Coriolis effect


Coriolis effect is an effect observed in a body that moves in a rotational system. Consider a powerful cannon at the north pole of the Earth and a big target at the equator. When someone fires the cannon towards the target, the cannonball curves to the right of the observer who fires it. This phenomenon observed is known as the Coriolis effect. As the Earth rotates from west to east, the speed of an object at different latitudes increases from the poles. Starting with zero at the poles and to a maximum of 1670 km/h at the equator. So when the cannonball is fired, it has the tangential speed of zero or the minimum, and due to inertia, it travels at the same speed as it reaches the equator. But, the target at the equator has a different and a faster tangential speed. So as the cannonball travels at a minimal tangential speed, it lags behind the target, which has a faster tangential speed. Therefore, the cannonball moves towards the right.

Coriolis effect is the reason why hurricanes spin anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere. As the wind flows from both the poles to the equator, they deflect towards right and left from the northern and southern poles respectively. And due to the low-pressure area in the eye of a hurricane, the high-pressure air rushes down towards the eye along with Coriolis force and swirls in the anti-clockwise direction in the northern hemisphere and clockwise in the southern hemisphere.

Frequently Asked Questions[edit]

Does the Coriolis effect influence the way the water swirl in the sinks?[edit]

No. This is a misconception about Coriolis effect. The reason why it does not influence the way the water behaves in a sink is that the system is so small and negligible to be affected by the Coriolis effect. However, a pool big enough will be affected by the effect.

Does the Coriolis effect influence the objects on equator moving sideways?[edit]

Yes, it does. But for most of the Coriolis effect, only the horizontal component is considered. The vertical component of the Coriolis effect is known as Eötvös effect. When an object at the equator moves towards east, the increase in its speed will cause the object to go a little upward. And in the westward object, the direction will be downward due to the centripetal acceleration. In both these cases, only the vertical component of the Coriolis effect is present. A practical example of this effect can be observed in long-range projectiles.