Tides: High Tide and Low Tide
The position of the moon relative to the earth causes lunar tide.
Tides are the rhythmic rise and fall of ocean or sea water caused by the combined effects of the rotation of the Earth and the gravitational forces exerted by the Moon and the Sun.
The earth has two high tides and two low tides everyday. High tide takes place on the side of the earth facing the moon as it circles the earth. The moon’s gravity pulls the water away from the earth. The water of the seas piles up and forms high tides.
As the earth turns, the part of the sea that was high moves away from the moon’s gravity. The water then sinks back. In about six hours, this part will go all the way down to a level called low tide.
As the earth turns, one high tide stays close to the moon. Another high tide stays on the opposite side of the earth where the force of the earth’s spin pushes the water outward.
Like the moon, the sun’s gravity also pulls the earth’s water to itself and causes solar tides.
During the new moon and full moon, the lunar and solar tides together produce the larger spring tides. At the first and last quarters of the moon, lunar and solar tides produce the smaller tides called neap tides.
Tides affect man and his activities. Fishermen take their boats out to the sea during the morning high tide and bring them back during the evening high tide.
At the beach, you can jump right in the water for a swim at high tide. At low tide, you may have to pick your way over the rocks to get to the water.
Harbor pilots bring in ocean liners at high tide when the water in the harbor is deep enough for them to sail on.