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How does our refrigerator work?

Dear Dr. Universe: How does our refrigerator work? -Brody, 12

Dear Brody and Friends:

While a stove or oven produces heat, a fridge can’t actually produce something called “cold.” So, how does a refrigerator manage to keep all your food cool? » More …

Is there such thing as cold?

Hi Dr. Wendy Sue: Me and my brother had a little bit of an argument about the point that there is no such thing as cold. He said liquid nitrogen produces cold, which I think is absurd, but lack the knowledge to explain it. Can you please explain to us why there is no cold?

– Brody, 12

Dear Brody,

It’s a snowy morning and the thermometer reads 20 degrees Fahrenheit. You grab a jacket and a pair of mittens for your paws. It’s going to be a cold day. » More …

Who came up with the word “science”?

Dear Dr. Universe: I was wondering, how did science get its name? Who thought of it? Does it mean something special? -Jada, 10

Dear Jada,

If you were to travel around the world, the word “science” might look or sound very different. In Spanish, it’s ciencia. In Japanese, 理科. In German, wissenschaft! And in French…well, it’s also science. But with an accent.  » More …

How are twins made?

Dear Dr. Universe: How are twins made?

Dr. Universe is a gray cat wearing her white lab coat, yellow pants, and red shirt in the forest when she runs into four nine-banded armadillos and starts thinking about what it would be like to have a twin. Her twin has blue glasses and a yellow shirt.

–Brody, 8, Kauai, Hawaii

Dear Brody,

By the time you finish reading this sentence, about twenty babies will have been born into our world. Sometimes they’re twins. » More …

How does rubber bounce?

How does rubber bounce?

-Evan H., Cimmaron, Kan.

Whether it comes from trees or is made by scientists in a lab, rubber can really bounce. Well, a rubber band or rubber on your shoes might not be very bouncy. But a super bouncy rubber ball? It can really catch some air. » More …

How much does an eyeball weigh?

Dr. Universe: How much does an eyeball weigh?

-Rahman, 10, Tollygunge, India

Dear Rahman,

Our animal kingdom is full of different eyes. The human eye weighs less than an ounce. That’s about as heavy as 11 pennies. But I suppose the answer to your question really depends on which eyeballs you are curious about. Perhaps you are looking for an answer about the biggest animal eyes on our planet. » More …

How do roller coasters go so fast?

Dr. Universe: How do roller coasters go so fast? How do they stay on their tracks?

–Bhayana, 10, Jacksonville, AR  

Dear Bhayana,

The very first roller coaster at Coney Island amusement park cost only a nickel to ride and was a big thrill for visitors—even if it did only go 6 mph. » More …

In space, which way is up?

Dr. Universe: In space, which way is up?

–Pablo, 10, Spokane, WA

 

Dear Pablo,

We might not always think about it, but every day gravity keeps us pulled to the Earth. It’s what brings us back down when we jump on a trampoline. It’s why a Slinky tumbles down stairs.

Now think about what it would be like to live in a place with very little gravity. Let’s say you were 200 miles off the ground, orbiting earth in the International Space Station. Here, the idea of up and down really gets flipped around.

On Earth, the human balance system helps the head figure out how move up and down under the force of gravity. It’s what helps people figure out to look up to the ceiling or down to the floor. If you are floating around in space, up and down is different.

I decided to visit my friend Afshin Khan to find out more about it. She is a researcher and astrobiologist at Washington State University.

Khan explained that even things in space have a little gravity, and whichever object is being pulled toward another due to stronger or larger gravity is what we call “down.” The opposite is what we call “up.” We use these words to help us navigate.

But in reality, there really are no true directions, Khan said. There is no up and down in space.

It’s kind of like when we look at a globe, she explains. If you are trying to get to Japan from the U.S., you can see it is both east and west of the U.S. It depends on the direction you want to travel. If you want to cross the Atlantic Ocean, you go east. If you want to fly over the Pacific Ocean, you go west. It’s all relative.

Inside the International Space Station, the ceiling might as well be the floor. The walls might as well be the ceilings. It’s enough to make your head spin.

In fact, researchers at NASA are asking big questions about what happens to the human brain when it can’t figure out which way is up or down. They are curious how it changes the activity of the brain.

Some scientists have even tackled questions about how to help plants “grow up” in these environments with very little gravity. To help plants grow upright, scientists have developed little plant pillows. The pillows are full of dirt, water and plant food to help the plants stay grounded. Otherwise, their roots would grow out in all different directions.

As the concept of direction may be different in space, engineers and scientists have to think about it when they are designing tools to help us navigate the universe. Who knows, maybe one day you’ll come up with a great idea that can help us explore, too.

Sincerely,
Dr. Universe

 

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