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Ask Dr. Universe Larry Clark
University Communications Network > Ask Dr. Universe > Articles by: Larry Clark

Dr. Universe: How come some rocks are easy to break and some are hard? - Natalie, 10, Russellville, Kentucky

Dear Natalie,

If you draw with a pencil, you can tell how soft the graphite inside is. Pieces of graphite break off to leave the pencil mark. But can you imagine drawing with a diamond? Diamonds and graphite are both what you might call rocks. How come they’re so different?

To find out, I talked to my friend Katie Cooper, a geologist and associate professor in the Washington State University School of the Environment. Geologists often study how different types of rocks and minerals form—and that’s the secret to whether they’re easy or hard to break.

Rocks are made of minerals, and minerals are made of elements, which are substances made of a single type of atom. You can get to know the Earth’s elements by looking at a Periodic Table.

Some minerals are made of a single element, like diamond and graphite, which are both made of carbon. Others are a mix, like limestone, which is made of calcium and carbon.

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Dr. Universe: How does electrical power travel through metal? - Gabriel, 4, Illinois

When you watch the zapping bolts during a lightning storm, you know how powerful electricity is. Humans have only been harnessing electricity to bring light and energy to our towns and homes for about 150 years—and metal is one of the main ways we get this powerful tool from place to place. To learn more, I talked to my friend Bob Olsen, a professor emeritus in the Washington State University School of Electrical Engineering and Computer Science. Olsen said it’s important to realize that we don’t need metal wires to move the waves that carry electricity, which are called electromagnetic waves. Some technologies, like cell phones, pick up waves that are sent through the air. Read More ...

Dr. Universe: How are sea animals affected by water pollution? - Natalia, 10, Florida

If you ever visit the beach, take a look at all the animals: crabs scuttling across the sand, seals bobbing on the waves and sea stars tucked into tide pools. Maybe there are even whales spouting on the horizon. Earth’s oceans are home to thousands of creatures. But, as you know, human pollution reaches our waterways and all the animals that live in them. To learn more, I talked to my friend Erica Crespi, an associate professor in the Washington State University School of Biological Sciences. Crespi studies how animals that live in water respond to all kinds of stresses, including pollution. Read More ...

Dr. Universe: Why does time fly when we are having fun? – Isaac, 7, Australia

If you’re having a great time playing at the beach or camping with your family this summer, the day might zip right by. But the long drive to get to your fun destination might seem to take forever. To understand why time seems to change based on our activities, I asked my friend Alana Anderson, who just earned her Ph.D. at Washington State University. Anderson studies how people, especially babies and little kids, manage their behaviors and emotions. Read More ...

Dr. Universe: Why do we get sleepy when we study? - Sadaf, 12, Pakistan

Dear Sadaf,

Like many good students, you’ve probably noticed that when you study, especially late in the day, you feel sleepy. Scientists don’t know exactly why, but they have a few clues.

The human brain is packed with tens of billions of cells called neurons, which process and store information that helps us observe, understand and make decisions about the world.

My friend Hans Van Dongen, director of the Sleep and Performance Research Center and a professor of medicine at Washington State University, said you might think about neurons as workers in a huge company. Each neuron is an expert in a piece of information, and neurons work together to share what they know and build new connections in the brain.

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Dr. Universe: Why do we have toenails and fingernails? – Chloe, 12, Texas

Dear Chloe, Maybe you like to paint your toenails beautiful colors or admire the dirt under your fingernails when you come in from playing outside. But you’re right to notice that nails must be more than just decoration. To learn more, I talked to my friend Edward Johnson, an assistant professor of anatomy and physiology at Washington State University. Johnson reminded me that humans are primates, just like gorillas or orangutans. If you look closely at a primate’s hand or foot, you’ll see their nails look a lot like yours. They’re wide and flat at the ends of their fingers and toes. Read More ...