How many cups fill the jug: capacity with uniform units · Concept Studio

The idea

Capacity is measured by counting how many times a smaller container fills a larger one, and the estimate can be improved after the first few cupfuls.

What you need

a clear measuring jug with the 1 L line marked by the adult with a thin strip of tape, and the rest of the scale taped over
a 250 mL plastic cup and a 125 mL cup
a 2 L ice-cream tub and a 600 mL water bottle
water, a funnel and a tray

How to do it

Estimate how many 250 mL cups of water will fill the jug. Write the estimate down.
Pour full cups into the jug one at a time, tallying each. After 2 cups, look at the jug and revise the estimate. Continue until the water reaches the 1 L line.
Empty the jug and repeat with the 125 mL cup. Compare the two counts.
Use the 250 mL cup to measure the ice-cream tub and the water bottle. Order the three containers by their cup counts.
Pour the full jug into the ice-cream tub and see that there is room left, matching the counts.

What you should see

The 1 L jug takes 4 cups of 250 mL and 8 cups of 125 mL, so halving the unit doubles the count. The 2 L tub takes 8 cups of 250 mL and the 600 mL bottle takes 2 cups with a little space left (600 divided by 250 is 2.4). After two cupfuls the jug holds 500 mL, half of the litre, which gives a better base for the revised estimate. Pouring the full jug into the tub fills it about half way, which agrees with 4 cups against 8.

What changes

What you change: the size of the cup used as the unit
What you measure: the number of cupfuls needed to fill the jug to the 1 L line
What you keep the same: the same jug filled to the same 1 L line
each cup filled level to the top
no spills

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

A taller cup always holds more than a wider one.
A bigger count of cupfuls always means a bigger container, whatever the cup.

Safety card

Low riskLearners carry it out

Hazards

water spills make floors slippery

Controls

work over a tray and mop spills at once

Note

No chemicals or heat are used, so the NSW Department of Education Chemical Safety in Schools package is not needed; ordinary classroom supervision under the school's usual risk management.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Mathematics K-10 Syllabus (2022), NSW Education Standards AuthorityMA1-3DS-02 MAO-WM-01
Australian Curriculum v9AC9M1M01AC9M2M01

Sources

The pages the author read to write this activity.