Lesson: Balancing Act

Open the article online and show students the first image. Draw a chart with three columns. Label the columns “I Notice,” “I Think,” and “I Wonder.” As a class, fill in the chart with students’ observations, students’ thoughts about what’s going on with the rocks, and students’ questions about the rocks.

Lay a large book facedown on a flat surface. Place another book on top of the first so it’s standing up on its bottom edge. Tell students that the second book represents a balancing rock as shown in the picture. Now simulate an earthquake by gently moving the bottom book back and forth, trying not to topple the top book. Move the bottom book more rapidly until the top book falls over. Ask students to describe what happened to the “rock” during the “earthquake.” Ask the class to keep their observations in mind as you read the article aloud. When you have finished reading, have them add a fourth column to their charts and label it “Now I Know.” Record key information as a class, and then compare their prior thinking with what they found out in the article. Distribute the “Investigate It! Balancing Act” skills sheet for students to complete.

Pair up students, with proper social-distancing precautions, and have them complete the “Check the Balance” activity. Then reconvene and discuss how the center of mass relates to the precariously balanced rocks. Ask: How might a rock’s center of mass influence how it’s affected by an earthquake? (e.g., rocks that have a high center of mass may topple more easily) How might scientists determine the center of mass of the rocks? (e.g., by analyzing their computer models)

Watch the video “Inside Earthquakes” to learn more about how and where earthquakes occur. Then distribute the “Shaking Strength” skills sheet and have students analyze the table showing strength and frequency of earthquakes.

Have students complete the article’s “Check for Understanding.” Ask students to explain whether they think the precarious rocks that scientists studied in the article will still be standing in 10,000 years. Discuss how other natural processes, like weathering, could affect these rocks.

⇨ VIDEO EXTRA: Watch a video about how and where earthquakes form.