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Ask Dr. Universe rcwebber

Dr. Universe: Why do we have five fingers and five toes? -Eli, 11, Edinburgh, Indiana

Dear Eli, While humans may be one of the few animals that can give a high five, they are one of many with five fingers and toes. Humans are part of the primate family, which also includes monkeys, apes, and even lemurs. As a member of the family, you also have fingernails instead of claws and pads on your fingertips that help with your sense of touch. Read More ...

Why does caffeine make us stay up longer? -Cooper, 12

Dear Cooper, You’re right, caffeine can help us stay awake—but only for so long. To understand exactly why it works, it helps to know about one of my favorite things: sleep. All animals need rest to stay healthy. But sometimes humans don’t get quite as much sleep as they need. They might be tired during the day or have a lot of work to do. To feel more alert, they might drink a cup of coffee, tea, or soda. These kinds of drinks contain caffeine, a chemical and stimulant that can trigger changes in the body. Read More ...

Who created the very first chocolate bar? – Emma, 11, USA

Dear Emma,

For most of human history, people have enjoyed chocolate in a spicy, bitter drink. But when people discovered how to turn chocolate into a solid, it opened up a whole new world of possibilities.

That’s what I found out from my friend Omar Cornejo, a scientist at Washington State University who is very curious about the history and life of the cacao tree. Chocolate comes from the seeds of leathery fruits that grow on the tree.

If we cut open the fruit, we would find about 20 to 60 seeds on the inside. In ancient times, people would grind up the seeds … » More …

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Why do you grow new taste buds? I read in a book once that you grow new taste buds every week. I started wondering how and why? I'm hoping you can help me with my question. -Tyra, 10, Jacksonville, NC

Dear Tyra,

You read it right— taste buds can have a lifespan of anywhere from one to two weeks. That’s what I found out from my friend Charles Diako who researched food science at Washington State University. Before he explained exactly how and why we grow our taste buds, he told me two important things about them.

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Dr. Universe: How is wasabi made and where does it come from? – Christian, 12

Dear Christian,

When you think of wasabi, you might think of that hot green paste people serve up with sushi. Some restaurants put a bit of wasabi on your plate, but it’s usually not real wasabi. It’s actually a mixture of horseradish, mustard, and green dye. Real wasabi is a lot different.

That’s what I found out from my friend Thomas Lumpkin, a plant scientist who studied wasabi as a researcher at Washington State University. Wasabi is a plant that mainly grows in Japan in the cool, running water of mountain streams and springs.

Illustrated, cartoon cat with labcoat» More …

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