Quote of the Day (long-form edition):
In De Motu, Galileo reported that the lighter body falls faster at the beginning, then the heavier body catches up and arrives at the ground slightly before the lighter one. Since this should not be true of the objects that Galileo used, a wooden sphere and an iron one, if they are released simultaneously, it has been inferred that Galileo was either a poor observer or making up his data. But in replications of Galileo’s procedure, it has been found that when a light wooden sphere and a heavy iron one are dropped by hand, the lighter wooden sphere does start out its journey a bit ahead—a natural, if misleading, consequence of the need to clutch the heavier iron ball more firmly than the wooden one. This causes the iron ball to be released slightly after the wooden ball even though the experimenter has the impression that he is opening his hands at the same time. Then, because of the differential effects of air resistance on objects of different weight, the iron ball catches up with and passes the wooden ball, just as Galileo reported. There is a satisfying irony in this finding. The modern critics of Galileo were making the same mistake that the ancients made, criticizing results on the basis of what “must be true” rather than going out and doing the work to find out what is true.
From Charles Murray, Human Accomplishment