Water and Seawater
1.
2.
3.
4.
Draw a diagram of a water molecule. Explain why it is polar (and what that word means).
What is an atom? What is a molecule?
What is a covalent bond? What is a hydrogen bond? Which is stronger?
Table 5-1 lists some of the unique properties of water and their significance to the oceans. Review
them all. What are the primary reasons for these unique properties?
5. Compare the heat capacity of the oceans to that of land. Which is greater? Why? How does that
affect climate?
6. Understand the exchange of heat that occurs as water changes from solid (ice) to liquid to gaseous
form (steam) and back. Explain heat requirements, phase changes, specific melting and vaporization
temperatures, and heat capacity. (Be able to complete Activity handout on this topic.)
Specific heat (or heat capacity) of
water: 1 calorie/gram C
Specific heat (or heat capacity) of
water vapor: 0.44 cal/gram C
Specific heat (or heat capacity) of
ice: 0.5 calorie/gram C
Specific heat (or heat capacity) of
granite: 0.19 calorie/gram C
Latent heat: heat used to change
the state of a substance (like from
solid to liquid). Heat is used to
break bonds, not raise temp.
Specific heat (or heat capacity) =
heat used to raise the temperature
of a substance. Specifically, the
heat required to increase the
temperature of one gram of material
by 1 C.
7. What happens to the heat of the surroundings during precipitation? Evaporation? How can this heat
exchange affect world climate?
8. What is the average salinity of seawater? What does salinity measure?
9. What are the main ions in seawater? Be able to name at least the two most important and give their
percentage.
10. Where do the dissolved components in seawater come from? Go to?
11. What happens to water’s unique properties as salinity increases? Why?
12. Table 5-5 reviews major processes that change seawater salinity. Review them and explain how
surface salinity changes in the world ocean. Where is it highest? Lowest? Why?
13. What is pH? What is the pH of seawater? What is the pH of freshwater?
14. How does seawater maintain pH?
15. What happens to the density of freshwater as it cools? Is heated? Why?
16. What important factors control seawater density? How do you make seawater denser? Less dense?
17. How do salinity and temperature change with depth in different latitudes in different seasons?
18. What happens to the following characteristics of water as salinity and temperature change?
NOTE: Latent heat of evaporation above is really of vaporization.
Density Freezing Boiling
point
point
Temp when
water is most
dense
Heat
capacity
Salinity 
Temp 
19. Define pycnocline, thermocline, and halocline. How are they related?
20. Review how and why the pycnocline development changes with latitude and seasons.
Polar seas
Temperate seas
Tropical and equatorial seas
When pycnocline best developed? Why?
Never – always vertical mixing – doesn’t warm up enough in
summer.
Summer – sun produces warm surface layer with no vertical
mixing. In winter, surface water and deep water mix.
Always – constant supply of sun keeps warm surface layer yearround. No vertical mixing.
21. How does changing salinity and temperature affect density? What are the global thermostatic effects
of this?