Water

Salinity is amount of salt in grams present in 1000 gm of water. The average salinity of the ocean is 35 parts per thousand.

When surface water gets heated by sun, water evaporates and increases the concentration of salts. Surface water becomes denser sinks and sub surface water rises up. Thus, salinity of sea water causes vertical circulation.

When the water on the surface of the ocean rises and falls alternatively they are called waves.

The rise of sea level is called the flood tide and fall is called the ebb tide.

Because it contains the large amount of dissolved salts. Most of the salt is sodium chloride.

The factors are-

1. Winds
2. Temperature
3. Coriolis force
4. Attraction of moon and sun depending upon its distances.

Ocean currents are broadly of two types of warm and cold currents. The warm currents flow from low latitudes in tropical zones towards the high latitudes in the temperate and sub polar zones. The cold current flow from high latitudes to low latitudes.

Tides are periodic rise and fall in the level of water in seas and ocean caused by the attraction of the moon and the sun. Twice a day, about every 12 hours and 26 minutes, the sea level rise and it falls.

Ocean currents are stream of water flowing constantly on the ocean surface in definite direction.