MARS 120
Week 3 Pre-lab exercise
Properties and composition of seawater
Due at the beginning of lab
Provide answers on a Scantron form
Refer to Chapter 6 Thurman & Trujillo
Match the numbered term to the lettered statement
1) Water molecule
a. sum of the dissolved inorganic salts in seawater
2) Hydrogen bond
atoms
b. dipolar molecule made up of 2 oxygen and 1 hydrogen
3) Heat capacity
molecule-thick
c. cohesive attraction of hydrogen bonds causing a
"skin" for form on water surfaces
4) Surface tension
dipolar nature
d. intermolecular bond that forms in water because of the
of water molecules
5) Salinity
g of water by
e. quantity of heat required to change the temperature of 1
1oC
Match the numbered term to the lettered statement
6) Density
a. mass per unit volume of a substance, such as
water
7) Convection
different relative
b. heat and salt transfer by ocean currents with
density
8) Thermohaline circulation
c. heat transfer of a gas or liquid by circulation
9) Effect of salinity on density
d. increase density
10) Effect of temperature on density e. decrease density
MARS 120 Laboratory
Week 3
Properties and composition of seawater
Objective:
1. to become familiar with the effects of relative density on convection
2. to recognize how convection influences ocean circulation
3. to measure temperature and salinity in seawater
Focus questions (to be discussed in small group after the experiments are completed)
1. What is density?
2. What is convection?
3. What is the relationship between relative density and convection?
4. Which earth materials (air, water, rocks) convect?
5. How does convection influence weather? Ocean circulation? Earth’s crust and
mantle?
6. What happens to the process of convection under low gravity conditions (for
example inside the space shuttle in space)? Why?
7. What is thermohaline circulation?
Experiment 1. The effect of temperature on density.
Experiment 2. The effect of salinity on density.
Experiment 3. The effect of temperature and salinity on density.
Experiment 4. Observation of a convection cell.
Synthesize the results of your experiments and present your synthesis to the class.
Reminders
Lab Quiz March 7
Field trip: Class-time trip to San Diego River channel. Assemble in ST 175 promptly
at 2:30. Wear closed toed walking shoes. Bring sweatshirt or jacket. Bring drinking
water.