In the Northern Hemisphere, the Coriolis effect causes moving air and water to turn toward which direction?

• A. Right
• B. Left
• C. Upward
• D. Downward

Answer: (A)

In the Northern Hemisphere, moving air and water are deflected to the right of their direction of travel. This happens because Earth rotates, and different latitudes spin at different speeds. As a parcel of air or water moves, it tends to keep its initial east–west momentum, while the ground beneath it is rotating at a different rate, so the path appears sideways relative to the surface. The deflection is horizontal and increases with latitude, being smallest near the equator. So, a northward or eastward motion will curve toward the right.