EVENT PARAMETERS: Students must bring a pencil and may bring any type of calculator. Supervisors will provide each team with a helium-filled balloon, balance, scissors, cardstock, and a metric ruler.

A TEAM OF UP TO: 2 APPROXIMATE TIME: 50 minutes

INTRODUCTION: The competition consists of designing and constructing a weight which when attached to a helium filled Mylar balloon and released will rise to finish line in the longest amount of time up to 300 seconds. The weight will be fabricated from a uniformly dense material such as cardstock. Student(s) will determine the density of the material through measurements and calculations.

THE COMPETITION: Teams will determine the lifting force of a helium-filled Mylar balloon by calculating the density of the uniform material, and determining the amount of uniform material needed to limit the ascent of the balloon. The supervisor may provide some mathematical relationships, but the students are expected to understand basic arithmetic, and the definitions of various densities.

I. Determine the net upward force exerted by a helium filled Mylar balloon to which a string and a paper clip are attached. Record the upward force in equivalent mass units (g). The easiest way to accomplish this task is to place a known weight on a balance, hook the balloon to the weight and measure the apparent weight loss.

2. Determine the area density of a uniformly thick piece of material provided by the contest official. Record the area weight density in gmlcm2

3. Calculate the amount of material needed to construct a weight which, when attached to the paper clip, can be lifted by the balloon. Record the area in cm2.

4. Construct a weight from the material supplied. Students will NOT be allowed to verify the mass of the weight by using the balance. Weights may be bent into any shape, however a flat edge must be provided so that the judge can easily attach the weight to the paper clip. If the weight falls from the paper clip during the rise of the balloon, the event supervisor will reattach the weight and restart the rise of the balloon.

5. The weight and the helium filled balloon are to be handed to the event official without having been attached or combined in any way to each other (on or off the balance). The official will attach the paper clip to the flat edge on the weight designated by the team and hold the weight against the surface of the launch site. The student may specify what edge or surface of the weight is to touch the surface of the launch site. Upon a signal from the timer the balloon-paper clip-weight assembly is released and permitted to rise. No part of the balloon weight assembly may be touched after the release. The paper clip may not be modified or distorted in any way. The timer will measure the rise time with a stopwatch from the release until the top-most-part of the balloon arrives at the finish line established by the contest officials. If the assembly fails to rise or if the balloon does not reach the finish line within five minutes (300 seconds), or if after the launch the weight touches the floor before reaching the finish line; then these balloons will be ranked below those who did meet this criteria. The balloon will be released within 5 minutes after students present their balloon for flight.

6. Either a platform balance, an electronic balance, or a double pan (Harvard trip) balance with double or triple beams and a resolution of at least 0.1 g will be provided by the supervisor.

7. Each team must complete all measurements, calculations and weight construction within 20 minutes. Event officials will record the time used. In the event of a tie, the team with the least elapsed time will win.

SCORING: Points will be awarded based on the accuracy of measurements and calculations, problem solving, and clarity of recorded data. Calculations and measurements will count for 50% of the total score and the ascent time will count for 50% of the total score. Weights that do not reach the finish line will be ranked below those that do. First Tiebreaker: slowest rise time. Second tiebreaker: fastest construction time.