1. Diffusion

2. objectives Gases can move from one place to another on their own
Know that this process is called diffusion and can be explained in terms of particles
Explain why the speed of diffusion can be changed by different temperatures.
Explain why diffusion is quicker in gases than in liquids.

3. Toast
Where does the smell come from?
How does the smell reach you?

4. answers
The smell starts in the corner of the room when the bread is cooked by the toaster
This makes a chemical reaction
The smell spreads through the air from one corner to the whole room (eventually)
Particles of gas carry the smell, moving through the air

5. What is diffusion? It is a type of spreading of particles
It happens in solids, liquids and gases
But mainly in liquids and gases

6. Speed of diffusion
Is it fastest in solids, liquids or gases?
Why?

7. An experiment
You will find out how temperature affects the speed of diffusion
Draw the results of your experiment and write down what you have found out

8. What is the best statement?
It was better in the hot water
It was fastest in hot water
The time was 10s in hot water and 67s in cold water so it was much quicker in hot water.
The time was 10 in hot water and 1.7 in cold water so it was much quicker in hot water because it diffuses quicker.
It was quickest in hot water (10s) than in cold water (67s) because the particles are moving faster.
It was quickest in hot water because the particles are moving faster and diffusing throughout the beaker. Cold water particles are moving more slowly and so don’t diffuse as fast.
why?

9. What makes it better is.. Use of figures Use of units
Use of scientific words
Reasons why

10. Even better if
Record the temperature of the water

11. summary Diffusion is spreading of particles
Fastest in gases because particles have more energy and are more free to move
Fastest in hot substances because particles have more energy too
The end