The injustice of volumes

Yesterday, I pumped up an exercise ball that I bought my wife for Christmas. Much like leaf-sucking, it’s a thankless, seemingly endless task.

The ball pumps to 75cm in diameter, a step up from the 65cm ball we had previously. (I can only measure progress by wrapping something around the ball and dividing that length by two pi. I’m figuring that it would be easier if they’d printed two dots on the ball that would be 10cm apart when the ball was pumped to the right size.)

I’m using the 15cm-long hand-pump that came with the ball. I figured that to exercise the mind while pumping, I’d work out the amount of extra air the 75cm ball would need over the 65cm ball. It turns out that the extra 10cm (15%) of diameter increases the volume by 53%. And when I’d reached a diameter of 60cm (80%), I was only half way through the pumping. Seems unjust.

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