Capacity
2.0 Measurement · 2.3 Capacity
Syllabus tag: Kenya CBC | Grade 6 Mathematics | Strand 2.0 Measurement | Sub-Strand 2.3 Capacity (6 Lessons)
Lesson objectives
By the end of this topic, you will be able to:
- Identify the relationship among cubic centimetres (cm³), millilitres, and litres
- Convert litres to millilitres
- Convert millilitres to litres
- Appreciate the use of cm³ and litres in measuring capacity in real life
Capacity
Capacity is how much a container holds. We measure it in millilitres and litres.
a) The units
A millilitre is a very small amount. A teaspoon holds about 5 ml.
A litre is a bottle of water or a packet of milk.
A cubic centimetre is the space inside a cube measuring 1 cm each way.
b) How they connect
One cubic centimetre holds exactly one millilitre. They are two names for the same amount, one describing space and one describing liquid.
A thousand millilitres make one litre.
So a thousand cubic centimetres also make one litre.
c) Converting
To change litres to millilitres, multiply by 1 000.
To change millilitres to litres, divide by 1 000.
A check: millilitres are smaller, so there are always more of them. Changing 3 litres into ml should give a bigger number, not a smaller one.
d) Reading a measure
Put the measuring jug on a flat table. Do not hold it up.
Bend down so your eyes are level with the liquid. Reading from above or below gives the wrong answer.
Read the mark where the surface of the liquid sits.
e) Everyday amounts
| Container | About |
|---|---|
| Teaspoon | 5 ml |
| Cup | 250 ml |
| Water bottle | 500 ml |
| Milk packet | 1 litre |
| Bucket | 20 litres |
| Jerrican | 20 litres |
Knowing a few of these helps you judge whether an answer is sensible.
f) Where this is used
Buying milk or cooking oil. Measuring medicine. Filling a jerrican at the tap. Following a recipe.
Words to know
- Capacity — the amount of liquid a container can hold.
- Millilitre (ml) — a small unit of capacity; 1,000 ml = 1 litre.
- Litre (L) — the standard unit of capacity for everyday amounts.
- Cubic centimetre (cm³) — a unit of volume equal to 1 millilitre of capacity.
:::checkpoint Check yourself
- How many millilitres make one litre?
- Change 5 litres into millilitres.
- Change 1 750 ml into litres.
- How much liquid does 1 cm³ hold? :::
Bridge to practice
Try the exercises below — converting between millilitres and litres, and adding, subtracting, multiplying, and dividing capacities.