Stand at the front and do the two turns yourself: face the window, then face the back wall, keeping your feet planted in one spot so the class sees you turn without walking. Then read the question off the board. Take two or three hands-up answers only, not open call-out. You are fishing for the idea that the way you are facing changed even though you did not move from the spot. Do not name the word 'angle' yet.

This is a real demonstration at the front, not the IWB. Use the joined-strip turning arm (two card strips, split-pin at one end) plus a paper corner folded twice into a sharp right-angle tester.

• Open the arm a little (a small turn), then a lot (a big turn). Name each as an angle as you go.
• Swing a clock hand from 12 to make a quarter turn, then a half turn, so pupils meet turn-as-angle a second way.
• The key demonstration: open the arm to a fixed gap, then slide one strip out longer. Ask the class first, before you reveal it, whether the angle got bigger. The angle does not change — only the arms got longer.

Hold out for a pupil to say the opening is the same before you confirm it. Do not announce the rule; let the demonstration show it.

Talk this one through together. Bring the large joined-strip arm and the paper right-angle tester to the front, and make sure every pupil has their own paper corner tester in front of them.

For each turn in the list, make it on the large arm at the front, then have the whole class check the matching opening against their own paper corner at the same time — so nobody is only watching. Before you open the front arm, the class predicts.

• Smallest opening → arms almost together.
• Square-corner turn → pupils check it against their folded paper corner; it should fit exactly.
• Wider than a square corner → the paper corner leaves a gap.
• Two openings side by side → the class judges which is the bigger turn, not which has the longer arms.

Revoice a strong answer: so the opening tells us the angle, not the length of the arms.

This is the practice round. Every pupil works their own joined arms at their seat while you circulate; there is no board work here. Hand out a joined-strip arm to each pupil (or one per small group if arms are short) and a folded paper corner each.

As you circulate, catch the common slip: pupils who make a 'bigger' turn by stretching the arms out rather than opening them wider. Point straight back at the opening. For the last task, bring the class together and have them confirm aloud which of their two openings is the bigger turn and how they knew.