Reading Scales and Part Marks
Interpret unmarked and partial units when measuring and comparing attributes of length, mass, capacity, duration and temperature, using scaled and digital instruments and appropriate units.
Read this first
Work out what one small mark is worth. Then count the marks.
Ten spaces make 100. So one space is 10.
Words you need
- Scale
- The marks on a ruler or jug that show amounts.
- Unit
- What we measure in. Grams, litres, degrees.
- Estimate
- A close guess.
Worked example
e.g. A jug is marked 0 and 100. There are 10 spaces. The water is on the third mark. How much is there?
- Count the spaces from 0 to 100. There are 10.
- Share 100 into 10 spaces. One space is 10.
- The water is on the third mark. Count 10, 20, 30.
- There is 30 in the jug.
Count the spaces, not the lines. Spaces tell you the size.
Practice
The pictures fade as you go. By the last few you are on your own.
1A scale goes 0 to 50 in 5 spaces. What is one space worth?with a picture
Answer10.
2A scale goes 0 to 20 in 4 spaces. The arrow is on mark 3. What is the reading?with a picture
Answer15.
3A ruler is marked in cm. The pencil ends halfway between 8 and 9. How long is it?with a hint
Need a hint?
Half of one centimetre is 5 mm.
Answer8 and a half cm, or 85 mm.
4A jug holds 2 litres. The water is halfway. How many millilitres?with a hint
Need a hint?
One litre is 1000 millilitres.
Answer1000 mL.
5Would you weigh a cat in grams or kilograms?on your own
AnswerKilograms. Grams would be a very big number.
6Would you measure a room in centimetres or metres?on your own
AnswerMetres.
7A thermometer reads between 20 and 21. Estimate the temperature.on your own
AnswerAbout 20 and a half degrees.
Think about it
1
Why count spaces and not lines?
One good answerThere is always one more line than space.
2
When is an estimate good enough?
One good answerWhen you only need to know roughly, like the weather.
Common mistakes
Counting the lines instead of the spaces.
Start counting from zero, after the first line.
Using the wrong unit.
Pick a unit that gives a sensible number.