<P> A tide clock is a specially designed clock that keeps track of the Moon 's apparent motion around the Earth . Along many coastlines , the Moon contributes the major part ( 67 % ) of the combined lunar and solar tides . The exact interval between tides is influenced by the position of the Moon and Sun relative to the Earth , as well as the specific location on Earth where the tide is being measured . Due to the Moon 's orbital prograde motion , it takes a particular point on the Earth ( on average ) 24 hours and 50.5 minutes to rotate under the Moon , so the time between high lunar tides fluctuates between 12 and 13 hours . A tide clock is divided into two roughly 6 - hour tidal periods that shows the average length of time between high and low tides in a semi-diurnal tide region , such as most areas of the Atlantic Ocean . </P>
<P> A tide clock is a specially designed clock that keeps track of the Moon 's apparent motion around the Earth . Along many coastlines , the Moon contributes the major part ( 67 % ) of the combined lunar and solar tides . The exact interval between tides is influenced by the position of the Moon and Sun relative to the Earth , as well as the specific location on Earth where the tide is being measured . Due to the Moon 's orbital prograde motion , it takes a particular point on the Earth ( on average ) 24 hours and 50.5 minutes to rotate under the Moon , so the time between high lunar tides fluctuates between 12 and 13 hours . A tide clock is divided into two roughly 6 - hour tidal periods that shows the average length of time between high and low tides in a semi-diurnal tide region , such as most areas of the Atlantic Ocean . </P>
how long does it take for the tide to come in
how long does it take for the tide to come in
6 - hour
6 - hour