In countries near the Earth’s equator, tourists are often dazzled by a demonstration of a mysterious physical phenomenon. A presenter will position three buckets of water – one in the Northern Hemisphere, one in the Southern Hemisphere, and one directly on the equator – and let the water drain out. Tourists are shown that, as the water drains, the water in the northern bucket rotates in one direction, the water in the southern bucket rotates in the other direction, and the water at the equator..