Oh, there you are.
How was your hike with Jesse?
Oh, you're tired.
I guess hiking up a mountain is a little harder when you don't have wings.
Oh, hi there.
Squeaks just got back from a hike.
We're really lucky that the fort is surrounded by mountains.
They're beautiful, but they sure are tall.
I was starting to think you weren't going to make it back either.
It's amazing to think that those giant things were formed from plates in the earth's crust, just pushing against each other.
Oh, come on, Squeaks.
Don't you remember learning about where mountains came from?
Hi, guys!
Squeaks and I are getting ready to go on a hike, and today we're going to explore something big and old and beautiful.
Do you know what I'm talking about?
I'm talking about a mountain.
We love climbing mountains, hiking through the mountains, and even just looking at them.
That's an interesting question, Squeaks.
How do mountains form?
Well, let's start with what mountains are made of.
Mountains are made of the same stuff that we're all standing on right now the hard rocky layer of the Earth's surface called the crust.
Sounds kind of tasty, and that makes it easy to remember.
The crust is the crispy, crunchy, rocky part of Earth.
The dirt, the rocks, and all of the land on the planet are parts of the crust, and it covers the whole Earth. even the land that's underwater.
So Earth's crust is kind of like bread crust.
It covers everything in the same way that bread crust covers the whole loaf.
But unlike bread crust, the Earth's crust isn't all in one piece.
It's broken up into pieces called plates.
Plates that cover Earth, like a giant jigsaw puzzle.
These plates are huge and heavy, but they don't just sit there.
In fact, they're always moving very slowly, just a tiny bit at a time, about a few centimeters a year.
But over long periods of time, all of that moving around can add up to some big changes.
Sometimes two of the plates in Earth's crust will move towards each other, and when they do, they start to press against one another.
But they have nowhere to go, so they'll just push and push against each other until they start to crumple.
Then, the rocks that make up the plates are pushed up and over each other.
The more they push together, the more the land rises.
And after a while, voila, you have a mountain.
And since the plates are so huge, when they push up against each other they don't just make one mountain, they could make a whole mountain range.
Mountain ranges like the Alps in Europe, the Andes in South America and the Appalachians in the United States were all made this way by two plates of the Earth's crust slowly crashing into each other.
But because the plates move so slowly, it takes a really, really long time for this to happen.
I'm talking millions and millions of years.
And you know what's even cooler?
Some mountains still growing.
Mount Everest, the highest mountain on Earth, grows about four millimeters every year.
And do you know why?
It's because the two plates that make up the land in that part of the world are still slowly smashing into each other.
That means that the mountain is just a teeny teeny bit taller this year than it was last year!
That's pretty amazing!
So the plates of Earth's crust are always in motion, which means that a long, long time ago, the mountains we see today weren't there at all.
The Earth will look different in the future, too, but it will take a really, really long time.
So the next time you're walking around on a beautiful mountain, you'll know where it came from.
Chances are it was made when pieces of the Earth's crust crashed into each other, and maybe they're still crashing.
Now you remember.
I can't believe you forgot all the fun you had making mountains.
Don't tell me you've forgotten when you and Jesse used towels to show how mountains form from different layers in Earth's crust.
Okay, it sounds like we need to do it all over again.
Let's show Squeaks how a simple experiment you can do at home explains how we ended up with all these giant mountains.
It is time to make more science!
Today, I would like to show you how to make little, tiny versions of some of the biggest things on Earth – mountains.
And you can make them right on your kitchen table!
Mountains can be made in lots of different ways, but the most common kind of mountain is made when pieces of the Earth's surface push up against each other.
This surface of our planet is called the crust, kind of like the crust of bread that goes around the outside of your sandwich.
But Earth's crust is broken up into lots of pieces, pieces called plates.
And even though it's hard to tell that it's happening, the plates of Earth's crust are always moving around very slowly.
Sometimes, two of these plates push into each other.
When that happens, those giant pieces of rock can start to bend and fold into curvy shapes.
And all that pushing makes part of the plates move up, to make mountains.
When mountains are made in this way, they're called fold mountains.
The Rocky Mountains in North America, the Himalayas in Asia and the Andes in South America are all examples of fold mountains.
Now that you know how plates of the Earth's crust come together to make fold mountains, let's make some mountains of our own.
All you'll need are a few towels.
We're going to use different color towels so we can really see the mountains forming.
And if you want some help, grab a friend, or a brother or sister, or a grown-up to lend a hand.
First, let's fold our towels in half.
Make sure that they're stacked on top of each other so they make layers, just like there are different layers inside the Earth's crust.
Now, since we're pretending that the towels are the Earth's crust, let's pretend that there's two plates slowly running into each other.
I'm going to use my two hands as plates, but if you need help, have a friend, get on one side of your stack and you go on the other.
Ready, set, push!
Look at that!
Pushing the ends together made the towels fold into miniature mountains.
Do you see how the different colored layers all bend and fold in the same places?
There are real fold mountains kind of like this all over the world, with the different layers of Earth's crust curving up and down together.
Now, what do you think would happen if we did this again?
Well, let's find out.
We'll smooth out our towels and give it another push.
Ooh, nice!
Do your mountains look different than the first time?
Just like with real fold mountains, your towel mountains might look different depending on how the layers that make them are pushed together.
What do you think would happen if you pushed the ends of the towels even closer together?
What if you barely pushed them at all?
Does it make a difference whether you push fast or slow?
Try it a bunch of different ways.
Make a plan, try to guess what will happen, and then do it.
And don't forget to have fun.
That really did look like so much fun.
I liked learning about the layers underneath the mountain too.
It reminds me of the magma that builds up under volcanoes.
Squeaks can be a little forgetful, but he does remember learning about volcanoes.
They're a special kind of mountain that has a secret brewing underneath.
And every once in a while, bang, they erupt and lava comes pouring out.
Yeah, Squeaks, I'm excited too.
Let's take a look back and see what we learned about volcanoes.
Oh hey Squeaks.
Did you know that while you were asleep last night, a volcano off the coast of Italy was wide awake?
The Stromboli volcano has been awake for at least the last 2,000 years.
That means it's been erupting for longer than any other volcano.
Stromboli's eruptions happen really often, practically non-stop.
At night, its glowing light shows have reminded some people of a giant lighthouse.
That's a really good question.
How does a volcano like Stromboli form in the first place?
Deep inside the Earth, and I'm talking way deeper than our fork goes, it's really hot.
It's so hot that the rock that makes up this layer of the Earth is actually melted.
It's called magma.
Now, sometimes magma can collect in a pocket just beneath the Earth's surface.
And if the magma breaks through all the way to the surface and reaches the air, it's called lava.
And now, my friends, you have a volcano on your hands!
Lava is bright red and very hot when it first erupts out of the ground.
But soon, the lava cools down and creates a layer of rock.
Over time, many layers build up around the spot where the lava came out, to form the mountain that many of us think of as a volcano.
And if the volcano keeps erupting, it keeps growing.
With each eruption of a volcano, more magma flows up the tube that forms in the middle, called the vent.
And it comes out the top, called the crater.
Then, once more, the lava cools and hardens into solid rock.
And the volcano has grown.
But not all volcanoes look and act the same.
Lava can come out of craters in different ways.
It depends on the type of volcano.
For some volcanoes, like Stromboli, lava shoots out like a fiery fountain.
When Stromboli erupts like this, big blocks of lava and stone can be thrown hundreds of meters away.
But for other volcanoes, lava just oozes out of the crater, more like a lazy syrup.
Over time, this slow-moving lava can create massive volcanoes, too.
One volcano like this, called Mauna Loa in Hawaii, is the tallest volcano in the world.
And in fact, all of the islands of Hawaii are made of volcanoes that began underwater.
They've been growing for millions of years and over time, all the layers of lava that have oozed out have built up until they reached above the surface of the ocean.
Our fiery old friend Stromboli in Italy formed this way too.
Its whole island is basically one big volcano.
So you don't have to have an underground fort to know that there's a lot of amazing stuff going on beneath the surface of the Earth.
There are incredible forces at work all the time, shaping the world that we live in.
That was pretty cool.
But I'm kind of glad the mountains around us aren't volcanoes.
I don't think I'd want to hang out on an active volcano either, Squeaks.
But at least we have the mountains.
Say, now that you've caught your breath, do you want to head back out for another hike with me?
Hmm, I think Squeaks might need a break.
If you love learning about things like mountains and volcanoes, be sure to subscribe to our channel.
Thanks for watching, and we'll see you next time here at the fort.
