Tuesday, June 17, 2008


Physics classes built model bridges as their year-end projects, and held their 38th Annual Rat Trap Car & Catapult Competitions. In the gym four students operated their working model cars. On the athletic field 23 students made working catapults and trebuchets. Click on the photos to enlarge them.

Catapults and Trebuchets: This was an accuracy and distance contest, based upon a points formula. Students were required to shoot six balls in three minutes: one ball for maximum distance and five balls for accuracy through two positioned hoops. Students were given a limited amount of energy (Catapults: yellow exercise band with Elastic Potential Energy of about 150 Joules) or 30 lbs of weight (Trebuchets: Gravitation Potential Energy of about 250 Joules).

Anna Gronauer and Portia Simermeyer had the best Catapult with a score of 624.4 points. The best Trebuchet scored 550.5 points and belonged to Cate Brown and Georgia Griffin.

Bridges: These had to be made of one-eighth-inch bass wood, maximum mass of 50 grams, and must cross an 11-inch gap, and must be capable of carrying an HO scale (1:87) Tractor-Trailer truck. The contest was scored on the strength-to-weight ratio with units of lbs/gram. The strongest bridge held 148 lbs of weight, while the winner of the contest had a strength to weight ratio of 5.43 lbs/g and was designed and built by Eleanor Thadani.

Rat Trap Car: All energy to drive the car comes from the two springs on a Rat Trap, which is 10 to 20 Joules of energy, depending on how it is harnessed. The best car this year went one HHS gym length (103.1 feet) and belonged to Lucie Torrey and Melissa Coffey. The best-ever car travelled about 3.5 gym lengths (363.9 feet) in 1994 and belonged to the legendary Seth Dunten.