Andrew -
'High altitude' tennis balls have diameters that are about 6%
larger than 'low altitude' tennis balls. The reason for this is because
at high altitudes, the air pressure is lower. When the tennis ball
flies through the air, the air pushes against it and slows it down
(this is called air resistance). How much air resistance there is
depends on the air pressure and the surface area of the ball. Since
less air pressure would mean less air resistance, they compensate by
making the balls bigger. This way there is about the same amount of air
resistance on a 'high altitude' ball at high altitudes as on a 'low
altitude' ball at low altitudes. So the game should play the same way.
For a detailed description of the different kinds of tennis balls, click .
-Tamara and Tim
(published on 10/22/2007)
