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Ask Dr. Universe January 2018

Dear Dr. Universe: How does a light bulb work? When one bulb in a string of lights goes out, why do they all go out? – Molly, 8

Dear Molly,

Just the other day I was taking down a string of lights from my lab, when I discovered the bulbs were burnt out. I visited my friend Aaron Crandall, an engineer at Washington State University, to see if I might get them working again.

Crandall explained when you plug in a string of lights to a power source, like an outlet, an electrical charge flows into the wires. A lightbulb works when an electrical current runs through thin metal wires in the bulb and electrical energy gets converted to heat and light. We can get this current of electricity to follow different paths, … » More …

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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.

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Dr. Universe: How do planes fly? -Tahira, 12, India

Dear Tahira,

Planes are very heavy, yet they stay up in the air kind of like a bird in the sky. They can get us across the world in less than a day. Humans went from learning how to fly a plane to putting a man on the moon in a little over 60 years.

But the answer to your question goes even further back. It goes all the way back to the 1700s and actually started not with air, but with water.

That’s what I found out from my friend Michael Allen, a physics and astronomy professor at Washington State University. He thought you … » More …

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May I ask how fish breathe? - Nghi, 11, Vietnam

Dear Nghi,

When you and I take a deep breath, we pull air into our lungs. That’s because humans and cats are mammals. But fish aren’t mammals. They usually don’t breathe air. They usually don’t have lungs.

That’s what I found out from my friend Michael Berger. He’s a biologist at Washington State University.

He told me that you can actually see a fish breathe water. Its face gets bigger when it takes in a big gulp of water. Just like when you take a big bite of food.

When you look at a fish, you can usually see the gill openings—called gill slits. … » More …

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Dr. Universe: Why do birds have feathers? –Karthikeya, 7

Dear Karthikeya,

Bird feathers are interesting. There are so many types, shapes, and colors. My friend Daniela Monk is a Washington State University professor who studies avian ecology, or the study of birds.

She told me about why the birds we know today have feathers and how they got them. Researchers believe that birds evolved from dinosaurs a very long time ago.

“One lineage of dinosaurs gave rise to birds,” Monk said.

Researchers around the world are finding dinosaur fossils that contain feathers. A fossil is the remains of a very old animal or plant that is preserved in a rock. From these fossils they … » More …

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