At the end of the Second World War, a number of different systems of measurement were in use throughout the world. In 1960, the 11th General Conference on Weights and Measures synthesised the results of a 12-year study and created a new system that was named the International System of Units, abbreviated SI from the French name, Le Système International d’Unités. The SI is the only system of measurement with an official status in nearly every country in the world, with some countries still using different measurement systems, such as the Imperial measurement system used in the UK.

Table 1 shows the units of measurements and some derived units for length, mass, and volume in the two systems:

Table 1. Units of measurements in different measurement systems.

Your child might be too young to learn all of these yet. However, your child will hear these measures being used all of the time in their daily lives. Showing your child how these are used in your everyday life and how they relate to each other (how many centimetres in a meter, how many millimetres in a foot) will help your child develop a full understanding of how and when we use these words. Moreover, you might want to create, with your child, visual resources to support their understanding of measurements in different systems and their relationships (Figure 1 and 2).

Figure 2

Figure 1 and Figure 2. Visual resources to support your child’s understanding of measurements.

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Mathematics is a term that is often used as if it is one thing. However, the Greek origin of the word actually refers to ‘learning or knowledge’ and includes a number of things, including quantity (numbers), algebra (structure), space (geometry) and analysis (change). As such there are a number of concepts that children need to learn.

When it comes to measurement there are two concepts that are often confused: volume and capacity. They are both properties of three-dimensional objects. Three dimensional objects can be a cube, a cone, a cylinder etc.

Volume is the space that a three-dimensional object occupies or contains. For example, the volume of a cube that is 3 cm by 3 cm by 3 cm is 27 cm³ (3 x 3 x 3 or 3³). As you can see in the drawing below it is the space that it occupies.

Capacity, on the other hand, is the property of a container and describes how much a container can hold. So, when we refer to a measuring jug or a glass/ beaker or mug and how much liquid it can hold, we should refer to the capacity of it.

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