Like HowStuffWorks on Facebook!

10 Things We Thought Were True Before the Scientific Method


2
Aristotle's Take on Physics
A print from 1561 of a gunner firing a cannon. The path of the projectile is shown according to Aristotelian physics. Ann Ronan Pictures/Print Collector/Getty Images
A print from 1561 of a gunner firing a cannon. The path of the projectile is shown according to Aristotelian physics. Ann Ronan Pictures/Print Collector/Getty Images

When Galileo demolished geocentrism, he also tore down several other cherished (but wrong) Aristotelian views. Aristotle explained motion by asserting that all matter had a proper place to which it tried to return, and that heavier objects should fall faster than lighter ones. But through meticulous experimentation, Galileo showed that objects falling or rolling downhill accelerate at the same constant rate, which we call acceleration due to gravity [sources: Alioto; Dristle].

Aristotle had also argued that a moving object in its natural place, such as a ball rolling along the ground, would gradually stop because it was its nature to stay there. But as Galileo realized, and as Newton later formalized, the apparent slowing of moving objects was caused by friction; take that away, and a ball would roll on forever [sources: Alioto; Dristle; Cardall and Daunt; Galileo].

Along similar lines, the Aristotelian-Ptolemaic view of physics implied that a piece of shot dropped from a ship's crow's nest would land some distance behind the mast because the ship moved forward while the ball fell. But Galileo showed that the cannonball, which shares the ship's forward velocity, would actually fall straight to the base of the mast. In these ways, Galileo, one of the fathers of experimental science, prefigured Newton's laws of motion, as well as the concept of reference frames while also disproving some of the chief arguments against Earth's movement [sources: Cardall and Daunt; Galileo].