Grady,
All good points, thanks.
Yes, we used three seperate new balls. We used compressed air because that is the standard that all balls are filled with for play. The idea for the project came from a conversation I had with my daughter at a college v-ball match. At half time the refs collect the balls and hold them until the second hald starts. My daugher asked me why they did this. I said so someone doesn't switch one of the balls out with one filled with helium in order to throw off the other team. This got the wheels in her head working and she said lets find out if it would make a differance.
We were inside so no air flow or temp changes.
To measure the bounce heights, we ( I mean she) set up a 10' steel bar with marks at every 2". I viewed the bounce while standing on a chair so my line of site would be even with the top of the bounce. I was several feet away from the drop zone. We had a video camera with us but after recording a few bounces we saw the camera would not focus on the ball fast enough and the ball was a blur. If we were to change any one thing it would be the method of measuring the bounces.
Our previous project was the strength vs weight of carbon fiber and fiberglass. She finished 4th with that one.
