Coriolis Effect Explained
Physics
Coriolis effect, an object in motion appears to be deflected from its course. As if a force is pulling its sideways to demonstrate this point, let's imagine a game of catch being played by two people on a merry go round that spins like the earth, but is flat. Without rotation, the ball appears to follow a straight path from thrower to catcher. Imagine the ball is tossed from the center to someone at the edge. With rotation, the ball still travels in a straight line in space, but because the catcher is moving, the ball misses. From the vantage point of the catcher, the ball appears to curve away.
The direction of apparent motion is to the right when following the path of the ball. Now the ball is thrown the other way. Because the thrower is moving, the ball has a velocity component to the right. The motion of the ball appears deflected to the right, and the ball misses the catcher again. Let's look at a throw across the merry go round. Both people move with the merry go round. The ball is thrown. Although it flies straight, it appears to be deflected from its original path. Apparent deflection increases as the ball travels farther. In the southern hemisphere, rotation is clockwise when viewed from over the pole.
Again, the ball follows a straight course, but its apparent flight path is diverted. This time, the effect is to divert the motion to the left. On earth, all free moving objects, including masses of air, are subject to the Coriolis effect. In the northern hemisphere, objects are diverted to the right as viewed from the direction of original movement. In the southern hemisphere, the deflection is to the left.