CLOSE
Chloe Effron
Chloe Effron

Why Do I Have to Go to Sleep?

Chloe Effron
Chloe Effron

Kids ask a lot of questions. mental_floss has answers. Today we launch WHY?, our new series for kids and parents. We'll tackle all types of questions children have about how the world works by providing science-based, kid-friendly content. Our answers are written with early readers (ages 4–7) in mind, but we think they're interesting—and educational—for everyone.

Have a question? Send it to why@mentalfloss.com. 

Sleep is a must for all animals, including you. You must sleep to live. When we sleep it may seem like we’re not doing much. But this is when our bodies are busy growing, healing, and learning—especially our brains. They make sense of the lessons, games, words, feelings, and thoughts we had during the day. 

We have something inside our bodies called a circadian (sir-CAY-dee-an) clock that tells our bodies when it’s time to sleep. It’s not a real clock! The circadian clock is a system controlled by neurons, or brain cells, behind your eyes that react to light. This clock tells us to be awake during the day and to go to sleep at night.

Because the human brain evolved before we created electric lights. You’re not reading this on the computer or phone in bed, right? Because that’s a bad idea. The light from the computer tricks your circadian clock into acting like it’s daytime, so you’re not as sleepy. When you stay up late and lose sleep, your brain and body don’t work as well the next day. It’s harder to learn new things, remember old things, and not be cranky. 

For fun further reading, check out MadScieNet's answer to the question, "Do worms sleep?"

nextArticle.image_alt|e
iStock/Chloe Effron
Why Do I Get Cavities?
iStock/Chloe Effron
iStock/Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Your mouth is a busy place. There are hundreds of different kinds of bacteria living on your teeth, tongue and gums. Bacteria, as you may know, are tiny little critters that can only be seen with a microscope. We need some of them to help keep us healthy. Others are more of a pain—especially when they cause cavities (CAA-vih-teez), or little holes in our teeth. If you get a cavity, a dentist will have to treat it. You may get a filling.

During the day, you put all kinds of food into your mouth. When you eat, the bacteria that live in there eat, too. Some bacteria make acid out of the sugar in food. So when you eat sweet stuff—candy, cookies, and sugary drinks—you are helping bacteria to make more acid. The acid eats through the enamel, or the hard coating on your teeth. Over time, this can cause cavities and infections. Ouch! Luckily your spit, or saliva (suh-LIE-vuh), has minerals in it, like calcium and phosphate, that fight back by making your tooth enamel stronger and cutting down on acid. The fluoride in toothpaste helps do this, too. If you have a cavity, a dentist can fill the hole to keep bacteria from getting in and causing a bad infection. Unfortunately, there’s another reason for cavities that you don’t control: genes (jeenz).

Genes are little codes inside our cells that get passed down from our parents. They are instructions to our bodies that affect how we look, act, and grow. Genes may play a big part in whether we get cavities. Some people end up with cavities because of their genes, even if they take really good care of their teeth. Other people hardly get any. We can’t change our genes, but we can control other things. Brushing your teeth, visiting the dentist, and avoiding sweets can all help you keep cavities away.

Want to find out more about what lives inside your mouth? Watch the cartoon below from the National Institutes of Health.

 

nextArticle.image_alt|e
iStock/Chloe Effron
Why Do Lizards Lose Their Tails and Regrow New Ones?
iStock/Chloe Effron
iStock/Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Many species of lizard lose their tails when they are being chased. When a predator (PREH-duh-tor)—an animal that wants to eat them, like a bird or cat—grabs for the tail, it falls off, and the lizard can run away. How does it happen? Scientists looking at geckos (a type of lizard) under a microscope have found out that some parts of the tail are weaker than other parts.

It’s no accident. The sections of a lizard’s tail will hold together until the lizard is in danger. Scientists think that’s when special cells inside the tail make chemicals that attack the weak points. Then—surprise!—the tail breaks off. It will also keep wiggling for a while to distract the predator while the lizard speeds off. Pretty awesome! That’s not the end of the story, either. Most lizard species can also grow a new tail. 

Lizard tails have a lot of jobs to do. Lizards move their tails around to “talk” to each other. It’s a kind of secret lizard language. The tail also helps lizards keep their balance when they’re scrambling up a tree or jumping from rock to rock. So even though losing the tail is a useful trick, growing it back is pretty important, too. Sometimes lizards can get carried away, though: one busy lizard from Argentina grew six new tails at once!

Watch a gecko regrow its tail in this video

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios