Science and Technology K–6 · Kindergarten

Ramp race: which shape rolls fastest and furthest

Physical World (NSW 2017); Science understanding, Physical sciences (ACARA v9)

Practical, model not builtLow risk

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The idea

An object's shape changes how it rolls down a ramp: a solid ball beats a solid roller, which beats a hollow ring, whatever their size.

What you need

A 1.00 m smooth ramp (plank or shelf) propped on a 20 cm stack of books, giving a rise of 0.20 m
A solid rubber ball, a solid wooden cylinder (for example a 10 cm length of thick dowel) and a hollow ring (a plastic bangle, an embroidery hoop or a roll of masking tape), all released from the same line; not a full tin (its liquid contents do not roll like a solid) and not a tin with its ends removed (sharp edges)
A 5 m strip of masking tape on the floor (on carpet if there is one) marked every 10 cm from the bottom of the ramp, with a catcher at the far end
A release card (a ruler held across the ramp and lifted) so nothing is pushed
Recording table with three rows (ball, roller, ring) and three trial columns for distance rolled

How to do it

Predict which shape will reach the bottom first and which will roll furthest on the floor. Record the prediction.
Place two objects behind the ruler at the top line. Lift the ruler straight up so both start together. Watch which reaches the bottom first.
Race every pair (ball against roller, roller against ring, ball against ring). Record the winner each time.
Release each object alone three times and read how far it rolls along the tape; a roll that goes past the end is recorded as past 5 m. Record all three and circle the middle value.
Compare with the prediction and say what was the same and what was different.

What you should see

Released from the same 0.20 m rise, the solid ball reaches the bottom first, the solid roller second and the hollow ring last. Speeds at the bottom computed from v = sqrt(2 g h / (1 + k)) with g = 9.80 m/s^2 and h = 0.20 m: ball (k = 2/5) 1.67 m/s, solid roller (k = 1/2) 1.62 m/s, hollow ring (k = 1) 1.40 m/s. The roller is 15 per cent faster than the ring, the figure HyperPhysics states for a cylinder against a hoop. Times down the 1.00 m ramp (rise 0.20 m, angle 11.5 degrees): ball 1.20 s, roller 1.24 s, ring 1.43 s. When the ball reaches the bottom the roller is 7 cm behind it and the ring 30 cm behind, so the ball-and-roller race is close and needs a clean release and a watcher at the finish line; no stopwatch is needed. A masking-tape roll has thick walls (for a 38 mm inner and 52 mm outer radius, k = 0.77 and the speed at the bottom is 1.49 m/s), so it is a little faster than a thin hoop but still slower than the solid roller. Distance along the floor is measured, not predicted: it depends on the floor and the object, and the middle of three trials is the class result. Rolling resistance on a hard floor is small: even with a coefficient of 0.06, the top of the range HyperPhysics reports for car tyres, energy reasoning (distance = rise divided by the coefficient) gives 3.3 m from the 0.20 m rise, which is why the tape is 5 m long and carpet helps. The learner knows it worked when the finishing order is the same in all three pairings.

What changes

What you change: shape of the rolling object (solid ball, solid roller, hollow ring)
What you measure: finishing order down the ramp; distance rolled on the floor (cm)
What you keep the same: ramp height 0.20 m
release from the same line with the ruler lifted, no push
same floor surface
three trials each

Common misconceptions

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

Heavier objects always win a ramp race (with rolling shapes, mass and size cancel; shape decides).
A bigger ball rolls faster than a smaller ball.
The ring should win because it is lighter.

Safety card

Low riskLearners carry it out

Hazards

Objects rolling into walkways; the propped ramp slipping

Controls

Ramp taped to the books; a catcher at the far end of the tape

Note

No chemicals or heat. Record the activity on the school's risk assessment (Primary School RiskAssess, Ecosolve Australia, riskassess.com.au).

Curriculum references

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

Science and Technology K-6 Syllabus (2017), NESA. Current syllabus; NESA's timeline is 2026 plan and prepare, 2027 start teaching the 2024 syllabus. Code read from the official syllabus document on 2026-09-22.STe-5PW-ST STe-1WS-S
Science and Technology K-6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the outcomes page on 2026-09-22.STE-SCI-01 STE-PQU-01
Australian Curriculum v9AC9SFU02AC9SFI01AC9SFI02AC9SFI03AC9SFI04

Sources

The pages the author read to write this activity.

All Concept Studio activities