Capacity and volume
Measure and begin to record capacity and volume using non-standard and standard units
What a learner can do afterwards
- Measure capacity by counting equal full cupfuls, and find how many cupfuls remain after some water is poured out
- Begin to use litres as a unit of capacity
- Record capacity measurements with a number and unit
1 · Read
Capacity is how much a container holds when full. The water inside may be less. Here, choose a container that fills exactly with full cupfuls. Start empty. Use the same full cup for every pour and count until full. Pour without spills. If water spills, empty the container and start again.
Omar fills an empty bottle without spills using five full cupfuls from the same cup. He writes '5 cups'. The number tells how many. The unit tells what he used. Writing only '5' or only 'cups' leaves out part of the measurement.
Each block represents one of Omar's five cupfuls.
Litres measure capacity and amounts of liquid. Fill a one-litre jug to its one-litre mark to measure one litre. Count each litre poured. Record the number and unit, such as '4 litres'. A ruler measures length in centimetres. A weighing scale measures mass in grams.
Cups can differ in size. Compare cup counts only when the measuring cups hold the same amount. More cupfuls then means greater capacity. A larger cup needs fewer full cupfuls to fill the same empty jug: six small cupfuls might fill it, or three large ones.
The bars count cupfuls needed for the same jug. They do not draw the cups or show their sizes.
If you pour in two rounds, count the cupfuls from both rounds together. Keep the same cup throughout. Two cupfuls followed by four more make six cupfuls. Count every block, or start at two and count on four: three, four, five, six.
Each block represents one cupful. The groups show the two rounds.
Pouring water out changes the amount inside, not the container's capacity. A jar with six cups of water has five cups left after one cup is poured out. Count the cupfuls left. To find how many more cupfuls will fill a container, count from the amount inside up to its capacity.
Each block represents one cupful. One of six cupfuls is poured out, leaving five.
To find how much more one container holds, use the same unit for both. Count from the smaller number to the larger number. A pot holding eight cups holds two cups more than one holding six cups, using the same measuring cup. This method also works with litres.
Count the cups, then write the number with a unit.
This capacity lesson, its questions and flashcards were written for this dataset.
These readings and extra questions were written for this dataset. The flashcards practise capacity and measurement facts.
More to read
Check each cupful
Use a container that fills exactly with full cupfuls from your chosen cup. Start with the container empty. Fill the same cup for each pour and count when all its water reaches the container. Stop when full. If water spills, empty the container and begin again. Write the count with 'cups'. A different-sized cup may give a different count for the same container.
Read a litre measurement
A measuring jug can have a line marked '1 litre'. Water reaching that line measures one litre. Pouring three of these litre amounts gives three litres. In the record '3 litres', the number tells how many and the unit tells what was measured. Two capacity records in litres can be compared by their numbers. For records in cupfuls, check that the measuring cups hold the same amount.
The container and the water
An empty bottle still has a capacity. Its capacity tells how much it can hold when full. Pouring water in or out changes the amount inside. Suppose a container holds nine cupfuls when full and now contains seven. Count from seven to nine to find the two cupfuls still needed. Use the same measuring cup for every cupful.
2 · Watch
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Where it sits
Learn first
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Where this leads
17 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.