Back to the lesson plan builder
Lesson length30 min45 min60 min
Questions🔀 New questions

Print the plan for yourself; the student sheet prints on its own page after it.

Science lesson plan · 7th grade (Year 8 in England) · 30 minutes

Pressure = force ÷ area

Forces and motion

CCSS NGSS.MS-PS2-2England: KS3 Physics: Motion and forces (pressure)England: GCSE Physics: Forces (pressure)

Objective and success criteria

Students will: Pressure = force ÷ area.

  • I can answer questions on today's skill on my own, without help.
  • I can explain each step and say why it works.
  • I can check my answer and spot a mistake.

Before and after

Needs first: Mass and weight (W = mg)

Leads to: the next skill in this area.

Materials: Force meters, Toy cars and ramps, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).

Warm-up · 4 min

  • 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 5 kg object on Earth? Use g = 9.8 N/kg. → 49 NPrompt: weight = mass × gravitational field strength (W = m g)
  2. An astronaut's mass is 60 kg. Gravitational field strength on Jupiter is 25 N/kg. What would their weight be there, in N? → 1500 NPrompt: Mass stays the same everywhere; weight changes.
  3. Mass and weight: which statement is NOT true? (Weight is measured in kilograms. / Your mass is the same on the Moon as on Earth. / You would weigh less on the Moon than on Earth. / Weight is a force measured in newtons.) → Weight is measured in kilograms.Prompt: Which one changes on the Moon?

Hook · 3 min

  • 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.

I do: model it · 7 min

  • 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.

We do: guided practice · 6 min

  • 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 200 N acts on an area of 4 m². What is the pressure, in pascals (Pa)? → 50 PaPrompt: pressure = force ÷ area
  2. A walker has a weight of 600 N. The total area in contact with the ground is 0.05 m². What pressure is exerted on the ground, in Pa? → 12000 PaPrompt: The weight is the force pushing down.

You do: independent practice · 7 min

  • 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 6 questions are on the student sheet below, with answers in the key.

Exit ticket · 3 min

  • Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
  1. Why does a sharp knife cut more easily than a blunt one? (Sharp knives are magnetic / The small edge area gives a much higher pressure for the same force / Blunt knives have less friction / Sharp knives are heavier) → The small edge area gives a much higher pressure for the same forcePrompt: Pressure = force ÷ area.
  2. A car has a weight of 12000 N. The total area in contact with the ground is 0.1 m². What pressure is exerted on the ground, in Pa? → 120000 PaPrompt: The weight is the force pushing down.

Watch out for

  • Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
  • Remembering facts without the reason: ask "why?" and "what is the evidence?"

Support and stretch

Support

  • Review first: Mass and weight (W = mg).
  • Use concrete materials: force meters.
  • Give the first step of each question, or a partly worked example to finish.
  • Pair with a confident partner for the guided practice.

Stretch

  • Explain a common mistake in writing and how to fix it.
  • Write a word problem that uses today's skill, then solve a partner's.

Homework and more practice

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

Free lesson plan from eurekami.com/lesson-plan-builder

eurekami

Pressure = force ÷ area

Name

Date

Score/ 6

  1. Question 1

    Why do drawing pins have a wide head and a sharp point?

    • A. The wide head gives low pressure on your thumb; the point gives high pressure on the board
    • B. To reduce the force needed
    • C. The head is magnetic
    • D. To make them look nice

  2. Question 2

    A force of 500 N acts on an area of 10 m². What is the pressure, in pascals (Pa)?

    AnswerPa

  3. Question 3

    A car has a weight of 12000 N. The total area in contact with the ground is 0.08 m². What pressure is exerted on the ground, in Pa?

    AnswerPa

  4. Question 4

    Why are deep-sea submersibles built with very thick walls?

    • A. To make them float
    • B. Water pressure increases greatly with depth
    • C. Deep water is hotter
    • D. There is no pressure deep down

  5. Question 5

    A force of 25 N acts on an area of 0.5 m². What is the pressure, in pascals (Pa)?

    AnswerPa

  6. Question 6

    An elephant has a weight of 50000 N. The total area in contact with the ground is 0.25 m². What pressure is exerted on the ground, in Pa?

    AnswerPa

Free from eurekami.com

for the adult only

Answer key: Pressure = force ÷ area

  1. 1. A. The wide head gives low pressure on your thumb; the point gives high pressure on the board

  2. 2. 50 Pa

  3. 3. 150000 Pa

  4. 4. B. Water pressure increases greatly with depth

  5. 5. 50 Pa

  6. 6. 200000 Pa