- Hey, cool cats.

I'm Dr. Universe.

Along with our friends at Washington State University, we'll explore the world of science, technology, engineering, and math.

In each episode, we'll talk with a scientists and discover how they became interested in their fields, and, of course, investigate a few science questions along the way.

(Music Plays) - Our first guest is my friend, Katie Cooper, associate professor from the School of the Environment.

Thank you, Dr. Cooper for joining us today.

- Thanks for inviting me.

I'm always excited to chat with you, Dr. Universe, as well as answer questions from curious minds.

- There are lots of different kinds of scientists in our world.

What kind of science do you do?

- I'm a geophysicist, which is a combination of the fields of geology and physics.

- So what exactly is it that you do as a geophysicist?

What kinds of things do you study?

- I use physics to study the formation and evolution of land on earth and other planets.

And for my research, I set up experimental worlds, using computers to see how and when large land features form and change over the planet's history.

I also study plate tectonics, which is the theory that explains how the surface of the earth slowly moves in large tectonic plates that interact with each other.

- That's really awesome.

So what is it that inspired you to explore geology?

When did you know that you wanted to make it a career?

- So I knew I wanted to be a geologist since about sixth grade.

I love thinking about big questions.

I grew up in west Texas and my family took a lot of day trips around the area.

And both my parents are very curious people and my dad would look out of the car and sometimes wonder out loud how some feature was formed and that really got me hooked on those big questions.

We would also go to viewing parties at a local observatory, and I found myself wondering the same kinds of questions about the planets we were looking at in the telescopes.

So geology was the field that I found that could allow me to couple those passions of mine and explore those big questions.

- Thanks so much for telling us about that.

Here on ask Dr. Universe, we like to investigate all kinds of questions from curious kids.

Would you be able to help us answer a few?

- Yeah, I'm ready and excited.

- All right, here's the first question from Sylvia, age nine in Spokane, Washington.

Let's listen.

Why are rocks gray?

You know, I've observed that rocks are gray a lot of the time and they come in lots of different colors.

Why exactly are some of them gray?

- So the color of rocks help geologists Understand what materials make up the rock as well as what happened to the rock during it's life.

Rocks have histories and stories to tell, starting from when they were formed up until today when we see them.

So rocks are made up of materials that are specific combinations of elements.

These combinations of elements are called minerals, but what minerals and elements get combined together, it depends on the conditions at that time.

Sometimes the color of the mineral can tell us about which elements are in the rock, as well as how the rock was formed.

So I noticed that Sylvia lives in Spokane.

So I'm guessing that Sylvia's rocks that are gray are basalt because basalt is a rock type that's commonly found in the Spokane area.

Basalt is made up of minerals that contain a lot of iron and that's what's contributing to that dark gray color.

Basalt is formed when certain rocks inside the earth melt and then are erupted at the surface.

So when you see a bunch of basalts around Spokane, that's telling you at one point in time, that was all lava.

Rocks can be other colors too, like Dr. Universe pointed out depending on their minerals.

So I've got a couple to share.

I've got a pink rock here.

This is granite.

And then a green rock here, which is pyrrhotite.

And those are two of my favorite colors, green and pink.

But these two rocks were formed in very different ways from each other, as well as different ways than basalt.

And we know that in part, because of their minerals.

So rocks can also change colors after the formation, depending on what happens to them.

So for example, pieces of basalt sometimes can look red on the surface and this red color happens when the iron and the basalt is exposed to the oxygen in that atmosphere.

So that part of the basalt essentially rusted.

But if you broke open that piece of basalt with the rusty surface, you'll see that it's still gray on the inside because that part of the rock wasn't exposed to the atmosphere.

So when you're looking at the color of rocks, you're really looking into that rocks life.

- That's amazing.

Thank you so much for telling us about all the different kinds of colors that rocks can be.

So you and I live in the Pacific Northwest where we have lots of different volcanoes and sometimes even experience earthquakes.

Our co-host Erin will be asking this next question for Fatima, age nine in Nigeria.

The question is, how do volcanoes form?

Yeah, how do volcanoes form?

- Volcanoes form when molten rock within the earth forces its way to the surface, sometimes in very dramatic eruptions.

So really the next question is why are there molten rocks below the earth surface?

If you looked at a map of recently active volcanoes, then you'll notice that volcanoes aren't everywhere on the earth.

Instead, there's a pattern to where those volcanoes are located.

That's a clue.

That also means that there's also a pattern to where there's molten rock below the surface.

Now I'm going to tell you, most of the Earth's interior is solid with the exception of the liquid metal outer core.

The Earth's crust and mantle, which are the two layers above the core, are mostly solid, even though the inside of the earth is really hot.

And this is because instead of there also has a lot of pressure in it because of all the rocks above.

So that pressure is keeping the rocks in the crust and the mantle from melting.

So on the whole, the conditions inside the earth, aren't really suitable for melting the rocks in the crust and the mantle, but we have volcanoes.

So that means that sometimes the rocks inside of the earth do melt, meaning that in the places that we have volcanoes, the conditions inside the earth have changed in a way that allows for melting to happen.

That could change can happen from like having extra heat in that region, decreasing the pressure in that region or moving material closer to the surface of the earth or changing the melting point of rocks by adding in other materials.

So what's causing those changes?

And if you're thinking that that connects back to that clue I gave you about the pattern of volcanoes that we see on the earth, then you're right.

That pattern of volcanoes is outlining the edges of tectonic plates.

The earth surface is made up of several tectonic plates that are slowly moving and interacting with each other.

As they're moving around, and then sometimes even entering inside of the earth, they're changing the conditions in those areas.

Depending on the plate boundary, melting of the surrounding rocks sometimes happens, which may then eventually lead to volcano.

Now there's a few volcanoes like Hawaii, or if you want to think about the Canaries, these are happening far away from plate boundaries.

These volcanoes happen because of blooms of hot rock, but not molten rock, are rising up from the core metal boundary up towards the surface.

As that plume gets closer to the surface, it's at lower and lower pressures.

and so melting starts happening.

That molten rock then forces its way to the surface eventually to be erupted in a volcano.

So in summary, volcanoes form when changes lead to conditions inside the earth that are appropriate for melting rocks.

And that's why volcanoes happen along plate boundaries or associated with mantle plumes.

- Got it.

So volcanoes form around the edges of tectonic plates and earthquakes happen when there is sudden movement along the faults within the earth, right?

- That's correct.

Plate boundaries are usually where we find most of the volcanoes and earthquakes on earth.

- Great, well, these sudden movements can cause damage to buildings here on earth's surface, but that's not the only thing that happens after an earthquake.

That leads us right into our next question from Ali, age 10 in Pullman, Washington.

What are the after effects of an earthquake?

What are some things that happen after an earthquake?

- So earthquakes happen because of sudden movement along existing faults.

My friends at the USGS cleverly compare this to what happens when you snap your finger.

To start a snap, you start applying pressure between your two fingers by squeezing down and applying force a bit sideways.

The snap doesn't happen until you apply enough pressure to overcome the friction between your fingers.

Once that happens, then you've released enough energy or you've released that energy that you've been applying in that sudden snap.

(snapping) We call that behavior stick slip, and the snap, your fingers are sticking together because of friction and an earthquake, the rocks on either side of the fault are sticking together because of their friction.

The earthquake or snap (snapping) happens when enough stress or pressure builds up to overcome that friction, then you have a sudden release of energy.

That's the earthquake.

That sudden release of energy travels in waves that moves through the earth, making their way to the surface and then causing the shaking that we might feel during an earthquake.

Depending on the type, location, and magnitude, they're different after effects that can happen of an earthquake.

So for example, if you have a small magnitude earthquake that happens deep inside the earth, there may not be that many after effects other than seismometers picking up those seismic waves.

That's because it's smaller magnitude and it's happening deeper in the surface, which means a longer distance for those waves to travel.

On the other hand, large magnitude earthquakes that have been closer to the surface and in populated regions can have many devastating and compounding after effects, including the heartbreaking loss of life and widespread damage.

Another contributing factor to the aftereffects of an earthquake is the quality of engineering of the buildings and structures in the area, and whether they were designed and built to withstand ground shaking.

It also depends on the type of soils that the structures are built on.

Some soils experience what's called liquefaction, which causes the ground to act like a liquid during the earthquake because of the ground shaking.

Now, if earthquake happens under water or near the coast, and there's a potential to generate tsunamis, which also pose significant hazards with the potential for devastating after effects like flooding.

We can't stop earthquakes and we can't predict when earthquakes will happen, but we can't identify hazards, hazardous regions, build safer buildings, use early detection warning systems, which will give us seconds of preparation time, and then also know what to do during and after an earthquake.

So do you know what to do if you're in an earthquake?

It's drop, cover, and hold on.

Drop, meaning get low to the ground.

This will help keep you from falling.

Cover your head with your arms, and then hold on.

If you can safely and quickly get to a sturdy piece of furniture, then get underneath that and then hold onto a leg during the earthquake.

If you use a wheelchair, lock your chair, cover your head and hold on.

If you're outside and if you can quickly and safely move to a clear area, do so, then drop, cover, and hold on.

Don't be afraid to practice it, just like I did.

Also talk to your family about your safety and emergency preparation plans.

- Thank you so much, Katie, for helping us answer that question and for the great advice about what to do if there's an earthquake.

We also want to thank Sylvia, Fatima and Ali for submitting those great questions.

Before you go, I have a couple more questions about you if you don't mind?

- Absolutely.

- All right.

So what kinds of jobs might someone who is interested in geology or earth sciences think about for the future?

- There's so many jobs for geologists earth scientist.

You could study volcanoes, earthquakes, rock compositions that would then help you answer questions like we had today.

Or you can help find national resources.

You could work on making safer and cleaner environments.

You could study climate change and its impacts.

You could study other planets and their surface features like me.

You could study past life like dinosaurs.

Geologists also assess natural hazard risks associated with earthquakes and volcanoes, as well as flooding and landslides.

And as part of that, they often worked for cities and states and countries.

Some geologists also work and study at national parks and museums.

Really geologists and earth scientists are needed to anytime you want to better understand the world that we live in, as well as the other worlds that we might want to explore.

- It sounds like the possibilities are endless.

Okay, this final question is up to you.

What is one really cool geological discovery that humans have made recently or what is something our viewers can do if they want to be a geophysicist one day?

- I'm gonna go with cool discovery.

So sometimes we like to describe the earth inside as looking like a peanut M&M cut in half with the candy shell being the crest, the chocolate layer being the mantle and the peanut in the middle as the core.

Now we probably need some sort of liquid peanut butter or something to be the outer core, but that's okay.

Now it's true that we have three main nested layers in the earth, but the chocolate region of the earth where the mantle is we like to call it, is way more interesting than a single layer.

There's even these strange blobs of material that are on the boundary between the core and the mantle and these blobs are fascinating.

So some geologists, geoscientist think that these blobs might be leftover from when the planet was forming.

And some of them even think that they may be part of the planetesimal that slammed into the earth, that then formed the moon, and then these pieces made their way to the bottom of the mantle to be stayed there until now.

- Great, well, thanks for sharing that amazing discovery.

It's always exciting to hear what scientists are finding out about our world and our universe.

Thank you, Dr. Cooper for coming on the show.

Thanks for telling us about your work and helping us investigate some big science questions.

- Thanks for having me and thank you for the questions.

- Thanks again to Dr. Cooper and all the young scientists who submitted questions.

If you have a science question of your own and would like a chance to see yourself on a future episode, go to askdruniverse.wsu.edu.

See you next time, cool cats.