Project 1: Ocean Soundings
Objective


To simulate the use of depth soundings or
SONAR in the creation of topographic
maps of the seafloor.
To understand the limitations of sounding
and SONAR technology.
Background
Prior to World War II, little was known about
the depths and structure of the ocean floor.
Figure 1
Oceanographers measured the depths of the oceans by dropping a weighted plumb line over the
side of a ship and calculated how much rope was let out. This type of depth measurement is
called a “sounding.” Later, SONAR (Sound Navigation Ranging) would be employed to create
a sound image of the ocean floor. These methods of probing the ocean’s depths have their share
of limitations and complications1.
On June 24, 1966, The National Science Foundation and the University of California began
the Deep Sea Drilling Project. The purpose of this venture was to drill and core the Atlantic,
Pacific, and Indian oceans as well as the Mediterranean and Red Seas.2 The drilling would be
accomplished by the D/V Glomar Challenger, which was launched from Orange, TX on March
23, 1967. Immediately, the value of this mission was realized. The core samples obtained by the
Glomar Challenger confirmed Alfred Wegener’s theory of continental drift and also identified
many lucrative seafloor features such as the location of underwater salt domes, a potential
indicator of deep sea oil reserves.
In 1985, the JOIDES Resolution replaced the Glomar Challenger. This new vessel operating
under the newly founded Ocean Drilling Program (ODP) employed more advanced drilling
techniques. With its crew of up to 50 scientists and 65 crew members, this vessel can suspend as
much as 30,020 feet of drill pipe to an ocean depth as great as 27,018 feet to obtain a “sounding”
and possibly a core of the ocean floor3. It contains seven floors of laboratories and a drill derrick
standing 202 feet.
In 2002, the scientific research conducted by the JOIDES Resolution was expanded to
include a strong partnership with Japan and other nations to form the Integrated Ocean Drilling
Program (IODP). This new partnership will coordinate global research on the ocean floor as well
as integrate satellite topography and altimetry to further science’s understanding of the ocean
floor.
Today, scientists use a variety of autonomous underwater vehicles (AUVs), robots, satellites,
and remote sensing equipment to accurately map and sample the ocean floor. Still there is much
to learn.
1
Gulf of Maine Aquaruim, © 2000.
Glomar Challenger: Drillship of the Deap Sea Drilling Project (www-odp.tamu.edu/glomar.html) taken from
Struhs, A. “Glomar Challenger unlocks the earth’s mysteries” On Location (Winter 1984), 8-12.
3
JOIDES Resolution History and Brief Description (www-odp.tamu.edu/shiphist.html)
2
Project Description:
In this project, you and a partner have been chosen to map a portion of the ocean floor for the
Integrated Ocean Drilling Program (IODP). The managers of the IODP project need to know
what topography, or sea floor surface features) they will encounter so they can bring the correct
equipment and enough cable to reach the ocean floor. You and a partner will make a twodimensional map of your portion of the ocean floor without being able to see it directly. You
must trust your “equipment” to determine the features of the ocean floor.
Due to IODP budget cuts, the only technology that you have available on your vessel to
accurately create a map of the ocean floor is a type of SONAR. You will perform a SONAR
simulation in this project that will enable your group to make a crude map of the topography of
the portion of ocean floor that you have been assigned.
Naturally, you and your partner are not pleased at having to use this somewhat antiquated
technology. You decide to collect information about the limitations of soundings and SONAR
during your project. You will use this information to lobby the IODP to update your boat and
provide you with the latest ocean floor remote sensing technology.
Materials
For each group:
 Baking tin
 Plaster of Paris model
 2 sheets of grid paper



tape
dissecting probe
ruler



marker
pen
colored pencils
Procedure
1. Obtain the portion of the ocean floor that you have been assigned from your project manager
(instructor). It is an aluminum baking pan with a piece of grid paper taped over the top.
Inside the pan is a plaster model of the ocean floor that you will be mapping.
2. Using the ruler and a felt-tip marker, make 0.5 cm markings on a pencil or plant stake. Each
centimeter represents one mile of ocean depth.
3. Each square of the grid paper of the
model that your group receives is coded
by a letter and a number. Letters run
along the width of the model (A-Q)
while numbers run the length of the
model (1-33). Therefore, each square of
the grid has its own letter number code
(i.e. the first square in the corner is
“A1”). This same grid can be found on
a sheet in this packet.
4. Using the pencil or plate stake, gently punch a hole in each square of the grid. Measure the
depth of each hole in the shoe box grid to the nearest 0.5 cm. One person makes the
soundings and reads off the depth of each hole, while another records it on the identical
second sheet of grid paper.
5. When you have completed taking all of the soundings, draw lines to connect all similar
depths on your recording grid paper. (See figure at right.)
6. Use colored pencils to shade in areas of similar depth.
7. Locate and label sea floor features such as plains, mountains, or
trenches on the grid paper as well.
8. Remove the grid paper from the model. Compare your map with the
topography of the sea floor model in the box. How similar are they?
Did you misinterpret any features or miss any entirely?
9. When you have finished, discuss the effectiveness of this
Figure 1.1
“sounding” technique with your partner. Write a one page report
that addresses the Further Analysis questions to present to the
project manager. Include your color-coded and labeled map with the report.
NOTE: A list of valuable resources for this portion of the project is available from Mr.
Bromwell’s intranet site under “Related Links.”
10. The project manager will grade your progress according to the attached Scoring Guide.
Further Analysis
1. How well does your grid paper sea floor map resemble the actual model of the sea floor in
the baking tin? Did you misinterpret any features or miss any entirely.
2. Which sea floor features were hardest to identify from the grid paper map? Easiest to locate?
3. Based on your experiences on this project, would you expect the business of taking soundings
in the ocean to be tedious? Labor intensive? Why or why not?
4. In your opinion, can an accurate image of the sea floor be obtained from soundings alone?
5. What other techniques or equipment might be helpful in creating the most accurate “image” of
the ocean floor? In your estimation, why are these equipment or techniques necessary?
Conduct extra research to support your answer.
Student Score ______
Perfect Score 20
Percentage:
Scoring Guide:
0
2
3
4
Grid map of ocean floor
contains all “depths”
marked clearly. All
similar depths are
connected by contour
lines. Areas of similar
depth not shaded.
Ocean Floor
Map
No grid map of ocean
floor is submitted.
Grid map of ocean floor
contains all “depths”
marked. No lines of
similar depth or shading
are included.
Grid map of ocean floor
contains all “depths”
marked. Similar depths
are connected by
sloppily drawn lines or
not at all. Areas of
similar depth not
shaded.
Project
Report
Project report is not
submitted.
Project report is 1 page
in length. Report does
not address all Further
Analysis questions.
Research
No evidence of extra
research on the part of
the student exists.
Project report is less
than 1 page in length.
Report does not address
all Further Analysis
questions. Questions
addressed lack detail
and understanding on
the part of the student.
Students demonstrate
poor understanding of
soundings, SONAR, and
remote sensing
techniques. No evidence
of extra research is
present.
Students demonstrate
basic understanding of
their research about
soundings, SONAR, and
remote sensing
techniques. Discussion
is adequate. No
references are included.
Students demonstrate
good understanding of
their research about
soundings, SONAR, and
remote sensing
techniques. Discussion
is adequate. Less than 3
references are included.
Style &
Punctuality
Project report is not
submitted.
Project report is
submitted later than
Friday, 10/8/2010.
Report is not in MLA
style.
Project report is
submitted later than
Friday, 10/8/2010.
Report is in MLA style.
Project report is
submitted in class on
Friday, 10/8/2010.
Report is in MLA style
with more than 3
grammar or spelling
errors.
______
5
Grid map of ocean floor
contains all “depths”
marked clearly. All
similar depths are
connected by contour
lines. Areas of similar
depth are shaded
similarly with colored
pencils. Legend is
complete.
Project report is 1-2
Project report is 1-2
pages in length. Report
pages in length. Report
does not thoroughly
addresses all Further
address Further Analysis Analysis questions in
questions.
detail.
Students demonstrate
excellent understanding
of their research about
soundings, SONAR, and
remote sensing
techniques as evidenced
by cogent discussion. At
least 3 references are
included.
Project report is
submitted in class on
Friday, 10/8/2010.
Report is in MLA style
with less than 3
grammar or spelling
errors.
A1
2
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
Integrated Ocean Drilling
Project Record Sheet:
4
Project Team:
______________________
______________________
5
Date of Recordings:
6
______________________
3
7
Site Code #: ___________
8
9
10
11
Map Legend:
12
13
Depth
14
5 cm or >
15
4.5 cm
16
17
4 cm
3.5 cm
18
19
3 cm
20
2.5 cm
21
2 cm
22
1.5 cm
23
1 cm
24
25
26
27
28
29
30
31
32
33
0.5 cm or <
Color