From 2006 Student Manual. Students will attach a weight to helium filled Mylar balloon and "race" them to a predetermined level. The objectives are to: 1. demonstrate skillful use of a balance; 2. demonstrate an understanding of density; and 3. make careful measurements and use good construction techniques.
Teams will have to determine the lifting power of a given balloon. To do so, they will have to calculate the density of the given material, and determine the amount of material needed to limit the ascent of the balloon.
- Zero out or level the balance given
- Mass the provided weight and record in grams
- Attach the balloon to the provided weight and remass. Record in grams.
- Find the lifting force of the balloon by subtracting Answer 3 from Answer 2.
- Set aside both the provided weight and balloon and mass the provided material. Record in grams.
- Determine the area of the material provided in sq. centimeters.
- Find area density of provided material by dividing Answer 5 by Answer 6. Record in grams per sp. centimeters.
- The tricky part. Determine the mass you want the material to be. In other words, if the balloon had a lifting force of 1.5 g, you could choose to use a percentage of the lifting force, or choose to create a weight that was within .1g of the lifting force.
- Divide Answer 8 by Answer 7. This gives you the area of the weight you want to create in square centimeters.
- Determine the length and width of the material you need to create the desired weight. You might want to use a side that is already measured. It prevents you from making any unnecessary measuring mistakes.
- Cut the material that you have created.
Things to watch for at the competition
- Ask the judge about the air condition of the room.
- Ask the judge if you can calibrate the balance. You don't want to have numbers that are way off.
- When finished with material, do not attach it to the balloon. You could be disqualified.
- Be consistent in your write up. Don't give out different names for the provided material. Keep writing down "provided material."
- Write out any equations you use. It shows the judges that you know how to determine the density or etc.
- If the measuring and the "race" takes part in one room, make sure no one is moving when your balloon is racing.
- To be safe, try to use smaller mass than the one you have caculated.
- Have both members practice making calculations and measurements. Then you can easily point out who's better at what.
- Use a variety of materials to practice with. Any material that has a uniform density and can be cut with scissors are acceptable.
- Use a variety of shapes of materials to practice with. The rules don't say it will be rectangular. Try circles, trapezoids, or triangles.
- Experiment with the cut out material. Fold it, bend it, cut it into a bird or something. Just experiment.
- Experiment with the position of the material when the balloon is about to take off. Do you want it flat on the floor, perpendicular to it, or something in between.
- Take into account the condition of the room. What will you do if the room is warmer? If it's cooler?
- Take into account the time used to complete an exercise. You will have a maximum of twenty minutes to do all the calculations and cut the material.
- Pay attention to what the judges' rules are. It may be different from the official one, but it's their interpretation that counts.
- Practice, practice, practice. It's the only way to get better. Try different locations, weather, material, etc.
Half of the score is based on the student's calculations and construction of the material. 50 points are rewarded to the highest scorer. The others are based on how close they came to the top score. The paper they give you to write on is half of your points. If your balloon does not run successfully, make sure you have a good write up. It can help. The other half depends on the "race." The team with the slowest time receives the 50 points. Others are based on how close they came to the slowest time. The first tie breaker is slowest rise time. The second, fastest construction time.
Students should provide their own writing instrument, preferably pencil, and may provide their own calculator. Supervisors will provide each team with a balloon, balance, scissors, cardstock (or other uniformly dense object), and metric ruler.
Good luck and have fun!!!