Part 1: The Deep Circulation of The Ocean
Question:
How does the temperature of water affect ocean circulation?
Independent Variable: ______________________________________________________
Dependent Variable: _______________________________________________________
Hypothesis:
__________________________________________________________________________
Control: Room temperature water, salinity
Materials
Room temperature fresh water
200mL cold water
200mL hot water
Salt
Red food coloring
Blue food coloring
Shoebox sized plastic bin
beakers
Procedure:
1. First make sure you have read over this entire lab
2. Identify the independent and dependent variable(s)
3. Make a hypotheses using an “if and then” statement about what will happen to the warm
water.
4. Fill a transparent plastic bin with 2000mL room-temperature water
5. Measure and add 70g of salt. Stir to dissolve the salt. This represents the ocean at 35‰
6. Prepare cold ocean water by measuring 200mL of cold water and adding 7g of salt. Color with
blue dye and stir.
7. Prepare warm ocean water by measuring 200mL of warm water and adding 7g of salt. Color
with red dye and stir.
8. Record the temperatures of the 3 different containers of water in the data section and take
observations/drawings of the appearance of the water in your bin before making any changes
9. Slowly add your warm ocean water from the right hand side of bin while slowly adding your cold
ocean water from the left hand side of the bin. Record your drawings/observations about what
you see
10. Wait one minute and take additional drawings/observations
11. Wait three minutes and take additional drawings/observations
Data:
Water
Room Temperature Seawater
Hot Seawater
Cold Seawater
Drawings/Observations
Before
During
1 min later
3 min later
Temperature (⁰C)
Questions:
1.
How did your results compare to your predictions? Explain any differences.
2.
Why did we choose to keep the salinity the same (35‰) with each different sample of water?
(Hint: think about what we are trying to test)
3.
What is one way you might improve the procedure for this experiment in order to get more
accurate results?
4.
How is this investigation related to deep ocean currents in our oceans? (hint:
think temperature, density, and salinity)
Part 2: The Deep Circulation of The Ocean
The properties of different water masses in the Atlantic and Pacific Oceans are shown in the data tables
below. The cross sections of both oceans are shown below in figures below these. Use your
understanding of how DENSITY influences ocean circulation to fill in the names (abbreviations) of the
water masses on the figures and answer the following questions. (Hint: think about which water mass
may sink to the bottom and which may float)
Water Mass
Antarctic Bottom Water (AABW)
Antarctic Circumpolar Water (AACP)
Antarctic Intermediate Water (AAIW)
North Atlantic Deep Water (NADW)
Water Mass
North Pacific Intermediate Water (NPIW)
Antarctic Circumpolar Water (AACP)
Antarctic Intermediate Water (AAIW)
North Pacific Deep Water (NPDW)
ATLANTIC OCEAN
Temp (°C)
-0.5
0
4
3
Salinity (ppt)
34.7
34.7
34.2
34.9
Density (g/cm3)
1.0278
1.0272
1.0269
1.0276
PACIFIC OCEAN
Temp (°C)
5
0
4
3
Salinity (ppt)
34.2
34.7
34.2
34.6
Density (g/cm3)
1.027
1.0272
1.0269
1.0273
1. Temperature and salinity are the two primary factors controlling the density of a water mass.
Propose two ways that temperature and salinity could change, thereby changing the density and
location of the water mass.
2. If a water mass became less dense, how might that affect ocean circulation patterns?
3. Does wind affect deep ocean circulation? Explain.
4.
Watch the video at http://www.youtube.com/watch?v=3niR_-Kv4SM. Describe what is
happening. What do you think is the primary reason for the water movement in this animation?
5. Read the article at http://www.windows2universe.org/earth/Water/circulation1.html as well as
your textbook to answer the following question: Another word for deep ocean circulation is
“thermohaline circulation” or the “the great ocean conveyor”. Why would ocean circulation
be described as a conveyor belt? What is being moved on this conveyor belt?
6. Some scientists believe that changes in the density of water masses may cause abrupt and
sudden climate change. Why do they believe this? Summarize their argument.
7.
Use the following resources at:
http://www.classzone.com/books/earth_science/terc/content/visualizations/es2405/es2405pa
ge01.cfm?chapter_no=visualization and
http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/eln/upw.rxml as well as your textbook
to help you answer the following question:
What is upwelling?