Mathematics K–6 · Kindergarten
Packaging sort: objects that stack, roll or do both
Measurement and space
The idea
Three-dimensional objects can be sorted by testing them: flat faces let an object stack and slide, curved surfaces let it roll, and an object such as a can has both.
Safety card
Hazards
- sharp rims on cans
- packages falling from a tower
Controls
- use cardboard tubes or cans opened with a safety opener
- build towers on the floor, not on tables
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.
What you need
- 12 clean, empty packages: 4 cereal or tissue boxes, 1 triangular chocolate-bar box, 3 cardboard tubes or cans with smooth rims, 2 balls, 1 party hat (cone), 1 small cube-shaped box
- a ramp: a board about 60 cm long with one end raised 10 cm
- 3 hoops labelled stacks, rolls, does both
How to do it
- Handle each package and describe it: flat parts, curved parts, corners, and something else in the room it looks like.
- Test each one on the ramp: place it at the top and let go. Record whether it rolls, slides or stays still.
- Test stacking: try to balance a second package on top of it. Record yes or no.
- Sort the packages into the three hoops and give the test result that decided each one.
- Build the tallest tower the group can from the packages, count how many were used and note which objects were left out.
What you should see
The boxes and the triangular box slide or stay still on the ramp but never roll, and they stack. Tubes and cans roll when laid on their sides and stack when stood on a flat end, so they go in the does-both hoop. Balls roll in any direction and nothing balances on them. The party hat rolls round in a circle about its point on the ramp, and it stands only on its open circular base with the point up, so it can go only on the top of a tower. The tallest towers are built from boxes and upright tubes, with the balls and the cone left out or placed on top.
What changes
This activity lists no variables to change, measure and keep the same.
Common misconceptions
Each of these ideas is wrong, and the activity is a chance to test it.
- A cylinder cannot stack because it rolls.
- Objects are sorted by colour or by what they held, not by their faces and surfaces.
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 AuthorityMAE-3DS-01MAO-WM-01
- Australian Curriculum v9AC9MFSP01
Sources
The pages the author read to write this activity.