[SciShow intro plays]

Jessi: Hey there everyone! Remember me? If you do remember me, that’s because you’re using one of the most awesome and powerful parts of your body. Your brain!

Your brain is also the reason that you can can see me —and hear me — and understand what I’m saying! Clearly, the brain isn’t just powerful; it’s powerfully important! So let’s learn some more about it.

A grown-up’s brain is about 16 centimeters long -- as long as a dollar bill -- and it weighs a little under one and a half kilograms, about as much as a bag of apples. Now, if you’re a kid, your brain is still growing— so it’s a little smaller. Kids’ brains are about the size of a grapefruit, and weigh a little less than a kilogram. That’s about as heavy as a liter of water.

But what does your brain look like? Well, have you ever stayed in the tub or pool too long, and your toes and fingers got all wrinkly? Well, the brain looks wrinkly, too. Scientists think that these wrinkles help the brain work properly. The brain is also grayish-white in color, and is pretty soft and squishy, kind of like gelatin. And because the brain is so soft, it has to be kept safe. And it is... inside your skull! Your head has bones, too, after all. They’re pretty thick and very hard, and together, these bones make your skull.

Now, your brain is the main part of your body’s nervous system. The biggest job of your nervous system is to help all of the different parts of your body work together by carrying messages back and forth. And the brain is like the command center... or HEADquarters... of your nervous system. It’s in charge of getting messages from the rest of your body, deciding what to do with those messages, and then telling your body to take action!

For example, if your nose starts to feel itchy, it sends a message to the brain that says, “Hey, your nose is itchy!” And your brain sends a message to the muscles in your arm and hand saying, “scratch your nose!” These messages that move between the brain and the body move very, very quickly, faster than the fastest computer we can make!

In fact, most of the messages move so fast that we don’t even realize they’re happening. And the best part is, your brain never takes a break. It never sleeps... even when you do! While you’re asleep, your brain makes sure that your heart keeps beating and your lungs keep breathing. It tells your eyes to blink and makes you jump when you hear a loud noise that you weren’t expecting.

You don’t even have to think about any of this! Your brain takes care of all of that important stuff without you even knowing about it! Your brain plays also a big role in your senses: seeing, hearing, smelling, tasting, and touching. For example, when you hear something, your ears send a message to your brain, which recognizes the sound as a squeak... a squeak made by a certain robot rat! And remember when I said the brain helps you remember? It does! Just like my brain helped me recognize the sound that Squeaks makes, your brain helps you remember all kinds of things!

Real quick, close your eyes for a second and think of your favorite food. Okay, now open them! Did you remember it? You were able to think of your favorite food just now, because your brain is the part of your body that remembers. When I asked you to think of what food you liked best, your brain was able to come up with the name of it, and also probably what it looks like, and even how it smells and tastes. You remembered all of those things, thanks to your brain!

And one of the brain’s most important jobs is to learn... like I hope you’re doing right now. You’ve already learned a lot of things since you were born, like how to talk, and how to recognize shapes and colors. But you have a lot more to learn as you get older, and your brain will be there every step of the way!

With all of the jobs it has, it’s important to take good care of your brain. You can help to protect your brain by wearing a helmet when you ride a bike or do other sports. You can also take good care of your brain by eating healthy foods... getting enough sleep... and getting lots of exercise. Oh, and using your brains to think and to learn is one of the best things you can do to keep your brain healthy! So I’ll see you again so to learn something new, and to use our brains!

Thanks for joining me on SciShow Kids. We’re so happy that you dropped by, and we’re very excited to see you next time because Squeaks and I are making some changes around the fort. So keep watching to see what’s new on SciShow Kids!

Do you have a question about the way your body works... or anything else? If you do, ask a grownup to help you write an email to Kids@theSciShow.com, or to leave us a comment down below! See you next time!