Before 1589, Aristotle believed that the falling speed of an object was related to the weight of the object, and people on that day believed it. Until 1589, Galileo made an experiment on the leaning tower of Pisa with two iron balls with the same shape and different mass, which proved that the falling speed of the object had nothing to do with the weight of the object, thus overthrowing Aristotle's view.

Galileo proved through repeated experiments that both wood and iron balls, as long as they are made of the same material, have the same falling speed, that is, the same acceleration.

Extended data

Galileo made a reasonable extrapolation of the above results, and extrapolated the conclusion to the case that the inclination of the inclined plane increased to 90, at which time the ball would fall freely and become a free fall. Galileo thought that at this time, the ball would still maintain the characteristics of uniform speed change. This extrapolation from inclined plane motion to falling body motion is very clever.

However, the conclusion obtained by extrapolation is not necessarily correct. Extrapolation is also commonly used in modern physics research, but the conclusions drawn by this method must be verified by experiments before they can be recognized.

Galileo's study of free fall initiated a scientific method to study the laws of nature, that is, the method of combining abstract thinking, mathematical deduction and scientific experiment. This method has great enlightenment to the later scientific research, and it is still one of the important scientific methods.

The experiment was rated as one of the "most beautiful physical experiments".