Pangaea - Wegener's Puzzling Evidence

79 teachers like this lesson
Print Lesson

Objective

SWBAT will use fossil evidence and maps to write an evidence based position statement defending or refuting continental drift.

Big Idea

The theory of Plate Tectonics was debated for decades. Is Wegener's evidence compelling enough to convince you that the continents have moved over time?

The Need For The Lesson

One of the learning outcomes for this lesson is evidence based writing. As students explore the movement of tectonic plates, they will examine the fossil evidence that links the plates. Students will make specific references to evidence found to defend their position - is there compelling evidence to support Wegener's theory of plate movement? I very rarely have students disagree with Wegener - the important idea for middle school students is choice. They can decide for themselves what the evidence means to them.

Another important learning outcome for this lesson is the ability to critically examine maps. In today's world students can travel from place to place by listening to directional cues from an app on their mobile devices. Many historical events are depicted on maps. Students need to develop map reading skills.

Finally, as scientists, students need to understand the ever changing, dynamic planet we call home. Although these changes take place over time and are barely noticeable in our lifetime; they are critical to understanding how our world has changed and is continuing to change.

Investigation Preparation & Summary

10 minutes

Investigation Summary & Standards

Students will begin their investigation of plate movement by determining the connection of continental plates as map pieces. (SP3 Planning and Carrying Out Investigations). They will use this evidence to develop an understanding Wegener's theory of plate movement by closely examining the fossils and continental shapes. (MS-ESS2-3 analyze and interpret data on the distribution of fossils and rocks, continental shapes, and seafloor structures to provide evidence of the past plate motions.)

Students will report, by authoring a position paper, whether or not they believe the evidence used by Wegener is indeed compelling enough to convince them, as scientists, that plates have separated over time from Pangaea to the positions we find them today. (WHST.6-8.2.D Use precise language and domain specific vocabulary to inform or explain the topic.)  (WHST.6-8.10 Write routinely over extended time frames (time for reflection and revision) and shorter time frames (a single sitting or a day or two) for a range of discipline-specific tasks, purposes, and audiences.) (WHST.6-8.9 Draw evidence from informational texts to support analysis, reflection, and research.)

Students in Action

60 minutes

Students in Action

The launch for this lesson is a short video about plate movement. A short video selection engages students as visual learners and provides background information for the independent activity to follow.


I share with students that Pangaea means that all land was once connected during prehistoric times. The land began to slowly drift apart forming the continents that we find on maps today. We will be taking a critical look at Wegener's evidence to see if we agree with this statement.

One of the key learning goals of this lesson is to help students learn to support their conclusions with evidence from their research. Using the video, we have a short conversation to model citing evidence. In this case evidence directly from the viewing of the video. What did you see in the film clip that provides compelling evidence of plate movement? Students should note that the video shows the continents seem to fit together like puzzle pieces. But is this compelling? Some students may not agree. I ask them to support their disagreement with evidence. Typically they cite that the boundaries are close but not an exact fit.

Students also have background information that they can add to what they see in the video. Do you think that the continental plates continue to move across the surface of the Earth? What evidence do you have that supports this thought? Students should note from the video that the subcontinent of India collided with the Eurasia continent to create the Himalayan mountains. This movement would take a long time. This should prompt students to think about other geological processes that indicate plate movement such as earthquakes. If students do not make this connection, I will ask them directly - What causes earthquakes? Students should note that plates shifting could cause the earthquakes. They may extend that thinking to volcanoes, citing the separation of plates as an opportunity for volcanoes to form.

Next students begin an independent investigation of plate movement. Students use puzzle pieces of current continents, a key to Wegener's puzzling evidence, and a current map of the World Today to create Pangaea as described by Wegener. A complete materials list is provided as a resource. As a class we review the first three instructions found on the key to Wegener's puzzling evidence student handout. 

    1. Label the land masses on each sheet. Color the fossil areas to math the legend below.
    2. Cut out each of the continents along the edge of the continental shelf (the outermost dark line. Alfred Wegener's evidence for continental drift is shown on the cut-outs. Wegener used this evidence to reconstruct the position of the continents relative to each other in the distant past.
    3. try to logically piece the continents together so that they form a giant supercontinent.

I remind students that our evidence and position statement will be placed in our science journals.

As students are working I walk around to observe their progress. A bit of important advice shared on the USGS website:

It is okay if students don't get the "correct" answer or the same solution Wegener proposed as long as they can explain their thought process and how they used the evidence to arrive at their conclusion. There is much information missing from the picture. For example, ancient shorelines were not the same as they are today due to changes in sea level and the tectonic process (continents colliding and pulling apart, causing rocks to be added or torn off). Scientists still debate the fine details of paleogeographic (ancient geography) reconstruction. It is far more important to have students grasp the concept of how scientists look for clues, or evidence, and put the pieces together to solve a problem.

I use this advice to guide my perspective as I watch students grapple with the puzzle pieces. Students tend to look at other's work and question their own. I encourage them by asking how they can support their own conclusions. By questioning students as they work, I am preparing them for the next step, writing their position statement.

Often I need to help students identify the puzzle pieces using the current map of the world. Students are applying their geography and mapping skills in a new context and need assistance.

Once students have assembled the puzzle pieces, I ask additional whole class discussion questions to prepare them for the writing process - modeling citing specific evidence. What evidence have they found working with the maps and evidence chart supports Wegener's ideas about plate movement? Students should note like the movie that continents seem to fit together like puzzle pieces. Why are the continental puzzle pieces not an exact match? This question probes for students ideas about what other geological processes happen over time. Students should mention erosion as a possible reason. Some students may not agree again because the puzzle pieces are not an exact match. What does the fossil evidence tell us? Students often respond first with a general statement such as the fossils are the same on two continents. I prompt them to give me more information. Which two continents - name them? What are the fossils? Provide the specific name from the evidence sheet. Rarely students disagree with the evidence. As long as their conclusion is evidenced based, their position is accepted. 

After modeling the stating of specific evidence as a whole class discussion, students write a position statement in their science journals. The requirement is to cite four pieces of compelling evidence that leads them to agree or disagree with Wegener's ideas about plate movement using their maps and fossil evidence. 

In the following video, I take a close look at student work. I am looking for student use of text evidence to support their positions. Middle school students need to learn to support their conclusions/opinions with specific evidence from the text. You will see how one student does a really great job of supplying supporting text evidence while the other student will need more support from me in future writing activities.

Taking a Close Look at Student Work

Easy to read samples can be found by clicking this link - Student Samples (also in Resources)

 

This investigation was developed by the USGS (United States Geological Survey) and can be found in its entirety at Wegener's Puzzling Evidence Exercise.

Connecting the Learning

15 minutes

My students are seated in lab table groupings of six. We take a few minutes to exchange lab journals and read what our fellow students wrote for evidence. Students exchange journals only at their table group of six. I ask student to exchange journals with the person sitting opposite them. Each review takes about 3-5 minutes. I let student actions give me a cue as to when to ask them to pass the journal they are looking at to the right. The cues are pretty obvious as students begin to fidget when they have finished reading. This is repeated three or four times. I do not require students to make any formal notes. I do not want them to think they are grading the work of other students. They are simply making observations. Did each student place the puzzle pieces together in exactly the same way? Was the evidence cited identical? Since students were only required to cite four examples, there is some variance of choices. Did everyone agree with Wegener? 

When Wegener first developed his ideas, he had some doubters in the scientific community. We watch a short video about Wegener.

Would Wegener have been more or less successful in convincing scientists today than he was when he proposed his ideas? Why or why not? Students may answer that the use of technology would enhance his ability to make his position known and understood. He can use videos and aerial photography. 

It took a long time for the scientific community to accept and develop Wegener's ideas about plate movement into the theory of Plate Tectonics. An important aspect of science is that we continue to question and ask for evidence. There is a lot of junk science in movies, on TV commercials, online videos and social media posts. Before you embrace the science from these sources ask for the evidence.