Mathematics K–6 · Years 1–2
Roll, stack or slide: sorting 3D objects by what they can do
Measurement and space
The idea
The flat faces and curved surfaces of an object decide whether it can roll, stack or slide, so objects can be sorted by testing them.
What you need
- a set of wooden solids: 2 cubes, 2 rectangular prisms, 2 cylinders, 2 cones, 2 spheres, 1 square pyramid
- a board propped as a gentle ramp about 10 degrees
- a sorting sheet with three overlapping circles labelled rolls, stacks, slides
How to do it
- Predict for each object whether it will roll down the ramp, stack on another of the same kind, and slide across the table without rolling.
- Place each object on the ramp on each of its faces or surfaces in turn and record whether it rolls. Then push each one gently across the table on each flat face and record whether it slides without turning.
- Try to stack two of the same object. Record whether the stack stands.
- Place each object in the sorting sheet, including the overlaps for objects that do more than one thing.
- Count the flat faces on each object and look for the rule that links faces to stacking and curved surfaces to rolling.
What you should see
Spheres roll in every position and never stack. Cylinders roll on their curved surface and stack on their flat ends. Cubes and rectangular prisms slide when pushed and stack but do not roll; on the gentle ramp they may stay still rather than slide, because friction can hold a flat face on a shallow slope. Cones roll in a curve on their curved surface and stand on the flat base. The pyramid slides on its faces and does not stack point to point. Every object with a flat face slides on it and every object with a curved surface rolls on it.
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.
- All round-looking objects roll the same way.
- A cylinder cannot stack because it is round.
Safety card
Hazards
- rolling objects on the floor
Controls
- catch objects at the ramp bottom; keep the area clear
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-01MAO-WM-01
- Australian Curriculum v9AC9M1SP01
Sources
The pages the author read to write this activity.