[clock_tower]

"But then Galileo made the troubling discovery that the heavier stone does not fall any faster than the lighter one."

It does fall faster, if you drop both stones in the atmosphere; the heavier stone has more mass per unit of surface area, to better overcome a constant level of air resistance.

Aristotle's physics were based on pretty accurate observation of the pre-industrial world, although they're surprisingly short on first principles. The really serious shortcomings were mostly related to impetus, the Aristotelian theory of motion -- it accidentally models friction well for objects in continuous contact with the ground, but it's very hard for Aristotelian physics to explain why an arrow keeps flying after it leaves the bowstring, and even gains speed after its apogee.

[defined]

> It does fall faster, if you drop both stones in the atmosphere; the heavier stone has more mass per unit of surface area, to better overcome a constant level of air resistance.

Not necessarily; for one thing, if the masses of the two stones are not significantly different, the difference in the effects of air resistance would be unmeasurable given the instruments of the day.

For another, the shapes of the stones are important. One with a much greater sectional density, oriented correctly, could fall faster than the other, even if it were lighter.

But that's just nitpicking. If I remember correctly, Galileo used inclined planes because there were only imprecise water clocks available to measure the passage of time. His choice of apparatus was brilliant :)

[clock_tower]

I see I shouldn't have let the article's reference to stones stand; the specific experimental apparatus used by both sides was lead balls -- Galileo rolled them down inclined planes, while his opponents dropped them from the Leaning Tower of Pisa.

The article lost me when the author blithely claimed that it was Galileo who dropped two <droppable-item>s from the Leaning Tower of Pisa. The author clearly has no idea what happens when you do that; while Galileo was far too good at choosing the experimental setup that would give him the answer he wanted, while ignoring any such setup that would prove him wrong, to make such an obvious mistake.

[adrianratnapala]

while Galileo was far too good at choosing the experimental setup that would give him the answer he wanted, while ignoring any such setup that would prove him wrong

By this you mean that he was good at designing experiments that were sensitive to the basic physics of what was going on, while being insensitive to confounding factors?

[clock_tower]

Yes. But did he know that?

This is the Renaissance we're talking about; I wouldn't be at all surprised if he just picked the experiment he wanted and laughed off the rest, applying Petrarch's style of rhetoric in the sciences.