Well here are the results...
It was the compressed air but only by the slimmest amount and you would really never know if someone slipped a helium ball into the game at halftime. I believe if we used beach balls which held a greater volume of gas the results would be more varied.
Don is correct, the heavier ball bounces higher because it falls with a greater force. The ball acts as if it were a spring as it is hitting the ground.
This is for my 5th grade daughter. The projects are being judged this week. If you finish in 1,2, or 3rd place you advance to the regional contest and from there the state level. We're hoping for a solid 4th place finish.
