Since the globe is rotating, any movement on the Northern hemisphere is
diverted to the right, if we look at it from our own position on the ground.
(In the southern hemisphere it is bent to the left). This apparent bending
force is known as the Coriolis force. (Named after the French mathematician
Gustave Gaspard Coriolis 1792-1843).
It may not be obvious to you that a particle moving on the northern hemisphere
will be bending towards the right.
Consider this red cone moving southward in the direction of the tip
of the cone.
The earth is spinning, while we watch the spectacle from a camera fixed
in outer space. The cone is moving straight towards the south.
Below, we show the same image with the camera locked on to the globe.
Look at the same situation as seen from a point above the North Pole.
We have fixed the camera, so that it rotates with the earth.
Watch closely, and you will notice that the red cone is veering in a
curve towards the right as it moves. The reason why it is not following
the direction in which the cone is pointing is, of course, that we as observers
are rotating along with the globe.
Below, we show the same image,with the camera fixed in outer space,
while the earth rotates.