measurement · Year 3 · Suggested learning sequence
Choose a sensible unit or estimate
First decide what is being measured. Length (how long) uses millimetres, centimetres, metres or kilometres. Mass (how heavy) uses grams or kilograms. Capacity (how much something holds) uses millilitres or litres. Then use a benchmark to picture the size of one unit: a paperclip is about 1 gram, a bag of sugar is 1 kilogram, a milk carton holds 1 litre, a teaspoon holds about 5 millilitres, a big step is about 1 metre. Ask whether the object is about as big as a few of the benchmark, or hundreds of them.
Sample questions
Which unit would you use to measure the mass of an apple: millilitres, kilograms, grams or centimetres?
- Mass is how heavy something is, measured in grams or kilograms.
- An apple is about 150 g, so the mass is a sensible number of grams.
- Use grams.
Answer: grams
Which unit would you use to measure the length of a reading book (its width): centimetres, metres, grams or kilometres?
- Length is how long something is, measured in millimetres, centimetres, metres or kilometres.
- A reading book (its width) is about 20 cm, so the length is a sensible number of centimetres.
- Use centimetres.
Answer: centimetres
Which unit would you use to measure the length of an ant: kilometres, millilitres, millimetres or metres?
- Length is how long something is, measured in millimetres, centimetres, metres or kilometres.
- An ant is about 5 mm, so the length is a sensible number of millimetres.
- Use millimetres.
Answer: millimetres