Tides

Tides are the rise and fall of sea levels caused by the combined effects of the rotation of the Earth and the gravitational forces exerted by the Moon and the Sun. The tides occur with a period of approximately 12 and a half hours and are influenced by the shape of the near-shore bottom.

Semidiurnal Tides: Two equal high and low tides. EX East Coast

Mixed Semidiurnal: Two different high tides and two different low tides. EX West Coast

Diurnal: One high tide and one low tide. EX. Gulf of mexico

Spring tide: When the sun and moon are in a straight tide so the difference between the high and low tide is greater

Neap Tide: When the sun and moon are at right angles so the difference between high and low tide is smaller

There is about 6 hrs between a high and low tide and about 12 hours between a high and high tide