How can I work out the length of an object?
How do you estimate the length of something?
Estimating means you work something out roughly
A good way of estimating a length is to measure it with part of your body:
- for short lengths try your hand span
- for something a bit longer try using the length of your feet
- for something even longer try using your arm span or steps
How do you measure length accurately?
To measure something accurately you should use standard units
You should use different units for different lengths:
- millimetres (mm) are good for very small lengths - like the width of a pencil or your finger
- centimetres (cm) are good for something a bit longer - like the length of a pencil or a book
- metres (m) are good for something even longer - like the width of a room or the length of building
- kilometres (km) are good for longer distances - like the distance between home and school, or between different towns
You should use proper instruments to measure accurately, like a ruler, tape measure, metre stick or trundle wheel.