When can you smell the deodorant?Put your hand up when you can

• What happened?• Why did this happen?• How did the smell get from one end of the

room to the other?

Diffusion

• Describe what diffusion is• Use the particle theory to explain why

diffusion is faster in gases than liquids• Use the particle theory to explain why

diffusion doesn’t happen in solids

Lesson Objectives

What is Diffusion?

• Video: Diffusion• Watch the video and make observations• Can you figure out what diffusion is?

– What would the jar look like after a few hours?– Why didn’t the colour stay in one place?

Can you explain…

• …using ideas about particles?• …using ideas about states of matter?

Diffusion• Particles are ALWAYS moving.• Diffusion is the spreading of particles.• In which states of matter are the particles

moving the fastest?

Diffusion

• Diffusion only happens in liquids and gases, NOT in solids.

• Use the particle model to explain why.• Diffusion only happens in liquids and

gases because the particles can move around.

• Solid particles are stuck in a fixed place and cannot move around much.

Diffusion Experiment• What affects the speed of diffusion? (how

fast the particles spread out)

• We are going to place tea bags in cups with different temperatures of water.

Purpose:• We are going to see how _____________

(independent variable) affects the ___________. (dependent variable).

Diffusion Experiment• What affects the speed of diffusion? (how

fast the particles spread out)

• We are going to place tea bags in cups with different temperatures of water.

Purpose:• We are going to see how temperature

(independent variable) affects the speed of diffusion. (dependent variable).

Diffusion Experiment• Use three different temperatures of water (Hot,

room temp, cold) and put into clear cups if possible (make sure its safe for hot water!).

• Place a tea bag in each cup and time for one minute.

• Take a photo or draw a picture into your books showing the colour of each cup of tea.

• Write a conclusion relating temperature to speed of diffusion.

Conclusion

• The higher the temperature, the faster the speed of diffusion.

• We know this because of how fast the colour changed.

• The higher the temperature, the faster the particles are moving around (faster they are spreading out) and the faster the speed of diffusion.