ABSTRACT
People who live near the seashore soon become accustomed to the periodic rise and fall of the water level twice daily. At certain times, rock pools and large stretches of sand will be exposed, yet 6 hours later they will be submerged. However, the traveller who examines the tides at many different locations will find a much more complex behaviour than the stay-at-home who studies it at only one location. The tide height varies considerably. On the Mediterranean coast the tides are almost unnoticeable. In the Bay of Fundy in Canada the shape of the bay augments the tidal range to over 15 m, one of the largest tidal ranges in the world. Even the periodicity changes — most of the world has semidiurnal tides with an average period of 12.42 hours, but certain locations, one of which is the southern coast of Western Australia, have diurnal tides with a period close to 24 hours.
