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Why Do We Poop And Fart?


How does your body make poop? How many germs are in an ounce of poop? Why do people fart and why are farts stinky? Look, everybody does it, so today we're going to tackle one of the areas kids seem to find fascinating: why and how we poop! Plus, we get some help from Chicago public radio station WBEZ's Curious City to learn about what happens after you flush the toilet.


"Why do we poop?" Violet, 5, and Nina, 3, Toronto, Ontario

Let's zero in on the very impressive and efficient system our body uses to take in food, use what it needs, and get rid of the rest. It's called your alimentary canal, your digestive system, or your gastrointestinal tract.

When we take a bite of food, that starts the process of digestion. The food mixes with saliva, which helps to break it down. After you swallow your lunch, your stomach muscles mix it like a blender with even more chemicals, your stomach juices, to break the food down even smaller. And then the sloshy mixture gets pushed into your intestines, where a lot of it is absorbed into your body.

Credit Curious City / WBEZ
Satchel asked WBEZ's Curious City about what happens when the toilet flushes.

Your body will squeeze all the good stuff it can out of the food you eat.

A lot of digestion happens in your intestines. And picture this: if you stretched out the intestines that are kind of curled up and stuffed inside your body, it would be really long!

In an adult, the small and large intestines are more than 25 feet long! That's longer than a city bus!

But the food that can't get absorbed into your body needs to go somewhere, and it can't stay in your body forever so it guessed it, poop!
Poop is a mixture of fiber and dead cells from your body, and lots of water. Poop is mostly water. Depending on what you've been eating and how healthy you are, it can have different textures and shapes.

For what it's worth, pee is made in a different but complementary system. Pee, or urine, is the way your body gets rid of nutrients and waste products from your bloodstream. You do make more pee the more liquid you swallow, but that's a good thing-you want to keep all your cells healthy and hydrated. You're generally on the right track if your pee is a light yellow. If it's dark yellow you need to drink more water!

Listen to the whole episode to find out what happens after you flush the toilet.

Read the full transcript

Find out more about Curious City here.

Melody is the Contributing Editor for But Why: A Podcast For Curious Kids and the co-author of two But Why books with Jane Lindholm.
Jane Lindholm is the host, executive producer and creator of But Why: A Podcast For Curious Kids. In addition to her work on our international kids show, she produces special projects for Vermont Public. Until March 2021, she was host and editor of the award-winning Vermont Public program Vermont Edition.
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