• Quick retrieval from earlier learning (Mass and weight (W = mg)). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. What is the weight of a 12 kg object on Earth? Use g = 9.8 N/kg. → 117.6 NPrompt: weight = mass × gravitational field strength (W = m g)
2. An astronaut's mass is 60 kg. Gravitational field strength on Mars is 3.7 N/kg. What would their weight be there, in N? → 222 NPrompt: Mass stays the same everywhere; weight changes.
3. Mass and weight: which statement is NOT true? (Mass is measured in kilograms. / Weight is a force measured in newtons. / You would weigh less on the Moon than on Earth. / Your mass is smaller on the Moon.) → Your mass is smaller on the Moon.Prompt: Which one changes on the Moon?

• Drop a sheet of paper and a scrunched-up sheet together and ask why one falls faster.
• Share the objective: Pressure = force ÷ area. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: A force of 40 N acts on an area of 2 m². What is the pressure, in pascals (Pa)?
• Step 1: 40 ÷ 2 = 20
• Step 2: So the answer is: 20 Pa
• Answer: 20 Pa
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. A force of 400 N acts on an area of 20 m². What is the pressure, in pascals (Pa)? → 20 PaPrompt: pressure = force ÷ area
2. A walker has a weight of 600 N. The total area in contact with the ground is 0.04 m². What pressure is exerted on the ground, in Pa? → 15000 PaPrompt: The weight is the force pushing down.

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. A force of 4 N acts on an area of 2 m². What is the pressure, in pascals (Pa)? → 2 PaPrompt: pressure = force ÷ area
2. Why does a sharp knife cut more easily than a blunt one? (The small edge area gives a much higher pressure for the same force / Sharp knives are magnetic / Sharp knives are heavier / Blunt knives have less friction) → The small edge area gives a much higher pressure for the same forcePrompt: Pressure = force ÷ area.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-7.