Idea 1of 22
Length, mass, capacity or area?
Before you measure, how do you know which kind of unit to use?
Today you'll discover
- four different things to measure about one object
- which units go with each one
- the first question to ask
Think firstOne water bottle, many things to measure
You want to know how much water the bottle holds. What are you measuring?
Decide first, then press Next. Ask: what do I want to know about it?
A water bottle at the left. Down the right, four questions: how tall it is, how heavy it is, how much water it holds, how much its label covers. Beside each, its kind and units: length in cm, mass in g or kg, capacity in mL or L, area in cm². The capacity line is ringed. The last step shows a classroom rug.
See the whole ideathe big idea and the key word, in one place
The big idea
First decide what you are measuring: length, mass, capacity or area. Then pick its unit.
One bottle, four measuresHow tall it is: a length. How heavy it is: a mass. How much it holds: a capacity. How much its label covers: an area.
Easy to get wrongMass and capacity are different. A litre of feathers and a litre of water fill the same space, but the water is far heavier.
Key words
- length
- how long, tall, wide or far something is
- mass
- how heavy something is
- capacity
- how much a container can hold
- area
- how much surface something covers
Ready to use it?
- Say whether a question is about length, mass, capacity or area.
- Pick a unit of the right kind.