Earthquakes and Seismic Waves

Active learning works for this topic because earthquakes and seismic waves are abstract concepts that students need to visualize and manipulate. Kinesthetic and hands-on activities make the invisible visible, helping students connect theory to physical experience. This approach also addresses common misconceptions by giving students immediate feedback through movement and measurement.

• Grade 7
• Science
• 4 activities
• 20 min–45 min

Learning Objectives

1. Explain the mechanism by which stress accumulation and release cause ground shaking during earthquakes.
2. Compare and contrast the movement and properties of P-waves and S-waves.
3. Calculate the distance to an earthquake's epicenter using seismograph data and arrival time differences.
4. Analyze seismic wave data to determine the location of an earthquake's epicenter on a map.

Simulation Game

⏱ 20 min·Pairs

Slinky Demo: P- and S-Waves

Pairs stretch slinkies end-to-end. Create P-waves by pushing and pulling longitudinally to see compression; then shake side-to-side for S-waves to observe transverse motion. Time wave travel across the slinky and note which arrives first at the far end.

Prepare & details

Explain what causes the ground to shake during an earthquake.

Facilitation Tip: During the Slinky Demo, emphasize the difference in wave motion by having students physically push and pull the slinky to simulate P-waves and shake it side-to-side for S-waves.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Simulation Game

⏱ 45 min·Small Groups

DIY Seismograph: Station Build

Small groups assemble seismographs using a hanging weight, string, marker, and paper drum. Place on a shaken table to record simulated P- and S-waves. Compare tracings for wave patterns and measure arrival time gaps.

Prepare & details

Differentiate between P-waves and S-waves and their behavior.

Facilitation Tip: When students build their DIY Seismograph, circulate to check that each group has a stable base and that the pen touches the paper at the right angle for clear wave traces.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Simulation Game

⏱ 35 min·Small Groups

Epicenter Triangulation: Map Activity

Small groups receive three seismograph data sheets with P- and S-wave arrival times. Calculate time differences, draw circles on a map from each station using a scale, and find where circles intersect as the epicenter.

Prepare & details

Analyze how seismographs are used to locate the epicenter of an earthquake.

Facilitation Tip: For Epicenter Triangulation, provide colored pencils and rulers so students can clearly mark distances and intersections on their maps without confusion.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Simulation Game

⏱ 25 min·Pairs

Jell-O Quake: Wave Observation

Pairs prepare trays of set Jell-O. Drop objects or shake trays to generate waves, observing how P-waves ripple through and S-waves cause shearing. Sketch wave paths and discuss solid-like behavior of Earth's crust.

Prepare & details

Explain what causes the ground to shake during an earthquake.

Facilitation Tip: In the Jell-O Quake activity, guide students to observe wave propagation from the sides of the pan to see how waves travel through different layers.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Teaching This Topic

Teachers should start with the Slinky Demo to introduce wave types concretely before moving to abstract diagrams. Avoid rushing through the physics of wave motion—instead, use analogies like a slinky or rope to build intuition. Research suggests that students retain more when they physically create and measure waves themselves, so prioritize hands-on time over lecture. Emphasize the relationship between wave speed and damage to help students understand why S-waves cause more destruction.

What to Expect

Successful learning looks like students correctly labeling faults, distinguishing P-waves from S-waves, and using triangulation to locate epicenters. They should explain the connection between wave types and damage patterns and justify why multiple seismograph stations are necessary. Evidence of understanding includes accurate calculations, clear diagrams, and thoughtful discussion contributions.

Watch Out for These Misconceptions

Common Misconception

During the Epicenter Triangulation activity, watch for students assuming earthquakes can happen anywhere equally.

What to Teach Instead

Encourage students to plot data points from a world earthquake map and observe that most clusters align with tectonic plate boundaries. Ask them to explain why these areas show more frequent quakes.

Common Misconception

During the Slinky Demo, watch for students believing P-waves and S-waves travel at the same speed.

What to Teach Instead

Have students measure the time it takes for each wave to travel the same distance on the slinky. Ask them to calculate the speed difference and explain how this affects seismic wave arrival times.

Common Misconception

During the Jell-O Quake activity, watch for students thinking the epicenter is where shaking is strongest.

What to Teach Instead

Ask students to mark the focus on their Jell-O model and compare it to where the surface waves appear to originate. Discuss how distance and geology affect shaking intensity.

Assessment Ideas

Quick Check

After the Slinky Demo, present students with a diagram showing a fault line and arrows indicating stress. Ask them to label the focus and epicenter and write one sentence explaining what happens when stress is released.

Exit Ticket

During the DIY Seismograph activity, provide students with a simplified seismogram showing P-wave and S-wave arrival times from one station. Ask them to calculate the time difference and explain what this tells them about the earthquake's distance.

Discussion Prompt

After the Epicenter Triangulation activity, pose the question: 'Why would a scientist need data from at least three seismograph stations to locate an earthquake?' Facilitate a discussion where students explain how triangulation reduces error and improves accuracy.

Extensions & Scaffolding

• Challenge students to predict how the seismogram would change if the earthquake occurred closer to or farther from the station during the DIY Seismograph activity.
• For students struggling with triangulation, provide a partially completed map with two stations already plotted and guide them to find the third intersection.
• Have students research historical earthquakes, plot their epicenters, and compare their observed damage patterns to the wave types expected in those regions.

Key Vocabulary

Fault	A fracture or zone of fractures between two blocks of rock where movement has occurred. Earthquakes are caused by sudden slips along faults.
Seismic Waves	Waves of energy that travel through the Earth's layers, originating from the focus of an earthquake. They include P-waves and S-waves.
P-wave (Primary Wave)	The fastest seismic wave, which travels through solids, liquids, and gases by compressing and expanding the material in the direction of its travel.
S-wave (Secondary Wave)	A slower seismic wave that travels through solids only, moving material perpendicular to the direction of its travel.
Epicenter	The point on the Earth's surface directly above the focus of an earthquake. It is the location where seismic waves are typically strongest.
Seismograph	An instrument used to detect and record the ground motion caused by seismic waves during an earthquake.