What is Coriolis effect?

It's like the way wind and water naturally moves while on earth which continually rotates. Depending on which side of the equator your one determines like, which way the water twirls as it go down the drain in the sink. Get it?

In rotating frame of reference, it's the effect that causes an object's radial velocity to induce a tangential acceleration. In other words, as the object moves inward toward the center of rotation it will experience an angular acceleration. Try this thought experiment - imagine a record rotating on a turn table, and you have a marble perched at the outer rim. As the record spins you flick the marble toward the center of the record. What you would see is that the marble will not roll directly towards the center, but will appear to be deflected in the direction of the record's rotation, and so will miss the center spindle.

Another example of the effect is the rotation of storm winds around a low pressure area.(Capuchin is correct - the water rotating down the drain is an urban myth - a sink or bathtub is way too small and the viscosity of the water is way too high to be effected by the rotation of the earth.)

Mathematically the acceleration of an object in a rotating frame is:


(\ddot r - \dot r \omega ^2 ) \hat r + (2 \dot r \omega + \dot \omega) \hat \theta


where \hat r is the acceleration in the radial direction and \hat \theta is acceleration in the tangential direction. The coriolis effect comes from the 2 \dot r \omega + \dot \omega term - if total acceleration is 0 (i.e. no force constraining the object) and both \dot r and \omega are non-zero, then \dot \omega must be non-zero.