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  • Hi, welcome back to the fort!

  • Did you know that the fort is a special secret underground hideout?

  • It's a cave!

  • A cave is just an underground space that's big enough for a person to get into.

  • ...or a robot like Squeaks!

  • Caves can be really small, narrow passages, or they can be a lot bigger -- like our fort

  • -- with a whole network of tunnels that connect different rooms, or chambers --

  • Some caves can be found on the sides of cliffs. Others are in forests. And some are even underwater.

  • But all of those kinds of caves have one major thing in common: They're made of rock.

  • Today, we're going to talk about a different kind of super-coolor should I say super cold?—cave:

  • ice caves!

  • Ice caves are a lot like other cavesthey're often underground and they're large enough

  • for people to get into.

  • But instead of rock, they're made of ice! There are two kinds of caves that are made

  • of ice. The first kind is called a glacier cave.

  • Glacier caves are made completely of ice. They form in glaciers, which are huge

  • chunks of ice that move like slow, frozen rivers.

  • The most common way for a glacier cave to form is when melted water runs through, or

  • under, the glacier. Because the water is warmer than the

  • ice that it's running over, it slowly melts the ice around it it, creating a tunnel, which

  • eventually forms a cave. The second kind of cave made from ice is

  • ice cave. To be called a true ice cave, a cave doesn't

  • need to be made completely of ice, like glacier caves are.

  • But it does have to have ice in it year 'round, and at least part of the cave has

  • to have a temperature below 0 degrees Celsius. Or 32 degrees Fahrenheit.

  • Ohh! Brrrrr!

  • Unlike glacier caves, Ice caves can form just about anywhere.

  • They form when cold air enters a space where it can't escape. These spaces then trap

  • the cold air inside, so any water that trickles in, quickly freezes and stays frozen, no matter

  • what time of year it is. Ice caves can be pretty smallsmall enough

  • to fit just one person...or they can be really big.

  • The world's largest ice cave is in Austria, Eisriesenwelt.

  • Which is German for "World of the Ice Giants.”

  • The cave is almost 50 kilometers long, and parts of it are open to visitors.

  • So, if you're ever lucky enough to go inside, you'll be able to see all kinds of amazing

  • ice formations!

  • And even though ice caves like this one may look like they're empty, there are living

  • creatures that make their home in ice caves and glacier caves.

  • But there aren't many, because very few living things can survive their freezing temperatures.

  • And in case you're wondering, you may not find anyice giantsliving in ice

  • caves. But I can tell you that

  • things that live in these spaces are oftenreally tiny!

  • As tiny as … a water bear! Also known as a tardigrade.

  • Tardigrades are super-small animals known as micro-animals that you can only see under

  • a microscope!

  • Tardigrades can survive in really harsh environments that other animals couldn't, like at the

  • very bottom of the ocean, and, you guessed itin glacier caves and ice caves!

  • So if you ever find yourself in an ice cave, you might feel like you're completely alone in

  • the quiet, cold space. But you're actually, probably surrounded by lots of tiny little

  • animals.

  • Oh Man! Looking at all these pictures of ice caves has made me chilly.

  • I'm glad our fort is a nice, warm, regular rock cave!

  • Thanks for learning about these cool caves with us!

  • And remember, if you have a question about anything you'd like to learn more about,

  • just let us know by getting help from a grown up, and leaving a comment below. Or send

  • us an email at

  • And we'll see you next time!

Hi, welcome back to the fort!

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B1 US cave glacier fort underground cold air form

Explore an Ice Cave! | Geology for Kids

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    joey joey posted on 2021/05/11
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