The rise and fall of water in sea and ocean from the normal level is known as Tides. Tides on Earth happen due to gravitational pull of the moon and the Sun. Highest high tides and lowest low tides occur when the sun, the earth and the moon align in a straight line. These are known as Spring tides. Neap tides happen when the moon and the sun align at right angles with the Earth. There is minimum difference between highest high tides and lowest tides during Neap tides.
