AlgebraLab

Biology Graphs: Tides

By L Chapman

In most places there are two high and two low tides each day. Usually where there are two high tides each day the successive high tides are about the same heights. The east coast of North America, including Florida, has semidiurnal tides. 

However, some places in the world have mixed semidiurnal tides where the two high tides in the same tidal day are of quite different heights. Mixed semidiurnal tides are common on the west coast of the United States.

Diurnal tides have only one high and one low tide in a tidal day. You can observe diurnal tides in the Caribbean.

Tide tables give the time and height of the high and low tides to expect in a given area. Tidal range is the difference in the heights of the water between successive high and low tides.

What is the greatest tidal range depicted?

What is the greatest difference in height between two successive high tides?

What is the main difference between the graphs of the mixed semidiurnal and semidiurnal tides?

What type of tide would California have?

Extension:

At what time is high tide in the diurnal graph? How do you convert this to our normal clock time?