The total area of the surface of an object.

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

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

Diffusion and surface area to volume ratio

Combined science

Pupils will learn how the components of the human nervous system enable us to respond to changes outside and inside our bodies.

Pupils learned about biological molecules that are essential to life, including sugars and other carbohydrates, proteins and lipids, and the role of enzymes in catalysing the chemical reactions in which these substances are used and made.

This unit covers the human circulatory system, its link to the gas exchange system, and the adaptations of the heart, blood vessels, and blood components. It explains transport mechanisms like diffusion, osmosis, and active transport, and the need for exchange surfaces in multicellular organisms.

Transport and exchange surfaces in humans

Physical activity and equipment requiring safe use

A 4 cm wide cube takes 60 minutes to fully discolour. If we cut the cube into 4 new cubes each 2 cm wide, how long would each cube take to discolour?

As the width of a cube doubles, the surface area to volume ratio also doubles.

As the width of a cube doubles, the surface area to volume ratio quadruples.

As the width of a cube doubles, the surface area to volume ratio halves.

As the width of a cube doubles, the surface area to volume ratio triples.

What is the relationship between the width of a cube and the surface area to volume ratio?

As the SA : V increases, the time taken for a substance to diffuse will ...

True or false? Diffusion is a passive process.

Net movement from a low to high concentration down a concentration gradient. 

Net movement from a high to low concentration down a concentration gradient.

Net movement from a low to high concentration against a concentration gradient. 

Net movement from a high to low concentration against a concentration gradient.

What is the correct description of diffusion?

What will happen to the particles of carbon dioxide?

Content guidance

Risk assessment required - equipment

Adult supervision required

This lesson will be removed by end of Summer Term 2025.

Diffusion and surface area to volume ratio

Lesson outcome

Content guidance

This lesson will be removed by end of Summer Term 2025.