Using Sonar to Map the Ocean Floor and Find Sea Monsters


Short Term Goals:

(1) To introduce students to the concept of sonar (i.e. functions, history, facts and figures, uses and meaning).

(2) To provide students with a hands-on approach to creating and mapping their own ocean floor.

(3) To make a correlation between the uses of sonar and the sea monsters discussed throughout the Curriculum Development Project.

Time Allotment: 1 hour

Content Areas Addressed:

(1) Science

(2) Math

(3) Language Arts

Concepts Addressed:

(1) Sonar

(2) Graphing

(3) Measurement


(1) Mud/gravel mixture

(2) Water basins, water

(3) Bowls, cups, rocks

(4) String, scissors

(5) Clay

(6) Rulers

(7) Graph paper

(8) Pencils, markers

(9) Sonar Reference Guide


(1) Introduce the concept of sonar (i.e. the functions, history, facts, and figures, uses, and meaning) to the students. Provide the students with a variety of books and magazines in order to research the various concepts relating to sonar. A list of informational references is included at the end of this lesson.

(2) Sonar has many uses to scientists and one important use it to map the ocean floor. The students are going to be participating in a graphing activity relating to mapping the floor of a water basin containing a mud and gravel mixture.

(3) Before the activity, create a mud and gravel mixture for the students. This mixture is going to represent the sediments of the ocean floor. A mud and gravel mixture is easier to mold, which is important for this lesson.

(4) In groups of three, the students are going to be creating their own ocean floor using a water basin, bowls and other objects to create landforms, the mud and gravel mixture, and water. Students can be assigned roles for this experiment, such as a recorder, leader, and go-for.

(5) Students should use the mud and gravel mixture to form various landforms found within the ocean. It is recommended to have a mud/gravel base at the bottom of the water basin. From this base, landforms such as trenches and mountains can be created using the appropriate materials (i.e. bowls, cups and rocks). Students should create a majority of these leandforms across the middle of the water basin, since the graphing aspect of this lesson is going to occur across the middle of the basin.

(6) After the landforms are created using the mud and gravel mixture, the group of students should add water until the water level almost reaches the top of the water basin.

(7) Each group may then cut two pieces of string. One string should be about one foot in length and the other string needs to be as long as the length of the water basin. With the one-foot string, students should tie a knot at the bottom and then place a piece of clay over the knot. Using the same string and ruler, students will make 1/2 inch increment markings starting from the bottom of the clay ball and going until the end of the string. This string is going to be used to measure the depth of the floor within the water basin. With the other string, the students should tape the string across the middle of the length of the water basin. Students will make 1/2 inch increment markings along this string as well starting from one end of the water basin and ending at the other end. These markings represent the plotting points for measuring the bottom of the water basin floor.

(8) Using the markings on the string taped onto the water basing, the groups can plot the depth of the water basin at these marking points. With the clay ball string, students should lower the string until they feel the ball hit any part of the mud and gravel mixture. Students can continue this procedure along all of the plotting points across the water basin and record the depths associated with the clay ball string.

(9) With the recorded results from the group, each students is going to create his or her own graph representing the bottom of the water basin floor. In order to create an accurate graph of the basin floor the students need to create a graph in the reverse fashion. For instance, the x-axis should be located at the top of the paper and the y-axis will still be located at the left side of the paper. By using the graph paper in this fasion, the landforms on the "ocean" floor will be seen more realistically.

(10) Review the concept of graphs with the students. Along the x-axis students should number their graphs according to the number of points on the string along with length of the water basin. Along the y-axis students should number their graphs according to the depths recorded during the experiment. For the y-axis, students need to determine the lowest depth marking and the highest depth marking in order to create an accurate distance span for this axis.

(11) Students should now use the recorded results from their experiments to graph the water basin ocean floor on the graph paper. Markers can be used to decorate the ocean floor graph. Students can empty the water within the basin to see the accuracy of their graphs by observing the landforms.

(12) Sonar is also used as a means to find sea monsters within the oceans. Make a correlation between the use of sonar to find sea monsters and the sea monsters already discussed within class and within The Odyssey.

NOTE: This lesson was modified from an experiment within Pioneering Ocean Depths by Sandy Markle.


(1) Experiment Rubric

(2) Group Participation Rubric

(3) Observation Checklist

(4) For the graphing components of this lesson, collect the graphs of the students to assess the concepts of graphing. Assess the graphs on appropriate use of the x-axis and y-axis, development of accurate scales for the axes, and using the coordinates of the graph correctly to create an accurate map of the ocean floor.


(1) To extend the idea that sonar is used as a means to find sea monsters within the oceans, have the students place a toy animal within the water basin. Students will then be encouraged to find the sea monster within the water basin using the stringing method described above. When plotting the markings on the graph, students will be asked to identify if any markings on their graph resemble a sea monster.

(2) Bring in a police officer to help the students further understand the concept of sonar. Police officers use radar guns, which run on the same principle as sonar eqipment. A school police liaison officer can be asked as a guest speaker, as well as a local police officer.

(3) Clip of Bob Ebben's video titled Physics Time relating to laser radar guns, which coincides with the principles of sonar.


Clark, J. (1992). Sea and Oceans. New York: Gloucester Press. [isbn: 0-531-17368-2]

Dane, A. (1990, January). Deep Quest Popular Mechanics, 167 (1). 56-59.[No ISBN availabe because this if from Ebscohost]

Fleisher, P. (1995) Our Oceans: Experiments and activites in marine science. Brookfield, Connecticut: Millbrook Press. [ISBN: 1-56294-575-0]

Ganeri, A. (1990) The Usborne Books of Ocean Facts. Tulsa, Oklahome: Educational Developmental Corporation Publishing. [ISBN: 0-7460-0621-7]

Graham, I. (1993). Boats, Ships, Submarines, and other Floating Machines. New york: Kingfisher Books. [ISBN: 1-85697-868-0]

Markle, S. (1995) Pioneering Ocean Depths. New York: Antheneum Books for Young Readers. [ISBN: 0-689-31823-5]

Pratson, L. (1997, June). Seafloor mapping Tools. Scientific American, 276 (6), 86-87. [No ISBN available because this is from Ebscohost]

Yulsman, T. (1993, July). Charting Earth's Final Frontier. Earth, 2 (4), 36-41. [No ISBN available because this is from Ebscohost]

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