I know it was your favorite.

Squeaks was in the yard playing with his favorite soccer ball, and he kicked it into a rock, and it popped!

Oh, no, I don't think we're gonna be able to fix it.

We could patch it, but the air would still leak out.

If you want, we could buy a new one.

I know; you're right.

A new one won't be the same because this one will still be popped.

It's okay to be sad about it.

Everybody gets sad sometimes, and crying is a natural thing that can happen when you're sad.

It's actually a really important thing that our bodies do.

Scientists aren't completely sure why we cry when we're sad, but they do have some guesses.

One of the main reasons has to do with what crying tells other people.

When I see you crying, Squeaks, I know that you're sad right away.

You don't even have to tell me with words⏤although, it does help if you do.

The more I know about how you're feeling, and the more you know about how I'm feeling, the better we can live together.

If you're really sad or angry or having other strong feelings and I don't know about it,

then I might do something insensitive without realizing it and make things worse.

For example, now would not be a good time to bring out my favorite ball and go play with it in the yard.

It wouldn't be a very nice thing, since yours just popped.

But if I didn't know you were sad, I might not realize it would be hurtful.

Knowing that you're sad also means I can try and find ways to help, even if that's just by staying with you until you feel better.

And remember the other day when I felt sad about the end of the book I was reading?

You gave me a hug and it made me feel so much better.

I'm so glad that we can show or tell what we're feeling so we can try and help each other.

And that's really important outside the Fort, too.

The whole world is a much better place when you can help people who are sad or having a hard time.

Besides helping us share our feelings, scientists also think we cry when we're sad because of what's in our tears.

If you taste your tears, you can tell that they're pretty salty, and that's because they have salt in them.

And one of the other ingredients in tears is a painkiller, something that makes pain go away.

It's kind of like the medicine your doctor might give you when you're sick, except this is something that your body makes by itself.

So, when you cry because you're sad, your tears have something in them that can make you hurt less, even if it's just your heart that hurts.

And then, hopefully, when you're done crying, you start to feel a little better.

Do you think you're starting to feel better?

Oh, I'm so glad!

And just like you're already starting to feel better now, over time, you'll start to feel even less sad.

It's all part of understanding our feelings and the different ways we show them, including by crying.

Thanks to everyone who asked about why we cry when we're sad.

If you have other questions about feelings or the way our bodies work or anything at all,

you can ask a grown-up to help you leave a comment below or send us an email to kids@scishow.com.

Thanks, and we'll see you next time, here at the Fort.