, after investigating this great science question, I think it’s prime time for a cat nap.
 
Sincerely,
Dr. Universe

Dr. Universe: What happens when you get stung by a bee? And what happens to the bee? – Fatima, age 9, Nigeria
 
Dear Fatima,
 
A few different things happen when a bee stings you, and a few things happen to the bee, too.
 
When I got your question, I called up my friend Brandon Hopkins, who works as a honeybee researcher at Washington State University
 
Just as bees have a defense system that helps them survive in the world, humans have a defense system of their own.
 
If you get a bee sting, it’s likely that your body’s immune system—which works to protect you—will kick into gear. The body will detect unusual invaders, or the molecules in the bee venom. As the immune system responds to these invaders, you might experience some redness, itchiness, swelling or rarely, a severe allergic reaction.
 
When Hopkins was first working with honeybees and got stung, he would swell up and itch a lot. But now when he gets stung it just looks like a little bug bite. The sting still hurts though. Over time his body’s immune system has recognized the venom in his body isn’t really going to do any harm. 
 
Of course, everyone’s body is a little different. The reaction from a bee sting in one person might be quite different from a reaction in another person.
 
Now, for the bee’s perspective. Hopkins reminded me honeybees, wasps, bumblebees and yellow jackets sting in different ways. Wasps, bumblebees and yellow jackets can sting you multiple times. They don’t lose their stinger when they fly away. But honeybees can only sting once.
 
Part of the reason for this has to do with the body parts the honeybee uses to sting. First, there is the honeybee’s stinger. It isn’t exactly like a needle, but rather a pair of saws that work side by side.
 
Then, there are the muscles. A honeybee uses its muscles to slide those saw-like parts back and forth. Meanwhile, the muscles help pump venom from the bee’s venom sack into the animal it wants to sting. All of these parts work together to help the honeybee defend itself. 
 
After the honeybee flies away, it leaves behind this little packet of stinger, venom, and muscles in your skin. This causes so much damage to the bee that it can no longer live. But the stinger packet can keep on stinging. As Hopkins put it, it’s a kind of “self-operating stinging machine.”
 
Before they fly off and die, honeybees will also release some chemicals called pheromones into the air. The pheromones set off a kind of alarm to let other honeybees nearby know what’s up. If another honeybee picks up on the chemicals, it might also go into stinging mode.
 
But for the most part, bees don’t really want to sting you, Hopkins said. Usually, they are busy taking care of their family or moving pollen around which helps us produce everything from flowers to fruits to vegetables. For the honeybee, a sting is truly the last resort.
 
Sincerely,
Dr. Universe

Dr. Universe: How do human hearts beat? -Jacob, 12, Forney, Texas
 
Dear Jacob,
 
You have a heart that beats every single day—even when you aren’t thinking about it. It likely beats about 6o to 100 times per minute. That adds up to more than a billion beats in a lifetime.
 
To find out how exactly how it all works, I talked to my friend Garry Smith, a researcher at Washington State University.
 
Smith told me the heart has its own electrical system which helps it beat. We can find the source of electrical signals in the upper right part of the heart called the sinus node.
 
Now, let’s imagine your fist is a heart. Squeeze your fist and let your muscles contract. Now stop squeezing and the hand will relax. The heart also contracts and relaxes in a similar way.
 
Before the heart contracts, the upper part of the heart fills with blood. The electrical signals from the sinus node make their way down into the top chambers of the heart. When this happens, the heart contracts, or beats.
 
This movement can also help squeeze the blood down into the bottom chambers of the heart. Next, the bottom part of the heart contracts, or beats. It brings blood down from the top of the heart and pumps it out to the rest of the body.
 
Smith said that when your heart contracts, that also means every individual cell, or building block, that makes up the heart also pulls in on itself and gets smaller.  
 
“All of those cells doing that together is what creates the whole contraction in the heart,” Smith said.
 
One way we can measure how well a heart beats is with a machine that can sense those electrical signals. These machines are called electrocardiograms, or EKGs.
 
The number of waves per minute that show up on the graph tells us a person’s heart rate. The distance between those waves is the rhythm. EKGs can also let us know if there might be some damage inside the heart.
 
You know, there is still a lot to learn about how human hearts work. Smith’s research is helping us improve human health and learn new things about the innerworkings of this important organ.  
 
By getting a better look at certain cells and molecules in the heart, Smith and the team at WSU are improving our understanding of how the human body works. Their research could one day help treat heart conditions that are passed down through generations.
 
Perhaps, you can do a little research into your own heartbeat. Place two fingers on the right side of your wrist down below the thumb. Count the number of beats you feel in 15 seconds. Now, multiply that number by four and calculate how many times your heart beats a minute.
 
As you go about your day, think about all the electrical signals that help make your heart beat. Yes, it’s true our hearts keep beating even when we aren’t thinking about it, but when you do stop to think about it, you sure can learn a lot.
 
Sincerely,
Dr. Universe

Dr. Universe: What are cells made of? – Lela, 10, Bogart, GA

Dear Lela,

You have all kinds of cells in your body that do lots of different things. In fact, there are about 200 different types of cells in the human body—from blood cells to skin cells to bone cells. To find out exactly what all those cells are made of, I visited my friend Deirdre Fahy.

Fahy is a scientist at Washington State University who is curious about how and why things work, including our cells. She reminded me the human body is made up of billions of cells. You might think about each cell as if it were a tiny room. But this room, or cell, is so small, you’d likely need a microscope to see it.

Now, picture a kind of barrier around the room that allows different things to move in and out of the cell. That’s the cell membrane. Inside of the room, we find a book with a set of instructions. The book is like the part of a cell called the nucleus. It holds all the information, the DNA, that tells the cells how to work.

Each of the cells in your body relies on the same instruction book to do its job. But what makes the cells do different things depends on which section of the instructions they use.

“You could imagine you had this enormous recipe book, but one cell only made breakfasts, and one cell only made snacks, and one cell only made dessert,” Fahy said. “They’re all in the same book, but just some of the recipes are being used by certain cells.”

Of course, the cells aren’t actually cooking you breakfast, snacks or dessert. Instead, they are helping your body do all the things it needs to survive. For instance, some cells use a recipe for building bone material, while other cells build muscle tissue. There are cells that carry oxygen around the body, and there are even cells that help you think, feel and move.

Like all things in our universe, the different parts of a cell are made up of atoms. The atoms come together to form molecules. One molecule that makes up most of the cell is water. In fact, about 70% of a cell is water. Using its wide range of recipes, the cell can also create other kinds of molecules that help the cell do its job.

You might say each cell has its own recipe for success. In her research, Fahy has used knowledge of how cells work to study everything from the inner-workings of plants to why some animals get sick when bitten by ticks that carry a particular bacteria.

When we better understand how cells work, we can learn more about ways to prevent different diseases and improve the health and well-being of all kinds of living things. Who knows, maybe one day you can also use your knowledge of cells—or other parts of science— to help make our world a better place.

Sincerely,
Dr. Universe

Dr. Universe: How do memory cards work? – Ngyuen, 10, Vietnam
 
Dear Ngyuen,
 
Memory cards can help us store all kinds of information—from pictures to songs to videos.
 
While some of the early computers were as big as two refrigerators, they had only enough memory to store what would today be a single photo. Now, we can store thousands of photos on a memory card the size of a fingernail.  
 
One device that changed the way we could store information was the super-tiny transistor. My friend Ganapati Bhat, an assistant professor at Washington State University, told me more about it.
 
A transistor is about 2,000 times thinner than a strand of human hair. You can think of it as an electrical switch inside the memory card.
 
Transistors help the memory card determine if an electrical current should “stop” or “go” along the circuit board—and there can be billions of these transistors on a memory card.
 
When you look at a memory card, you may also notice it has several shiny terminals at the top. Some of those terminals help bring power into the memory card from your device. Others help the memory card communicate with your device in a language called binary.
 
The language has just two symbols: 1 and 0. The 1 and 0 are known as bits. When enough bits come together, we call them bytes.
 
In computer language, a “0” means “off”, so the transistor will stop the flow of electricity. A “1” means “on”, and the tiny transistor keeps the electricity flowing.
 
If we wanted to store the word “hello!” on the memory chip, it would require this binary code:
01001000 01100101 01101100 01101100 01101111 00100001. Each letter of the alphabet has its own set code in binary and it is known as ASCII (American Standard Code for Information Interchange) encoding. Even numbers have their own code.
 
Meanwhile, your device uses software to translate the binary language, so all those ones and zeroes show up in the form of photos, music or the phrase “hello!”.
 
In fact, most computers store data this way, but some devices can’t store it forever. As soon as you turn off the device, the data is lost. Scientists and engineers who wanted to come up with a way to store data for longer amounts of time designed something called a flash transistor.
 
A typical transistor has a part called a source, which is where the electrical current comes into the transistor. The current leaves the transistor through a part called the drain. Sandwiched between the source and drain is a part called the gate.
 
But flash transistors in a memory card have two gates. Some of the electricity sneaks up from the bottom gate into the top gate stays there. It sort of traps the electricity, so the memory card can continue to store information, even when it isn’t inserted into your device.
 
Over the years, humans have figured out how to put a lot of information into tiny storage devices. It’s something to think about the next time you text a friend a picture, listen to your favorite song or upload a school project on a flash drive.  
 
Sincerely,
Dr. Universe

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Dr. Universe: When would a clam open its shell? Why do the shells open? As far as I know, it opens when boiled for food. – Teng, 5, China
 
Dear Teng,
 
There are a lot of different reasons why a clam might open its shell. My friend Jonathan Robinson, a marine ecologist at Washington State University, told me all about it.
 
If we spent some time where the ocean meets the shore, or the intertidal zone, we might observe how clams open their shells when they need to eat, breathe or move around.
 
One thing most clam species have in common is they can open and close their shells using two super-strong adductor muscles. Some clams will use those muscles to open their shells when they are in search of food.
 
These filter-feeders eat and breathe through a tube-like part of their body called a siphon, which sticks out from the top of their shells.
 
A clam will use its siphon to bring a bunch of water into its body for two main reasons. The clam gets some oxygen from the water so it can breathe. It also gets important nutrients, or its food, from the water so it can survive.
 
If there’s any leftover stuff in the water that the clam doesn’t need, it gets filtered up and out a second tube-like siphon. If you ever have a chance to watch this happen, it will look like the clam is spitting into the air.
 
When people harvest clams for food, they often use a knife to open the shells, and in the process, they also cut the adductor muscles. That’s why we see clams that are partially open on the dinner table—they can no longer open and close their shells on their own.
 
Humans aren’t the only ones that sometimes eat clams. Clams are an important food source for critters like sea stars, sea otters, seagulls and fish, too.  
 
Another reason a clam might naturally open its shell is to stick out its foot and dig into the ground. Yes, you read that right: a clam has a foot. Of course, it isn’t quite like a human foot.  
 
“It’s one big muscle, and it kind of looks like a human tongue,” Robinson said.
 
Some clams will use this foot to dig into the ground and hide away from predators. A cockle clam can use its foot to sort of flip itself over and propel itself forward. It can use its foot to create this hopping-like motion on both land and in the water.
 
Along with the WSU Beach Watchers, a group of volunteers who help protect the Salish Sea and Puget Sound, Robinson often explores the shores where there are several different kinds of clams, including the kind known as geoducks.  
 
It turns out that not all clams have a shell that can actually open and close. The gooey duck has a foot that is so large it can’t even fit inside the shell. But the big foot helps the gooey duck dig really deep down into the sand or mud to escape any predators.  
 
It’s great to hear you are making observations and asking big questions, Teng. Maybe one day you will help us learn more about the intertidal zones that so many living things call home. 
 
Sincerely,
Dr. Universe

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Dr. Universe: What happens in our brain and body when we hear a funny joke? – Candace, 13, Irvine, Calif.
 
Dear Candace,
 
When we hear a funny joke, there are lots of different things that happen in the brain and body. My friend Paul Bolls, the director of the Media Mind Lab at Washington State University, told me all about it.
 
Bolls said one part of the brain that gets “tickled” when we hear a joke is called the frontal cortex. This is an area at the front of the brain that helps make sense of the joke and determine if it is funny.
 
Of course, exactly what someone finds funny depends on everything from culture to experiences they’ve had in life and their own sense of humor.   
 
“When our brains get tickled, regardless of our different backgrounds and beliefs or what divides us, the brain processes involved in humor unite us as humans,” Bolls said.
 
Bolls said scientists have learned more about how the brain responds to humor with the help of MRI technology, which can capture images of people’s brains.   
 
Scientists have observed that when a person experiences something funny, it also activates the brain’s emotional center. The emotional center includes a structure called the amygdala as well as the limbic system. Together, these different parts of the brain bring about that human experience of humor.
 
You may have observed that people also often get big smiles on their faces when they laugh. There are 42 muscles in the face, and laughter can give them a great workout.  
 
Meanwhile, there is also a chemical called dopamine at play. It’s a kind of happy hormone that can make us feel good as we watch a silly cat video, read a hilarious meme or hear a funny joke.  
 
The joke might make you chuckle, but if it’s a super funny joke, you might feel your heart beat faster, get tears in your eyes or even have trouble catching your breath. Laughter can be a full-body experience.
 
It can also be really good for your health. Some research has shown that laughter can decrease the number of molecules in the body that make people stressed. Meanwhile, it can also increase immune cells and infection-fighting antibodies that help protect people from getting sick.  
 
Alright, here’s a challenge for you: Try to write up a few jokes of your own. Or check out a book of jokes from your local library. Next, test them out on friends and family, and see how they react. Bolls said jokes often work best when there is an element of surprise or when a couple of ideas come together in unexpected ways. Here’s one science joke to get you started. Q: How does the moon cut its hair? A: Eclipse it.
 
Bolls and I want to thank you for helping us take a step back and think about something funny. It’s always fun to investigate the innerworkings of the brain, especially when it’s sparked by a great science question like yours.     
 
Sincerely,
Dr. Universe

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Dr. Universe: How do lungs work to help keep you alive? – Ellie, 11, North Carolina

Dear Ellie,

Take a deep breath. As air travels through your nose and mouth into your lungs, it brings oxygen into the body. To find out exactly how it all works, I talked to my friend Kim Chiok, a researcher at Washington State University.

In the lab at WSU, she designs experiments to help us learn about diseases that impact the lungs and other parts of the body that help us breathe.

When you breathe in, little hairs in your nose help filter out particles like dust, so they don’t enter the body. The air warms up as it flows into a tube-like structure called the trachea. The trachea leads down to the bronchial tubes and into the pink, spongy lungs.

Chiok said to explore how lungs work, we can also think about them as if they were made up of bubble wrap.

“But imagine that the bubbles don’t pop. Instead, whenever you squeeze the bubbles, they deflate but then go back to their own shape,” she said.

The air sacks in the lungs are like the individual bubbles in the bubble wrap. We call these air sacks alveoli and there can be hundreds of millions of these sacks in the lungs. The alveoli fill up with air and release air all day long.

The air sacks are lined with lots of tiny, living things called cells. These cells may be small, but they have a big job to do. They help bring the oxygen into the blood, so the blood can transport it around the body.

Oxygen in your blood can help do all kinds of things — repair cells, boost the immune system that helps protect you from getting sick, and even give you energy.

Not only do the air sacks bring oxygen to the body, they also help release carbon dioxide, which is a kind of leftover from the work some of your cells do.

When you get the flu or have other respiratory problems, it can sometimes make it hard to breathe. That’s because the alveoli lining becomes thick when fluid and inflammatory cells build up in the thin layer of tissue. The alveoli then have a hard time collapsing and expanding.

This also happens when smoke from wildfires or from smoking cigarettes fills up the lungs. While smoke can make it hard to breathe, it can also kill lung cells.

Lung cells can repair themselves, but it takes a long time for them to get back to normal. In some cases, the cells never fully recover. Chiok said it’s as if the bubbles in our imaginary bubble wrap, those alveoli, get destroyed.

That’s also why it is really important to protect ourselves from smoke and other small particles that might make it hard for the lungs to do their job. When we keep our lungs healthy, it allows life-giving oxygen to flow into our bodies and carbon dioxide to flow out, so we can all live our best lives.

Sincerely,
Dr. Universe

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Dr. Universe: Why do astronauts need astronaut suits? -Zamaria, 8, Sioux Falls
 
Dear Zamaria,
 
When astronauts leave Earth, a spacesuit can help them stay safe in places that are quite different from their home planet.
 
I learned all about it from my friends Stasia Kulsa, Lauren Reising and Ian Wells, a few members of a team at Washington State University researching how to clean moon dust from spacesuits.
 
On Earth, dust can sometimes be annoying, but dust from the moon can cause lots of problems for astronauts. The team is working on a “spacesuit car wash” that will keep astronauts healthy and their equipment clean. They told me that spacesuits help astronauts stay safe in lots of different ways.
 
Let’s say you were an astronaut heading to the moon. Here on Earth, we breathe oxygen all day, but on the moon there isn’t nearly enough oxygen to breathe. Astronauts may carry oxygen tanks on the back of their suits or use a hose that connects their spacesuits to a space station and delivers oxygen they can breathe.  
 
On the moon, it can also reach about 260 degrees Fahrenheit during the day and -200 degrees Fahrenheit at night. The human body can’t handle those temperatures, so spacesuits are designed with materials that allow astronauts to survive in extreme conditions.
 
Some of these materials are called insulators, and they work similarly to a sleeping bag. When the astronaut’s body temperature rises, the material absorbs the heat. But when the temperature drops, the material gives off heat. The spacesuit can help astronauts maintain a healthy body temperature.
 
Another reason astronauts need spacesuits has to do with changes in air pressure. As we go about our day, air is always pressing down on us. We don’t get crushed by this pressure because just as air pushes down on us outside of our body, it’s also pushing from the inside out. These two opposing forces help keep things in balance, or equilibrium.
 
If you left Earth’s atmosphere and headed to a place like the moon where there was less air pressure around you, that equilibrium would get out of balance. The body would likely start swelling as it tried to find balance again. A spacesuit also helps provide just the right amount of air pressure. It’s not quite as much air pressure as there is on Earth, but it’s enough to keep the astronauts safe.
 
There are many details that go into an astronaut’s complex spacesuit, but those are just a few. It turns out astronauts even wear a Maximum Absorption Garment which allows them to go to the bathroom in space. They also have helmets that contain a little block of foam they can use to scratch their noses. People who design spacesuits think of everything, don’t they?
 
Of course, spacesuits have changed quite a bit over the years. Creative people—like my friends at WSU— are always coming up with ways to help improve spacesuits. Who knows, maybe one day you can help design spacesuits or become an astronaut who wears one on a mission.   
 
Sincerely,
Dr. Universe

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Dr. Universe: Why do we have to keep things like ice cream and popsicles in the freezer? -Asia, age 9, Seattle, WA
 
Dear Asia,
 
You may have noticed ice cream and popsicles will melt when they are out of the freezer for too long. To find out exactly why this happens, I headed to the Washington State University Creamery.
 
My friend John Haugen, the creamery manager, was happy to help with your question. He said a big part of the answer has to do with something called matter. All things in our universe are made up of matter—even ice cream and popsicles.
 
Matter is made up of tiny particles called atoms. There are also three main states of matter: solids, liquids and gases. Temperature is one thing that has a big effect on a frozen treat’s state of matter.
 
Haugen reminded me ice cream starts as liquid milk. At the WSU Creamery, the workers add a few different ingredients, including fats and sugars, to the milk. They keep the ice cream mix liquid at exactly 40 degrees Fahrenheit, which is about as cold as the inside of your refrigerator.   
 
At this temperature, all the atoms that make up the liquid mix are able to spread out and move around. They can travel freely in their container. But when the mix goes through a cooling process, things begin to change.
 
First, the creamery workers put the liquid into a machine with a blade that stirs the ice cream mix to help it freeze into ice cream as it moves through a tube. The ice cream mix comes out a bit like soft-serve. It’s thicker than a liquid, yet not quite a solid.  
 
Next, that ice cream goes into a -20 degree Fahrenheit freezer. Under these very cold conditions, the atoms slow down a lot. They get into a kind of organized, or orderly pattern, and they don’t move around nearly as much as they do in a liquid state.
 
The ice cream that’s in the -20 degree Fahrenheit freezer becomes way too solid for anyone to scoop. It has to go into a regular freezer at 0 degrees Fahrenheit for a whole day before it’s ready to serve.  
 
If you eat ice cream on a warm day, the atoms start absorbing some of that heat energy. The energy causes the atoms to start moving quicker again. The solid becomes a liquid—and you might just end up with a melty mess on your hands.
 
Another part of the reason we keep ice cream and popsicles in the freezer has to do with food safety. If ice cream is out of the freezer for too long, it could invite bacteria to eat it. Those bacteria could potentially make us sick. Keeping foods at just the right temperatures is important for our health.
 
The next time you go out for an ice cream, or maybe even make some of your own at home, think about all the atoms that make up your frozen treat. Now, that’s some sweet science.
 
Sincerely,
Dr. Universe

Dr. Universe: What are some of the challenges of growing organic food? –Sabrina, 11, Scarsdale, New York
 
Dear Sabrina,
 
There are all kinds of different things to think about, along with a few challenges, when it comes to growing organic food.
 
My friend Lynne Carpenter-Boggs is a soil scientist at Washington State University who works with many different farmers and knows a lot about what it takes to produce food that is organic.
 
First, she told me about seeds. Whether you want to grow a pepper plant, a flower or any other crop, when people grow organic food, it all starts with organic seeds.
 
Once you have your organic seeds, you’ll want to put them in some healthy soil. People who grow organic food must keep track of everything they put into the soil.
 
“They can use anything that’s considered natural, unless it hurts people or the environment,” Carpenter-Boggs said.
 
The seeds will grow up into a small plant called a seedling, and their roots will grow deeper down into the soil. When the leaves start to form on the plants, that’s often when insects will show up. They like to chew on plant leaves or lay their eggs in the plants. That can sometimes make the plants sick.
 
One challenge for growers is that they have to find ways to manage the insects and keep the insects from causing damage to the plants. They can’t use most products made by humans to kill the insects.
 
But one thing they can do is bring other insects that like to eat those pesky pest insects into the field or garden. We can actually find lots of beneficial insects on farms—from pollinators to the pest-eaters.
 
It’s also important for people growing organic foods to pick just the right varieties of plants for their farm. The plants need to be able to grow well in a particular climate or environment.
 
Those are just a couple examples of the challenges farmers sometimes face, but Carpenter-Boggs said there are actually about 90 pages of rules that people who grow organic food must follow.
 
“Every year, the growers have to prove they’re following the rules,” she adds. “They keep track of everything they do, everything they buy, everything they feed to their animals, every fertilizer, anything that they put into the soil and even the seeds that they buy.”
 
As people grow organic food, they often learn how all of these different elements on the farm work as whole system. They may also try out different techniques they learn about through research to help grow better fruits and veggies. That’s good news for all of us who like to eat dinner.
 
While farmers and farm workers may face challenges, they work hard knowing they’re bringing food to people who need it. Who knows, maybe one day you will help us learn more about growing organic food and maybe you’ll even have an organic farm of your own.
 
Sincerely,
Dr. Universe

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Dr. Universe: Why do we have to blink? – Michael and Virgil, 3 and 5, in Sioux Falls, SD
 
Dear Michael and Virgil,
 
If you’ve ever had a staring contest with a friend, you may have felt your eyes start to get tired and dry. Eventually, you just had to blink.
 
Blinking helps our eyes stay healthy, and my friend Dr. Karen Janout, a clinical assistant professor at Washington State University, told me all about it.
 
She said that with each blink, your eyelids help spread tears over the surface of your eyes—and you actually do this a lot. Humans blink an average of 15 to 20 times a minute, which adds up to somewhere around 5.2 to 7.1 million blinks a year.
 
Of course, the exact number of blinks also depends on how many hours you sleep and your personal blinking style. 
 
As you blink, you spread out tears made up of three layers: a mucus layer, a water layer and a layer made of fats, called lipids. These layers work together to help keep the eyeball moist and prevent the tears from evaporating.
 
If humans didn’t blink, the transparent part of the eye covering the iris and the pupil, which we call the cornea, would get dry and bumpy. Because the surface is bumpy, light would travel through it in an unusual way and things would get out of focus.
 
While too much exposure to air can cause some eye damage, eyes do need to use something important from the air to work: oxygen.
 
The oxygen that comes into your eyes is only used by the cornea, and those tears you spread around your eyes when you blink help absorb some oxygen from the air. In just the right amounts, oxygen helps your eyes do all the things they need to do to help you see and stay healthy.  
 
You may have also observed blinking is something you don’t really have to think much about. You might blink quickly when a bright light shines in your eyes.
 
But blinking is also something you have some control over. For instance, you might blink quickly to help spread tears and get a bit of dust out of your eyes.
 
Of course, there is one time of day you don’t blink much at all. When you go to sleep, your eyelids close to keep your eyes moist as you rest.
 
Janout also told me while some animals blink a lot like humans do, other animals have different ways of protecting their eyes.
 
Some animals have membranes, which are like thin, transparent films that help shield their eyes. Some birds have both eyelids and a membrane. They don’t blink much but do close their eyes to sleep. Meanwhile, fish just have a membrane covering their eyes. But they don’t have eyelids, so they don’t blink.
 
Who knows, maybe one day, you’ll be an animal scientist, a doctor, a researcher or an ophthalmologist who helps us learn more about the amazing world of eyes and how they work.
 
Sincerely,
Dr. Universe

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Dr. Universe: How do tiny seeds make huge trees? – Robin, age 8
 
Dear Robin,
 
If you’ve ever eaten a handful of trail mix, you’ve likely eaten quite a few seeds from trees. Some nuts, like cashews and almonds, are also seeds that can give us energy when we hike or play.
 
Seeds actually store up their own energy in the form of something called starch, which is kind of like the food a seed needs to survive. The seed will use this stored up energy to start growing into a tree.
 
My friend Soon Li Teh, a scientist at Washington State University who researches apple and pear trees, told me more about it.
 
When we water a seed, it triggers a process that allows the plant or tree to start germinating. Under the soil, the seed pops open and little roots and leaves start to develop.
 
It is completely dark under the soil, but once the seed sprouts up through the top of the soil, it can start to sense light.
 
That’s really important because at this point pretty much all the energy that was contained in that tiny seed has been used up in the growing process. But now that the tree has leaves, it will be able to use those leaves to absorb sunlight and help make a new kind of energy.
 
“Sunlight, water and carbon dioxide combine together to give the trees resources to build its own food system,” Teh said.
 
The trees can use those ingredients to make something called carbohydrates which they need to survive in the world. You also take in carbohydrates when you eat food. These important nutrients help power our bodies and help us grow.
 
For trees, this food system that makes carbohydrates helps the tree grow more leaves, fruit and a thicker trunk as well as grow taller.    
 
At WSU, Teh and his team are asking big questions about pear trees. They are curious about ways to grow trees that produce lots of delicious fruit for farmers to harvest and for us to eat.
 
It turns out that researchers and farmers don’t always need a seed to grow a tree. They can actually take a branch or twig from a tree, called a scion, and connect it to another tree’s healthy root system.
 
Through this process, which is called grafting, a huge tree can start to grow from an individual branch. In fact, this is how farmers and researchers help grow a lot of the trees that produce apples and pears that end up in the supermarket.  
 
Whether a tree starts out as a seed or scion, remember how its ability to make and use energy is really important for growing up big and strong.
 
Perhaps you can keep an eye out for seeds in nature or even at the dinner table. Maybe you’ll spot the helicopter like seed pods of the maple tree, discover tiny seeds inside a pinecone or even find a few seeds in the food on your plate.

Sincerely,
Dr. Universe

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Dr. Universe: Why does it make noise when you snap your fingers? – Amelia, Michigan, 12

Dear Amelia,
 
When I got your question, I snapped my fingers a few times to try and find the exact source of the sound. After a few tries, I decided to ask my friend Troy Bennefield, the director of Athletic Bands at Washington State University.
 
While we may start a snap with the top of our thumb and middle finger touching, he said that the snapping sound actually happens when the middle finger hits the palm area at the base of the thumb.
 
As the middle finger hits the base of the palm, you actually send some vibrations out into the air. Vibrations are a big part of the reason we can hear all kinds of things—from snaps to claps to a variety of musical instruments. 
 
When an object vibrates, it creates waves of energy that travel to a listener’s ears. The outer part of the ears collect those waves and the ear canals channel them inside of the ears. Meanwhile, the brain helps interpret the incoming information and allows you to put a name to the sound you hear.
 
You know, there are so many different sounds to hear in our world. Part of the reason a snap sounds different from a clap or a musical instrument like a violin or drum is that the objects are made up of different materials. The materials vibrate in slightly different ways, giving us all kinds of sounds to hear and music to make.  
 
Bennefield is really interested in how we can use snapping in making music. One famous scene with a lot of snapping comes from the musical “West Side Story.” Maybe you know a song or two that incorporates a lot of snapping, too. Think about how that sound can bring a certain emotion or feeling to the song.
 
Maybe you can even try some snapping experiments of your own. Try a snap in your right hand. Now try the left. Did you notice any differences? Now, try playing with some different rhythms. Snap at a nice, slow steady pace or pick up the pace for a quicker rhythm.
 
If you are up for the challenge, see how many snaps you can do in a minute. Record your results. Just a couple of months ago, Guinness World Records announced that the new world record for most snaps in a minute is 437 snaps.
 
Perhaps you can also experiment with the volume of your snaps. The loudest snap on record was recorded at 108 decibels. For comparison, a motorcycle makes sounds that are recorded at about 100 decibels.
 
Try a super loud snap or try to make the quietest snap you possibly can. Observe how the volume changes depending on how much force you create between your finger and your thumb.
 
Whether your snaps are quiet or loud, slow and steady, or super-fast, remember that the sound all comes back to those vibrations in the air.
 
Sincerely,
Dr. Universe

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