Look for: The up-and-down motion of the pan bottom (or…

3.A.1 Analyze and interpret data from different wave models to identify patterns in how the wave forms initially and moves toward shore, changing the height (amplitude) of the wave as it interacts with the ocean floor.

Students use three different wave models in this lesson. After analyzing each model, the class pauses to share what has been figured out about the waves in the model and real-life tsunamis in the ocean. From the Foil Pan Model, listen for students to identify the following key ideas:

• The up-and-down motion of the pan bottom (or ocean floor) causes the water above it to move in a similar pattern (up and down), causing large waves to form.
• Waves form above the spot where the pan bottom is disturbed (moved). These waves move outward in a circular or ripple pattern from that location.
• These waves continue to move out in all directions until they reach the edge of the pan.
• At the edge of the pan, the waves collide with the pan wall and then reflect back away from the wall.
• The waves get smaller over time. Waves seem to transfer energy to the pan wall.

Some students may struggle with recording observations while watching the video of this model. Make the video available to students to watch repeatedly on their own outside of class, so they have enough time to make sense of what they are observing and can find patterns of cause and effect to explain how a tsunami forms and moves. Another option, if the technology is available in your classroom, is to watch the video once as a class and then have students play it again in small groups to make their observations. As they rewatch the video, encourage them to focus on the interactions between the waves and the sides of the pan. Also, encourage them to think about the movement of the bottom of the pan as the earthquake. This will help them make stronger connections between an earthquake on the ocean floor and a tsunami forming and moving.

In addition to these ideas, if time is available and you have the materials, this model can be shown as a live demonstration in the classroom, where students would gather around the pan and make observations in small groups or as a class. This demonstration could be repeated multiple times.

Combine analyses of the model and connect to tsunamis. Display slide D. Say, I heard some of you mention that the waves in the foil pan are many times smaller than a tsunami in the ocean, but I also heard some of you describe how analyzing the waves in this model can help us figure out more about tsunamis. Let’s share our thinking. Facilitate a Building Understandings Discussion using prompts like those below. Remind students that they can add notes to their handout about each other’s observations and interpretations.

Suggested prompt

Sample student response

What were some connections that you and your partner captured about how the wave moved in the Foil Pan Model?

• The wave began when the bottom of the pan was moved.
• Once it started, the wave continued until it reached the edge of the pan.
• The wave moved out in all directions from the point where it started.
• When the wave reached the edge, it collided and reflected back toward the middle.

And, how does this compare to a tsunami? What can this tell us about how tsunamis form and move?

• We think tsunamis also move like these waves, but are much bigger because the ocean is so big.
• The tsunami also probably starts where the ocean floor is moved by the earthquake.
• The tsunami probably moves away from this spot in all directions like the wave in the pan, until it reaches the shore or an island.

In the pan, we saw the waves reach the edge and then reflect back, and over time get smaller and smaller. We also thought the wave transferred some energy to the pan edge. How might a tsunami be similar to this?

• Maybe when the wave reaches the shore, it transfers energy to the shore.
• Yeah…like waves on the shore of the ocean or lake, they move back and forth…maybe that is like the waves reflecting off the edge of the pan.