Year 4 · Autumn 1.2 · Step 3

Earth & Space

Change states

Melting, freezing, evaporation and condensation — how heating and cooling change a material's state.

Arrival Starter I do We do Independent Exit ticket

🌱 Seedling · Working towards 🌿 Sapling · Expected 🌳 Oak · Greater depth

⏱ Whole lesson ≈ 44 min · pick a tier in the bar, or leave on "All"

Arrival 4 min

Recap of last lesson: tricky materials.

Recap: sorting materials

🌱 Seedling

Working towards

Is sand a solid or a liquid?

🌿 Sapling

Expected

Why can sand pour?
Name a slow liquid.

🌳 Oak

Greater depth

What happens to an ice cube left in a warm room? Why?

Bridge into todayMaterials don't always stay the same state. Heat and cold can change the state — today we meet melting, freezing, evaporation and condensation.

Starter 5 min

Introduce the four changes of state and their names.

Changing state

Melting (solid→liquid) and freezing (liquid→solid) happen with temperature. Evaporation (liquid→gas) and condensation (gas→liquid) do too. These changes are reversible — you can go back.

🌱 Seedling

Working towards

Ice turns to water when it is ____ (heated/cooled).

🌿 Sapling

Expected

Name the change from solid to liquid, and liquid to solid.

🌳 Oak

Greater depth

Why is melting called a reversible change?

I do · 1 6 min

Teacher models. Watch, then name each change of state.

Four changes of state

▶ Can't see it? Watch "Changing states of matter — melting, freezing, evaporation, condensation" on YouTube

Swap the clip: change the ID after /embed/ (now LTfHaWFhBBw).

Say thisHeat an ice cube and it melts. Cool water and it freezes. Heat water and it evaporates into a gas. Cool that gas and it condenses back to a liquid. Same water — just changing state.

🔥

Melt / evaporateheating

❄️

Freeze / condensecooling

🔁

Reversibleyou can go back

We do · 1 6 min

Match each everyday example to its change of state.

Name that change

ice cream melting water freezing into a lolly a puddle disappearing mist on a cold window

Sort together

Melt · Freeze · Evaporate · Condense. Ask "did it get hotter or colder?"

Heating melts and evaporates; cooling freezes and condenses.

I do · 2 4 min

Play the animation. Bust: once melted it can't go back / boiling is the only evaporation.

Melting and freezing go both ways

Heat melts ice to water; cooling freezes it back. It's the same water either way.

Model the ideaMelted chocolate or a melted ice cube can become solid again if it cools — the change is reversible. And water can evaporate slowly at everyday temperatures, not only when it boils at 100°C.

Watch for: "once it melts it can't turn back" and "evaporation only happens at 100°C".

We do · 2 5 min

Heating or cooling? Sort statements together.

Heating or cooling?

Decide together

"Butter melting in a pan." "Water freezing into ice." "A puddle drying up."

Which need heating and which need cooling?

Independent 10 min

On your own. Sort each change, then write at your tier.

Changing states sorter

🔥 Heating change

❄️ Cooling change

🚫 Myth to bust

Tap a card to sort it…

🌱 Seedling

Working towards

Sort the cards. Then finish: Melting is a ____ change (heating/cooling).

🌿 Sapling

Expected

Sort them, then name the four changes of state.

🌳 Oak

Greater depth

Sort them, then explain why melting is a reversible change.

Exit ticket 4 min

Answer at your tier, then hand it in.

Show what you know

🌱 Seedling

Working towards

What is melting?
What is freezing?

🌿 Sapling

Expected

What is evaporation?
What is condensation?

🌳 Oak

Greater depth

Explain why changes of state are reversible.