Coriolis effect

apparent or fictitious force on objects moving within a reference frame that rotates with respect to an inertial frame

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, they spin counter-clockwise (because the earth spins counter-clockwise), and in the Southern Hemisphere they spin clockwise.[1]

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.

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. [2]


  1. NOVA PBS Official (2013-07-19), The Coriolis Effect, retrieved 2018-03-20
  2. "Gyres and the Coriolis effect". Blue Planet: Infobursts. British Broadcasting Corporation. Archived from the original on 4 July 2013. Retrieved 6 October 2013.