Capacity

Capacity means the measurement of how much a container can hold.

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Why do we need to know the capacity of something?

• Knowing the capacity of your water bottle will help you to know if you are drinking enough water to stay hydrated.

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• Using a measuring spoon will help you to measure the correct amount of medicine to take when you are sick.

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• You need to know the capacity of measuring jugs and containers of ingredients in order to get to follow a recipe.

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How can we measure the capacity of something?

Using a spoon, we can fill a container with water and count how many spoonfuls of water fit into the container.

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We can fill a container with cubes and count how many cubes fit in the container.

�These are useful ways to get an idea of how much a container can hold but if you need to go to the shop to get some milk to bake a cake, can you ask for 20 cubes of milk or 10 spoonfuls of milk?

�Instead of using cubes or spoonfuls to measure capacity, we use units of measurement that are specific and do not change, like litres.

A Litre

A litre is about the capacity of a carton of milk.

Can think of any containers that are about� the same size as a carton of milk?

Can you think of any containers that are about a litre?

These containers can hold a litre:

• A carton of milk
• A litre bottle of water
• A jug��

Estimating

What does estimating mean?

�Estimating means having a good guess at something before you do it.

�Why do we estimate?

�If we estimate before we measure it can save us time. We can use an estimate if we don’t need to find a specific amount of something.

How do we estimate?

Estimating Strategy:

• When estimating it is a good idea to have an estimating benchmark. Can you think of something that is about a litre?�
• You could visualise something that is about a litre, half a litre or quarter of a litre and try to see if another container is about the same size.

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• You need to know the capacity of measuring jugs and containers of ingredients in order  to follow a recipe successfully.

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• Can you think of any other strategies?

Estimating

Remember, estimating is not about getting the answer right or wrong. �We estimate to save time before we start to measure.

If we think about what we are about to measure before we begin our work, we will get a good idea of what our actual answer will be.

Let’s Estimate

Estimate how much each container can hold, more, less or about a litre. Click each item to find out

the answer.

Next Slide

Questions

1. How many children could have a full cup of water from a� litre bottle?�
2. Why do you think some liquids are sold in cartons that are different shapes and sizes?