Sense of measure – capacity, volume, mass

This topic is part of the National Curriculum but is not included in the DfE 2020 guidance or the NCETM Mastery PD Materials. There are no NCETM classroom slides to download for this unit. We hope that teachers/schools will plan to cover this material from their own existing high-quality resources and using the information and suggestions below.

National curriculum statutory requirements (p14)

Pupils should be taught to:

• choose and use appropriate standard units to estimate and measure length/height in any direction (m/cm); mass (kg/g); temperature (°C); capacity (litres/ml) to the nearest appropriate unit, using rulers, scales, thermometers and measuring vessels
• compare and order lengths, mass, volume/capacity and record the results using >, < and = .

Notes and guidance (non-statutory)

• Pupils use standard units of measurement with increasing accuracy, using their knowledge of the number system. They use the appropriate language and record using standard abbreviations.
• Comparing measures includes simple multiples such as ‘half as high’; ‘twice as wide’.

When planning this unit, build on children’s current understanding of length, developed previously (see Year 1, Unit 8). Comparing two or more two-digit numbers in a measures context will give the opportunity to apply number knowledge acquired in Year 2, Unit 1. Also, children should be familiar with the concepts of double and half from previous work (see Year 2, Unit 13) in order to compare measures multiplicatively.

Concepts of length, mass, capacity/volume and temperature

Precision of language is a key feature for children. Everyday vocabulary such as ‘how much does this weigh?’ rather than ‘what is the mass of …?’ will need to be discussed. The distinction between capacity (how much a container holds when full) and volume (how much space is taken up by something) is can also be quite abstract for young children so showing plenty of examples builds understanding.

Plan for plenty of practical experience of concepts alongside the introduction of units of measure and their abbreviations. Sensory experiences of units of measure develop pupils’ conceptual understanding. Having a 1ml of water drop on their hand or tongue gives a sense of scale of that unit, to be able to make decisions and compare measurements later.

The need for standard units

Demonstrate the need for a uniform unit of measurement. For example, using different people’s handspans to measure the length of a table would mean it is inaccurate and cannot be replicated. ‘How big is a foot?’ by Rolf Myller is an example of a story which demonstrates the need for a standard measurement.

The book ‘Jim and the Beanstalk’ by Raymond Briggs might be a starting point for discussing a standard measure - what might have happened if the wig maker had a different tape measure to the giant? It might also challenge a misconception that only straight objects have a length.

Discuss the need for an appropriately sized unit choice. For example, would you measure the capacity of a lake in millilitres? Why, or why not?

Estimating and comparing measures

Challenge some preconceptions that the children might have. For example, that a tall, narrow container always has a greater capacity than a short wide one or that a tall box has a greater mass than a smaller one. This may cause cognitive conflict initially but once discussed and experienced, children will realise the importance of measure rather than estimation by observation alone!
Posing questions such as ‘What has the greater mass - a kg of feathers or a kg of coins?’ is often something that causes wonder and therefore is memorable for children. Can they ‘trick’ their grown-ups?

Give children opportunities to reason about their estimations and adjust them if necessary. More accurate estimations will arise from experience of engaging with different measurements and more developed conceptual understanding about the units of measurement of length, mass, volume/capacity and temperature.

Opportunities to address this topic in other Units in the curriculum prioritisation materials

Year 2 Unit 1 includes work on length and reasoning about number lines, which could be linked to reading and marking on different scales.

Cross-curricular opportunities to address this topic

• Science - when working scientifically, children should be encouraged to estimate and make measurements in order to observe the world around them and to ensure when investigating, that tests are fair.
• Geography - identifying seasonal and daily weather patterns and identifying features of places could include opportunities to measure.
• Design Technology - measure ingredients for a recipe and consider the temperatures of storing and cooking the food. Measure materials for projects involving cutting and measuring in a variety of contexts.
• Create a role-play post office or visit a real one - measuring the length of and finding the mass of parcels and letters.
• Create a role-play shop or visit a real one - looking carefully at measures on packaging.