Physics and Astronomy

Yo-Yo Challenge
Objective Each team entering this event constructs a yo-yo. This yo-yo is released from rest and must complete at least one cycle. The height of the yo-yo above its lowest position at the end of the first cycle is measured and recorded (see diagram).
Purpose To learn about rotational motion.
Participants Teams of up to six.

Teams will construct their own yo-yo prior to the event.


1. The suspended mass may not exceed 1 kg.

2. The maximum distance between the point of suspension and the floor is not to exceed 6 m. The yo-yo must start between the point of suspension and the floor.

3. The yo-yo may travel in a vertical direction only. A horizontal displacement which does not exceed 3 cm from the vertical will be allowed.

4. Only the initial gravitational potential energy of the yo-yo may be used as an energy source for the yo-yo.

5. The yo-yo or any part of the apparatus may not touch the floor and must be supported at one point only.

6. To help the judges, you might try suspending a stick or piece of wood from the ceiling close to the area where the yo-yo will be suspended. Attach this to the floor and use a marker for determining the score. Instead of wood, you might consider a piece of tape on the wall or a piece of string.



You should have two people marking - one person to record B and one to record C (see diagram).
All measurements must be done in metres.


The distance between the position of the yo-yo at at its lowest point (B) and the position of the yo-yo at the end of the first cycle (C) is measured and is entered as the score.

Three attempts will be allowed. No modifications to the apparatus are allowed between runs.

Picture of the Yo-Yo
Canadian Record The Canadian record for the Yo-Yo Challenge was set in 1983 by a team in the Physics Olympics run by the University of British Columbia. The winning team recorded a distance of 5.21 metres using a yo-yo built from two thin plates about 20 cm in diameter with carefully machined brass rings cemented to the periphery. The string was braided lubricated nylon. The best designs overall were similar to a conventional yo-yo but with greater density near the periphery. If you break this record, let us know.
Source Youth Science Foundation Manual.

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