Earth
Driving Question: How did the formation and evolution of Earth increase complexity?
Earth, the planet where we make our home, didn’t appear overnight. Earth took billions of years to slowly evolve into its current form—4.567 billion years to be exact.
Learning Objectives:
- Describe the formation of the Earth.
- Explain how Earth changed over time, including evaluating the evidence for plate tectonics.
- Analyze the physical processes that shaped Earth’s surface.
Vocab Terms:
- collective learning
- continental drift
- Earth
- geology
- gravity
- planet
- plate tectonics
To kick off this lesson, ask your students if they want to be lava surfers. You might get some puzzled looks, but whether they want to or not, we’re all lava surfers! You can share this article with them or read passages aloud to get them thinking about plate tectonics.
This activity is a bit of a challenge in terms of showing student work. Once your students complete their matching exercise, you can do one of two things: 1) Have them use the snipping tool and snip their answers to turn them into your LMS as an image; or 2) share the answer key so students can check their work. The Google Slide activity does not “lock” results once students move the images the way some other matching edtech tools might.
We have finally touched down on Earth, and there’s already a ton going on beneath our feet. Let’s explore what’s rumbling down there!
The early days of the Earth were a time of fire and liquid metals. Imagine you’re in a super-safe spacesuit, traveling across a very different planet than the one you’ve known.
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Guiding Questions
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Before you watch
Preview the questions below, and then review the transcript.
While you watch
Look for answers to these questions:
- What challenges would humans have faced if they lived on the early Earth?
- What are the four layers of the Earth?
- What is Pangaea?
- What are the two different types of crust?
- What is the theory of plate tectonics?
After you watch
Respond to this question: How is the Earth still forming and changing today?
The plate tectonics activity aligns with Standard 3 of the National Geography Standards (NGS) and helps students analyze spatial concepts such as dispersion and distribution. Explore Big History’s geography resources and see how each activity aligns to the NGS in this alignment and placement doc.
For decades people believed that something as huge as a continent could not move. But the discovery of plate tectonics proved them wrong.
Earth's Tectonic Plates
Did you know that there’s an easy way to give students feedback on their claim-testing skills? The Claim Testing: Feedback Form breaks down the elements so you can assess how well they did crafting a claim and a counterclaim and if their responses are historically accurate. You can adapt the feedback form to focus only on the skills that are assessed by crossing out sections of the form that don’t apply to a particular activity.
Now you know a little about plate tectonics! But it’s just important to know how we as humans made these discoveries. Your claim-testing skills are about to come in handy.
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Guiding Questions
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Before you read
Preview the questions below, and then skim the article. Be sure to look at the section headings and any images.
While you read
Look for answers to these questions:
- What evidence did Alfred Wegener use to explain his theory of continental drift?
- Why didn’t the scientific community accept Wegener’s theory?
- How did Harry Hess and Marie Tharp expand on Wegener’s theory?
- What is the scientific theory of plate tectonics?
- How do Earth’s plates move and what happens when plates collide?
After you read
Respond to this question: How do you think the movements of the plates might change life on Earth in the future?
Informal writing routines like the Unit Notebook are incorporated in each unit of the course. These routines are part of how students learn the content and help them make connections to core Big History concepts. Learn more about writing routines on pages 3–4 of our Writing Guide.
From the Big Bang to the formation of Earth, you’ve covered a lot of time and space. Now that you’re back on solid ground, how has your thinking changed?
Marie Tharp spent much of her career in the shadows of male scientists. Yet her work helped prove the theory of continental drift and our understanding of plate tectonics.
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Guiding Questions
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Before you read
Preview the questions below, and then skim the comic, paying attention to things like prominent colors, shapes, and types of text and fonts. How do you know where to start and in which direction to read? What’s in the gutters (the space between panels)? Who or what is the focus of the comic?
While you read
Look for answers to these questions:
- What were some challenges that Marie Tharp faced in her work as a geophysicist?
- How did Tharp’s mapping of a Mid-Atlantic Ridge and rift valley help prove the theory of continental drift?
- Why was Tharp’s discovery important to collective learning?
- Look at the way the panels of the biography progress, moving clockwise from the top-left panel. How does the artist use design to depict Marie Tharp’s career as a geophysicist?
After you read
Respond to this question: What does Marie Tharp’s story tell you about how theories become generally accepted?
We know that writing a full DBQ essay might be challenging for middle-school students. This optional assessment can be adapted in a few ways: 1) Have students focus on the prewriting exercise, modeling how to unpack the prompt and write a claim. You can use the table on page 2 of the Claim Warm-Up activity to help students parse the prompt and craft their claim. 2) Create learning stations for student groups to examine a smaller selection of the DBQ sources and decide how each source helps to answer the prompt. 3) Shorten the essay in the writing activity to a paragraph or have students create a different product such as a Google Slide or infographic.
This writing assignment is available through Khan Academy’s Writing Coach, an AI-powered tool that guides students through the writing process and provides feedback—without doing the thinking or writing for them. Learn more and find a direct link to this assignment in our Writing Coach Guide.
You’ve learned a lot about how Earth has changed over billions of years. Now, it’s time to show how much you’ve learned.