Practical We are going to do an experiment to see how particles of one substance move through a liquid.

Potassium permanganate in paper Stopwatch Beaker half full with water

How did the potassium permanganate move?

What was happening? Remember that particles in a liquid and gas can move around.

What was happening? Remember that particles in a liquid and gas can move around. We call the movement of one substance through a liquid or gas diffusion.

Diffusion

Diffusion is the spreading out of a substance from a high concentration to a low concentration.

Fill in the missing gaps on the sheet using the words in the box. Draw diagrams in the three boxes showing what happened as the potassium permanganate diffused. Try and mention particles in your answer.

Copy the boxes into your books Copy the boxes into your books. For each one draw a picture to show how the particles would be moving after those time periods. In your own words describe what the particles are doing under each picture. Write a definition of diffusion – use the words move, particles, high, low and concentration. Experiment at the start 2. Experiment after 2 minutes 3. Experiment after 10 minutes

Making Diffusion Quicker Sometimes diffusion needs to go faster. There are lots of ways to increase it. You are going to do an experiment to see one in action.

Rhubarb Rhubarb Pieces Time (seconds) 1 2 4 What happened to the time when the size of rhubarb increased? Write your answer in a sentence.

The more room there is, the more particles able to move. Rhubarb: Surface Area The more room there is, the more particles able to move.

In Humans Our lungs and our small intestines have lots of spaces for diffusion. We get oxygen quickly and absorb our food quickly because of this.

Low Concentration

Greater concentration difference High Concentration Greater concentration difference

Warm Particles

Hot Particles: Particles move more quickly

Task Answer the missing word sheet and questions.