Dr. Universe

Ask Dr. Universe – Sleep

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.
Dr. Universe

Ask Dr. Universe – Bee Stings

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.
Dr. Universe

Ask Dr. Universe – Human Hearts

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.
Dr. Universe

Ask Dr. Universe – Cells

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.

Dr. Universe

Ask Dr. Universe – Memory Cards

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.  
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post. 

Submit a question!

Ask Dr. Universe – Clams

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. 
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – What Funny Jokes Do

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.     
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Lungs

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.

Dr. Universe


Know a kid with a science question?
Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Astronauts’ Suits

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.   
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post. 

Submit a question!

Ask Dr. Universe – Frozen Treats

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.
Dr. Universe

Ask Dr. Universe – Growing Organic Food

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.
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Blinking

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.
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Seeds & Trees

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.

Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Finger Snaps

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.
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Poisonous Berries

Dr. Universe: Why are some berries poisonous? Where does the poison come from and how does it get in the berries? – Bianca, 4 1/2, California  
Dear Bianca,  
A lot of living things on our planet have defenses they use in the wild to help them survive. For some plants, being poisonous may help keep them from becoming someone’s dinner. 
That’s what I found out from my friend Wendy Hoashi-Erhardt, a scientist who directs the Small Fruit Plant Breeding program at Washington State University.  
Berries like deadly nightshade, holly berries, and snowberries—just to name a few— are not safe for humans to eat. These kinds of plants naturally produce poisonous compounds in their berries.  
You may remember that everything in our universe, including berries, is made up of atoms. When the atoms come together, they form compounds. Those compounds can sometimes form in a way that interfere with the work your body’s cells are doing to try and keep you healthy.  
In fact, the poison from some berries may make insects, birds, animals, and even humans really sick. That sends a kind of message or reminder to those creatures to avoid the plant and its berries in the future—or else they’ll likely get sick again.  
Humans have even discovered different types of compounds in different berries that can make us sick. For instance, there are the toxic compounds in snowberries and holly berries called saponins. Meanwhile, deadly nightshade contains compounds named trophine, scopolamine, and hyoscyamine.  
Throughout history, humans have actually learned quite a lot about which plants are dangerous to eat versus which ones are good to eat.  
For the nutritious and delicious plants, humans have been able to take those plants and make them even more useful through a process called plant breeding, Hoashi-Erhardt said.  
For example, we can take a raspberry and blackberry and cross them to create an entirely new berry called a tayberry. 
Hoashi-Erhardt does a lot of work helping us breed raspberries and said scientists have different categories for what we call “berries.” Part of what makes a berry a true berry has to do with an organ in the plant called an ovary.  
A raspberry, for instance, grows from a single raspberry flower. But that flower has many ovaries and they become all the little segments, which are called drupelets, that make up raspberry. It turns out a raspberry is not a true berry even though we call it a berry. 
Meanwhile, a blueberry comes from a single flower with just one ovary. Scientists call these berries that come from just one plant ovary “botanical berries.” True berries grow from a single flower with just one ovary. I was surprised that means bananas and cucumbers are technically true berries, too. 
It’s great to hear you are curious about berries, Bianca. They are truly an interesting part of the plant to observe. It’s also important to learn which types of berries are safe to eat and which are not. You can’t tell just by sight; becoming familiar with edible species of berry plants happens by talking to a botanist or carefully studying a field guide to wild edible plants.      
Dr. Universe


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Trees’ Growth

Dr. Universe: Why do trees grow so slow? – Ana, 7, Covert, MI

Dear Ana,

When you eat food, you get a lot of important nutrients that help you grow. The trees that live on our planet also need some nutrients to grow.

Trees use their leaves to help capture energy from the sun to make their own food. But as you may have noticed, a lot of trees lose their leaves during certain times of the year.

Without leaves, they can’t make nearly as much food, and without those important nutrients, they can’t grow very fast.

That’s what I found out from my friend Tim Kohlhauff, a certified arborist and urban horticulture coordinator at Washington State University. He is very curious about the lives of trees.

“These trees only get to make food part of the year,” he said.

Usually, we see slower growth in these trees between March and October. Of course, maybe you are thinking about the kind of trees that do not lose their leaves, like pine trees or evergreens. When it is really hot or really cold out, these trees will also experience slower growth. They may be trying to save energy and make it through tough times.

For instance, in the redwood forests of California where some of the tallest trees on our planet live, a redwood tree might grow two or three feet a year. But if the trees are stressed or don’t have water and sunlight, they might grow just an inch per year. Trees are pretty good at adapting to changes in their environment.

Not unlike humans, a lot of trees that live in forests grow faster in their younger years, too. In the forest, it can be a bit of a race to the top. There is a lot of competition between trees to grow tall so that they can get enough sunlight. After all, that sunlight is where they get energy to make their food.

While most humans don’t grow much taller after they reach ages 18 or 20, some trees can grow for up to 100 or 200 years. One slow-growing tree is the magnolia tree, which can reach heights of about 60 to 80 feet and sometimes even 100 feet tall. These trees can grow about one foot—the length of a ruler—a year.

Meanwhile, some trees will grow slowly but may never get very big. Dogwood trees only reach about 15 to 20 feet tall and grow about a foot a year.

Some trees may grow slowly, but they don’t grow forever. At a certain point, they stop growing taller and start growing wider. Not only does the trunk itself get wider, but the branches also grow out around the tree to form its canopy.

You know, we are still learning a lot about how the ways that the thousands of species of trees on our planet grow. But one thing we do know is that at least for some trees, growing slow and steady is just the right pace.

Dr. Universe


Know a kid with a science question?
Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Learning Hard Things

Dear Dr. Universe: How do you learn something hard? – Kai, 12, Alaska

Dear Kai,

There are so many different things we can learn in our world, but that doesn’t mean learning is always so easy. Maybe you want to learn a process, like how to complete Rubik’s cube, code an app, design a solution to a problem or answer science questions.

My friend Sarah Fick, an assistant professor of science education at Washington State University, was excited to hear your question. She said one way to learn something hard is to ask a lot of questions of yourself and other people.

Questions like: Why is it hard? Are you trying to remember something? Are you trying to understand how it works? Are you trying to solve a problem that’s hard to solve? Can you design something or come up with an idea that will help you solve that problem? Where can you find more information about your problem or who can you ask about it?

“Depending on what experiences you’ve had in learning—and the knowledge you’ve gained from your family and community—you are going to come at these problems with your own strengths,” Fick said.

Things that are easy for you, might be hard for someone else or the opposite could be true.

Fick reminded me that while we can learn a process, we can also learn more about how a process works. That’s what scientists do—they help us bring deeper knowledge into the world.

Through collecting data, researchers can help us build on current knowledge to create new knowledge. Another thing scientists do is create a model or draw a picture showing how they think the process works. A model can sometimes help us understand what we know and what we still have questions about.

When you are learning something hard, it also helps to ask yourself what is motivating you to learn. Maybe the motivation is that you want a good grade on a test. We call that extrinsic motivation. But maybe you want to learn how to do something for, well, you. Then, you have intrinsic motivation. When motivation comes from within, it often helps us learn.

Finally, while it may feel frustrating to learn difficult subjects or tasks, that’s sometimes a good sign. You might just be wrestling with knowledge that’s new to you and might be on your way to an “Aha!” moment when you gain a better understanding.

One of the areas Fick researches is helping us better understand how students can use their knowledge from one subject, such as math, to help them learn more about another area, like science. Learning often happens when we find connections, including connections to our daily life.

There are a lot of different factors that go into learning something hard, and these are just a few. The next time you find yourself facing a learning challenge, take a deep breath, ask yourself some good questions and get ready for the next step on your learning journey—wherever it takes you.

Dr. Universe


Know a kid with a science question?
Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Right-handed, Left-handed, or Both?

Hi Dr. Universe. My questions are: Why are people most commonly right-handed? Who/what deicides if we are left-handed or right-handed? Are you left-handed or right-handed? Thanks, Mya, 8, Alexandria, VA

Dear Mya,

We don’t know exactly why so many people are right-handed, but one place we might look for answers is in the material that makes a person who they are: genes.

The genes in your body help control all sorts of things from the color of your hair to your skin to your eyes. These traits can be passed down through generations—from grandparents to parents to you.

My friend John Hinz, who is a right-handed professor at Washington State University, knows a lot about genes and the study of how organisms pass their genes through generations.

He said that while there isn’t a single gene that helps determine if you will be right-handed or left-handed, scientists have found around 40 genes that seem to be related to handedness. Sometimes there is just one gene that causes a certain trait, but often it is combinations of genes that contribute to each of your characteristics.

“Genetics is clearly part of it but not the whole story,” Hinz said.

He also said when both parents are left-handed, they are more likely to have a child who is also left-handed. Some studies have shown that if both parents are right-handed, there is a 10% chance of having a child who is left-handed. Meanwhile, if both parents are left-handed, there is about a 25% chance the child will be left-handed.

But all we have to do is look at twins to realize there is more to it. Identical twins have all the same copies of every gene, but they don’t always use the same hand.

This question has left a lot of researchers wondering about the very question you’ve asked, Mya. People have looked into how the language centers in our brains might be connected to our handedness or how our experience as babies might be connected to our handedness. Some researchers have even observed dominant hands as a fetus develops in a mother’s womb.

They’ve also investigated how people’s different abilities are connected to handedness. Of course, just because there are a lot of connections or correlations between what hand a person uses and other traits or behaviors, that doesn’t mean we can say for certain. We haven’t found a clear answer to your question. Yet.

Whether you are left-handed, right-handed, or both-handed, hands can be really helpful tools. They can help us pick up things, climb to great heights, and even give a high-five. Perhaps one day you can join the community of creative and smart scientists to help us investigate more about genetics and handedness. There’s still a lot of research to do among our four-legged animal friends, too. As for me, I’m a righty. How about you?

Dr. Universe


Know a kid with a science question?
Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Weights of Planets

Dear Dr. Universe: How did people figure out how much a whole planet weighs? They could not have just put it on a scale! How did they do it? – Angel, 14, California

Dear Angel,

About 300 years ago during another pandemic, there was a person named Sir Isaac Newton who spent a lot of time at home thinking about the universe.

He was thinking about how objects fall and started to wonder if the same force that made objects fall also kept the moon in its orbit. He called this force gravity.

That’s what I found out from my friend Guy Worthey, an astronomer at Washington State University. Gravity plays a big part in the answer to your question, and we’ll explore that in just a moment.

When scientists talk about how much planets “weigh,” they often talk about mass. Worthey reminded me that all objects—from cats to planets—have mass. Mass is the amount of matter that makes up an object.

Worthey told me astronomers can measure a planet’s mass using what we know about gravity. He said one planet that taught us a lot about the relationship between mass and gravity was Pluto.

“I remember when I was a kid, the textbooks said that Pluto was twice the mass of Earth,” Worthey said.

The mass of Earth is a whopping 5,970,000,000,000,000,000,000,000 kilograms—in pounds we’d write that out as 13,170 followed by 21 zeroes. When Worthey was growing up, scientists were using clues about Pluto’s brightness to make some educated guesses about its mass. But it wasn’t until they discovered Pluto’s moon that it gave them a chance to do some more calculations.

When there is an object around a planet, such as a moon or a satellite, we can study how that planet pulls on the object. We can use our understanding of this gravitational force to help discover the planet’s mass.

When scientists discovered Pluto’s moon, Charon, they learned about not only the pull Pluto had on Charon but also the size of the moon’s orbit and how long it took the moon to orbit around Pluto. They needed to use all of this information in their calculations to figure out Pluto’s mass.

It turned out that Pluto was much smaller than they had originally thought. Instead of being twice the mass of Earth, they found Pluto had a mass that was 1/200 the mass of Earth.

It turns out some planets, such as Venus and Mercury, do not have an orbiting object like a moon. It wasn’t until humans were able to send satellites to these planets that we were finally able to gather precise information about gravity and learn about mass.

You know, gravity is an important force. It’s what makes things fall. It’s what keeps planets in orbit. It’s what keeps us on the ground. While we may not have a scale to weigh planets, we can use what we know about gravity and mass to make all sorts of calculations and investigate questions about our universe.

Dr. Universe


Know a kid with a science question?
Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Fish Migration

Dr. Universe: How do fish migrate and why? – Norma, 10, Indiana

Dear Norma,

While a lot of fish swim from one region to another to find food or have babies, different fish species migrate in different ways.

That’s what I found out from friend Steve Katz, a professor at Washington State University who knows a lot about our planet’s natural resources and has researched fish such as steelhead trout, tuna and seven-gilled sharks in the Pacific Northwest.

He said that steelhead trout often navigate through the water with help from a sense of smell. Steelhead trout use their nostrils to pick up on chemicals from rocks that have dissolved in the water. The differences in the scents of the water help them know which river or stream to follow.

This is a helpful tool, especially as steelhead trout can swim for long distances over the course of a few years—in some cases, over 1,300 miles upstream after they swim through the ocean for more than 3,700 miles.

Katz reminded me that not all fish migrate. For instance, some of the steelhead trout males will stay behind in the streams when the females and other males head for the ocean. There is some risk in traveling long distances, so it can pay off for some fish to stay home and wait for the females to return.

If you think a few thousand miles is a long way to swim, wait until you learn about tuna. Albacore tuna cross the Pacific Ocean twice a year cruising at speeds of 5-10 miles per hour. In a lifetime, that might add about 20 to 25 round trips. When it comes to migration, these fish are marathoners.

“It’s spectacular,” Katz said. “Tuna are elite swimmers because they’ve got this extra red muscle and machinery that helps them swim at a steady, fast pace.”

A fish that moves much slower is the seven-gilled shark. These fish live where the saltwater meets the freshwater, or often where rivers meet the ocean, which we call an estuary. But when it starts raining a lot in the winter, there isn’t enough saltwater in the estuary anymore. They have to head out into the ocean.

The sharks travel up and down the coast for anywhere from 100 to 1,000 miles while they wait for the estuary to become saltier, and then they make their journey home for the summer.

Katz said that some research has also explored how fish might use Earth’s magnetic field—which extends from our planet’s interior out into space— or the angle of the sun to know which direction they should be going. But the truth is, scientists are still learning a lot about exactly how fish navigate the waters on their migration.

Perhaps you can find a species of fish that lives in your state and learn more about its migration journey. The more species you learn about the more you’ll realize just how many migration stories there are to discover.

Dr. Universe


Know a kid with a science question?
Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Horses and Feelings

Dr. Universe: How do horses sense how you feel? –Taylor, 11, New Zealand

Dear Taylor,
When I got your question, I called up my friend and veterinarian Dr. Macarena Sanz who had just finished checking up on the horses at the Washington State University Teaching Hospital. She was happy to help.
“It’s a hard question to assess scientifically,” Sanz said. “But I think everybody who has worked with horses can tell you that horses really do have a certain sense about humans.”   
One part of the answer to your question is that horses may be able to respond to a situation using clues from both a person’s facial expression and the emotion in their voice.  
In a study from Japan, researchers showed horses some photos of humans with different expressions on their faces, such as happiness or sadness. Along with the photos, the horses also listened to recordings of human voices.
Sometimes the voice and facial expression matched, for example, a happy face with a happy voice. But other times the horse might have seen a photo of a happy expression but heard a sad voice.   
“Horses were able to pick on that,” Sanz said. “When the horse didn’t feel like things matched, they would stare at the screen a lot longer.”
It kind of makes you wonder what exactly the horses must have been thinking. These kinds of studies will help researchers start to put together a better picture of how horses respond to humans.
You know, your question also made me curious about the ways humans figure out what horses are feeling. It turns out that horses have 17 expressions they can use to communicate, such as puckering their lips or dropping their jaw. Some expressions communicate they are in pain.
If you’ve ever stubbed your toe or broken a bone, maybe you know that feeling that makes you scrunch up your face in pain. That’s a kind of expression called a grimace.
Sanz said veterinarians use a scale called a grimace scale, which includes photos and information about different horse expressions and behaviors, like when they hold back their ears. It’s a tool many veterinarians who work with horses will use in their careers.
“I remember when I was starting my career, my boss would come in and say, ‘Oh, this horse has –that look–and it’s going to need surgery’ and she was right. The horse needed the surgery. And now I can see that look too,” she said.
While humans and horses have been a part of each other’s lives for thousands of years, there is still a lot to learn. Sanz said it’s likely we will continue to learn even more about the way humans and horses interact, especially as many studies have been showing that these interactions can have lots of health benefits.
Perhaps one day you’ll be a veterinarian who helps us provide the best care for horses or a researcher who helps us better understand the ways in which horses sense the world.
Dr. Universe

P.S. Do you want to support science education and find out how to get an Ask Dr. Universe face masks? Visit askDrUniverse.wsu.edu/masks


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Worms

Dr. Universe: How do worms help protect the dirt? -Fisher, 7, Palouse, WA
Dear Fisher,
Worms can help the soil in a few different ways. One helpful thing worms do is move around different materials, such as leaves and grasses, and make holes in the soil.
That’s what I found out from my friend Lynne Carpenter-Boggs, a soil scientist at Washington State University, who was happy to help with your question.
“Worms are actually very strong,” Carpenter-Boggs said. “They can break through soil and make holes that allow air, water and plant roots to follow those channels.”
As the worms wriggle down into the earth, sometimes they also pull leaves and dead grass down into their burrows. These materials can break down and add important nutrients to the soil.
Meanwhile, worms sometimes bring leaves and grasses down into their burrows to save as a snack for later. For earthworms, soil is almost always what’s on the menu for breakfast, lunch and dinner.  
Worms eat all kinds of things in the soil. Scientists often call these things organic materials. This includes grasses, leaves, roots and other materials that make up the soil.
After worms digest their food, they poop. It turns out there is a particular word scientists use when they talk about earthworm poop: castings. These castings look pretty much like the dark soil and blend right into the mix. Castings are also a kind of natural fertilizer that can help plants grow.
We also find another important thing in the castings that help the soil: bacteria. Bacteria are so small we’d likely need a microscope to see them, but they also help with soil health. Different bacteria have different jobs in the soil.  
Some bacteria help break down—or decompose— different organic materials. There are even some bacteria that give off the very chemicals that create that earthy soil smell. Just as various types of bacteria live in your gut, a range of bacteria also live in the guts of worms.  
“We can see that there is this incredible diversity of bacteria in the earthworm stomach,” Carpenter-Boggs said.
Through digging holes, moving materials around, eating and dropping their castings, worms do a lot to help protect the soil.
When you think about it, the soil is a pretty amazing material. Soil gives worms what they need to survive, and the worms help give the soil what it needs to thrive. That’s great for animals and humans who eat plants that grow in soil, too. 
The next time I go outside, I’m going to take a closer look at the soil. Maybe you can try it out, too. Perhaps you will see some rocks, roots, grasses or maybe even a wriggling earthworm. If you have a magnifying glass, you might be able to get an even closer look. Take some time to think about how important the health of the soil is to all the life that lives in it—and how important soil is to all life on our planet.  
Dr. Universe
P.S. Dr. Universe is looking for questions for an upcoming Northwest Public Broadcasting program! Do you have a science question about plants, fruits, or flowers? Or a question about rocks, volcanoes, or earthquakes? Guardians can send an e-mail to Dr.Universe@wsu.edu with the subject: Meet the Scientists to find out more!


Know a kid with a science question?

Adults can help kids submit a question for a chance to be featured in a future video, podcast, or Q&A post.

Submit a question!

Ask Dr. Universe – Sunburn

Hey, Dr. Universe: Why do we humans get sunburns when we are out in the sun too long? – Gavyn, 13, Indiana

Dear Gavyn,

Humans need sunlight to help keep their bones, blood and other body systems healthy, but too much time in the Sun can sometimes leave people with a sunburn.

Sunburns often strike when the body gets too much of a type of light, called ultraviolet light, from the Sun. As your body recognizes there is too much ultraviolet light, it turns on a defense system.

The immune system, which responds to invaders like viruses and other harmful things like ultraviolet light, kicks in. Some people might see their skin get red or blistered. They might feel itchy or painful. But not everyone experiences sunburn in quite the same way.

A big part of the answer to your question also has to do with human cells. My friend Cynthia Cooper, a researcher at Washington State University, knows a lot about cells and how they work.

She said the human body is made up of billions of cells, and they do all kinds of different jobs. Some cells help us get energy from food, some cells help us grow hair, and other cells in the skin can even make something like a shield that protects us from the Sun’s ultraviolet rays.

These natural shields are what scientists call melanin, a kind of dark pigment. You may remember that pigments are colors we find in nature. Melanin is also part of what gives human beings their skin color.

You can think of the melanin-making cells in your body like a hand with fingers reaching out to the neighbor cells called keratinocytes. The “fingers” of a melanin-making cell can help pass melanin to several keratinocytes at the same time. Then, the keratinocytes can move melanin to the cell’s control center: the nucleus.

This nucleus is really important because it protects your DNA, which contains the instructions your body needs to grow and develop. DNA has all the information that makes you, well, you.

“The melanin almost acts like a little flying-saucer that hovers over the nucleus,” Cooper said. “It reflects the ultraviolet rays to protect the DNA from damage.”

So, if you don’t make a lot of these shield-like flying saucers of melanin pigment, you may be more likely to experience a sunburn. Meanwhile, there are some people who don’t produce any melanin at all. People with this condition called albinism must be very careful in the sun because they don’t have a lot of those natural shields.

In the lab at WSU, Cooper and her team are investigating the innerworkings of cells to learn more about new treatments for people with cell diseases like albinism as well as treatments for the most serious types of skin cancer. When we understand more about how cells work, we can continue help improve human health for everyone.

Speaking of health, one thing you can do to help protect your body and its cells from ultraviolet light is to wear sunscreen when you go outside.

When you wear sunscreen, you can help take care of your body, so your body can keep taking care of you.

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Saturn’s rings

Dr. Universe: How did Saturn’s rings form? -Amelia, 9, Washington State

Dear Amelia,

We still don’t know exactly how the rings around Saturn formed, but scientists who study Saturn’s rings have come up with a couple of ideas.

One common theory many scientists agree upon is that Saturn’s rings are made from the little leftover pieces of what used to be a moon.

My friend David Atkinson is really curious about the solar system and told me more about it. He is a graduate of Washington State University and now works at the NASA Jet Propulsion Laboratory. He also worked on the Cassini-Huygens space research mission which helped us learn more about Saturn, Saturn’s large moon Titan, and the entire Saturn system.

He said that when we investigate questions about Saturn’s rings, it helps to know about both moons and gravity.

Moons are usually smaller than their planets. Our Earth has just one moon, but Saturn has 82 moons. Each moon has a name, such as Titan, Enceladus, Mimas, Dione — just to name a few.

According to NASA, there are likely another 29 moons around Saturn, but we are still waiting to confirm the discoveries and give the moons their names.

Saturn, like Earth and other planets, also has gravity around it. The gravity gets weaker the further away you travel from the planet.

Atkinson said that for each moon, Saturn’s gravity on the side of the moon that faces the planet is stronger than the gravity on the side that faces away from the planet.

“The gravity stretches the moon out a little bit,” he said. We call this a tidal force.

He told me the story about a scientist named Édouard Roche who figured out that if a moon gets close enough to a planet, this stretching force will be so strong that it can break a moon apart.

“The theory is there was a small moon of Saturn that got too close to the planet. That small moon got inside Saturn’s Roche Limit, or inside that special distance, and the tidal force broke the moon into pieces,” Atkinson said. “Those pieces spread themselves around the planet and that is the ring.”

Throughout the years, scientists have been able to study the size, thickness and materials that make up Saturn’s rings. We’ve learned that the rings are made up of rocks, ice and dust. Scientists have also asked what would happen if we took all of the materials that make up Saturn’s rings and packed them together.

“It turns out that it would pack together into a pretty small-size moon,” Atkinson said.

You know, Saturn isn’t the only planet that has ring systems. Jupiter, Uranus and Neptune also have rings, too. But the rings are pretty faint and much harder to see, even with a telescope.

There is still so much to discover about our solar system and the worlds beyond our Earth. Maybe one day you can help us learn more about the way different planets form and help us find answers to big questions just like this one.

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Toothpaste

Dr. Universe: How does toothpaste clean your teeth? -Lucy, 10, Pullman, WA

Dear Lucy,

If you are anything like me, every day you squeeze a little toothpaste onto your toothbrush and brush your teeth. Toothpaste gets its cleaning power from a few different ingredients.

My friend Mark Leid was happy to tell us about how they work. Leid spent part of his career teaching future dentists. He is also dean of the Washington State University College of Pharmacy and Pharmaceutical Sciences.

First, he told me the outer covering of a tooth is called enamel. It’s the hardest tissue in the whole human body—even harder than bone—and it helps with things like chewing your food.

Inside your mouth and on your teeth, there are lots of tiny living things called microorganisms. They are so small you’d probably need a microscope to see them, but they like to eat the leftover food bits that get stuck in your teeth.

As they eat those leftover bits, they also make acid. That acid can break down your enamel, which can lead to cavities or tooth decay.

“We can’t make new enamel,” Leid said. “Once our enamel is gone, it’s gone.”

That’s part of the reason it is so important to brush our teeth. When you brush your teeth with toothpaste, it helps get rid of that acid.

Leid said some ingredients that help get rid of the acid and leftover food in your teeth are called abrasives. These create scrubbing power and sometimes give the toothpaste a gritty texture. Abrasives are combinations of atoms, which are like building blocks, that come together to form something called a chemical compound.

One example is calcium carbonate, which is made up of carbon, oxygen and calcium atoms. Another is silica gel, which is made up of silicon and oxygen atoms. Some other compounds create scrubbing power, but these are two of the main ones.

Meanwhile, other toothpaste ingredients help create foaming action, such as sodium lauryl sulfates and sodium N-lauryl sarcosinate. These are the same compounds that give soaps their foamy qualities.

Take a look at the back of your toothpaste tube and see what ingredients you can find. Another ingredient you might notice is fluoride, which helps strengthen your enamel. You might also see other flavoring agents that give toothpaste its taste, like mint.

“Otherwise, it would taste pretty chalky and bitter,” Leid said.

When you brush your teeth, you are helping your mouth stay clean and healthy. In addition to brushing, flossing is also important. Floss helps remove any excess food between your teeth that might invite those acid-making bacteria.

It’s great to hear you are curious about toothpaste, Lucy. Who knows, maybe one day you will be a chemist, a dentist, a pharmacist or anything else you dream. Keep up the great brushing, keep asking great science questions and don’t forget to floss.

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Touchscreens

Dr. Universe: How do touch screens work? -Nicholas, 11, Florida

Dear Nicholas,

When I got your question, I decided to do a little experiment. First, I tapped my paw on a tablet and sent a message to a friend. Next, I put on a pair of wool mittens and started typing, but the screen did not respond. Finally, I used a banana to see if I could use it to swipe the screen. It actually worked.

I wondered what exactly was going on here and decided to take our questions to my friend Praveen Sekhar. He’s an associate professor in the Washington State University School of Engineering and Computer Science.

Sekhar told me our touch screen devices use electricity to work and that different materials can impact how the electricity flows. Some materials called insulators keep electricity from flowing, such as the wool mittens. Then there are objects such as your finger or a banana that allow electricity to flow from one place to another. We call these conductors.

When your finger touches the screen, it creates a sort of pathway for electricity to flow from your finger to the device. You read that right: you have electricity in your body— from your toes to your fingers.

Sekhar said you can think of how these touch screens work sort of like a battery. If you look at a battery, you will see it has a positive charge end and a negative charge end. Electricity will start to flow if both ends are connected to your device.

A touch screen device on its own has a negative charge, he said. But once your finger connects with the touch screen it becomes positive. The electrical charges can work together to help your device work. This kind electrical ability is called capacitive technology and is found in many touch screen phones, tablets, and computers.

Sekhar also told me about another kind of touch screen. These are the kinds of touch screens we see at ATMs and in grocery stores. These screens aren’t quite as bright as your computer or phone. We call these resistive screens, and they are made of layers of glass and plastic with a chemical coating and a sheet of metal underneath them.

When you press these screens with your finger, you apply pressure to the material. Inside the material, the electrical charges start moving inside as they respond to pressure from your finger and allow the device to work.

Whether it is capacitive or resistive technology, touch screens have become part of many people’s daily lives.

With help from an adult, perhaps you can do a little investigation into touch screens, too. Collect a few small items from around the house to find out which ones are insulators and which ones are conductors.

Screens are quite fragile so you may want to use materials that will be gentle to your screen, like a cotton swab, an eraser or a banana. Touch the objects to the screen to see if they allow your device to respond. Make a list of which objects conduct, or allow electricity to pass through, and remember how electricity helps your phone do all kinds of amazing things.

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Flying Squirrels

Dr. Universe: Do flying squirrels really fly? – Gwendolyn, 9
Dear Gwendolyn,
Flying squirrels may not really fly, but they do have flaps of skin on their bodies that act like parachutes and help them glide through the air.
My friend Todd Wilson told me all about it. He’s a wildlife biologist with the U.S. Forest Service in Oregon and graduate of Washington State University who researches Pacific Northwest ecosystems and the animals that call them home— including flying squirrels.
When flying squirrels are trying to avoid predators, like weasels, sometimes they will run to the top of a tree. The weasel might think the flying squirrel has nowhere else to run. That’s when the flying squirrel makes its move.
“The flying squirrel can just take off and glide,” Wilson said. “When they launch themselves from a tree, they can actually go quite a ways out, but they’re not actually flying.” 
Depending on the tree, flying squirrels can sometimes glide for hundreds of feet. As they glide, they can use their tail to steer around and between other trees.
Flying squirrels are not only amazing to watch, but they also play an important part in forest ecosystems.
While other tree squirrels eat a lot of nuts or seeds from tree cones, a big part of a flying squirrel’s diet is something different. They eat an organism called fungi that live under the soil.
“Flying squirrels eat the fruits of the fungi in the forest—if the fruit is above ground, it is called a mushroom. If the fruit is below ground, we call it a truffle. Flying squirrels eat a lot of mushrooms and truffles, and then pass them through their digestive system,” Wilson said.
Flying squirrels help spread the fungi around the forest through their, well, poop. As new fungi grow, they suck up nutrients from the soil and pass on those nutrients to trees. In exchange, the trees give fungi some sugars that help the fungi grow.   
While flying squirrels play a big part in our forests, we rarely see them during the day. They are nocturnal, or active at night. But sometimes we can hear them.
They are pretty quiet compared to other squirrels, but they occasionally make a chittering sound as they meet up with other flying squirrels. We sometimes hear a big slap when they land on a tree. After all, there’s a lot of power and speed in that glide. 
When flying squirrels glide during the night, they may pass other nocturnal neighbors in the sky, like bats.
Of all the thousands of mammal species on our planets, bats are the only mammals that can truly fly.
You know, the living things in the forest are linked together in important ways. They need each other to live and grow. Humans also play a big part in our forest ecosystems.
Can you think of ways humans are connected to the forest? Maybe you can even find some connections between you and a flying squirrel. Share your answers and ideas with us some time at Dr.Universe@wsu.edu.
Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Dogs’ and Cats’ Behavior

Dr. Universe: Why do dogs and cats spin around before they sit down? – Antonio, 10, Richmond, Va.

Dear Antonio,

That’s a great observation about cats and dogs. Even I wasn’t sure why cats spin around before they sit down, so I took your question to my friend Dr. Jessica Bell.

She is a veterinarian at the Washington State University Veterinary Teaching Hospital and has seen quite a few cats and dogs walk in a little circle before they sit down.

“It’s a common thing we observe as veterinarians, but we can’t talk to cats and dogs and ask them ‘why,’” she said. “From a behavioral standpoint, it probably stems back to their wild instinct.”

An instinct is a behavior that animals don’t have to learn. They are born with this behavior, and it often helps them survive in the world.

When cats and dogs spin in a full-circle, they have a chance to observe their environment. They might even spin in circles a few times to be certain the spot where they want to sit is safe.

They are likely keeping their eyes out for any danger, such as predators. This behavior was especially important when felines and canines lived in the wild. While a lot of cats and dogs may live in homes with humans these days, they never lost this instinct.

You may have also noticed that sometimes cats and dogs sniff around as they get ready to lie down. Both senses of sight and smell can help these animals make sure the coast is clear. Bell also told me that once the animal knows a space is safe, it will often return to the same spot.

“They often position themselves in the same place on their bed every time or face the same direction,” she said.

While that may be the more scientific answer to your question, she also offered another idea.

“I think many dogs and cats are just finding a good, comfy, fluffy spot to lay down with just the right depth and cushiness,” she said.

Finding a good place to rest can also be helpful for dogs who are getting a bit older. For instance, dogs that have arthritis, a condition where the joints get stiff or swollen, will often walk in a slow circle before they lie down.

If you keep your eye out, you may notice that other animals, such as horses or birds, walk in a circle before they sit, too. You might see birds getting comfortable in their nests or a birdhouse. They even flip around their feathers and move different parts of their nest to get everything just right before they settle in.

You know, a lot of veterinarians pay close attention to animal behavior and ask a lot of questions about it as they take care of our pets. If you keep up the great observations and continue to ask questions, you might just help us learn more about the amazing animals on our planet one day.

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Stinky Cheeses

Dear Dr. Universe: Why do some cheeses stink? – Cody, 11
Dear Cody,
When you take a whiff of stinky cheese, that smell is coming from one of its very important ingredients: microorganisms. 
Microorganisms are so small, you’d need a microscope to see them, but sometimes they give off a big stink. To find out more about stinky cheese, I talked to my friend Minto Michael.
Michael is a professor of dairy science at Washington State University and told me microorganisms do a few different jobs to help make cheese. These microorganisms can consist of bacteria, yeasts or molds, but bacteria are the most important in cheesemaking.
When cheesemakers add lactic acid bacteria to milk, the bacteria help get the milk ready for another ingredient called rennet, an enzyme. This enzyme helps turn the milk from a liquid state into more of a solid that will become cheese.
While the bacteria may do a lot of work to help make the cheese, there are benefits to the job.  
“These bacteria eat up the milk sugar, milk proteins and milk fat, so that they can get energy and multiply,” he said.
As the bacteria eat to get energy, they can also produce a stinky gas. The gas is made up of molecules. Some of these molecules that include ammonia or sulfur compounds are responsible for the smell in a lot of stinky cheese.  
When certain molecules come in contact with receptors in your nose, your brain helps you figure out what you are smelling. Maybe your brain tells you to stay away from stinky cheese—or maybe it makes you want to try it.   
Michael told me about some of the most smelly, or pungent, cheeses. One of them is called Roquefort cheese. This is a kind of a blue cheese that gets its odor from a mold named Penicillium roqueforti. If we looked at it under a microscope, we might notice that it is a kind of paint-brush shape. Penicillium in Latin means “painter’s brush.”
Meanwhile, a different kind of bacteria called Brevibacterium linens is responsible for the smell and flavor of some other blue cheeses. Brevibacterium linens is not only the bacteria responsible for one of the smelliest cheeses on the planet called Époisses, but is also the same bacteria that makes the smell of human body odor. 
When people make cheese, sometimes they will let it age for a while. For some cheeses it may be two months or even two years before they are eaten. As the cheese ages, the aromas often start to get stronger and stronger. Of course, not all microorganisms produce gases that are stinky.
One of my favorite non-stinky cheese varieties was developed at Washington State University. It’s a sharp white cheddar called Cougar Gold that comes in a can.
After investigating your question, I was curious to find out what kind of bacteria is in this cheese. It turns out the answer is a top-secret recipe even I’ll never know. But it’s no secret that it tastes and smells delicious.
Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Bird Migrations

Dr. Universe, How do birds know where to migrate? – Jasmine, 10, Gainesville, Florida 

Dear Jasmine,  

There are all kinds of different birds on our planet, and they migrate to different places.

My friend Heather Watts, a researcher at Washington State University, is really curious about bird migration and told me more about how birds know where to go.  

She said there are some birds that make a round-trip flight when they migrate. For instance, the bar-tailed godwit will make long flights between Alaska and New Zealand, traveling more than 7000 miles without stopping.  

Meanwhile, a blue grouse makes a much shorter round-trip flight. It migrates less than a quarter of a mile.   

Scientists think that some birds may know where to go because of a kind of program that’s built into a bird’s DNA. It’s sort of like being born with a set of directions they know how to use. This genetic information is passed down from bird grandparents to bird parents to the offspring.  

“What we think a lot of birds do the very first time they migrate is use a program that tells them what direction to go and how far to go in that direction,” Watts said. 

On a bird’s first migration, it may also follow other birds. The next migration season, the bird may be able to use clues from the environment to find its destination.   

There’s another kind of migration that has scientists, like Watts, asking lots of big questions. It turns out there are actually birds that do not migrate to the same location every year.  

We might see birds like pine siskins breeding in California one year and then in Canada the next year.

“We don’t know as much about this type of migration,” Watts said. “It’s really hard because we don’t know where the birds are going to be and when they are going to be there.”  

Watts and her lab are studying the pine siskins to learn more about the ways these types of nomadic birds migrate and what might be going on behind that behavior.  

Different birds may migrate in different ways, but they will often migrate for similar reasons. While there are some unsolved mysteries around migration, one thing we do know is that migration is really important for helping birds find what they need to reproduce and survive.  

You know, it can be quite fun to watch all the different birds in our neighborhoods. Here’s a science challenge for you: the next time you go for a walk or gaze out the window, see what birds you can spot. With help from a grown-up, see if you can find the name of the bird online or at the library. Finally, do a little research to find out how it migrates and discover the journey your bird takes.  

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Mushroom Rings

Dr. Universe: Why do mushrooms grow in rings? We have a lot of giant ones in our yard right now! – Layne, 8, Spokane 
Dear Layne,
When you see a ring of mushrooms, it’s likely they are exploring for food under the ground.    
Giant mushrooms in your backyard are not animals or plants. They are part of another class of living organisms called fungi. But like you and me, they do need food to survive.
That’s what I found out from my friend David Wheeler, an assistant professor at Washington State University, who knows a lot about fungi.
He said the mushrooms are just one part of fungi. The other part that explores the soil for food actually lives under the soil.
This part is called the mycelium and looks a bit like cobwebs or stretched out cotton candy.
Mycelium help the fungi explore different spaces and absorb nutrients from things like dead logs or decaying leaves.
Wheeler said we might think about the way a mushroom ring forms, including how the mycelium spreads out, as if it were a ripple in a pond.
Just as ripple starts with a raindrop or stone, a mushroom ring begins with a tiny spore.
To help grow new fungi, mushrooms will release spores, which are sort of like seeds. After a mushroom releases the spores, they float through the air and when they land in soil, the mycelium begins to grow beneath it.
It starts expanding outward from the place where the spore landed. This allows the fungi to cover a lot of ground on the hunt for food.
It’s at the outer edge of the mycelium where we see the ring of mushrooms grow up from the soil.  
I found out there are some mushroom rings that have been around for a really long time. For instance, one mushroom ring in France has been around almost 700 years.
As the fungi spread out in search of food, the ring got wider and wider. Now, the ring is almost a half mile wide. You would have to walk the length of eight football fields to get from one side to the other.
Even though fungi don’t have legs, they sure know how to go the distance. And a big part of that has to do with their mycelium.
“Every step you take in the forest, under one foot—even one kid foot—there could be lots of cells of mycelium,” Wheeler said.
Wheeler also told me that fungi sometimes compete for food. If you look at the mushroom ring in your backyard, you may notice something unusual about the grass around it.
Sometimes grass inside the ring may be brown, and the grass inside the ring might be bright green. That’s because fungi and grass both like to eat the same thing.
They are both after the nutrients in the soil. But as the fungi grow, they can steal nutrients away faster than the grass can handle. 
You know, it’s great to hear you are observing nature in your own backyard. It’s a good reminder that we can find science questions almost anywhere in this big, wide world—even in a ring of mushrooms.
Dr. Universe

docKnow a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Foggy Mirrors

Dr. Universe: Why do mirrors fog up when you breathe on them? -Zinnia, 7, Richmond, Virginia 

Dear Zinnia,

That’s a great observation. When you breathe out, you let a couple of different things into the air.

Not only do you breathe out carbon dioxide, but you also breathe out teeny tiny droplets of water. These water droplets are so small we can’t see them with our eyes.

Scientists actually have a name for these little droplets of water in the air: water vapor. You may remember from our question about the states of matter that there are all kinds of different gases, liquids and solids in our world. Water vapor is a kind of gas.

My friend Cigdem Capan, a physics instructor at Washington State University, said one big factor that can help water move between these different states of matter is temperature.

When you breathe on a mirror, you are helping water move from a gas state to a liquid state. The surface of the mirror is a lot colder than the water vapor that comes from your warm human body. If you breathe on a mirror, you can easily feel that heat releasing into the air.

As water vapor in your breath reaches the mirror’s cool surface, the vapor droplets come together to form a liquid. When this happens, you can see thousands of super tiny liquid droplets form on the mirror: the fog.

Scientists also call this transition from a gas to a liquid, condensation. It’s the same process that helps form big, fluffy clouds in the sky, tiny drops of morning dew, or the water droplets on the outside of your cool water glass.

“If you are wearing eyeglasses and you are wearing a face mask, you can also see the glass fog up,” Capan said.

That’s condensation, too. While you may not always be able to see the water vapor from your breath, when the temperatures drop it is a bit easier to observe this condensation in action.

It’s been pretty cold here in the Northwest, so I’ve noticed this happen when I go outdoors. As we breathe into the chilly air, the warm water vapor condenses into tiny droplets of liquid water—and even some solid water, or ice—that form a kind of miniature cloud. It’s pretty fun to watch.

Whether you fog up the cool air, a window or your glasses, you may have also noticed that the moisture doesn’t stick around forever.

Try breathing on the surface of a glass mirror or windowpane and watch what happens. Eventually, the liquid droplets disappear from the mirror. Why do you think that might be?

Share your ideas with your friends or family, and see if you can work together to figure out where those water droplets go. If you need a hint, do a little bit of research on how puddles dry up or investigate the water cycle on our planet. Tell us what you discover at Dr.Universe@wsu.edu

Dr. Universe

docKnow a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Shadows

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

Dear Aven,

When we look around our world, we can find all kinds of shadows. One way we can explore the answer to your shadow question is with a little experiment.

My friend Anya Rasmussen, a physics professor at Washington State University, told me all about it.

First, you will need to cast your shadow on a wall. Rasmussen reminded me shadows form when an object—such as your body— blocks light and keeps the rays from reaching a surface—like a wall.

To see how this works, you can ask a grown-up or friend to shine a flashlight or a lamp behind you and onto the wall.

You can also take some time to see how the shape and length of your shadow change as you move closer or farther from the wall.

“If you want to see if your shadow casts shadows, now shine a light on your shadow,” Rasmussen said.

Point another flashlight at the shadow, then take a few moments to observe what happens. Alright, it’s almost time to reveal the answer, so if you want to experiment, come back and finish reading this after you try it out.

If you have continued reading, here is a spoiler alert: A shadow can’t make a shadow. Unlike you and me, a shadow cannot reflect or absorb light. It can’t block rays of light and keep that light from reaching a surface.

While you’ve got your flashlight out, there are a few other ways you can play with light and shadows, Rasmussen said.

Perhaps you’ve noticed that sometimes two shadows will come from one object. If you have two flashlights or two light sources, you could try to create multiple shadows by shining the light on an object from two different angles. Maybe you can even see what happens when you use three flashlights.

If you are anything like me, you might also be surprised to learn not all shadows are black. Rasmussen said that if we experimented with red, blue and green lightbulbs we could make shadows in different colors.

We can make small shadows or big shadows. Even our enormous Earth makes a shadow. As the moon passes through Earth’s shadow, it creates a lunar eclipse.

Light and shadows are not only an important part of understanding physics, but they are also a big part of creating art and telling stories, Rasmussen said.

When we look at paintings from impressionist artists like Claude Monet and Edouard Manet, we can see how they paid a lot of attention to these two important elements. After all, shadows and light go hand in hand.

After you’ve finished experimenting, see how many shadows you can spot around your home or around the neighborhood. Perhaps you can even sketch a few different shadowy shapes out on a piece of paper.

Who knows, maybe one day you’ll be a scientist or an artist—maybe you’ll even be both. You are well on your way.

Dr. Universedoc

Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Rainbows in Oil

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

Dear Jorgos,

When it rains, sometimes we can see oil on the street rise to the top of puddles and spread out into a rainbow of colors.

One of the main reasons we see color is because of light, said my friend Cigdem Capan, a physics instructor at Washington State University.

She reminded me that when our eyes sense colors, we can trace those colors back to different wavelengths of light. Perhaps you can make some waves in the air with your hand. Make small, tight waves. Now make a big, wide waves.

The light waves that help us see color are a lot smaller than any wave we can make with our hand. According to our friends at the National Oceanic and Atmospheric Administration, blue or violet wavelength is about 125 times smaller than the width of a human hair.

When these light waves reflect, or bounce, off different surfaces such as an oily puddle, our eyes and brain work together to help translate the information into color.

It turns out there are two places in an oily puddle where the light waves can bounce off or reflect. If you’ve ever mixed oil and water together, you know that they like to be in separate layers.

One place where the light reflects is the top of the puddle where the air meets the oil. The other place is where oil and water meet. Lightwaves have to travel a bit farther through the puddle to reflect where the oil and water meet.

Let’s say you see some purple spots in an oily puddle. You see this color because red, orange, yellow, green, and blue waves reflect off the puddle and overlap with each other in the air. When the waves overlap, they actually cancel each other out, so you can’t see them with your eyes.

But the violet waves reflect off the surface and travel in unison through the air to your eyes. As they travel, these violet wavelengths get a bit of a boost from each other, and the purple appears bright to your eyes.

The differences in the thickness of the oil can make some wavelengths reflect in unison and that is how we see not just the purple spots, but all the different colors in an oily puddle.

The colors that you see in an oily puddle are also a kind of phenomenon we call iridescence. We can see this phenomenon when we observe the outside of soap bubbles or the colorful feathers of the male peacock.

There are so many different colors in our world. Perhaps you even have a favorite one. A couple of my favorite colors are crimson and gray. No matter what colors we see in our world, remember that we can trace all of them back to waves of light.

Dr. Universe


Know a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Black Holes

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

Dear Krisha,

While we can’t see black holes with our eyes, astronomers have figured out how to spot these objects in our universe.

One astronomer who is really curious about understanding black holes is my friend Sukanta Bose, a researcher at Washington State University.

First, he told me there are different kinds of black holes. Supermassive black holes can be millions to billions of times the mass of the Sun. We have a supermassive black hole in our own Milky Way galaxy called Sagittarius A*, which is pronounced as Sagittarius A-star.

Scientists think supermassive black holes may be found in the center of most large galaxies.

If you are anything like me, you might be wondering: why not just count all the different galaxies to find the number of black holes?

“Of course, we cannot see every galaxy,” Bose said. “We see many galaxies that are closer because they are brighter.”

For galaxies that are farther away, you have to use very powerful telescopes, he adds.

That also means we have to make an inference about the number of galaxies in the universe. An inference is an educated guess based on evidence and current knowledge about how things work.

Using telescopes, math and their inference skills, astronomers estimate there are hundreds of billions of galaxies and likely hundreds of billions of supermassive black holes— that’s just in the observable universe.

Bose told me there’s another kind of black hole that sometimes forms when a star dies and collapses in on itself. We call these stellar mass black holes.

The Sun is a star, but it is far too small to become a black hole. Only heavier stars make black holes. When it comes to stellar mass black holes, astronomers estimate there are ten million to a billion right here in the Milky Way galaxy.

On the hunt for these massive objects, scientists often look for different interactions among stars or gases, clues that there may be a black hole in the neighborhood.

For instance, when a black hole and a companion star are in a tight orbit, their interaction can sometimes create high energy light we can’t see, but that scientists can detect with their high-tech tools.

“When you open a new way of probing the universe, you see objects that challenge your previous wisdom or theories,” Bose said.

Bose and fellow researchers have been able to spot black holes because of a new way to detect something called gravitational waves. When two black holes collide, they can create a kind of wave that brings information to Earth about its source and helps us learn more about the universe.

It’s a bit like listening for sound waves from particular instruments in an orchestra, Bose said. But instead of picking out the sound of a cello or a flute, they are listening for gravitational waves from those colliding black holes.

Who knows, maybe one day you can help us learn more about black holes and discover ways to help astronomers count them all.

Dr. Universe

Thanks to all our kid readers who voted for this question in our recent poll. Stay tuned for future polls at askDrUniverse.wsu.edu.

Know a kid with a science question?
With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.
Submit a question

Ask Dr. Universe – Tears and Yawning

Dr. Universe: Why do we get tears when we yawn? – Ella, 8, Australia

Dear Ella,

You’re right, a lot of people get tears when they yawn. When you yawn, you actually use lot of muscles in your face. Maybe you can feel the stretch in your jaw, cheeks and eyes.

As the muscles in your face contract, they can put a lot of pressure on the plumbing system that is in charge of making your tears.

That’s what I found out from my friend Karin Biggs, an adjunct professor at Washington State University who teaches anatomy.

She told me that we have two little almond-shaped structures called the tear glands, or the lachrimal glands, that produce our tears. These glands are located up near the eyelids, and it is likely they are making tears at this very moment.

“Tears are made all the time,” Biggs said. “They are responsible for keeping our eyes moist, helping us see and keeping our eyes healthy.”

Meanwhile, there are also two tiny tubes located near the inside corner of your eyes. These tubes, or lachrimal canals, are where the tears can exit your eyes as you yawn.

Like a very slow faucet, the teary fluid is constantly being released from the gland. Gravity pulls the fluid down and around the eye. You might think of it like putting a ball in your bathroom sink then running the water faucet over it. The faucet is your gland, the drain is where tears exit and the ball is the eye.

“When we yawn we are contracting all the muscles in our face,” Biggs said. “We are just squeezing the tears out of the gland and out of the tubes because we have squeezed all of our face at once.”

Biggs also told me there are 43 muscles in the human face. You may squish up a lot of those face muscles when you sneeze or laugh, too.

The muscles in our bodies can help us do all kinds of things. Biggs told me there are even some muscles people have that other people seem to be missing. The plantaris muscle in the knee is one of them. Only about ten percent of people do not have this muscle, but they usually seem to be fine without it.

But tear ducts and tear glands in our eyes are among the many body parts that humans have in common. This plumbing system helps you create, transport and drain all your tears.

The ability to make tears is all a part of the human experience. But other animals like cats and elephants can make tears, too. Tears are mostly water with some other ingredients that help keep our eyes in good shape.

Whether your tears come from crying, sneezing, laughing or yawning, they are often a good sign your body is taking care of you and that your eyes are working well.

Dr. Universe

docKnow a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Frost Shapes

Dr. Universe: When frost freezes, it makes shapes like flowers and ferns. Why does it look like that? – Grace, 13, in Calgary

Dear Grace,

You’re right: frost can sometimes form patterns that look like the ferns or flowers we find in nature.

Those frosty shapes we see on the surface of windows start out as water in the air, said my friend Kai Carter. Carter is a meteorologist with Washington State University’s AgWeatherNet team.

If you’ve ever had a glass of ice water, you may have noticed droplets formed on the outside of the glass. The droplets actually came from water in the air. This water condensed from the air onto the surface of your cup, which means it turned from a gas to a liquid.

This is similar to what’s happening when dew forms on grass. But frost is a little bit different, Carter said.

When frost forms, conditions have to be just right. As water from the air lands on a really cold surface like a windowpane, the water molecules freeze and join together with other water molecules to form patterns of ice crystals.

An ice crystal is made up of two building blocks: hydrogen and oxygen. These hydrogen and oxygen atoms form a hexagon shape that is a kind of six-sided ring. Even though we may not be able to see them with our eyes, these hexagon shapes can repeat in a pattern across the frosty surface of the window.

Sometimes the water molecules can form into one big sheet of frost. But sometimes things can get in the way of the water molecules. They may have to take a new path as they freeze to the surface of the glass.

If the molecules run into something like a speck of dust, salt or even a bit of washer fluid from a car window, they may change their direction. As you’ve observed, they can start to branch out into shapes that might look to us like feathers or ferns or tree limbs.

In mathematics, we call this kind of thing a fractal design. A fractal pattern repeats itself at different scales. One other place you can also find fractal patterns in ferns. The fern frond looks like it’s made up of little fern fronds which look like they are made up of even smaller fern fronds. Next time you see some frost take time to observe its detailed patterns with a magnifying glass.

Even if you don’t live someplace where it gets really cold, you can actually make your own frost right in the kitchen. All you need is a tin can, salt and ice. Fill the tin with ice and 4 tablespoons of salt and mix it up for a minute. Wait a few minutes and see what forms on the outside of the tin.

The salt is important because it melts the ice, while at the same time helping the mixture drop below freezing. Why do you think that might be? What happens when you add more salt or more ice? Tell us about your frosty experiments sometime at Dr.Universe@wsu.edu.

Dr. Universe

druniverseKnow a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Pond Water

Dr. Universe: Why does water in ponds not get soaked up by the dirt at the bottom? – Rocky, 11, California

Dear Rocky,

That’s a great observation. If we investigated the bottom of a pond, we might find a few different things. Besides a few fishes and frogs swimming around, we might observe mud, algae, rocks and soil at the bottom.

My friend Joan Wu, a hydrologist at Washington State University, is really curious about the water on our planet. She told me a few different earth materials help keep pond water from seeping down into the ground.

Let’s imagine we filled a jar with one of these earth materials: rocks. Inside the jar, we would see some gaps between the rocks. If we poured water into the jar, the water will be able to move into those empty spaces. But now let’s say we had a jar of rocks, and we poured in some sand.

This time, the grains of sand would fill spaces between the rocks. Next, we could add particles of earth called silt that are so small they could fill in any spaces between the grains of sand.

Finally, we could add some even smaller particles of clay. In the jar—or the bottom of a pond— these materials are packed together. The material isn’t very permeable, which means it can keep the liquid from passing through it.

“Over a long, long time, the bottom of the pond itself evolves and changes,” Wu said. “The materials settle and the little particles, or sediments, fill in the large pores.”

As water, wind, gravity and even animals break down rocks, the rocks become smaller and smaller particles that sink to the bottom of the water. When water runs across the Earth’s surface during a storm or as snow melts, these fine materials can also end up in a pond.

For the most part, these materials keep the pond from losing too much water, but sometimes a little does escape into the ground. Meanwhile, a little water can also escape into the air.

“Eventually, you will lose water from the top and from the bottom of a pond,” Wu said.

We lose the water from the top of a pond because of something called evaporation. You may know about evaporation if you’ve ever seen a puddle on a sidewalk that was there one day and gone the next.

When the sun heats up the surface of water, the water can turn from a liquid into teeny tiny drops called vapor. The vapor rises up into the atmosphere where it can eventually become clouds. Those clouds help produce rain and snow that fall back into lakes, rivers and ponds.

When we take the time to look, we can find a lot of connections between our atmosphere, water and earth. These systems shape many habitats for life on our planet.

The next time you visit a pond, see what kinds of living things call it home. Who knows, maybe one day you’ll be a scientist who can help us learn more about the world of water.

Dr. Universe

druniverseKnow a kid with a science question?
With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Tree Sap

Dr. Universe: Why do trees have sap? -Aliyah, 8, Kirkland, WA

Dear Aliyah,

Just as blood moves important stuff around the human body, sugary sap moves important things around a tree.

My friend Nadia Valverdi told me all about it. She’s a researcher at Washington State University who studies how apple and cherry trees survive in different environments.

When we eat food, like a delicious apple or a handful of cherries, we get important nutrients.

Along with some help from the digestive system, our blood helps carry nutrients to different parts of the body to keep us strong.

Trees need nutrients, too. They use their roots to suck up nutrients and water from soil. They also have the ability to make their own food: sugars.

Trees absorb sunlight through their leaves and can use this energy from the sun to make sugars from water, carbon dioxide gas from the air and a few other ingredients.

A lot of sugars are made in the leaves, but they don’t do the tree much good if they just stay in one spot. The sugars have to get to other parts of the tree to help it survive. That’s where the sap comes in.

“Its main task is to make sure that every organ is well-fed and growing,” Valverdi said.

While our blood moves through tube-like veins and arteries, sap flows through two different tube-like parts of the tree.

One part, called xylem, moves important stuff like water and nutrients from the bottom of the tree to the top—from its roots to its leaves.

The other part, called phloem, moves important stuff from the leaves to other parts of the tree, such as the branches, roots and fruit.

I asked Valverdi how a sticky, gooey liquid like sap could move through these tubes. After all, sap doesn’t seem to move on its own.

It turns out that some liquids, such as sap, can move through a narrow space without any help from gravity or other outside forces.

This can happen in plants or trees when sap escapes through tiny, microscopic holes in the leaves. When sap molecules escape the leaf, more sap molecules move in to fill the empty space and keep the sap flowing upwards through the tree.

It’s a phenomenon we find happening everywhere from house plants to big apple trees to celery stalks.

“All trees and plants have sap,” Valverdi said. “The difference is that sometimes in big trees, we can see it with our eyes because it is more gooey.”

One really gooey kind of sap you might have seen before comes from sugar maple trees. You may even put it on your pancakes or waffles. You guessed it, maple syrup is a kind of sap.

Just like us, trees have systems that help them move important stuff around. These systems help the plants survive. When trees do well, that’s good for us, too. They do so many things for us from making the oxygen we all breathe to giving us delicious fruit to eat.

Dr. Universe

You can learn more about the xylem and phloem in this simple activity using food coloring, water and some celery. https://www.youtube.com/watch?v=KIug9Foou3s

docKnow a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!

Ask Dr. Universe – Stained Glass

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

Dear Emily,

Ever since humans discovered they could use sand to make glass, they’ve been experimenting with it. They even learned how to control the colors.

My friend Dustin Regul is a stained glass artist and painter who teaches fine arts at Washington State University. He told me more about where glass gets its color.

“It’s actually metals that help change the color of the glass,” he said.

We can add these metals to glass in the form of a compound. A compound is a combination of one or more elements. For example, table salt is a compound made up of the elements sodium and chloride.

Yellow glass can be made using a compound called cadmium sulfide. Red glass can come from adding gold chloride. Manganese dioxide can make glass purple. Blue glass comes from adding the compound cobalt oxide.

Glassmakers add in compounds when they melt the sand. The temperature has to be just right for everything to work. They heat the sand to about 3,000 degrees Fahrenheit—that’s even hotter than lava. As the melted sand cools, it becomes glass.

It turns out, glass made from melted sand doesn’t always instantly become transparent. The glass sometimes has its own natural color.

“You can imagine really old glass bottles,” Regul said. “They kind of have that bluish or greenish tinge.”

Glassmakers also figured out that a compound called sodium nitrate could help clear up the glass.

Regul said glass is a pretty unusual material. It’s not a solid or a liquid. Scientists call it an amorphous solid, which means a state somewhere in the middle of those two states of matter. It’s also a very fragile material.

Regul must be very careful when he works on stained glass projects. Before he gets started, he makes a plan and draws out his design on paper.

Next, he cuts up the paper drawing into pieces. It’s a guide that will help him as he cuts pieces of glass into shapes with a special glass cutting tool. Finally, he uses copper tape to connect the pieces together and applies heat to seal it all up.

In medieval times, when stained glass first became really popular, people used a different technique. The glass pieces were held together with long strips of a bendy material made of lead. On each side of the lead strip was a little channel where the edge of glass could be tucked in. And like the technique Regul uses, adding heat to the strip helped keep the glass in place.

Humans can use these really small pieces of glass—in all sorts of colors—to form a bigger picture or story. Whether you are in the lab or the studio, it’s amazing what you can create and discover when you set your mind to it.

Dr. Universe

P.S. Be sure to check out the Ask Dr. Universe podcast on Spotify, iTunes, or at https://askdruniverse.buzzsprout.com/.


docKnow a kid with a science question?

With help from my friends at Washington State University, we’re investigating tough and smart questions from curious kids around the world.

Submit a question!