<P> Tidal phenomena are not limited to the oceans, but can occur in other systems whenever a gravitational field that varies in time and space is present . For example, the shape of the solid part of the Earth is affected slightly by Earth tide, though this is not as easily seen as the water tidal movements . </P> <P> Tide changes proceed via the following stages: </P> <Ul> <Li> Sea level rises over several hours, covering the intertidal zone; flood tide . </Li> <Li> The water rises to its highest level, reaching high tide . </Li> <Li> Sea level falls over several hours, revealing the intertidal zone; ebb tide . </Li> <Li> The water stops falling, reaching low tide . </Li> </Ul> <Li> Sea level rises over several hours, covering the intertidal zone; flood tide . </Li>

Is low tide when the tide is out