At the north or south pole, the pendulum is moving in a fixed plane (if we disregard the fact that the Earth is also revolving through space), so the plane of the pendulum seems to rotate through 360° as the Earth makes one full rotation. ... The plane in which the pendulum swings is similarly in motion.

Why does a pendulum turn?

Changes in potential and kinetic energy as a pendulum swings. pendulum, body suspended from a fixed point so that it can swing back and forth under the influence of gravity. Pendulums are used to regulate the movement of clocks because the interval of time for each complete oscillation, called the period, is constant.

Why does a pendulum appear to change direction?

It's the Earth which is rotating underneath the pendulum, which makes it appear that the pendulum is in fact changing direction. At the North Pole, the pendulum would appear to rotate through a whole 360 degrees once a day, because the Earth rotates all the way round underneath it.