(c) McGraw Hill Ryerson 2007
10.2 How Ocean Water Differs from Fresh Water
• Ocean water’s salinity = 200X greater than fresh water Average salinity of oceans is 35 parts per thousand Oceans at equator (evaporation) and poles (ice) have the
highest salinity (removing water increases salinity) Ocean locations near rivers have low salinity, due to
addition of fresh water
See page 368 - 370
from the World Ocean Atlas 2001
(c) McGraw Hill Ryerson 2007
Composition of Salt Water
• Salt water is composed of minerals dissolved during run-offs occurring over millions of years Volcanic eruptions also release minerals from
inside Earth Sodium ions (Na+) and chloride ions (Cl-) are most
common solids in ocean water Na+ ions and Cl- ions > 75% of all solids in ocean
water Mixed and joined in the ocean, NaCl is chemical
name for salt See page 370
(c) McGraw Hill Ryerson 2007
Density of Salt Water
•
Density = how tightly packed the molecules are in an object
Less dense always floats on more dense Eg. warm air rises above cool air, and oil floats on water We float better in salt water than
fresh water
• Salt water has slightly different properties than fresh water Salt water freezes at –1.9 ºC
See page 371
Density of ocean water (kg /m3) =
Mass (kg)Volume (m3)
Take the Section 10.2 Quiz