Look at these dry seeds. What do you think they need before they can grow into healthy plants?

Hands up one idea. We will turn one of your ideas into a real test today.

Soil and warmth matter too, but today every group will test either light or water so the class can compare fair results.

Your teacher will now think one whole test through out loud, using cress in light and cress in the dark. Listen for four things: the question, the prediction and the reason behind it, the one thing that changes, and the list of things that stay the same.

Listen too for how long the test takes. Plant tests are watched over days, so nothing will be decided this afternoon.

In your group, choose one factor to test: light or water.

You will see five cards on the board: amount of light, amount of water, how healthy the seedlings look, type of seed, and amount of soil or cotton wool.

We will sort them together for a test nobody is running: does it matter if the seedlings sit somewhere warm or somewhere cool? Watch how the cards land, because the shape is the same whatever you change.

Then your group plans its own test on the Investigation Journal page. One card goes into Change. Work out what that forces into Keep the same.

Before anyone moves, we agree the places together: bright windowsill for light cups, dark cover or cupboard for dark cups, and one shared sill for all water-test cups.

Watch one labelled pair set up at the front first, so everyone sees matching amounts and a clear single-factor change.

Now set up the test your group planned.

Place your cups only in the places we just agreed.