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Year 10
OCR
Higher

Pressure in a fluid

I can explain the causes of pressure in a fluid.

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New
New
Year 10
OCR
Higher

Pressure in a fluid

I can explain the causes of pressure in a fluid.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. The particles in liquids and gases move very quickly and randomly in every direction; they are both fluids.
  2. Particles in liquids are very close together; the gaps between particles in gases are much larger than the particles.
  3. The pressure at any point in a fluid is the same size in every direction.
  4. The particles in a fluid exert pressure on a surface by colliding with it.
  5. Pressure is calculated using the equation: density = force ÷ surface area.

Common misconception

The pressure at a particular depth depends on the shape of the container the liquid is in.

Demonstrate different shaped containers with the same depth of water in each and an identical shaped hole 1 cm above the base of each. Identical sized jets of water should shoot out of each hole as the pressure at each hole is (initially) the same.

Keywords

  • Atom - the building block of matter; even small pieces of matter have trillions of atoms

  • Particle - a term used to describe atoms or molecules which make up matter

  • Fluid - a liquid or a gas; fluids can flow as the particles can move around each other

  • Pressure - caused by a force acting over an area on a surface; it can be calculated using: pressure = force ÷ area

Allow pupils to try to compress gases and liquids in a sealed syringe. A solid (such as sand) can also be used and discussed.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Which of the following words means ‘apply force to make something smaller’?
shrink
depress
Correct answer: compress
compound
Q2.
Which of the following types of motion can be described as a vibration?
rapid movement in a circle
rapid movement in any direction
Correct answer: repeating movement up and down
Correct answer: repeating movement left and right
Q3.
The three states of matter are liquid, solid and .
Correct Answer: gas, gases, gaseous
Q4.
Which of the following statements about atoms is correct?
All atoms are identical to each other.
They are similar in size to a living cell, such as a red blood cell.
Correct answer: They cannot be seen using microscopes that are used in schools.
The nucleus of an atom is the same size as the nucleus of a living cell.
Q5.
Which of the following diagrams accurately represents the arrangement of the particles in a liquid?
An image in a quiz
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
Q6.
Which of the following describe the weight of an object?
the amount of matter in the object
Correct answer: a gravitational force that acts on the object
Correct answer: the force exerted on the object by Earth's gravitational pull
a measure of the number and size of particles in the object

Exit quiz

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6 Questions

Q1.
Which of the following statements about particles are correct?
Correct answer: All atoms are particles.
All particles are atoms.
Correct answer: All molecules are particles.
All particles are molecules.
Q2.
Which of the following statements about fluids are correct?
Correct answer: Air is a fluid at room temperature.
Correct answer: Petrol is a fluid at room temperature.
In all fluids, the particles are far apart.
Correct answer: In all fluids, the particles can move around each other.
Q3.
Which of the following statements explains why it is difficult to compress a liquid?
The particles are heavy.
Correct answer: The particles are close together.
The particles are relatively large.
The particles are moving very fast.
Q4.
Which of the following statements explains why all fluids exert pressure?
The particles in fluids vibrate.
The particles in fluids are close together.
Correct answer: The particles in fluids are moving around.
Fluids are made of a different type of particle from solids.
Q5.
The following diagrams all show the same solid cuboid, resting on a table in different positions. In which diagram does the block exert the greatest pressure on the table?
Correct Answer: An image in a quiz
An image in a quiz
An image in a quiz
An image in a quiz
Q6.
A swimming pool has the same depth everywhere. Its area is 1250 m² and it contains water with a weight of 2 500 000 N. The pressure caused by the water on the bottom of the pool is N/m².
Correct Answer: 2000, 2 000, 2,000, 2 thousand, two thousand