High school students will get to send pumpkins soaring at the 2008 High School Design Competition on Tuesday, Oct. 28, at the University of Kansas School of Engineering.
The annual competition will let teams of students in ninth through 12th grade test their creative and technical talents as they design and build a small trebuchet that can send a small pumpkin pillow flying. A trebuchet is a gravity-powered machine similar to a catapult that is capable of launching an object into the air.
Working in teams of two to four students at their schools, participants must design, construct and test their trebuchet to accomplish three pumpkin chuckin’ objectives: land the payload as close as possible to a point of their choosing, land the payload as close as possible to a point announced the day of the event, and send the payload the farthest distance. Moreover, teams will be required to use some recycled materials in their construction.
Teams must register at the KU School of Engineering Web site by Oct. 10, and one week before the event each team must submit a written report of all recycled materials used in their design.
All activities will take place in Eaton Hall on the KU Lawrence campus. Check-in begins at 8 a.m. and competition gets under way at 9:30 a.m. Lunch will be provided for all participants and parking passes will be available for registered schools. All high schools, virtual schools and home-school programs at the high school level are welcome to participate.
Rules and a schedule of activities are available at the KU School of Engineering Web site. Rules will be clarified and modified as questions arise. Teachers, mentors and students are encouraged to check back often. Questions on the competition, including rule clarifications, should be directed to Alexis McKinley Jones, (785) 864-3402, or
Design, build and operate a small gravity-powered trebuchet that can launch a tiny toy “pumpkin” to a specified distance. Competitors will be judged based on greatest distance, accuracy of launch to a point of the team’s choosing and accuracy of launch to a point announced the day of the event. A special award also will be given to the team displaying the best use of recycled materials, as determined by a separate committee.
The competition will be Tuesday, Oct. 28, 2008, in the atrium of Eaton Hall on the KU campus. Teams must register online by Oct. 10.
Trebuchets have parts that move quickly. Students should practice safety precautions when building and testing their designs. Always wear safety glasses. Never stand in front of a loaded trebuchet.
1. The entire trebuchet (when ready to fire) must be able to fit in a box measuring 20 inches wide, by 20 inches tall by 20 inches deep.
2. Only gravity may be used to power the trebuchet.
3. The payload is a small irregularly shaped pumpkin pillow that weighs approximately 45 grams, or 1.5 ounces. Its peak latitudinal circumference is 14 inches; peak longitudinal circumference is 12.75 inches.
4. The counterweight may not touch the floor or launching site. The design must include a platform to “catch” the descending counterweight.
5. Any loose or liquid materials used for the counterweight must be contained at all times (no spills).
6. No remote control devices will be allowed.
7. Purchased trebuchet “kits” will not be allowed.
8. Each trebuchet must use at least two recycled materials.
9. Teams are encouraged to use as many recycled materials as possible in the design and construction of their trebuchet. In the event of a structural failure during competition (something breaks), teams will be allowed to make repairs and replace parts, however, broken components may only be replaced by a component made of similar material.
10. Each team must prepare and deliver a printed report that details the use of recycled materials in the trebuchet. This report must be submitted to the KU School of Engineering staff by
Tuesday, October 21st at 5:00 PM. The report may be emailed to
with the subject line of Trebuchet Report.
11. Each team will have two opportunities to launch their pumpkin for each portion of the competition. The team’s best attempt in each of the three contests will be used for judging that portion of the competition.
12. Safety glasses must be worn by team members during each launch.
13. Team members must be in ninth through 12th grade. Minimum team size is two students. Maximum team size is four students.
14. Each team will be allowed up to three minutes to set the trigger before each launch.
15. Anyone violating “the spirit of the competition” will be disqualified.
16. Rules will be modified/clarified as questions arise. Check back to this site often.
Questions & Rules Clarifications
1. How do you pronounce “trebuchet?”
Merriam-Webster’s Online Dictionary says the word is pronounced: tre-byə-ˈshet, tre- bə-, -ˈchet Listen to a pronunciation
2. May a gear system or pulley system be used in the trebuchet?
Yes. The device must still comply with Rule 2. Submitted Oct. 1, 2008
3. Since this competition will be inside, how high is the ceiling in Eaton Hall?
In the atrium, where the competition will take place, the ceiling is about 21.5 feet above the floor. In addition, there are two rows of pendulum lighting, where light fixtures extend downward approximately 3 feet from the ceiling. Posted Oct. 6, 2008
4. Is there a limit on the number of teams from each school?
No, there is not a limit on the number of teams from each school. Posted Oct. 7, 2008
5. Can the trebuchet have adjustable arms?
Yes, as long as the trebuchet fits in a box measuring 20 inches wide, by 20 inches tall, by 20 inches deep when it is ready to launch. Posted Oct. 7, 2008
6. Could you define “recycled material” more thoroughly?
Recycled material = taking materials whose original purpose was for something else, and repurposing it for use in the trebuchet. Example, using an old coat hanger as part of the trebuchet. Posted Oct. 8, 2008
7. Is the trebuchet allowed to have wheels?
Yes, wheels are allowed as long as the trebuchet is not moving while launching “the pumpkin.” Posted Oct. 8, 2008
8. What are the options for releasing the trebuchet? Can the students just hold it, or does there need to be a different type of release mechanism?
Due to safety precautions, we need to make sure that students are protected from moving parts during launch and are not just holding the trebuchet down to release it. Therefore, they will need to create some kind of release/trigger mechanism. Posted Oct. 9, 2008
9. Is there a limit on how much the tebuchet's counterweight can weigh?
No. There is not weight limit for the counterweight. Posted Oct. 14, 2008
10. Can the sling that is attached to the trebuchet be longer than the 20" by 20" by 20" specification?
Yes. The sling can be longer, however, the trebuchet (and all its parts) must fit into those dimensions when it is ready to launch. Posted Oct. 14, 2008.
11. When determining the target, is it where the pumpkin first hits the ground or where it ends up?
Judges will be looking at where the pumpkin first hits the ground. Posted Oct. 17, 2008
12. How large is the pumpkin and how much does it weigh?
The payload is a small irregularly shaped pumpkin pillow that weighs approximately 45 grams, or 1.5 ounces. Its peak latitudinal circumference is 14 inches; peak longitudinal circumference is 12.75 inches. Posted Oct. 17, 2008
13. Can team members hold the trebuchet down while it is being fired?
Due to safety precautions, we need to make sure that students are protected from moving parts during launch and are not just holding the trebuchet down to release it. Therefore, they will need to create some kind of release/trigger mechanism. Posted Oct. 17, 2008
14. Can team members pull the arm on the trebuchet back, or do they have to crank it back?
Only gravity may be used to power the trebuchet. How they set the launching arm is up to them - as long as they are safe when doing so. Posted Oct. 17, 2008
15. Does the trebuchet have to be 20 by 20 by 20 before, during and after the launch?
It just needs to fit in the 20 by 20 by 20 inch box when loaded for launch. Therefore, it would just be before the launch. Posted Oct. 17, 2008.