Capacity
🎯 In this topic you will
- Estimate and measure capacity in millilitres and litres.
- Use instruments that measure capacity.
🧠 Key Words
- capacity
- litres (L)
- millilitres (ml)
Show Definitions
- capacity: The amount of liquid a container can hold.
- litres (L): A metric unit used to measure larger amounts of liquid capacity.
- millilitres (ml): A metric unit used to measure small amounts of liquid; 1000 millilitres equal 1 litre.
🥄 What Is Capacity?
Capacity is the total amount that something can hold. A teaspoon holds 5 millilitres. It can be used to measure how much medicine you need to take.
🍼 Measuring a Bottle
This bottle can hold half a litre. If the bottle is not full, you will have less than half a litre.
🥣 How Much Can a Bowl Hold?
Your bowl can hold a quarter of a litre. If you fill it with cereal and add milk, then the amount of milk will be less than a quarter of a litre.
❓ EXERCISES
1. Describe the scales on each of these containers. They all have the same capacity of $1$ litre but are not filled to the top.
d. Put the containers in order from the highest amount of water to the lowest.
e. Write how much each container is holding.
f. Put markings on this jug.
g. Draw a line for the level of water.
h. What is the capacity of your jug?
i. Write how much water is in it.
👀 Show answer
a. Container a is filled to about $250$ ml.
b. Container b is filled to about $750$ ml.
c. Container c is filled to about $500$ ml.
d. Order from highest to lowest: b, c, a.
e. a: $250$ ml, b: $750$ ml, c: $500$ ml.
f–g. Mark the jug at equal steps (for example every $250$ ml) and draw the water level.
h. The jug capacity is $1$ litre ($1000$ ml).
i. The water shown is about $\dfrac{1}{2}$ litre ($500$ ml).
2. Label each set with the total amount of drink. Each tin has a capacity of $250$ ml. Four cans hold $1$ litre. How many litres are in each of these boxes?
👀 Show answer
a. $250$ ml = $\dfrac{1}{4}$ litre.
b. $3 \times 250 = 750$ ml = $\dfrac{3}{4}$ litre.
c. $6 \times 250 = 1500$ ml = $1.5$ litres.
d. $8$ cans = $2$ litres.
e. $12$ cans = $3$ litres.
f. $16$ cans = $4$ litres.
3. Marcus says container $1$ has more because the water goes higher up the side. Is Marcus correct? Look at the capacity markings on both jugs. Explain your answer.
👀 Show answer
Yes. Container $1$ shows about $800$ ml, while container $2$ shows about $750$ ml. The scales are different, but reading them carefully shows container $1$ really does have more water.
4. Each jug has the capacity to hold $1000$ ml of liquid. Use what you know to estimate these measurements. Round each value to the nearest marked division.
👀 Show answer
a. About $600$ ml.
b. About $400$ ml.
c. About $200$ ml.
🧠 Think like a Mathematician
Task: You have two cups with different capacities. Use only full cups to measure different amounts of water.
Cup A holds $500$ millilitres.
Cup B holds $300$ millilitres.
Challenges:
Show Answers
- a. Use two full Cup A pours: $500 + 500 = 1000$ ml.
- b. Use one full Cup A and one full Cup B: $500 + 300 = 800$ ml. Then pour back $100$ ml (by filling Cup B from Cup A once more and stopping early) to leave $700$ ml.
- c. Fill Cup A ($500$ ml). Pour into Cup B ($300$ ml). This leaves $200$ ml in Cup A. Repeat once more to isolate $100$ ml by transferring between cups.
- d. Yes. Because $500$ and $300$ have a difference of $200$, and repeated pouring lets you create $100$-ml steps, you can make: $100, 200, 300, 400, 500, 600, 700, 800, 900,$ and $1000$ ml.