Gravity’s Metronome (Galileo’s experiment)
Galileo Galilei (1564-1642) was an Italian scientist who discovered many groundbreaking things. One was discovering how gravity works. His experiment used a ball rolling down an inclined plane. He found that the position of the ball along the plane, (vertically, horizontally, and diagonally) is proportional to the square of the time elapsed.
The vertical lines are spaced by the pattern of perfect squares: 1, 4, 9, 16, 25, etc. The time to get from one line to the next is constant.
Galileo’s father was a musician, which may have given him the idea to put sound-making devices at each line: frets, as on a guitar, or bells that ring as the ball passes. You can get the experience by setting an external metronome to the setting on the screen. Start the metronome, then start the applet at one of the clicks. You will hear a click as the ball passes each line.
This Applet was adapted from an excellent GeoGebra file made by Rafael Losada.