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Curious Kids: is everything really made of molecules?

Is this it? Shutterstock.

Curious Kids is a series for children of all ages, where The Conversation asks experts to answer questions from kids. All questions are welcome: find out how to enter at the bottom of this article.

People say that everything is made of molecules. Are feelings made of molecules? Is sound made of molecules? – Claire, age six, Bristol, UK

Thanks for the question, Claire. First things first: when people say “everything”, often they actually mean the stuff that scientists call “matter”. Matter is stuff you can touch. But feelings are not matter, and neither is sound.

Things that are matter include stars, air, water, tables, chairs, trees, your body, your brain, and pretty much everything that you see around you.

All of these things are made up of molecules – but molecules aren’t the smallest pieces of matter, because every molecule is made up of even smaller pieces called atoms.

And atoms themselves are made up of even tinier pieces. One of the tiniest types of pieces that makes up matter is called the electron.

Electrons and emotions

Things that are not matter include feelings, thoughts and light. Light allows us to see all of the things around us, but it’s different from matter. The main difference is that it doesn’t weigh anything. Even air has a weight, but light doesn’t.

Feelings and thoughts also don’t have a weight, and are not matter. But they’re not light, either. Feelings and thoughts live inside our brains.

The way that the matter in our brains acts affects our feelings and thoughts, and our feelings and thoughts can affect the way the matter in our brain acts.

Feelings aren’t matter, but your brain is. Shutterstock.

Scientists don’t yet know exactly how thoughts are made, but they do know that it has something to do with the way those tiniest pieces of matter – electrons – move around to create an electrical signal, like the signals that are sent from a light switch to turn a light on.

For example, scientists have found out that your brain holds on to memories by keeping electrons in certain places.

There are different kinds of feelings. There are feelings that your body tells you, like when you burn your finger on a candle or when you feel hungry. And there are feelings that we call emotions, like when you’re sad or excited.

Both kinds of feelings are made in your brain and both kinds have to do with those electrons again, with how they move and where they sit in your brain.

Sensing sound

Sound is a different thing again. Sound is made of waves, but not really like waves on the ocean. Soundwaves are created when the molecules around us move in a certain way.

Imagine you’re playing some loud music through a speaker. If you touch the front of a speaker while the music’s playing, you should be able to feel it jiggle.

The jiggle of the speaker causes the molecules in the air around it to jiggle and bump into each other.

That little jiggle causes the other molecules nearby to jiggle, and the jiggles pass from one group of air molecules to another, until they finally reach the air molecules next to your ear drum.

Your ear drum is very sensitive, and can tell that the air molecules are jiggling, so it sends a special message to your brain. Your brain gets the message and says, “that’s music!” – and that’s how you hear the song.

So, neither feelings nor sound are made of molecules in the same way that matter is. But they both have a lot to do with the way molecules – and their smaller parts, atoms and electrons – move around.

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