# Diffusion and surface area to volume ratio

I can calculate the surface area, volume and surface area to volume ratio of different sized cubes and observe how long it takes for a liquid to diffuse into them.

# Diffusion and surface area to volume ratio

I can calculate the surface area, volume and surface area to volume ratio of different sized cubes and observe how long it takes for a liquid to diffuse into them.

## Lesson details

### Key learning points

- The concepts of surface area, volume, and surface area to volume ratio.
- Calculation of the surface areas, volumes and surface area to volume ratios of cubes of different sizes.
- Use of coloured agar cubes of different sizes to observe time taken for acid to diffuse to the centre of each cube.
- Interpretation of results and explanation using ideas about surface area to volume ratio and diffusion.

### Common misconception

Mistakes with the calculations of surface area or volume are common. The concepts of surface area, volume and their ratio, with the effect that changing these have on diffusion, are difficult.

Plenty of practise on how to calculate surface area and volume, and compare these as a ratio, some simplified, is included. The experiment results are used to show the impact of changing surface area, volume and width on diffusion.

### Keywords

Surface area - The total area of the surface of an object.

Volume - The total space of an object.

surface area to volume ratio - The relationship between the surface area and the volume of a shape.

Diffusion - Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration.

### Equipment

Beakers; cubes of agar containing phenolphthalein indicator and 0.5M sodium carbonate; 0.1M hydrochloric acid; timer

### Content guidance

- Risk assessment required - equipment

### Supervision

Adult supervision required

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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