###### Worksheets and lesson ideas to challenge students aged 11 to 16 to think hard about diffusion (GCSE and Key Stage 3)

*There are some great demonstrations to introduce diffusion. Give students a stop clock and ask them to record when they first smell deodorant that has been sprayed at the front of the class. If you also get students to raise their hands when they first smell the deodorant you will get a lovely ‘ mexican wave’ effect. Try adding lead nitrate and potassium iodide to a Petri dish of water, yellow lead iodide will form – this provides a great starting point for introducing the idea that particle size effects the rate of diffusion. *

#### Factors affecting rate of diffusion

Key Stage 3 worksheet on factors that effect the rate of diffusion. In this activity, students put a series of particle pictures in order of diffusion rate. The idea of this task is that it (hopefully!) will illicit the idea that the rate of diffusion depends on temperature and particle size. (PDF)

#### Measuring the rate of diffusion

GCSE practical to investigate how the rate of diffusion is affected by temperature. Students measure the rate of diffusion of food dye at different temperatures. Students also apply their understanding of diffusion and temperature to gas exchange in cold-water worms. (PDF)