Year 8 ScienceDiffusion

Dr Lakshmi Sharma

Lesson Objective: To understand the process of diffusion & its relationship to living organisms.

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What is Diffusion ?

DiffusionParticle net movement from;

a region of HIGH concentration to a region of LOW concentration

High Concentration

Movement of Particles to Low Concentration Diffused Throughout

Equilibrium Lakshmi Sharma Diffusion - Cell membranes and Transport

Think Waterfall !!!!

High Low

Lakshmi Sharma Diffusion - Cell membranes and Transport

Does the diagram below represent Diffusion ?

Discuss for 1 minute in pairs

Answer – Why or Why not is this diffusion?

Explain what is happening to the dye particles at each stage

Lakshmi Sharma Diffusion - Cell membranes and Transport

Lakshmi Sharma Diffusion - Cell membranes and Transport

Does Diffusion require Energy ?

Lakshmi Sharma Diffusion - Cell membranes and Transport

NO !!! Diffusion is a PASSIVE process

How Diffusion Works

• http://www.youtube.com/watch?v=VY0mZUDvbH4

Lakshmi Sharma Diffusion - Cell membranes and Transport

Why is Diffusion Important in Biological Systems?

Using computers find out why diffusion is important

Work in pairs 5mins starting now

Lakshmi Sharma Diffusion - Cell membranes and Transport

Cell Membranes

Semi-PermeableCertain molecules can enter & leave the cell membrane-selective

High Concentration

Low Concentration

Nutrients

WasteCell

Lakshmi Sharma Diffusion - Cell membranes and Transport

Diffusion Across Cell Membranes

BEFORE DIFFUSION AFTER DIFFUSION

Lakshmi Sharma Diffusion - Cell membranes and Transport

Revision

1. Define Diffusion2. Why is Diffusion Important3. What does Semi-Permeable mean

Lakshmi Sharma Diffusion - Cell membranes and Transport

Extension – Further Knowledge

https://www.youtube.com/watch?v=RPAZvs4hvGA

Lakshmi Sharma Diffusion - Cell membranes and Transport

Look at the following youtube video on transport across the cell membrane.

Hope You Enjoyed The Lesson