Measurement
Length, Mass and Capacity: Comparing and Measuring
Year 1 · Year 2
- ✓By the end of this lesson students will be able to compare lengths, masses, and capacities using non-standard units.
- ✓By the end of this lesson students will be able to use appropriate vocabulary to describe and compare measurements (e.g., longer, shorter, heavier, lighter, more, less).
- ✓By the end of this lesson students will be able to measure lengths using standard units: centimetres (cm) and metres (m).
- ✓By the end of this lesson students will be able to measure mass using standard units: grams (g) and kilograms (kg).
- ✓By the end of this lesson students will be able to measure capacity using standard units: millilitres (ml) and litres (l).
Key concepts
Length tells us how long or short an object is, or how far it is from one end to the other. We can compare lengths to see which is longer or shorter.
Mass tells us how heavy or light an object is. We can compare masses to see which is heavier or lighter.
Capacity tells us how much liquid or other material a container can hold. We can compare capacities to see which container holds more or less.
Sometimes we measure using things like hand spans, paper clips, or small cups. These are called non-standard units because they are not always the same size for everyone.
Standard units are special units that everyone agrees to use, so our measurements are always the same. For length, we use centimetres (cm) and metres (m). For mass, we use grams (g) and kilograms (kg). For capacity, we use millilitres (ml) and litres (l).
Key facts to remember
- 1Length tells us how long or short something is.
- 2Mass tells us how heavy or light something is.
- 3Capacity tells us how much a container can hold.
- 4We use words like 'longer', 'shorter', 'taller', 'heavier', 'lighter', 'more', and 'less' to compare measurements.
- 5Centimetres (cm) and metres (m) are standard units for length.
- 6Grams (g) and kilograms (kg) are standard units for mass.
- 7Millilitres (ml) and litres (l) are standard units for capacity.
- 8Always start measuring from the '0' mark on a ruler or measuring jug.
Worked examples
Example 1
Look at the two pencils. Which pencil is longer?
Answer
The red pencil is longer. (Assuming a visual example where the red pencil is visibly longer)
This is called direct comparison.
Example 2
You have an apple and a feather. Which is heavier?
Answer
The apple is heavier.
We can feel the mass of objects to compare them.
Example 3
How many small cups of water will fill this jug?
Answer
It takes 5 small cups of water to fill the jug. (This is an example answer, the actual number would depend on the size of the cup and jug.)
This is measuring capacity using a non-standard unit (the small cup).
Example 4
Use a ruler to measure the length of your pencil in centimetres (cm).
Answer
The pencil is 15 cm long. (This is an example answer, the actual length would depend on the pencil.)
Always start measuring from the '0' mark on the ruler, not the very end of the ruler.
Common mistakes
- ✗Not starting at the '0' mark when using a ruler or measuring jug, leading to incorrect measurements.
- ✗Confusing units, for example, saying something is '5 kg long' instead of '5 kg heavy'.
- ✗Not understanding that standard units help everyone get the same measurement, no matter who is measuring.
- ✗Guessing measurements instead of using a proper measuring tool.
- ✗Thinking a taller container always holds more than a shorter one, without considering how wide it is.
Exam tips
- ★Always read the question carefully to know if you need to compare objects or measure them.
- ★When measuring, make sure your measuring tool (like a ruler or measuring jug) is placed correctly and you start from '0'.
- ★Use the correct unit (cm, m, g, kg, ml, l) in your answer to show what you are measuring.
- ★Practise comparing and measuring different objects at home and school to become confident.
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