How Does Coriolis Effect: IDTIMWYTIM Work?

The Coriolis effect makes things move in a curve when they're going straight on a spinning object, like Earth.

Imagine you’re on a merry-go-round that’s spinning really fast. You throw a ball to your friend who's sitting across from you. From your point of view, the ball doesn’t go straight, it curves toward the outside of the merry-go-round. That’s because while you're throwing the ball, both you and the merry-go-round are still moving.

Now think of Earth as that spinning merry-go-round. When something moves across Earth, like air or water, it also follows a curve because of this spinning motion. This is why winds swirl around hurricanes and why ocean currents bend as they move.

That funny phrase IDTIMWYTIM stands for If You Don’t Think It Moves, It Might Not Move. It’s a fun way to remember that even though the Earth is spinning, we don’t feel it, so things like wind and water seem to move in curves without us realizing why.

It's like when you're on a train moving at constant speed, you don't feel the movement. But if you throw a ball while the train is moving, it still seems to curve from your friend’s point of view!