Course Content
Why Atoms?
Why learn about atoms? How does knowing about atoms change how we see EVERYTHING? What is everything made of? Why do things move, change, mix, burn, or grow?
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Let’s take a little journey.
Alright, Now for a Challenge!
How did humans first guess atoms existed?
The story of ancient Greece, Democritus, and "what if you kept cutting?"
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The Story of a Curious Man Named Democritus… and a Big Idea That Changed Everything
Challenge Time
How Do We Know Atoms Are Real—Not Just Made Up?
The Hidden Proof That Atoms Are All Around Us.
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How You Can Discover Atoms Yourself!
Ok, so ready for a challenge?
Why don’t atoms ever sit still?
How does atomic movement create everything we see?
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Nothing In The Universe Ever Truly Stands Still
Ready for a challenge?
How does this atoms affect weather, clouds, water cycles, etc.?
Ok. Let's Test What You Learnt!
The Secret Life of Atoms: How Atoms Build Our World

Let’s Begin with a Thought

Have you ever thought the floor under your feet was perfectly still?
Or that your water bottle was just sitting there doing nothing?

Well, guess what?

Even things that look still are not really still at all.

Because deep inside them – hidden where our eyes can’t see –
tiny little particles are always moving.

Those particles are atoms.
And they never, ever stop.

 

Let’s Imagine a Super Zoom-In

Imagine you had magic glasses.
Not just any glasses—these can zoom in a million times!

You look at your hand.
You zoom in, and the skin becomes soft hills.
Zoom more, and you see teeny-tiny bumps.
Zoom even more…

And there they are—atoms!

They’re bouncing, spinning, jiggling, and wiggling around.
Even though your hand looks still, all those atoms are dancing.

Crazy, right?

 

So… Why Do Atoms Move All the Time?

Because that’s just how the universe works.

Atoms are never asleep.
They have something inside them called energy – and this energy makes them move.

Even when it’s cold.
Even when it’s quiet.
Even in the darkest cave or the bottom of the sea… atoms are moving.

They might be moving slowly.
They might be moving super fast.
But they’re always in motion.

 

What Kind of Motion Are We Talking About?

Imagine atoms like tiny balls.

They:

  • Shake in place like nervous dancers

  • Bounce off other atoms like bumper cars

  • Slide past each other like kids on a slip-n-slide

  • Fly around wildly like popcorn popping in a microwave

The way they move depends on what they’re in.
Let’s break that down.

 

1. In Solids: Atoms Dance in Place

Think of an ice cube.

It looks solid. Hard. Still.

But its atoms are dancing!
They’re shaking in place—like kids wiggling in their chairs but not leaving their seats.

They don’t have space to run around, because they’re packed tightly together.
But they still jiggle.

1. In Solids: Atoms Dance in Place Think of an ice cube. It looks solid. Hard. Still. But its atoms are dancing! They’re shaking in place—like kids wiggling in their chairs but not leaving their seats. They don’t have space to run around, because they’re packed tightly together. But they still jiggle. That’s why solids can hold their shape. The atoms are locked in—but they’re still alive with motion. 2. In Liquids: Atoms Slide Around Now think of water. In a glass, it sloshes, moves, and takes the shape of the glass. That’s because the atoms in liquids are not stuck like in solids. They can slide and move around each other. They’re still close together—but they can squeeze by, like people bumping past each other in a crowded room. This is why you can pour water and why it can splash. Atoms in liquids love to move more freely. 3. In Gases: Atoms Fly Everywhere Now picture steam coming out of a hot cup of tea. That’s gas. Atoms in gases are wild and free. They move super fast. They bounce, zoom, and spread out in all directions. There’s lots of empty space between them, and they don’t want to stay in one place. That’s why smells can travel, balloons can grow, and steam rises. Gas atoms are like super dancers at a party, leaping and spinning with wild joy. So What Makes Atoms Move Faster or Slower? The answer is… temperature. Let’s say that again: Temperature is really just how fast atoms are moving. Hot = fast-moving atoms Cold = slow-moving atoms Let’s look at some examples. 🔥 When You Heat Something Up When you heat soup on the stove: The atoms in the soup move faster and faster They start bumping and jiggling harder Some jump into the air as steam! The hotter something gets, the more its atoms dance. This is why: Ice turns to water (atoms start slipping) Water turns to steam (atoms start flying) ❄️ When You Cool Something Down Now imagine putting water in the freezer. What happens? The atoms slow down They stop sliding and start just shaking in place The water becomes ice—a solid This is because cold takes energy away. Less energy = slower atoms. They still move… just not as much. But Wait… Do Atoms Ever Stop Moving Completely? Good question. Scientists have found that atoms can almost stop at something called absolute zero. That’s -273 degrees Celsius (super, super cold). Colder than Antarctica. Colder than space! At that point, atoms move soooo slowly, they almost stop. But here’s the cool thing: They never really stop 100%. There’s always just a little bit of wiggling left. So the answer is: Atoms never truly stop moving. Why Does This Motion Matter? You might be thinking: “Okay, so atoms move… so what?” Well, it matters a lot! Because atomic motion: Explains heat and cold Explains how ice melts and water boils Explains how smells travel Explains why things mix, spread, and change Let’s look at some real-life examples. 🍫 Chocolate in Your Hand Hold a piece of chocolate. If your hand is warm, it starts to melt. Why? The heat from your hand makes the chocolate atoms move faster They break away from their solid pattern The chocolate becomes gooey That’s atoms in motion, making a change you can feel (and taste!). 🌬️ Perfume Across a Room Spray perfume in one corner of the room. After a few seconds, you smell it on the other side. How? The perfume atoms are in a gas They move fast and spread out They bounce through the air and reach your nose Even though you can’t see them, you can smell their movement. 🧊 Ice in a Drink Drop ice cubes into water. The cold ice atoms move slowly The warmer water atoms move faster When they meet, energy moves from water to ice The ice melts and the water cools down It’s like a dance party where some dancers are fast, some are slow, and they start moving together. 🌡️ Thermometers and Motion Thermometers tell us how hot or cold something is. But what they’re really doing is measuring how fast atoms are moving! That’s right—your thermometer is like a motion detector for atoms! The Big Idea: Atoms in Motion Make Life Possible Without moving atoms: No heat No change No smells No food cooking No energy No life The motion of atoms is what lets plants grow, water flow, and people live. Everything depends on tiny invisible dancers working all the time.

That’s why solids can hold their shape.
The atoms are locked in—but they’re still alive with motion.

 

2. In Liquids: Atoms Slide Around

Now think of water.

In a glass, it sloshes, moves, and takes the shape of the glass.

That’s because the atoms in liquids are not stuck like in solids.
They can slide and move around each other.

They’re still close together—but they can squeeze by, like people bumping past each other in a crowded room.

This is why you can pour water and why it can splash.

Atoms in liquids love to move more freely.

 

3. In Gases: Atoms Fly Everywhere

Now picture steam coming out of a hot cup of tea.

That’s gas.

Atoms in gases are wild and free.
They move super fast.
They bounce, zoom, and spread out in all directions.

There’s lots of empty space between them, and they don’t want to stay in one place.

That’s why smells can travel, balloons can grow, and steam rises.

Gas atoms are like super dancers at a party, leaping and spinning with wild joy.

 

So What Makes Atoms Move Faster or Slower?

The answer is… temperature.

Let’s say that again:
Temperature is really just how fast atoms are moving.

  • Hot = fast-moving atoms

  • Cold = slow-moving atoms

Let’s look at some examples.

 

🔥 When You Heat Something Up

When you heat soup on the stove:

  • The atoms in the soup move faster and faster

  • They start bumping and jiggling harder

  • Some jump into the air as steam!

The hotter something gets, the more its atoms dance.

This is why:

  • Ice turns to water (atoms start slipping)

  • Water turns to steam (atoms start flying)

  •  

❄️ When You Cool Something Down

Now imagine putting water in the freezer.

What happens?

  • The atoms slow down

  • They stop sliding and start just shaking in place

  • The water becomes ice—a solid

This is because cold takes energy away.
Less energy = slower atoms.

They still move… just not as much.

 

But Wait… Do Atoms Ever Stop Moving Completely?

Good question.

Scientists have found that atoms can almost stop at something called absolute zero.

That’s -273 degrees Celsius (super, super cold).
Colder than Antarctica. Colder than space!

At that point, atoms move soooo slowly, they almost stop.

But here’s the cool thing:
They never really stop 100%.

There’s always just a little bit of wiggling left.

So the answer is:
Atoms never truly stop moving.

 

Why Does This Motion Matter?

You might be thinking: “Okay, so atoms move… so what?”

Well, it matters a lot! Because atomic motion:

  • Explains heat and cold

  • Explains how ice melts and water boils

  • Explains how smells travel

  • Explains why things mix, spread, and change

Let’s look at some real-life examples.

 

🍫 Chocolate in Your Hand

Hold a piece of chocolate.

If your hand is warm, it starts to melt. Why?

  • The heat from your hand makes the chocolate atoms move faster

  • They break away from their solid pattern

  • The chocolate becomes gooey

That’s atoms in motion, making a change you can feel (and taste!).

 

🌬️ Perfume Across a Room

Spray perfume in one corner of the room.

After a few seconds, you smell it on the other side.

How?

  • The perfume atoms are in a gas

  • They move fast and spread out

  • They bounce through the air and reach your nose

Even though you can’t see them, you can smell their movement.

 

🧊 Ice in a Drink

Drop ice cubes into water.

  • The cold ice atoms move slowly

  • The warmer water atoms move faster

  • When they meet, energy moves from water to ice

  • The ice melts and the water cools down

It’s like a dance party where some dancers are fast, some are slow, and they start moving together.

 

🌡️ Thermometers and Motion

Thermometers tell us how hot or cold something is.

But what they’re really doing is measuring how fast atoms are moving!

That’s right—your thermometer is like a motion detector for atoms!

 

The Big Idea: Atoms in Motion Make Life Possible

Without moving atoms:

  • No heat

  • No change

  • No smells

  • No food cooking

  • No energy

  • No life

The motion of atoms is what lets plants grow, water flow, and people live.

Everything depends on tiny invisible dancing particles working all the time.

 

How Do We Know Atoms Are Moving?

Let’s go back to Mr. Brown and Brownian motion (remember that from last lesson?).

He looked through a microscope at pollen in water… and saw it jiggling.

That pollen wasn’t moving on its own.

It was being bumped and bounced by water atoms dancing around!

Even though the atoms were invisible, their motion was clear.

 

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