Coriolis effect

The picture at the top shows an inert frame of reference, where the black object moves in a straight line. In the picture at the bottom the observer(red dot) sees the object follow a curved path, because of the Coriolis and Centrifugal effects

This storm over Iceland spins counter-clockwise due to balance between the Coriolis force and the pressure gradient force.

The Coriolis effect is a force that is found in a rotating object. Gaspard Gustave de Coriolis first described the Coriolis effect in 1835 using mathematics. The Coriolis effect can best be seen in hurricanes. In the northern hemisphere, or part of the earth, they spin clockwise, in the southern hemisphere they spin the other way. This happens because the earth spins on its tilt.

One example of the Coriolis effect that is often described is that water flows down a drain in the opposite direction in the northern and southern hemispheres. However, in reality, the force of the Coriolis effect is not strong enough to see in such a small amount of water.

The Coriolis effect or force can only be observed from the perspective of a rotating object. For example, if you throw a ball off a spinning merry-go-round while sitting in the center of it, the ball will appear to move in a curve to the thrower since the merry-go-round is also moving. The direction of the curve will depend on the direction of the merry-go-round. However, from an outside observer, it will look like it is just moving in a straight line, since the only force is acting in a straight line. In a sense, the Coriolis effect is not a real force and just based on the observer moving.