Ask A Scientist General Science Archive

Question:
We have several questions which relate to oceans. 1) Why can't
humans drink salt water? 2) Why are oceans made of salt water?
3) Do all oceans contain the same level of salt water?
wallyb, Gower Middle School

Answer 1:
You can drink sea water but it doesn't alleviate your thirst; in fact
it makes you more thirsty.  No, all oceans and seas do not contain
the same level of salt: inland seas are often saltier, for example
the Great Salt Lake in Utah; the Mediterranean is saltier than the
Atlantic.
--- jade

Answer 2:  Even if you restrict yourself to oceans like
Pacific, atlantic, Antarctic, Indian, etc, there are
variations in saltiness (salinity). This depends on
a lot of variables but the most obvious is temperature.
Your question WHY are oceans are made of salt water is a very
good one.....I'm not sure I have a good answer for that.
salt is Most of the "saltiness" in salt water is due to soduium chloride
(NaCl), which happens to (a) be very common in the earth's
upper crust , (2) and (2) is very soluble (it dissolves easily in
water). Why there's so much NaCl, well, I don't know.

-dr topper

Answer 3:  The salt in the oceans is derived from
two sources.  The major source of salt is river runoff.
Salt is dissolved from the Earth's crust into
water as it flows to the oceans.  This accounts
for sodium chloride (which is the salt we eat).  But sodium
chloride is not the only salt to be found in the
ocean.  Some of the other salts found in the ocean
are the products of outgassing during volcanic eruptions.
 grant l