Surface Area to Volume Ratio

Key Stage 4

The surface area to volume ratio is the relationship between the volume of an object and the surface area of that object which can be used to explain how the properties of a material or object can change due to the size of the object.

As the size of an object decreases the surface area becomes larger compared to the volume of the object.

Surface Area : Volume Area of 1 face x 6 : Volume 3x3 x 6 : 3x3x3 54cm² : 27cm³ 2cm² : 1cm³	Surface Area : Volume Area of 1 face x 6 : Volume 2x2 x 6 : 2x2x2 24cm² : 8cm³ 3cm² : 1cm³	Surface Area : Volume Area of 1 face x 6 : Volume 1x1 x 6 : 1x1x1 6cm² : 1cm³

The surface area to volume ratio explains why

A mouse will freeze quicker in cold temperatures than a bear because the larger the surface area the quicker an object can emit thermal energy and the smaller the volume the less thermal energy in the object.

A mouse has a large surface area compared to its volume so it loses thermal energy quickly.

Multicellular organisms need specialised tissues with large surface areas to absorb nutrients and Oxygen because the larger the surface area the quicker an object can absorb chemicals and the larger the volume the more chemicals the object needs.

A multicellular organism has a large volume compared to its surface area so it needs parts of its body to have a large surface area to absorb enough nutrients and Oxygen.

Catalysts work better when made into nanoparticles because their atoms interact with the chemicals to increase the rate of a reaction so when a catalyst is made into nanoparticles the number of atoms on the surface of the object is greater compared to the volume of catalyst.