FOUNDATIONS OF CHEMISTRY FOR YOUNG STARS - Lesson 18: States of Matter and Changes — From Ice to Vapour and Back Again

 

🌿 Light for the Living – Science with a Village Heart

💧 Lesson 18: States of Matter and Changes — From Ice to Vapour and Back Again

📍 Scene: Umuahia-Ngwa, Abia State
👨🏾‍🏫 Main Character: Teacher Nwankwo, “The Laughing Chemist”

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🏡 Scene 1 – “Smoke, Dew, and Boiling Soup”

It was dawn in Umuahia-Ngwa, a peaceful village wrapped in the silver mist of early morning.
Dewdrops sparkled on zinc roofs like tiny diamonds, while the aroma of ukazi soup simmering over firewood floated through the air.
Thin smoke curled lazily upward from Mama Ngozi’s kitchen, twisting like a dancing spirit.

Under a mango tree beside the village square, Teacher Nwankwo arranged a curious display — a block of ice, a bowl of water, and a steaming kettle.
His pupils gathered round, their eyes wide with wonder.

“Children,” he began with his trademark grin, “today we shall see how matter — everything around us — behaves like our village people: it can change its form but remain itself!”

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⚖️ 1. What Is Matter?

He picked up the ice block.

“Matter,” he said, “is anything that has mass and occupies space.”

He looked around.
“Chidinma, is your slate matter?”
“Yes, sir.”
“And the smoke from Mama Ngozi’s kitchen?”
“Yes, sir.”
“Correct! One is solid, the other is gas. Both are matter.”

He continued:

• Mass is the amount of matter in a body — we measure it with a weighing scale.

• Weight is the pull of gravity on that mass.

He wrote on the board:

$$\text{Weight} = \text{Mass} \times g \quad \text{and} \quad \text{Mass} = \frac{\text{Weight}}{g}$$

“Even the smallest piece of dust,” he said, “has mass. And if you could look closely enough, you’d see it’s made of atoms — the tiniest building blocks of matter.”

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🪨 2. The Three States of Matter

Teacher Nwankwo placed a stone, a bowl of water, and a plastic bottle filled with air on the table.

“These,” he said, “are the three physical states of matter — solid, liquid, and gas.”

State of Matter	Local Example	Particle Motion	Spacing	Shape	Volume	Compressible?
Solid	Stone, chalk, yam	Vibrate about fixed points	Closely packed	Fixed	Fixed	No
Liquid	Water, palm oil	Move freely	Close but not tight	Takes container’s shape	Fixed	Slightly
Gas	Air, smoke, cooking gas	Move fast and freely	Far apart	No fixed shape	No fixed volume	Yes

“Solids are firm — like stubborn elders,” he joked.
“Liquids are flexible — they flow wherever you pour them.
Gases are restless — they run everywhere like playful children!”

The class laughed.

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🧺 3. Classification of Matter

He drew two boxes on the board and labelled them:

• Pure Substances

• Mixtures

Then he explained with local examples:

Type	Definition	Examples	Can Be Separated?
Element	One kind of atom	Iron, oxygen	❌ No
Compound	Two or more elements chemically joined	Water, salt, soap	❌ No (except by chemical means)
Mixture	Two or more substances physically combined	Gari & sugar, sand & rice	✅ Yes (physical means)

He smiled.

“When you mix gari and sugar, you can separate them again — that’s a mixture.
But if you cook cassava to make fufu, can you get cassava back? No o! That’s a chemical change!”

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🔥 4. States and Changes of Matter

He pointed to the ice block as it slowly began to sweat under the sun.

“Watch, children — ice is a solid. As it warms, it melts into water.
Heat it again, and it becomes vapour — gas!
Cool that vapour, and it turns back into water. Freeze it again, and it’s ice once more.”

He drew a neat diagram in the sand:

HEAT ADDED →
Solid → Melting → Liquid → Evaporation → Gas
↑                                   ↓
Freezing ← Condensation ← HEAT REMOVED

Then he added, “There are two more changes: sublimation (solid straight to gas, like camphor) and deposition (gas to solid, like frost during harmattan).”

Change	From → To	Heat Effect	Village Example
Melting	Solid → Liquid	Gains heat	Ice block melting
Freezing	Liquid → Solid	Loses heat	Ice cream hardening
Evaporation	Liquid → Gas	Gains heat	Water boiling
Condensation	Gas → Liquid	Loses heat	Dew on roof
Sublimation	Solid → Gas	Gains heat	Camphor disappearing
Deposition	Gas → Solid	Loses heat	Frost on grass

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🌬️ 5. Physical and Chemical Changes

He picked up a candle stub and melted it.

“When I melt this wax, it’s still wax. That’s a physical change — no new substance is formed.”

Then he lit a piece of paper.

“Now this — when it burns, it becomes ash and smoke. That’s a chemical change — something new is made, and we can’t turn it back.”

Type of Change	What Happens	Reversible?	Example
Physical	Only form changes	✅ Yes	Melting, boiling, cutting
Chemical	New substance formed	❌ No	Burning, rusting, cooking

“So,” he said, “a physical change is like removing your wrapper and wearing another — same person.
But a chemical change is like roasting yam — once roasted, you can’t unroast it!”

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⚡ 6. The Energy and the Dance of Particles

He waved his hand in the air.

“When you heat something, you give its particles more energy — they dance faster and move apart.
When you cool it, the energy reduces — they move closer and stay calm.”

He laughed.

“It’s like at weddings — when the drummer beats fast, everyone dances and spreads out.
When the music stops, we all sit close and whisper again!”

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🌿 7. Everyday Examples in Umuahia-Ngwa

Process	Village Example
Melting	Ice block under the sun
Freezing	Ice cream in the freezer
Evaporation	Wet clothes drying
Condensation	Water drops on cold bottle
Sublimation	Camphor disappearing
Deposition	Dew on grass at dawn

Teacher Nwankwo looked around proudly.

“You see? Chemistry is not far from you. It lives in your kitchens, your farms, even your morning dew.”

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📘 8. Practice Exercises

A. Fill in the Blanks
1️⃣ Matter is anything that has _______ and occupies _______.
2️⃣ When a solid changes to liquid, the process is called _______.
3️⃣ When a liquid changes to gas, it is called _______.
4️⃣ When vapour changes to liquid, the process is called _______.
5️⃣ A change in which no new substance is formed is called _______.

B. Short Answer Questions
1️⃣ State three differences between solids, liquids, and gases.
2️⃣ Explain why ice melts when exposed to heat.
3️⃣ Give two examples of chemical changes in your home.
4️⃣ Describe what happens to particles when heat is added or removed.

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💬 9. Moral Reflection

As the sun rose higher and the dew began to fade, Teacher Nwankwo looked at his pupils and said softly:

“Children, matter teaches us something beautiful — that change is not destruction.
When water becomes steam, steam becomes rain, and rain gives life again.
So, when your life changes, don’t be afraid. It might just be your turn to shine like water in the sunlight.”

The class clapped and laughed as the kettle hissed and whistled beside them.
Science had come alive under the mango tree — just as real as dew on the roof and soup on the fire.

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🧠 Lesson Summary

• Matter: Anything that has mass and occupies space.

• States of matter: Solid, liquid, gas.

• Changes: Occur when heat is added or removed.

• Physical change: Reversible; no new substance formed.

• Chemical change: Irreversible; new substance formed.

• Energy drives all changes — heating makes particles move apart; cooling brings them together.

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✏️ Practice Quiz

1️⃣ Define matter.
2️⃣ List the three states of matter.
3️⃣ What is the difference between evaporation and condensation?
4️⃣ Give two examples of physical and chemical changes.
5️⃣ Explain why heating ice causes melting.

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🌾 #LightForTheLiving #ChemistryInTheVillage #AbiaScience #MatterAndChange #UkaziSoupAndSteam #EverydayChemistry