Choose a container. Will it hold enough?
Useful purpose: Interpret labelled capacity markings and distinguish amount currently present from maximum capacity.
1 · Find the starting point
Revisit mL for small liquid amounts; read 100, 200 and 300, and find the difference between 450 and 300.
2 · Prepare a suitable invitation
Adult reviews a stable unbreakable jug, clean familiar water if suitable, safe small volume and dry clear surface away from electrical devices. No tasting or compulsory pouring. Use descriptions if water or kit is unsuitable. Adult verifies the jug's units, spacing and capacity; a tall narrow shape alone proves nothing.
3 · Brief worked model
MODEL jug labels 0, 100, 200, 300, 400 and 500 mL, with a middle mark between labels. Each gap is 50 mL. Water at the 300 mL label means 300 mL is present. It does not mean the jug can only hold 300 mL. A container labelled capacity 500 mL can hold a target 450 mL; a 400 mL container cannot hold that target without another container.
4 · Guided new try
Read a new pictured or real labelled level together. Compare two container capacity labels rather than judging height. Demonstrate eye-level reading only with safe adult support, no bending/handling expectation.
5 · Own attempt
Choose a route; name mL, read the markings, compare target with capacity and explain a choice. State whether the child poured, directed, observed or interpreted a model.
6 · Observe and respond
Record unit, increment, level and capacity reasoning. The child can correctly choose a container without physically pouring; describe that evidence accurately.
Specific next teaching
If height is treated as capacity, offer two unrelated containers with known labels and discuss shape. If level and capacity are confused, label an empty 600 mL jug and ask what its empty state tells us.
Pick a route
1 · Small pour or direct
Stop at your chosen mark.
On adult-reviewed kit choose a safe marked amount, estimate it, and pour or direct a helper to approach it. Stop safely, read the actual level, and compare with the estimate. No correction needs to happen secretly.
Observe: Actual increment and level reading; roles and safety recorded.
Next teaching: Choose another small suitable amount and explain whether the same jug has enough capacity.
Evidence boundary: Observed action/directing/reading, not an invented exact result.
2 · Jug detective
How much more is needed?
MODEL: 300 mL present; target 450 mL. Work out 150 mL more and check 300 + 150 = 450. Choose a 600 mL capacity container rather than a 400 mL one for the whole target.
Observe: 150 mL more and capacity at least 450 mL.
Next teaching: Use a new target with new levels; keep supplied numbers separate from real measurements.
Evidence boundary: Supplied diagram and additive choice only.
3 · Tall is not enough
Which label helps us choose?
MODEL: tall narrow container capacity 350 mL; short wide container capacity 650 mL. Target 500 mL. Choose short wide and explain why the numbers matter more than the drawn height.
Observe: 650 mL capacity meets 500 mL; shape alone not evidence.
Next teaching: Read an unrelated actual adult-reviewed label and mark its source/date.
Evidence boundary: Supplied capacity comparison only.