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Year 7

Diffusion

I can explain how particles spread through a fluid.

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New
New
Year 7

Diffusion

I can explain how particles spread through a fluid.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. Brownian motion is the random motion of particles suspended in a medium.
  2. Particles of a substance released into a fluid (a gas or liquid) move around and are pushed by other particles.
  3. Substances that have particles that are free to move will eventually reach a random distribution throughout.
  4. At higher temperatures, particles in a gas or solution move more quickly.

Common misconception

Pupil confuse diffusion and Brownian motion.

Brownian motion is the random movement of particles due to collisions. Diffusion is due to concentration differences between 2 substances.

Keywords

  • Diffusion - The movement of particles from an area where there are lots, until there is a random distribution of particles throughout a medium.

  • Random - Happens without a clear pattern, making it unpredictable.

  • Brownian motion - The random movement of particles in a fluid, due to colliding with particles in the surrounding medium.

  • Medium - A medium is usually a liquid or gas that other substances can mix into or move through, enabling other substances to mix or interact.

  • Fluid - A fluid is a substance that flows or takes the shape of its container. Liquids and gases can be described as fluids.

Demo gaseous diffusion using a perfume / air freshener. Demo liquid diffusion in a 600ml beaker of water - via a straw, carefully add a few crystals of potassium permanganate and observe. Could heat another beaker of the same to show heat effect.
Teacher tip

Content guidance

  • Risk assessment required - equipment

Supervision

Adult supervision required

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 particle diagram shows a substance in the solid state?
An image in a quiz
a
Correct answer: b
c
Q2.
Which of these are mixtures?
oxygen
Correct answer: air
Correct answer: orange squash
pure water
carbon dioxide
Q3.
If a gas was placed into a container, what would you expect the gas particles to do?
The particles would collect on one side of the container.
The particles would sink to the bottom of the container.
Correct answer: The particles would spread to fill the container.
Q4.
Match the following scientific keywords with the correct description.
Correct Answer:gas state particles,are randomly moving and take the shape of the container

are randomly moving and take the shape of the container

Correct Answer:liquid state particles,are randomly moving and have no fixed shape

are randomly moving and have no fixed shape

Correct Answer:solid state particles ,are vibrating and have a fixed shape

are vibrating and have a fixed shape

Correct Answer:mixture,two or more substances that can be physically separated

two or more substances that can be physically separated

Correct Answer:solution,formed when a substance dissolves in a liquid

formed when a substance dissolves in a liquid

Correct Answer:fluid,a substance which flows and can be a gas or a liquid

a substance which flows and can be a gas or a liquid

Q5.
What is the scientific term used to describe a substance whose particles can be pushed together into a smaller volume?
Correct Answer: compressible, compression, compress
Q6.
What is the correct working out to show how much solute was used with 145.63 g of water to create a solution with mass 147.59 g?
147.59 + 145.63 = mass of solute
mass of solute = 145.63 - 147.59
Correct answer: mass of solute = 147.59 - 145.63
145.63 x 147.59 = mass of solute

Exit quiz

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6 Questions

Q1.
Which word best describes when something happens without a clear, predictable pattern?
casual
particular
specific
Correct answer: random
Q2.
The random movement of particles due to collisions in a fluid is known as motion.
Correct Answer: Brownian, brownian
Q3.
What is the name given to a material that other substances mix into or move through?
Correct Answer: medium, media
Q4.
Jacob is sat in his first floor bedroom. He can smell bread baking in the kitchen on the ground floor. This is due to the process of .
Correct Answer: diffusion, diffusing, diffuse
Q5.
Which of the following is a true statement about how quickly diffusion occurs?
Only the temperature of the medium will affect it.
Only the temperature of the diffusing substance will affect it.
Correct answer: The temperature of both the diffusing substance and the medium will affect it.
Temperature does not affect how quickly diffusion occurs.
Q6.
Complete the 3 sentences describing what is happening in the picture: The ink and water particles are ____ moving. They ____ together and this causes them to mix. The ink will ____ through the water.
An image in a quiz
not, hit, spread
Correct answer: freely, collide, spread
freely, smash, compress
not, collide, spread