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Why are animals symmetrical?

Dear Dr. Universe: Why are animals symmetrical?

– Theo, 10, Rupert, British Columbia, Canada

Dear Theo,

That’s an excellent observation. If we drew an imaginary line straight down the middle of the human body, it would look pretty similar on each side. » More …

Do you have any experiments you can recommend?

Dr. Universe: Do you have any experiments you can recommend? Thanks! -Etta, 7, Milwaukee

Dear Etta and Friends:

You can try all kinds of fun experiments at home. It really all depends on what you are curious about. Lately, I’ve seen some really great sunsets and started wondering what gives them their colors.

I decided to ask my friend Tom Johnson, who leads fun physics demonstrations for kids visiting Washington State University. I asked him if he had any simple ideas for an experiment I could try out in my lab, or even the kitchen. One idea he had was to create a sunset in a cup.

Maybe you can try it, too. You’ll need a flashlight, a transparent cup or two, water, and some milk. We cats have a reputation for liking milk. But it really isn’t so great for our digestion. So instead, I like to use it for science.

Once you’ve collected all your supplies, you’ll want to fill your glass about 2/3 of the way with water. Then, you’ll want to add milk until the liquid gets pretty cloudy. Be sure and stir it up well.

Turn on your flashlight and turn down any other lights in the room. Now you can shine the flashlight down into the water and look through the side of the glass. What color do you see?

This time, shine the flashlight through the side of the glass while looking at it from the opposite side. Any changes? Then hold your glass up off the table. Shine the flashlight up through the bottom of the glass and look down into the liquid. What colors can you see now? Perhaps the colors are looking more like those you’d see during a sunset.

Milk in the water scatters the light from the flashlight. It’s similar to the way different molecules and dust in our atmosphere scatter light from the sun.

Light travels from one end of the glass to the other and then up to your eyes. The further the light has to travel through the water, the more blue light gets scattered. That leaves more red light for your eyes to pick up.

Now that we’ve started to get an idea of how light scatters, runs into particles, and travels long distances, you can really get to experimenting.

What happens when you use less or more milk? Will you see any changes if you use a different kind of flashlight, like an LED? What kind of milk gives off more orange or reddish colors? Two percent? Whole milk?

Does the shape of the glass change anything? Why do you think that might be? Make a prediction and give it a try sometime. I’d love to hear more about your experiments and how your own sunset in a cup turns out. E-mail: Dr.Universe@wsu.edu.

Sincerely,
Dr. Universe

ABOUT ASK DR. UNIVERSE

  • Ask Dr. Universe connects K-8 students with researchers at Washington State University through Q&A. Students can submit science questions on the ASK page.
  • Are you a teacher, parent, or curious grown-up? Follow along on Twitter or Facebook.
  • Do you want to reprint this Q&A? Just send a message to Dr.Universe@wsu.edu.

Glass: How is it made?

Dr. Universe: How is glass made? And, what is it made out of? What about thick glass like they are putting up on the Space Needle? – Tali, almost 8 years old, Seattle, Wash.

Dear Tali,

We can make glass in factories and we can find it in nature. Some volcanoes make glass. When they spew out lava, it often cools into obsidian, a black glass. Glass can also form on sandy beaches. Small tubes with smooth glass on the inside may appear after super-hot lightning strikes the sand. » 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 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

 

ABOUT ASK DR. UNIVERSE

  • Ask Dr. Universe connects K-8 students with researchers at Washington State University through Q&A. Students can submit science questions on the ASK page.
  • Are you a teacher, parent, or curious grown-up? Follow along on Twitter or Facebook.
  • Do you want to reprint this Q&A? Just send a message to Dr.Universe@wsu.edu.