1.  The most common salt in ocean water ____sodium chloride_____. (p. 340)

2.  When water carried to the shore in waves returns to the ocean, an _______undertow____ forms.

3.  The density of ocean water is ____greater_____ than that of pure water. (p. 341)

4.  Currents that flow from the poles toward the equator are _____deep water  currents. (p. 348)

5.  Surface currents in the Northern Hemisphere flow in a _______clockwise_ direction. (p. 347)

6.  The daily changes in ocean water level caused by the gravitational pull of the sun and the
     moon are ________tides___________. (p. 356)

7.  The major gases dissolved in ocean water are ____nitrogen_____, __oxygen_____, and
     ____carbon dioxide______. (p. 340)

8.  A thermocline is determined by a change in ___water temperature_____. (p. 341)

9.  Areas that have one high tide and one low tide each day are described as having a
     ______diurnal_____ tide pattern. (p. 357)

10. Areas that have two high tides and two low tides each day are described as having a
      ___semidiurnal_____ tide pattern. (p. 357)

11. Current tide patterns repeat every __24___ hours and _50__ minutes. (p. 357)

12. When the moon and sun form a right angle, their gravitational forces pull in different
      directions to form a ______neap_____ tide. (p. 358)

13. Periods of spring tides and neap tides occur ___twice___each month. (p. 358)

14. Tides with the least difference between high and low are called _____neap____ tides. (p. 358)

15. The Coriolis force causes the earth's __winds and ocean currents____ to move in a curved
      path.

16. The earth's rotation causes winds blowing toward the equator to curve westward.

17.  Upwelling occurs as a result of differences in water __density_____.

18.  As water depth increases, pressure ______increases____________.

19.  The water in an estuary has ______lower______ salinity than most of the ocean.