Can you fill a basketball with nitrogen?

Question

I've heard of people filling tires with nitrogen to improve gas mileage. The theory is that because the nitrogen does not have moisture, then it will not expand or contract as much. Would this mean that if nitrogen were put into a basketball that was used outside year round, the ball would bounce more consistently in different temperatures (becasue it would have a more consistent air pressure)?

Answer 1

This is really more of a chemistry question than math.  As the other two answers said, I do not think it will make much difference for the reasons given.  However, unlike nitrogen cylinders, normal air does contain humidity (water vapor).  If the relative humidity of the air is high enough, then some of the water vapor will condense inside the ball when you are putting air under pressure in the ball.  The water will accumulate in the lower part of the ball, and could make it not bounce evenly.  This effect will be stronger if you are filling the ball with air from a hot and humid air (Houston or Miami in the summer).

Having said that, I expect the amount of condensation at such conditions will be very low as the pressure inside the ball is not that high (even lower than that of tires).  That is why I agree that it would not make much difference.

Note that temperature variations in tires are much greater that you would have in a basketball, because of friction with the road.  Condensed water in such tires will re-evaporate after the tires heat, which will cause the pressure to increase even more.  Basketballs do not see such extreme temperature variations.

Of course if the air is dried before filling the ball or tires, then it will act exactly the same as nitrogen (though it is slightly denser because oxygen is heavier than nitrogen).

Answer 2

If what you say is true why wouldn't a a basketball filled with nitrogen have more consistent bounce?

Answer 3

Regular air is approximately 80% nitrogen anyway, and pressure is a function of temperature, not moisture content. Given that nitrogen is #7 on the periodic table and oxygen (most of the other 20% of air) is #8, I don't think that there would be much difference, and I think that the hassle and cost of filling tires with nitrogen would offset any savings in gas mileage.

On the other hand, filling a basketball with nitrogen and testing its bounce at different temperatures (with a control ball filled with air, of course) might make an interesting science project.