for use with materialworlds Galileo's balls simulation
© materialworlds.com 2001
In 16th century Europe there was growing skepticism about the Aristotelian theory that the speed of a falling object is proportional to its weight. In a legendary experiment (that might or might not have really happened) Galileo (1564-1642) dropped two cannon balls of different sizes from the Leaning Tower of Pisa. Would the heavier ball take a fraction of the time of the lighter one to reach the ground - as the conventional theory predicted?
In our simulation of this experiment two balls (the larger weighing 5 times the smaller) are dropped at the same time from the same height. You can adjust the amount of air friction and the density of the balls (which would have the same effect as changing the material they were made from).
Press the
pause
button to freeze the simulation at any moment. Press the
play button to
continue the simulation.Press the
rewind button to move the balls back to their initial position. Press the browser's "Refresh" button to reset the controls to their original settings.
Use the "Pause on collision" control to help you record the exact time (displayed on the simulation toolbar) that either ball hits the ground.
1. How long does each ball take to reach the ground?
(Activate the "Pause on collision" control, record the time of the first ball's fall, then press the play button to continue the simulation until the second ball hits the ground).