Expert: Ed - 9/20/2006

Question
its my daugther's school assigment

Answer
Jing,
It's salty because rivers have been washing tiny amounts of salt into it all day long, every day, for billions of years.  Also, some salts were dissolved from rocks on the ocean floor.  Finally, some salts are from volcanic vents underneath the sea, or from (very small) amounts of impurities in the atmosphere.

The salt in the sea is very old.  Every day, lots of water evaporates from the surface of the sea, to become clouds in the sky, and eventually to form rain.  But the salt NEVER evaporates.  Most of it has been there for billions of years, although new salt gets washed in every day.

Look at this scientific website:
http://www.palomar.edu/oceanography/salty_ocean.htm

Keep Looking Up!
--Ed