Measure It Right
Class 6 Science: motion and measurement of distances
Measure a bench in handspans and see why we need standard units. Then read a pencil on a broken ruler, keep your eye in the right place and change cm to mm.
Words to know
- Measurement
- Comparing an unknown quantity with a known fixed quantity (a unit).
- Standard unit
- A unit that is the same everywhere, like the metre, so everyone gets the same answer.
- SI unit
- The international system of units. The SI unit of length is the metre (m).
- Centimetre
- One hundredth of a metre. 1 cm = 10 mm, 100 cm = 1 m.
- Parallax
- A wrong reading you get when your eye is not straight above the mark.
Quick check
Answer 3 questions to check what you learned.
Try at home
Measure the length of your bed in your handspans, then ask an adult to do it with theirs. Now measure it with a measuring tape. Which answer would a shop selling bedsheets want?