Year 4 · Autumn 1.2 · Step 5

Earth & Space

Plan: a melting experiment

Planning a fair test — does the temperature of the water change how fast ice melts?

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: using equipment.

Recap: measuring

🌱 Seedling

Working towards

A stopwatch measures ____.

🌿 Sapling

Expected

What does a thermometer measure?
How do you read it accurately?

🌳 Oak

Greater depth

To see if warm water melts ice faster, what would you change and measure?

Bridge into todayToday we plan a fair test: does the temperature of the water change how fast ice melts? We decide what to change, measure and keep the same.

Starter 5 min

Introduce fair testing in child-friendly words (no variable jargon yet).

Planning a fair test

In a fair test we change one thing, measure what happens, and keep everything else the same. Our question: How does the temperature of the water affect the time it takes for ice to melt?

🌱 Seedling

Working towards

We will change the water's ____.

🌿 Sapling

Expected

What will we change, and what will we measure?

🌳 Oak

Greater depth

Why must we keep the ice cubes the same size?

I do · 1 6 min

Teacher models planning. Watch to recall how ice melts.

What shall we change and keep the same?

▶ Can't see it? Watch "Melting — how heat changes a solid to a liquid" on YouTube

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

Say thisWe'll change the water temperature (warm vs cold), measure how long the ice takes to melt, and keep the same the ice cube size, the amount of water and the container — so the test is fair.

🔧

Changewater temp

⏱️

Measuretime to melt

🟰

Keep sameice, water, cup

We do · 1 6 min

Make a prediction and agree the plan together.

Predict and plan

Prediction: "The ice will melt faster in the ____ water, because…"

Agree the steps

Same ice cube in warm and cold water · start timing together · watch until each cube fully melts · record the times.

I do · 2 4 min

Play the animation. Show the fair-test setup clearly.

Our fair test

Same ice cube in warm and cold water — we change only the temperature and keep everything else the same.

Model the ideaOnly one thing changes — the water temperature. If we also changed the ice size or the amount of water, we wouldn't know which change caused the difference. That's why we keep them the same.

Watch for: wanting to change more than one thing at once, which makes the test unfair.

We do · 2 5 min

Change, measure or keep the same? Sort together.

Sort the plan

Decide together

"The water temperature." "The time to melt." "The size of the ice cube."

Is each one something we change, measure, or keep the same?

Independent 10 min

On your own. Sort each part of the plan, then write at your tier.

Fair test sorter

🔧 We change it

⏱️ We measure it

🟰 We keep it the same

Tap a card to sort it…

🌱 Seedling

Working towards

Sort the cards. Then finish: We will change the water's ____.

🌿 Sapling

Expected

Sort them, then write what we change, measure and keep the same.

🌳 Oak

Greater depth

Sort them, then explain why keeping things the same makes the test fair.

Exit ticket 4 min

Answer at your tier, then hand it in.

Show what you know

🌱 Seedling

Working towards

What will we change?
What will we measure?

🌿 Sapling

Expected

Name two things we keep the same.
What is our prediction?

🌳 Oak

Greater depth

Explain what makes our melting test a fair test.