Why would a soccer ball at 0 PSI roll farther than a ball at 15 PSI?

Question

This is for my science fair project, have no idea why that happened, but the balls at 0 consistently went the farthest. Any explanations?

Answer 1

Negative!
Any ball that relies on the gas to maintain its shape will roll only a few feet with a gage pressure of 0 PSI. (With 0 PSI absolute pressure it would be as flat as well dried prune.)
At 15 PSI it will roll better than at 0 PSI.

Also it is recommended that a soccer ball to be inflated to 7-9 PSI. The 15 PSI will make a bit to stiff but will roll well.

Answer 2

I would assume that the only difference is the weight. Since air has weight, a ball at 15 psi would have twice as much air and therefore some additional weight which would increase the amount of rolling friction.

Answer 3

I assume the temperature is the same and the cause of the pressure difference is the difference in elevation. If such is the case, then the air is thinner at higher elevation and the air resistance is relatively weaker than at the low land where the air is denser.