Today’s Wonder of the Day was inspired by Leah. Leah Wonders, “Why does your stomach growl when you are hungry?” Thanks for WONDERing with us, Leah!

Does this sound familiar? You’re sitting in class in the middle of the morning. It’s a couple of hours since you had breakfast. Lunch is a long ways away. You’re trying hard to pay attention, but your stomach starts distracting you.

In fact, it may start distracting the whole class. When a stomach starts growling, it can sometimes be loud enough for the whole class to hear! Has your stomach ever started growling so loud that it seemed like it wanted to ask the teacher a question? Perhaps it wanted to ask, “When is lunch?”

What’s up with that? You probably already knew you were getting hungry. Do you really need your stomach to chime in with groans and weird sounds? Probably not! So why does it do that?

There’s no need to be embarrassed. Everyone’s stomach growls, gurgles, grumbles or rumbles from time to time. It’s just a friendly reminder that your body is always working to keep you in tip-top shape.

Although it might sound like growling coming from a throat, that rumbling and grumbling you hear comes from the stomach and the small intestine. And it happens at all sorts of times — not just when you’re hungry!

As the muscles of your digestive system push food through the digestion process, the food gets broken down to be used by your body. Gas and air bubbles also get into the mixture.

It is these pockets of gas and air that make the sounds you know as stomach growling. They’re not as loud when you have food in your stomach. That’s because the food absorbs some of the sound.

When your stomach is empty, though, these sounds are much easier to hear. That’s probably why we associate stomach growling with being hungry. A couple of hours after you eat, your stomach sends signals to your brain to get your digestive system muscles working again.

This process cleans up any food that was missed earlier. The stomach muscle contractions also help to make you hungry, so you eat more food that your body needs. Since your stomach is empty, those gas and air pockets make a lot more noise that you hear as stomach growling.

There’s actually a scientific word for the noises your stomach makes. It’s called borborygmi after a Greek word (borborygmus) that’s an onomatopoeia: a word that imitates the sound of what it describes!

Are you tired of your tummy grumbling? Eat several smaller meals each day rather than a few large ones. Keeping more food in your stomach throughout the day will help to quiet those annoying noises!

Standards: NGSS.LS1.C, NGSS.LS1.D, CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.R.4, CCRA.R.10, CCRA.SL.1, CCRA.SL.1

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