WATER ncert_CLASS7

• SALINITY : 

  It is The amount of salt present in 1000grams of water .
  Average salinity of ocean is 35 parts per 1000 grams  
  DEAD SEA in ISRAEL have 340 grams per litre of water 

  • OCEAN CURRENTS : 

    It is the stream of water flowing constantly on the ocean surface in definite directions
    LABRADOR Ocean Current is cold current 
    GULF STREAM is a warm current 
    Areas where cold and warm currents meet experiances Foggy weather 

  • WAVES : 

    Rise and Fall of ocean water 
    

    TIDES :

     Rhythmic rise and fall of ocean water that too twice a day 
    

    TYPES OF TIDES : 

     1.SPRING TIDES : occurs when sun moon and earth comes in a single line. also called as High hides
    2. NEAP TIDES : occurs when Sun and Moon are in Right angle to each other i,e earth will be quarter to the sun and moon , because of that water on the surface of ocean rises up diagonally due to gravity of the sun and moon. Neap tides are also called as low tides