- Idea of continental drift
- Evidence for continental drift
- Be able to explain the continental drift hypothesis.
- Describe the evidence Wegener used to support his continental drift idea.
- Describe how the north magnetic pole appeared to move and how that is evidence for continental drift.
continental drift: early 20th century hypothesis that the continents move over Earth’s surface
magnetic field: area surrounding a magnet over which it exerts magnetic force
Introducing the Lesson
Show students a map of the world. Ask them if the continents have always been where they are now. Students may think that the continents are unmoving. They may be surprised when you tell them that the continents used to be in very different positions millions of years ago. Have them look at the map of Pangaea in the FlexBook® student edition lesson, and explain that this is how Earth looked about 250 million years ago. Tell them they will see evidence for it when they read this lesson.
Demonstrate continental drift to the class with the animation at the URL below. The animation shows the movement of the continents over the past 250 million years, starting at the time of the dinosaurs, when all of today’s continents formed the supercontinent Pangaea. Students can watch as Pangaea breaks apart and the continents move to their present positions. Point out how quickly India travels toward Asia near the end of the animation at about 60 million years ago. Explain that when the two landmasses collided, the collision formed the Himalaya Mountains.
Building Science Skills
You may want to use the lesson plan at the following URL when you teach students about Wegener’s hypothesis and the evidence that supports it. Students will follow steps similar to those taken by Wegener to examine fossil evidence for continental drift. They will map the locations of fossils and discuss how well the fossil evidence supports the hypothesis.
Provide kinesthetic learners with cutouts of the continents (see URL below). Have them try to fit the continents together to form the supercontinent Pangaea. Tell them to look at the map of Pangaea in the FlexBook® student edition lesson if they need help. In simple terms, relate the puzzle to the hypothesis of continental drift. Ask students how the shapes of the continents help support the hypothesis.
Assign interested students the self-paced lesson “Continental Drift: What’s the Big Idea?” at the URL below. The online lesson, which reviews and extends FlexBook® content, includes a video and reading passage, as well as several quizzes. As a final assignment, students are asked to choose one of two topics and write an essay that includes supporting details and vocabulary from the lesson. Ask students to read their essay to the class.
You can use the “Great Continental Drift Mystery” at the following URL when you teach the lesson. It allows students to explore and interpret a diversity of evidence for continental drift. Students will study and draw maps and add clues to maps as they try to solve the mystery.
Students may have many misconceptions about continental drift. For example, they may think that continents drift because they float on the oceans. This and other misconceptions about continental drift are discussed at the URL below. The Web site also provides links to multi-media materials you can use to counter the misconceptions.
Reinforce and Review
Copy and distribute the lesson worksheets in the CK-12 Earth Science for Middle School Workbook. Ask students to complete the worksheets alone or in pairs to reinforce lesson content.
Lesson Review Questions
Have students answer the Review Questions listed at the end of the lesson in the FlexBook® student edition.
Check students’ mastery of the lesson with Lesson 6.2 Quiz in CK-12 Earth Science for Middle School Quizzes and Tests.
Points to Consider
Why is continental drift referred to as a hypothesis and not a theory?
Why is Wegener’s continental drift idea accepted today?
Explain how each of these phenomena can be used as evidence for continental drift:
the fit of the continents
the distribution of fossils
the distribution of similar rock types
rocks from ancient climate zones