Earthquakes- an Introduction

Overview

  • This lesson explores what earthquakes are, in the context of plate tectonics, by demonstrating what occurs along a fault line during an earthquake.

Estimated Time

  • 45 minutes.

Materials

  • Bubblegum (for engagement activity)
    • chewing gum won’t work here, as you are attempting to blow a large bubble
  • Handouts
  • Wooden blocks with sandpaper pasted on, or sanding blocks

Objectives

  • Students will be able to understand and describe how an earthquake occurs in terms of plate tectonics (faults, plate boundaries, and plate movements).
  • Students will be able to diagram the movement of two plates, relative to each other, during an earthquake.

National Standards Addressed

Math (Presented by National Council of Teachers of Mathematics in 2000)
Problem Solving
  • Solve problems that arise in mathematics and in other contexts
Representation
  • Use representations to model and interpret physical, social, and mathematical phenomena
Science (Presented by National Research Council in 1996)
Physical Science
  • Motions and forces
  • Properties and changes of properties in matter
  • Transfer of energy
Science and Technology
  • Abilities of technological design
Earth and Space Science
  • Structure of the Earth System
  • Earth’s history
Technology (Presented by the International Society for Technology in Education in 1998)
Technology research tools
  • Students use technology to locate, evaluate, and collect information from a variety of sources.

Engagement Activity (optional)

  • Place a piece of bubblegum in your mouth, (or use a student volunteer). Blow a bubble, slowly, until it pops. Ask the students why the bubble pops. (Continue to demonstrate, as necessary).
  • Discuss the fact that the bubble pops because the surface of the bubblegum gets thinner and thinner and the air pressure in it causes it to burst when the gum can no longer contain the air. When a bubble pops, the pressure that has been building up releases, abruptly.

Instructional Plan

Students will be using wooden blocks to demonstrate the movements of continental plates along a boundary or fault. As a result of these demonstrations they should be able to infer how earthquakes occur.

  • The activity handout will instruct the students to take a wood block (which represents a continental plate) in each hand and firmly press them together. This will represent the pressure of two plates pushing against each other.
  • The students will then be instructed to maintain this pressure while simultaneously starting to pull one block toward them and push the other block away from them. As they begin to increase the force on the wood blocks both toward and away from themselves (all while firmly pressing the blocks together) they will reach a point where the two blocks slip and suddenly slide across one another.
  • Arrows that line up when the blocks are in their original position will allow the students to see how the “plates” have moved in relation to each other. This sudden slide is contrary to the normally slow, steady movement that they have been told plate tectonics usually exhibits. This sudden thrust is due to the build up of pressure along the plate boundary.
  • The students will be asked to repeat the activity using the wood blocks. Throughout the activity they will be asked to record their observations and make inferences based on what they see and what they know about plate tectonics.

The goal of this activity is for them to determine that this sudden movement results in an earthquake. The details of the activity will be explained on the accompanying students and teacher activity sheets.

  • Divide students into groups of two or three (depending on class size and available materials).
  • Provide each group with a handout for the activity and briefly explain what they will be doing.
  • As the students complete the activity they will be asked to record their observations and make inferences about what the observations mean relative to plate movements and the resulting effects.

Sustaining, Concluding, or Extending Activities (optional)

Concluding:

  • Students will then discuss in their small groups and as a whole class what this means on a larger scale. If those blocks represent two large continental plates, what is happening when they abruptly slide past each other?

Extending:

  • Using available online maps of the plate boundaries, have students discuss the likelihood of an earthquake occurring in their area.

Evaluation and Assessment

Students will be able to:

  • Explain what an earthquake is and how it is caused (in the context of plate tectonics).
  • Include a diagram of a fault or plate boundary in the above explanation as a means of further demonstrating their understanding of earthquakes.

E-Resources, Print Materials, and Hands-on Activities

Public Broadcasting Service (PBS) offers an interactive animation demonstrating Plate Tectonics; please follow the link to explore their Web site.

Download the Introduction to Earthquakes Worksheet to supplement the tectonic plate exercise.