Tides are generated because of the gravitational pull which is generated because of the moon’s rotation around the earth and earth’s rotation around the sun. However the pull of moon has the most influence on the formation of tides.

The gravitational pull of the moon is very powerful. The oceans would have experience a high tide once a day when the coasts align with the ocean’s bulge facing the moon but there are two high tides in a day. The reason lies in a principle called inertia. Inertia can be best understood with the example of a bucket containing water. When we swing the bucket in a circular motion, the water remains in the bucket due to the centrifugal forces exerting pressure on the water. The earth also moves in slow circular movements which affect the oceans too. Inertia which makes a moving object to keep moving is also involved in the tide formation. This Inertia or the centrifugal force causes the oceans to bulge towards the opposite side which is facing the moon. Due to this the oceans bulge twice in a day, first when they are in direct alignment with the direction facing the moon and next when they are in the opposite direction. There are solar tides too, which are caused due to the gravitational pull of the sun. These are generated for the same reasons as the lunar tides. Though the sun is 27 million times bigger than the moon, it is also 390 times farther from the earth as compared to moon. As a result, solar tides are much weaker than the lunar tides.