To explore how an indefatigable scientist used her knowledge of math and map making to create a map of the ocean floor, confirming the theory of continental drift (plate tectonics).
This lesson uses a book called Solving the Puzzle Under the Sea, written by Robert Burleigh with illustrations by Raúl Colón. It is one of the finalists of the 2017 SB&F Prize for Excellence in Science Books. SB&F, Science Books & Films, is a project of the American Association for the Advancement of Science.
In this illustrated biography, Burleigh tells the story of Marie Tharpe’s imagination and perseverance and shares the story of this pioneering woman scientist, who was the first person to ever successfully map the ocean floor. Her map helped confirm the theory of plate tectonics to the scientific community.
According to the Benchmarks for Science Literacy, "It is important that not all of the historical emphasis should be placed on the lives of great scientists, those relatively few figures who, owing to genius and opportunity and good fortune, are best known. Students should learn that all sorts of people, indeed, people like themselves, have done and continue to do science." This book about Marie Tharp tells the story of a scientist who faced many obstacles in her day because she was a woman. Nevertheless, her tenacity and driving curiosity led her to overcome many of those barriers.
Her story also demonstrates how, even though Marie was unable to participate in adventures at sea, she could still participate in scientific discovery. Using the data collected from others, she applied her mathematics and mapping skills to create a map that beautifully revealed the nature of the ocean floor, helping to confirm the revolutionary theory of plate tectonics.
Ideas in this lesson are also related to concepts found in these Common Core State Standards:
- CCSS. ELA-Literacy.RI.3.1
Ask and answer questions to demonstrate understanding of a text, referring explicitly to the text as the basis for the answers.
- CCSS. ELA-Literacy.RI.3.3
Describe the relationship between a series of historical events, scientific ideas or concepts, or steps in technical procedures in a text, using language that pertains to time, sequence, and cause/effect.
- CCSS. ELA-Literacy.RI.3.7
Use information gained from illustrations (e.g., maps, photographs) and the words in a text to demonstrate understanding of the text (e.g., where, when, why, and how key events occur).
- CCSS. ELA-Literacy.RST.4.1
Refer to details and examples in a text when explaining what the text says explicitly and when drawing inferences from the text.
- CCSS. ELA-Literacy.RST.4.3
Explain events, procedures, ideas, or concepts in a historical, scientific, or technical text, including what happened and why, based on specific information in the text.
- CCSS. ELA-Literacy.RST.4.7
Interpret information presented visually, orally, or quantitatively (e.g., in charts, graphs, diagrams, time lines, animations, or interactive elements on Web pages) and explain how the information contributes to an understanding of the text in which it appears.
- CCSS. ELA-Literacy.RST.5.1
Quote accurately from a text when explaining what the text says explicitly and when drawing inferences from the text.
- CCSS. ELA-Literacy.RST.5.2
Determine two or more main ideas of a text and explain how they are supported by key details; summarize the text.
- CCSS. ELA-Literacy.RST.5.3
Explain the relationships or interactions between two or more individuals, events, ideas, or concepts in a historical, scientific, or technical text based on specific information in the text.
If possible, you should get one or more classroom copies of Solving the Puzzle Under the Sea by Robert Burleigh.
You might want to print out copies of the Map of Tectonic Plates that you'll use at the end of the Development section.
While the lesson includes links to videos and maps for the students, if you would like more information on Marie Tharp and plate tectonics, you should investigate these resources:
- Dr Nicky Howe Marie Tharp: Mapping the Deep
- Primary Sources in Science Classrooms: Mapping the Ocean Floor, Marie Tharp, and Making Arguments from Evidence
- Seeing Is Believing: How Marie Tharp Changed Geology Forever
- Making Continents Move: The Ocean Cartography of Marie Tharp
Begin the lesson by asking students what they know about surface of the earth. You could ask them:
- Do you know the names of the continents and oceans?
- Do the continents move, or are they always in the same place?
Then lead them into a discussion of the ocean floor. You can ask them questions like these: Is the ocean floor flat? How deep is the ocean? Is the floor at the same depth all around the planet?
Students can use the Solving the Puzzle Under the Sea student esheet to look at Google Maps by themselves on their own computers if possible (or you can project a computer screen for the entire class). They should zoom out so that they can see most of the Atlantic Ocean. Then they should locate the ridge in the middle of the Atlantic Ocean. Ask these questions (students can write responses on the Ocean Floor Exploration student sheet):
- What might this ridge be? What might it be telling us about the earth?
- (Student answers may vary. Encourage students to explain their answers.)
In this part of the lesson, students should read the book Solving the Puzzle Under the Sea: Marie Tharp Maps the Ocean Floor, either in class or as a homework assignment. If they do read it in class, then you may want to allow at least two class periods for completing the lesson.
After reading the book, students should fill out the Solving the Puzzle Under the Sea student sheet to answer questions about the book. After students write down their answers, go over them in class. Follow up with discussion of these questions:
- What characteristics did Marie have that would make her a good scientist?
- Is it fair that she was discouraged from becoming a scientist? Have things changed for women interested in science today?
- Can you name any women scientists (either famous or known personally to you)? What is/was their field of study?
- (Answers will vary, but students should pick up on her curiosity about the world, her sense of adventure, her determination in the face of problems, her enjoyment in solving problems, and her willingness to put in long hours to achieve her goal.)
- (Answers may vary. Encourage your students to explain their answers.)
- (Answers may vary. Encourage your students to explain their answers.)
Next, students should use the student esheet to view Marie Tharp's groundbreaking map and watch two animated videos about plate tectonics and Marie Tharp's role in confirming the theory.
First, students should watch an animated video called How One Brilliant Woman Mapped the Secrets of the Ocean Floor. As the video shows, it took scientists a long time to agree that continents moved. Ask students: What are some of the steps shown in the video that convinced most scientists that the continents actually moved? They should write down the steps on the Ocean Floor Exploration student sheet.
- Using sonar, scientists took soundings of the depth of the ocean floor.
- Using the soundings, Marie Tharp mapped the ocean floor.
- Howard Foster mapped the epicenter of the world's earthquakes. (View a comparison of his map and Tharp's map from the Library of Congress site.)
- They found that where there were mid-ocean ridges, there were also earthquakes.
- This still did not convince most scientists, until Jacques Cousteau filmed the ocean floor. The films showed the deep valley, how it split the ridge in half, and how Tharp's maps were right all along.
- Finally, scientists found enough evidence to convince them of the theory of plate tectonics.
Students should use their student esheet to revisit the map of the ocean floor created by Marie Tharp and explore it some more. After students have explored the map, have a class discussion using the questions from the Ocean Floor Exploration student sheet.
- Did you locate the Atlantic Ocean?
- Did you find the ridge in the middle of the Atlantic Ocean?
- What does it look like?
- Are you surprised to see that the floor isn't flat?
- Follow the mid-ocean ridge all around the world. This ridge is actually a mountain range. Look for mountain ranges on the land. Can you find a mountain range that is longer than the one on the ocean's floor? (They won't be able to, because this mid-ocean ridge is the longest mountain chain in the world at 40,389 miles!)
For more about the theory of plate tectonics, students should watch this short animated video titled Plate Tectonics Explained. It goes pretty fast, but it should give them a good idea about how plate tectonics works. [This video is embedded in the esheet, to avoid exposing students to the comments section on YouTube.] Since the video moves fast, use the following guiding questions to help students retain the information. They can record their answers on the Ocean Floor Exploration student sheet.
- How old is the idea that the continents drift around the globe?
- When did most geologists believe in continental drift?
- How do we track the movement of tectonic plates?
- The video states that tectonic plates are carried along on currents in the upper mantle. What is the upper mantle?
- What type of current drives two plates into each other?
- What type of current pulls two plates apart?
- Do all the plates move at the same speed?
- When an oceanic plate collides with a continental plate, which will be forced under the other?
- (It is at least 200 years old.)
- (Most believed in the theory by the 1960s.)
- (We track it from space, using satellites.)
- (It is a slowly moving layer of rock just below earth's crust.)
- (Converging current drives two plates into each other.)
- (Diverging current.)
- (No. Some move faster than others.)
- (The oceanic plate will be forced under the continental plate because it is denser [unlike stated in the video, not because it is thinner].)
For a closer look at a map of the plates similar to the one shown in the video, print out the Map of Tectonic Plates. Show students how the arrows point out the direction of the movement of the plates.
Student understanding of the book and lesson can be assessed according to their answers on the student sheet and their participation in class discussions.
For more advanced or older students, student understanding of maps and plate tectonics can be assessed with a classroom mapping project. Since the theory of plate tectonics was confirmed by the mapping of earthquakes around the world, students can see if their mapping data also confirms the theory. The Earthquake Mapping Project teacher sheet provides information to help you guide students through the mapping project.
Print out one large classroom copy of the Map of Tectonic Plates from worldatlas.com. Provide students with copies of the Earthquake Mapping Project student sheet and the Earthquake Mapping Project spreadsheet (downloadable from the student sheet), which contains a list of major earthquakes (taken from a Wikipedia list of deadlhy earthquakes since 1990). Let students choose or assign to each student two major earthquakes found on the spreadsheet. They will locate the earthquakes using Google Maps, mark the locations of the earthquakes on the classroom map, and then answer the questions on their student sheet to answer the question: Do all the earthquakes correspond to where the tectonic plates meet?
These Science NetLinks lessons could be used as extensions:
The NEA resource on Marie Tharp includes five lesson plans on ocean floor mapping, as well as an interactive on exploring the Arctic seafloor.
There are some National Geographic activities on mapping that are useful:
PBS Learning Media Plate Tectonics introduces students to the theory of plate tectonics and explores how the theory was developed and supported by evidence.