Physics and Astronomy

Water Balloon Launch
Objective Each team will attempt to launch a water balloon and hit targets at each of two distances such as 50 and 80 metres, using a launching device (standard goal posts and surgical tubing) provided.
Purpose To investigate the physics of trajectories.
Participants Teams of up to four people.
Materials 200 g of spaghetti, 2 metres of masking tape, 1 Styrofoam cup
  1. Two parallel strands of 5/8" surgical tubing will be strung between the uprights of a football goal post. The two strands will be threaded through an aluminum cooking pot with approximately 4 inches of polyurethane cushion about its mid points. The pot shall have an approximate depth of 15 cm and a width of 30 cm and be partially concave facing the football field. The pot shall be provided with a harness ending in a rope to be used to pull it into launch position.
  2. Each team will provide their own balloons, each of which must satisfy visual inspection of a judge that they contain a minimum of 400 ml. of fluid each.
  3. Each team will compete in each of two rounds with no more than three other teams included in each competing set.
  4. Rounds will be conducted against targets (a garbage can) on the 30 and 60 yard lines of the football field.
  5. Each team will be allowed an initial practice shot at each distance immediately prior to the competition.
  6. During a round, once the team is on site and the field clear the judge will blow an initial whistle. The team is then allowed one minute to launch their initial shot and an additional one minute to complete their second shot, for a total time of two minutes per team per round.
  7. All competition for the first round will be conducted before the range is changed for the next round.
  8. The order of competition within each round can be changed by the judges.
  9. Example: The target is on the 50 meter line,-and the range is 40 meters.

    If the two shots were 5 meters and 3 meters from the target, the sum of the difference would be
    (5 and 3 = 8 m). And 40-8 is 32 thus 32/40 or 80% is the score for the round.


  1. Each shot is marked on the field. The distance from the point of impact to the centre of the base of the target is recorded.
  2. A direct hit on any part of the target is recorded as zero distance.
  3. The distances from the target for the two attempts a team makes are added together. This aggregate distance is subtracted from the target distance and is expressed as a percentage of the target distance; as illustrated in the example above. This figure reflects the accuracy of the team's launches.
  4. The sum of the percentage value for each round is the team total for the competition. The highest team total will be the winner. In the event of a tie, both teams may have a shoot-out to determine the winner and 1st runner up.
Source Youth Science Foundation Science Olympics Manual.

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