The surface area of an object refers to the sum of the areas of the faces of the shape. A cube has six faces and therefore its surface area is the sum of the six faces that make up the cube. This will be measured in square metres and the square metre is the base unit for area. 

Figure 1 shows a cube with its net (its appearance if opened and laid out flat). There you can see the six faces of the cube which comprise its surface area.

Volume refers to the amount of space that an object occupies. For example, your water bottle may take up about 0.002 cubic metres of space. The cubic metre is the base unit for volume.

Capacity is similar to volume where calculations are concerned. The same formulae can be used for both. However, capacity deals with the amount of liquid an object can hold. The base unit for capacity is the Litre but millilitres are commonly used as well. Hence, the capacity of a tetra pack is 250 ml. 

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