1. (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 2001World Ocean Atlas

2. (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

3. Composition of Salt Water (c) McGraw Hill Ryerson 2007

4. 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 Take the Section 10.2 Quiz