Tides are defined as the periodic rise and fall of sea levels caused by the combined effects of gravitational interaction between the Sun, the Earth and the Moon, and the rotation of the Earth.
An important point to be kept in mind is that the gravitational force exerted by the sun on the earth is only 46% that of the moon. Therefore, the moon is the single most important factor for the creation of tides.
High tides and low tides occur every day. On a daily basis, there are two high tides and two low tides that occur alternatively after a gap of about 6 hours. During high tides water gushes towards the coast, while in low tides water recedes back.
Difference between high and low tides
We can appreciate low tides in the gulfs and not in the open seas. In the Gulf of Kutch, we can walk almost a mile deep inside during low tides. In the open seas of Mumbai and Chennai water goes back but not to a great extent. For instance, water will not recede in the Marine drive as much as it would in Jamnagar.
Even in the open seas, we need shallow beach with a slope for the water to recede back appreciably during the low tides. On the other hand, in the open seas of Mumbai and Chennai the high tides are more turbulent. When the moon is full or new, tides are generally very high.
Image credit- blendspace.com
