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      Lesson details

      Learning outcome

      I can describe and calculate pressure, the effect of a force acting over an area.

      Key learning points

      1. Pressure is a measure of how concentrated a force is.
      2. Pressure = force ÷ area.
      3. Pressure is measured in newtons per square metre or per square centimetre.
      4. Another name for newtons per square metre is the pascal (Pa).

      Keywords

      • Pressure - The effect of a force acting over an area.

      • Concentrated - When a force is concentrated on a small area the pressure is higher.

      • Newton per square centimetre - A unit for pressure.

      • Newton per square metre - The standard unit for pressure, and this is also known as the pascal (Pa).

      Common misconception

      Pressure and force are terms that are often used interchangeably.

      Explore examples with pupils in which similar sized forces are used to create different pressures that the pupils can experience first hand.

      Teacher tip

      Show the pupils the effect of high pressures on surfaces by demonstrating cutting, this should be linked to prior learning on increasing forces with levers.

      Content guidance

      Risk assessment required - equipment

      Supervision

      Adult supervision required

      Licence

      This content is © Oak National Academy Limited (2026), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      Complete the sentence: The unit of force is the , which has the symbol N.

      Correct Answer: newton, newtons

      Q2.
      The figure shows a force acting on a balloon resting on a table with a hand pushing downwards on it. Which statements are correct?

      An image in a quiz
      The force causes the balloon to speed up.
      Correct answer: The force causes the balloon to change shape.
      Correct answer: The balloon will put an upwards force on the hand.
      Correct answer: The balloon will put a downwards force on the table.
      Correct answer: The table will put an upwards force on the balloon.

      Q3.
      Which force on objects like springs or rubber bands will cause them to stretch?

      gravitational force
      Correct answer: tension
      magnetic
      upthrust
      electrostatic

      Q4.
      A set of bathroom scales shows a reading of 110 kg. What is the weight of the object on the scales? The gravitational field strength on Earth is 10 N/kg

      An image in a quiz
      110 N
      11.0 N
      Correct answer: 1100 N
      11 000 N
      1.1 N

      Q5.
      A spring is used in a newton meter. The total length of the spring increases by 2 cm when a force of 4 N acts on it. Which of the following statements is correct?

      An image in a quiz
      The total length of the spring will double when 8 N is placed on it.
      Correct answer: The extension of the spring will double when 8 N is placed on it.
      The total length of the spring will stay constant when 8 N is placed on it.
      The total length of the spring doubles every time 4 N is added to it.

      Q6.
      This boat is floating on the surface of the water. The boat has a mass of 120 kg and passengers have a total mass of 80 kg. What is the size of the upthrust acting on the boat?

      An image in a quiz
      120 N
      200 N
      1200 N
      Correct answer: 2000 N
      400 N

      6 Questions

      Q1.
      Which of these will increase the pressure acting on a surface?

      Correct answer: Increasing the size of the force.
      Decreasing the size of the force.
      Increasing the area the force acts over.
      Correct answer: Decreasing the area the force acts over.

      Q2.
      Which of these are units of pressure?

      newtons
      newtons per centimetre
      Correct answer: pascals
      Correct answer: newtons per square metre
      Correct answer: newtons per square centimetre

      Q3.
      A force of 300 N acts over an area of 20 cm$$^2$$. What pressure does the force cause?

      0.07 N/cm$$^2$$.
      Correct answer: 15 N/cm$$^2$$.
      6000 N/cm$$^2$$.
      280 N/cm$$^2$$.
      320 N/cm$$^2$$.

      Q4.
      Which of these is the same pressure as 100 000 Pa?

      100 000 N/cm$$^2$$.
      1000 N/cm$$^2$$.
      Correct answer: 10 N/m$$^2$$.
      1 N/m$$^2$$.
      0.000 1 N/cm$$^2$$.

      Q5.
      A bench of weight 800 N makes contact with the floor over an area of 400 cm$$^2$$. What pressure does it put on the floor in pascals?

      0.5 Pa
      2.0 Pa
      5000 Pa
      Correct answer: 20 000 Pa
      200 000 Pa

      Q6.
      Starting with the largest, sort the following into order of pressure.

      1 - A force of 5000 N acting over an area of 1 square metres.
      2 - A force of 5000 N acting over an area of 2 square metres.
      3 - A force of 6000 N acting over an area of 3 square metres.
      4 - A force of 2000 N acting over an area of 50 square metres.

      To help you plan your 9 science lesson on: Pressure, download all teaching resources for free and adapt to suit your pupils' needs...