Explain spring tides and neap tides with the help of diagrams.

The periodic rise and fall of water levels in the oceans are called tides. The rise in water level causes high tides while the lowering of the same causes’ low tides. It occurs due the gravitational pull of the moon as well as the centrifugal force due to earth’s rotation. The gravitational pull of the sun also plays a role in the creation of tides.

• Spring Tide – During full moon and new moon, the earth, moon and sun are in a straight line. This increases the intensity of the gravitational forces from the sun and the moon, creating stronger tides. Such tides are called spring tides.

• Neap Tides – Seven days after the full moon and the new moon, the moon and the sun will be at an angular distance of 90° from the earth. Due to angular position of the sun and moon, the gravitational pull from the celestial bodies work against each other reducing the intensity and effect on the earth. This causes weak tides which are called neap tides.