(Intro)

Hey everybody!  It's really cold and snowy out tonight where we live, so Squeaks and I decided to get nice and cozy and watch some videos about winter, and you can watch along with us.  Grab a blanket and some hot cocoa and snuggle in as we learn why there's a winter season in the first place.

Spring is here!  Now, instead of building snow forts and licking icicles, we can skateboard and ride our bikes and we don't have to worry about Squeaks getting rusty in the snow.  Speaking of seasons, you know we have four of them: spring, summer, autumn, and winter, but do you know why we have more than one season?

Well, we have seasons because the Earth is tilted.  Instead of standing straight up and down, it leans a little bit.  Whoa.  How'd that happen.  A really, really long time ago, billions of years ago, scientists think something big hit the Earth.  The impact was so strong that it knocked our planet over a little bit so now Earth is tilted, and our tilted planet travels around the Sun, completing one full trip all the way around every year.  I mean, that's what a year is: the time it takes for the Earth to go around the Sun once, and depending on where the Earth is in its journey around the Sun, our exposure to sunlight changes.  That means the seasons change.  That's why we have four seasons in one year.

Sometimes during the year, part of the Earth tilts toward the sun.  Sometimes it tilts away from the Sun.  When the part of the planet you're on is tilted toward the Sun, it's, you guessed it, summer.  When it's tilted away from the Sun, it's, yep, winter, and when it's in between, well, the weather's pretty much in between too.  That's when we have spring and autumn.  They're both a little bit warm and a little bit cool and often windy.  But if the season also depends on where on Earth you happen to live, that means that not everyone experiences the same season at the same time.

It can be summer in some parts of the world when it's winter in others, because those different parts of the planet are getting different amounts of sunlight.  When the Northern hemisphere is tilted toward the Sun in the summertime, the Southern hemisphere is tilted away, so it's wintertime there, so the tiltyness of our planet explains a lot.

It's why we have seasons and why it's not always winter or always summer all of the time, and it also helps us understand why different parts of the world can experience different seasons at the same time.

Okay, I remember now.  It's cold and snowy out right now because the part of the world that we live in is tilted away from the Sun.  Ohh, where do snowflakes come from?  Good question, Squeaks, and I think I have the perfect video to answer it.

Who's up for a word game?  When I say science, what picture comes into your mind?  Is it stuff like test tubes and telescopes?  Maybe it's computers or microscopes?  Or living things like flowers or frogs?  But did you think of anything that looks like art?  A lot of science is really beautiful and there might be no better way to study the beauty of nature than by looking at snowflakes.  Have you ever taken a close look a snowflakes in the winter when they land on your coat or mitten just before it melts?  

Each snowflake is a six-pointed work of art, as cool and as individual as the ones you've probably made with paper and scissors, but how does nature make snowflakes?  First thing to know is the little six-pointed pieces of ice that you and I call snowflakes are really made up of snow crystals.  Scientists use the word snowflake to describe the fluffy white things that fall from the sky which are actually bunches of snow crystals all stuck together and the journey of a snow crystal begins in a cloud.

Up there, water in the form of gas called water vapor, freezes around a piece of dust or pollen that's just floating around in the cloud.  This forms what's called a seed crystal and seed crystals can become snow crystals if conditions inside the cloud are just right.  As the seed crystal bumps around inside the cloud, lots of particles that make up water stick to it.  The particles that make up water have a very specific shape.  They kind of look like the letter 'V', and when enough of these particles stick together, they form shapes that have six sides called hexagons, and that's your most basic kind of snow crystal.  But if there's enough water around, then more water particles will attach at the little points of that  six-sided crystal, each becoming an arm or a branch.  From there, all kinds of different things can happen.  

Even though all snowflakes have six sides, they can end up looking totally different from one another.  In fact, scientists have names for more than 30 different shapes of snow crystals.  Some are big and flat and are called plates.  Others look long and narrow, called needles.  Still others are tall and wide, like columns, and then there's probably the most famous shape, called dendrites.  They look kind of like stars that have sprouted tree branches.  The shape that each snow crystal takes depends on what the conditions were like as it formed in the cloud.  Things like temperature and how much water is in the air can make a big difference if you're a snowflake.  So for example, colder temperatures often make flakes with more pointy and fancy arms while snow crystals that are made in warmer temperatures and air with less water in it tend to be smaller and simpler.  

Now, you might have heard that no two snowflakes are alike.  A lot of them do look really similar to each other, but scientists think that it would be really hard for any two to end up being exactly the same.  That's because the conditions of the clouds are always changing, so the flakes that they make are always changing, too.  Once a snowflake takes shape, its journey has only just begun.

After bouncing around in the cloud for a while, it falls to the ground, and as it falls, it keeps changing, depending on the temperature, the amount of water in the air, and other things, like wind that it passes though.  Since each flake takes a different path all the way to the ground, each one ends up being slightly different and that's why scientists say that no two snowflakes are exactly the same, but they're all really interesting and beautiful.

Hey, Squeaks, all that snow that's coming down outside means that there will be lots of fresh snow for us to play in tomorrow morning.  We love sledding and snowball fights, but our favorite thing to do in the snow is build a snowman.  

Hi guys!  We're all bundled up for some winter fun.  Squeaks wants to build a snowman.  Oh, I mean, my bad, a Snow Rat.  Whether it's a snowperson or a snow rat, building a snowbeing is all about balance. 

Can you guess what kind of scientist has to spend a lot of time thinking about how things balance?  That's right--engineers.  There are all kinds of engineers, but I'm thinking about building engineers.  They build tall buildings like houses and even skyscrapers.  So when we're planning on building a snowman, we need to think like engineers.

Squeaks and I like to build with three different sized snowballs: a big one, a small one, and a medium one that's smaller than the big one but bigger than the small one.  To make the snowballs, I first pack a bunch of snow in my hands to make a ball.  Then, once the ball is almost too big to hold, I put it on the ground and roll it.  The ball will pick up snow and get bigger and bigger.  Then, I do this twice more, so I end up with three snowballs to build my snowman.  Let's try a few different ways to stack our snowballs and see what works and what doesn't work.

First, just for fun, let's try putting the smallest ball on the bottom and the medium ball in the middle and the biggest ball on top.  Oh man!  The two balls on top toppled over.  That's because the bigger balls don't have enough room underneath them to sit on.  With the smaller balls at the bottom, they have to be very carefully balanced to stay upright, and if there's just a little too much weight on one side or the other, you've got a snowman down.  That's why snowmen aren't very good at headstands.  Now, what if we put the medium ball on the bottom, then the smallest ball, and the biggest ball on top?  Agh, the big one falls off right away, but the smaller ball stays where it is.  That's because the little ball has a lot of room to rest on.  It's totally supported by the medium ball, so there's nowhere for it to fall, but the biggest ball doesn't have nearly enough room underneath it to sit on.  But how about this?  What if we put the biggest ball on the bottom, the medium sized ball in the middle, and the smallest ball on top?  Finally, we have a snowman that can actually stand up.  Now we're really thinking like engineers.  Engineers have to make sure that buildings are supported at the bottom just like our snowman so they don't topple over.  The biggest snowball goes on the bottom to support the medium ball in the middle and the smallest ball rests on the top.  

Now we just need a carrot for a nose, some sticks for arms, some rat ears made out of snow, a tail made out of rope, and cute button eyes.  Hey, it looks a lot like you, Squeaks!  

I've been wondering, you and I have to get all bundled up before we go out to play in the cold, but there are lots of animals that have to live outside all the time, even during the winter.  Animals don't have coats and scarves, so how do they keep warm?   Let's find out.

One of the best parts of winter is curling up with a blanket and a cup of hot cocoa, watching the snow fall outside while you stay nice and warm, but what do animals do when it gets cold?  They don't have blankets, hot cocoa, or heated houses like we do?  Well, different animals have different ways of dealing with the winter weather.  Some animals migrate, or move to a warmer place for the winter, and some of them hibernate, or hang out in their cozy dens underground.  They don't come out until it's warm again.  But other animals don't migrate or hibernate, and they manage to live in places with really cold winters, but how do they do it?  

Well, they've come up with a pretty cool way to fit in with their snowy environment.  I'll give you a hint: it involves a winter coat.  Not a jacket with buttons or a zipper like you or I might wear.  Instead they have fur and feathers that cover their bodies when it gets cold.  When the days get shorter, these animals shed their brown or grey colors and grow white fur or feathers to help them make it through the winter.  Let's meet some of these color-changing animals and find out how their special coverings help them survive the chilly season.

First up is the arctic fox.  The arctic fox gets its name from where it lives, in the Arctic.  The Arctic is located at the most Northern part of the world around the North Pole.  Arctic foxes live on the land and sea ice where they hunt birds and other small animals, but they don't always look the same from season to season.  When the days get shorter and colder, their coats get thicker and whiter.  This is what an arctic fox looks like in the spring, and this is what it looks like in the winter with its winter coat.  The most important thing about the fox's winter coat is that it keeps the animal warm with its extra thick fur coat and bushy tail to wrap around its body, the arctic fox is better at holding on to its body heat than nearly any other arctic animal.  

But their fur does more than just give them warmth.  Their white coat also camouflages them or helps them blend in with their surroundings.  Blending in with the snow lets the foxes sneak up on their prey, like arctic hares and small birds and it also helps them hide from bigger animals that might wanna sneak up on them, but when the seasons change, so do their coats.  In the summer, arctic foxes shed their white coats and grow new ones that are brown or grey to blend in with their surroundings after the snow is gone.  

Now, things can get tricky for the arctic fox because one of the animals that it likes to eat, the arctic hare, uses some of the same tricks to survive the winter.  Arctic hares also live, you guessed it, in the Arctic, mostly in forests, and like the foxes, they have thick white coats of fur to keep them warm, plus pads of thick hair on the bottoms of their feet.  Now, some arctic hares live further south where there's less snow, so they actually grow darker coats that help them blend in in those environments where there are more rocks and plants than there is snow.  No matter where they live, though, arctic hares like to keep their fur clean, so they groom themselves like cats do by licking their fur.  The cleaner their fur is, the warmer it keeps them.

Our last animal with a winter coat doesn't have fur at all.  It's a bird called a ptarmigan.  The ptarmigan lives in the Arctic too and can often be found hiding in bushes or behind rocks to avoid predators.  They have feathers that change from brown in the summer to white in the winter to help camouflage them from bigger animals.  Their soft fluffy feathers are pressed close to their skin, trapping in their body heat and keeping the birds toasty warm in the snow.  They also have extra feathers on their legs and feet to help keep them warm and ptarmigans have other ways of staying warm in the winter, too.  Sometimes, they'll fly straight into a pocket of powdery snow.

This makes a burrow or tunnel in the snow that they can snuggle up in, kind of like the fort.  Whether it's an extra thick coat to help keep them warm, or white fur and feathers to keep them out of sight, when it comes to living in winter, these Arctic animals have it covered.

So animals have their own natural ways of keeping warm and finding food in the winter, but there are ways that you can help the animals in your neighborhood, too.  We invited our pal Dino over to show us how.

I love watching out for animals.  All year long, I look for squirrels, deer, foxes, and any other critters that I can find.  In the winter, animals can be a little bit harder to see, but there's one animal you'll probably be able to spot even in your backyard: birds, and you know what?  I think I see one now.  Hey, Dino.

D: Hi, Jessi.

J: We were just talking about how birds spend the winter.  Some of them fly off to warmer places during the coldest part of the year, but many birds stay put, and for those birds, winter can be a tough time.  They have to find food, even though the food that they like, like insects and berries, might be covered in snow.  

D: That's right, but people can make winter a little bit better for birds.

J: That's a good point.  There are all kinds of things people can do for birds to help them in the wintertime.  We can put out birdseed or raw nuts in bird feeders for them to eat and we can put fresh water in birdbaths so they have something to drink.

D: That would be great.  I love it when people leave me snacks.

J: And there's something else you can do, too.  Do you know what season comes after winter, Dino?

D: Spring.

J: That's right, and do you know what spring brings?  

D: I do.  Baby birds.  Chicks.

J: Yes!  In the winter, birds have to get ready for their chicks to hatch and their first order of business is to make a place to lay their eggs.

D: A nest.

J: Yeah.  Some birds start building their nests in the winter so they're ready to lay their eggs in the spring.  Dino, how do birds build their nests?

D: Well, different birds can build their nests using different kinds of things that they find around them.  Around here, many birds use things like twigs, leaves, and grass, and for a lot of the year, those things are pretty easy to find.

But in the winter, the leaves have fallen and twigs and grass can be covered with snow.  

J: But that's where we can help.  You can pull out leaves, sticks, pine needles, and other stuff from under the snow to make them easier for birds to find and gather up, and if you happen to find something cool like a spiderweb or even a snakeskin, leave it where you found it.  A nesting bird might pick these things up and weave it into their nest.

D: Snakeskin and spiderwebs?  Sounds like home sweet home to me.  

J: Well, we can put out other stuff for the birds, too.  Do you have things at home that are similar to twigs and grass?  What about a piece of string or a strip of paper?  Thread, yarn, even pet hair can make good nest materials, so you can put those things outside for birds, too.  Just lay a few pieces of string on the ground or in a tree branch and then see how long before it disappears.  If you're quiet and patient, you just might get to watch a bird pick it up.  If you do, pay close attention to where the bird takes it.  It may be building a nest in your neighborhood.

D: That would be great.  You'd get to do some serious bird watching and in the spring, you might even get to see some baby birds.  So cute!

J: So this winter, think of the birds.  They're busy.  They've got to find food and water and build their nests.  So if we put out a little food, water, and nesting materials for them, we not only give them a helping hand--

D: Or wing!

J: --we also get the fun of watching animals, and you know that watching animals is one of my favorite things.

D: What can I say?  We birds are pretty interesting to watch, and some of us are downright handsome.

J: I don't think this snowstorm is gonna let up anytime soon, so Squeaks and I are gonna grab some more blankets and a couple of books and settle in.  If you have any questions about snowy weather, amazing winter animals, or anything else, let us know.  Grab a grownup to help you leave a comment down below or email us at kids@scishow.com.  Thanks, and we'll see you next time.

(Outro)