The Coriolis Force

Anything moving on the Earth experiences a deflection caused by the Earth's spin. In the northern hemsiphere, an object is deflected to the right of the direction it is moving. In the southern hemisphere the object is deflected to the left.

The strength of the deflection depends on the speed of the object's motion and its latitude.

The result of the Coriolis effect is that objects set in motion travel along a curve as seen on the spinning Earth. That curve arises because the Earth's surface rotates under them, as you can see in the following short animations.

Hold a ruler or other straight object along the particle track to see that it moves in a straight line.

Note, however, that the path it traces on the Earth's surface is a curve.

The following short movie shows how an object moving in a straight line through space travels along a curved path with respect to the Earth's surface.

Simple animation of Coriolis Effect for a particle moving away from the pole.

Animation of Coriolis Effect for a particle moving away from the equator.