Here's is a unique opportunity to see how the direction of a pendulum's swing

changes when it NOT located at the North Pole. The result may be a bit

surprising. Here the pendulum at Buffalo is started swinging along the

North-South axis, represented by the red line. Note the yellow handle of

the tool in the upper right hand corner of the frame. This will serve as a

reference marker. The entire model, including the earth and pendulum is

slowly rotated in a counterclockwise direction. The time on the screen

roughly indicates how far the model earth has rotated, with 24 hours

corresponding to 360 degrees. As the model earth rotates, notice how

the pendulum no longer is swinging along the red starting line. The

direction of the swing is steadily shifting in the clockwise direction with

respect to the earth's surface. This shift is called precession. After a

full rotation, as seen by the yellow handle appearing again in the upper

right hand corner, the pendulum has not returned to the starting line.

In fact, the model must be rotated an additional amount of approximately

130 degrees to bring it back to the starting line.