Q.The direction of wind around a low pressure in northern hemisphere is:

Think of a merry-go-round. If you stand at the centre and throw a ball straight at a friend standing on the edge, the ball doesn’t travel in a straight line from your hand to your friend — at least, not from your friend’s point of view. By the time the ball arrives, your friend has moved around the circle. To them, the ball seems to have curved away to one side. But you, standing at the centre, see the ball travel perfectly straight. The ball didn’t curve; the ground beneath it was moving.

That is the heart of the Coriolis Effect. It is not a force that pushes things. It is an illusion created because we measure motion from a spinning platform — and the Earth is exactly that: a giant, slowly spinning merry-go-round. When something moves over the Earth’s surface, the Earth rotates beneath it. From our fixed position on the ground, the moving object appears to veer off course, even though nothing is actually shoving it sideways.

The key is that different parts of the Earth move at different speeds. At the equator, the ground is whipping eastward at roughly 1,670 km/h because that point has the farthest to travel in one day. Near the poles, a point barely moves at all — it just spins in place. So when air or water moves from the equator toward a pole, it carries that fast eastward speed with it. As it travels north, the ground underneath it is moving eastward more slowly. The moving air therefore races ahead of the ground, and from our perspective it bends to the east. Move from a pole toward the equator, and the opposite happens: the ground is moving faster than the air, so the air lags behind and bends to the west.

This is why the effect is strongest for things that travel long distances over time — winds, ocean currents, missiles, aeroplanes. A cricket ball bowled across a pitch is over too quickly and covers too little distance to show any noticeable bend. But a wind system spanning a thousand kilometres, or a current flowing for weeks, accumulates the deflection until it becomes dramatic.

The most famous result is the way winds curve. In the Northern Hemisphere, moving air is deflected to the right of its direction of travel; in the Southern Hemisphere, to the left. That single rule explains the spin of large storms. A low-pressure system in the north draws air inward, but the Coriolis deflection bends that inward flow to the right, producing a counter-clockwise swirl. In the south, the same inward flow bends left, giving a clockwise spin. You can see this in satellite images of cyclones — they always rotate opposite ways on either side of the equator.