Provided courtesy of the United Nations Educational, Scientific and Cultural Organization (UNESCO) and Discovery Education.

A tsunami races through the ocean deep at jet-aircraft speed. Approaching the shore, it can crest to more than 100 feet, hitting coastal areas with devastating force. In this package of lessons and activities, students will learn what causes a tsunami, the physics behind its movement, and how scientists know when one is forming. They can also study its impact on a model town, view tsunami-resistant house designs and learn about a 10-year-old girl credited with saving dozens of lives when a tsunami struck Samoa.

Background

Tsunamis are gigantic waves that come ashore with little or no warning. A tsunami is caused by earthquakes or volcanoes that move the land on the bottom of the ocean. Movement of the earth’s land is called an earth tremor. When a tremor shakes the land under the sea, it causes the water at the surface to rise up in a hump. This high swell of water starts moving away. After a long trip, this swell finally reaches shore. It roars onto the beach as a wave. This tsunami wave can be a wall of water 7 meters (21 feet) to 33 meters (100 feet) high.

The name tsunami comes from two Japanese words. Tsu means “port” and nami means “wave.” Many tsunamis hit the coasts of the Japanese islands. To understand why, look at Japan on a world map. Its eastern and southern coasts face the whole Pacific Ocean. A tsunami can form far away in the southern or eastern Pacific. It starts moving towards Asia and builds up size and speed as the tsunami heads west. For thousands of miles, there is no land to stop it or slow it down. Then it hits the coast of Japan. This is why Japan has more tsunamis than anywhere else in the world.

Today scientists have more warning that a tsunami is forming. They can find earthquakes under the ocean using a machine called a seismograph. Also, photos taken from airplanes and images taken by space satellites show ocean waves. Scientists send early warnings to port cities that a big wave is on the way. See a factsheet and find out what government research can tell us. Read a typical tsunami alert message.

In late September, a severe earthquake struck off American Samoa, triggering a series of tsunamis that killed more than 180 people and flattened villages in Samoa and Tonga, according to news reports. Even more people might have died had it not been for 10-year-old Abby Wutzler, who had been taught tsunamis at school. She ran along the beach telling people to head for higher ground. See video.

The Physics Behind a Tsunami

Earthquakes generate tsunamis when the sea floor abruptly deforms and displaces the overlying water from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium. The main factor which

determines the initial size of a tsunami is the amount of vertical sea floor deformation. This is controlled by the earthquake’s magnitude, depth, fault characteristics and coincident slumping of sediments or secondary faulting. Other features which influence the size of a tsunami along the coast are the shoreline and bathymetric configuration, the velocity of the sea floor deformation, the water depth near the earthquake source, and the efficiency which energy is transferred from the earth’s crust to the water column. Read more.

Lesson

Student Objectives

• Discover the causes of tsunamis in oceans and fjords.
• Learn that tsunamis in oceans and fjords can create great surges that cause much destruction.
• Learn why ocean tsunamis and fjord tsunamis behave differently.

Grade Level: 6-8; Duration: Two class periods

Materials
For each group:
• Two plastic containers with the same lengths but different widths; one should be significantly
narrower.
• Water
• Small rock, ball of clay, or other object to drop in the containers
• Ruler or tape measure

Procedures
1. Review what students know about tsunamis. Discuss the causes of a tsunami: undersea earthquakes or landslides, volcanic eruptions, or the impact of a large meteorite in the sea.

2. Tell students that a tsunami can also occur in a fjord, a narrow ocean inlet surrounded by cliffs. Portions of icebergs breaking, or calving, into the water can cause a fjord tsunami.

3. Tell students they will perform an experiment to discover how calving icebergs can create different wave patterns in the ocean and in a fjord. Before the experiment, students should write a hypothesis about how wave patterns might differ in the two environments.

4. Divide the class into groups and distribute materials to each group. Ask students how they can use these materials to test their hypotheses. Remind them that water depth should not be a factor in their experiments; they should consider the widths of water in an open ocean and in a fjord. (The wider plastic container represents the ocean, the narrow container represents a fjord, and the small object represents the calving iceberg.)

5. Have students fill each container with water, using the ruler to make sure that the depth is the same in both containers.

6. Next, students will drop an object from the same height into each container and observe the resulting wave patterns. Have students record their results.

7. Hold a class discussion about the experiment. Ask students how they know that the difference in wave pattern was not due to differences in water depth. Have students hypothesize in which environment a calving iceberg might cause a greater ocean surge.

8. Have each student draw a diagram showing the results of the experiment. A brief paragraph should describe each diagram.

9. Hold a discussion to compare the effects of fjord tsunamis as a result of a calving iceberg and ocean tsunamis that are the result of an underwater earthquake.

Discussion Questions

1. Why do tsunamis occur more frequently in the Pacific Ocean than in the Atlantic or Indian Oceans?
2. Describe how tsunamis affect people who do not live on a coastline.
3. Do you think it is possible to make architectural changes that can protect a beachfront home from a tsunami?

Assessment

Use the following three-point rubric to evaluate students’ work during this lesson.
• 3 points: Students’ created carefully executed diagrams that clearly showed the experiment’s results; wrote clear, accurate, and error-free descriptive paragraphs.
• 2 points: Students created diagrams that somewhat clearly showed the experiment’s results; wrote satisfactory descriptive paragraphs that included some errors.
• 1 point: Students created unclear diagrams; wrote vague descriptive paragraphs that included numerous errors.

Vocabulary

crest
Definition: The top of a wave
Context: The crest of a wave may rise only a foot or two above normal.

fjord

Definition: A narrow sea inlet between cliffs or steep slopes
Context: The falling ice creates a wave that spreads rapidly across the fjord.

surge
Definition: A large wave or billow
Context: The water builds and then breaks into a huge surge that rushes ashore.

trough
Definition: The lowest point between waves
Context: For every wave peak is a trough. If the trough appears first, the sea recedes before a wave arrives on land.

tsunami
Definition: A series of catastrophic ocean waves generated by undersea earthquakes or
landslides, volcanic eruptions, or the impact of a large meteorite in the sea.
Context: The word “tsunami” comes from the Japanese term for great harbor wave.

Academic Standards

The National Academy of Sciences provides guidelines for teaching science and a coherent vision of what it means to be scientifically literate for students in grades K–12. To view the standards, visit this Web site.
This teacher’s guide addresses the following national standards:
• Earth and Space Science: Structure of the earth system
• Physical Science: Motions and forces; Transfer of energy
• Science in Personal and Social Perspectives: Natural hazards; Risks and benefits
Mid-continent Research for Education and Learning (McREL)
McREL’s Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education addresses 14 content areas. View the standards and benchmarks.
This teacher’s guide addresses the following national standards:
Science: Physical Science: Understands the sources and properties of energy.
Science—Earth Science: Understands Earth’s composition and structure.

Geography—Physical Systems: Knows the physical processes that shape patterns on Earth’s surface.

The National Council for the Social Studies (NCSS) has developed national standards to provide guidelines for teaching social studies in the early grades, middle grades, and high school. View the standards.
This teacher’s guide addresses the following thematic standards:
• People, Places, and Environments
• Individuals, Groups, and Institutions
• Power, Authority, and Governance
• Science, Technology, and Society

Activity: Survive That Tsunami!

(Provided courtesy of TeachEngineering and the Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder)

In this activity for groups of 10 in grades 3 to 5, students use a table-top-sized tsunami generator to observe the formation and devastation of a tsunami. They see how a tsunami moves across the ocean and what happens when it reaches the continental shelf. Students make villages of model houses and buildings to test how different material types are impacted by the huge waves. They further discuss how engineers design buildings to survive tsunamis. Time required: 50 minutes.

Engineering Connection

No one can stop tsunamis from forming since we cannot prevent earthquakes, volcanoes and landslides, but we can devise ways to minimize the impact of these killer waves on human communities. Engineers design and install seismographs, tide gauges, ocean floor pressure sensors and loud sirens. Engineers also design buildings using materials and shapes that are more likely to survive a tsunami. Between high-tech detection systems and smart structures, the impact of a tsunami strike can be lessened dramatically. But, in many areas, dense populations, unreliable local communication, and poor or nonexistent roads remain the biggest obstacles to quick evacuation to safety.

Educational Standards :

Click here and scroll down to ‘”Educational Standards” to see how this activity fits your state’s requirements.

Learning Objectives: After this activity, students should be able to:

• Explain what causes tsunamis, including movement under the surface of the ocean.
• Communicate that buildings constructed with materials that are heavier are more likely to survive a tsunami, but may be too expensive or not available.
• Describe how engineers cannot prevent tsunamis, but they can design and build buildings so that they are more resistant to tsunamis.

Materials

Divide the class into three groups.
Students in group A need:
• 2 sheets of tissue paper (the gift wrap type)

Students in group B need:
• 3 sheets of cardstock or manila envelope material

Students in group C need:
• 3 sheets of notebook paper
• 40 toothpicks

To share with the entire class:
• Masking tape
• Scissors
Model House Template (pdf)

To make brass model houses:
• 1 piece brass sheet metal, 4-in x 10-in x .01-in thick (or 10-cm x 25-cm x .025-cm thick, available at hobby or hardware store)
• Tin snips (scissors also work, but cutting the brass dulls them)

For the table-top-sized tsunami generator:
• 1 large, shallow, plastic waterproof tub (8-in x 14-in x 30-in or 20-cm x 36-cm x 76-cm, clear plastic is better but not necessary)
• 20 to 30-pound (9 to 14 kg) bag of sand
• 1 piece of sheet metal, ~20-in x 10-in x 0.1-in thick (as long as it is rigid, it is thick enough) or 51-cm x 25-cm x .25-cm thick
• Duct tape

Introduction/Motivation

What is a tsunami? Well, it is a really large wave — much larger than the waves you see when you splash in a pool or surf at the beach. The difference between a regular wave and a tsunami is that a regular wave is just a surface disturbance of the water, and a tsunami is a disturbance that reaches all the way to the ocean floor!

What do you think causes a tsunami? Well, tsunamis can be caused by anything that moves the ocean or sea floor, like earthquakes, volcanoes and landslides. Think about an underwater earthquake that is caused by the moving of tectonic plates. Do you think that this could move the sea floor and create a tsunami? Yes, it could! Do you think engineers can prevent tsunamis? Engineers cannot prevent natural events like earthquakes or volcanoes, or the tsunamis that can result from them. So, what can engineers do about tsunamis? One thing engineers can do is build structures that can survive a tsunami.

In December 2004 a huge tsunami hit the beach in Indonesia. Do you know from what material most of the destroyed houses were made? Most were made of wood, and some were actually made of paper. What do you think are the advantages and disadvantages of wooden or paper houses? How might houses made of these materials be disadisadvantage when it comes to a tsunami? Well, a house made out of weak material, such as wood or paper, probably will not survive the great forces of a tsunami. So, what can engineers do so that a building or structure is able to survive a tsunami? (Possible ideas: Build it out of stronger material; build it on stilts.) What might be some disadvantages of these types of the new houses? (Possible ideas: More costly and difficult to construct, look different than usual buildings.)

Today, we are going to explore some of the choices that engineers have when designing buildings with tsunamis in mind and make some conclusions as to what shapes and materials make the most tsunami-resistant buildings. Today you are going to make a model building and see if it will survive a tsunami. Are you ready?

Procedure

Before the Activity

Gather materials and make copies of the Model House Template for the students.
(Optional, for younger students, or to speed up the activity) Pre-cut the model house materials, using the Model House Template. Prepare as many sets (one roof and one wall) of each material (tissue paper, cardstock, notebook paper) as you want the students to construct of each material. For example, for a class of 30 students, prepare 10 sets of each of the three types of material.

How to construct the model houses.

Figure 1 Copyright © Geoffrey Hill

Make 4 brass houses. Using the Model House Template, use tin snips to cut out four walls and four roofs. Fold the walls and roofs as shown in Figure 1. Tape the roofs to the walls.
Set up the tsunami generator. It is best to set it up outside, although indoors may work, too.
Fill one end of the tub with sand, creating a continental shelf and beach (see Figures 2 and 3).
At the opposite end of the tub, attach the metal sheet to the bottom of the tub using a piece of duct tape along one edge,

so it works like a hinge (see Figures 2 and 3).

Figure 2 Copyright © Geoffrey Hill

Fill the tub with water so that most of the sand is covered, but leave some sand above the waterline to represent a sandy beach (see Figure 3).

Figure 3 Copyright © Geoffrey Hill

Test the tsunami generator by first leaning the metal plate against the back wall of the tub and then pushing the plate all the way down into the water. A tsunami should form that covers most or the entire beach. To adjust the wave height,adjust the speed with which you push down the plate (see Figure 4).

Figure 4 Copyright © Geoffrey Hill

Figure 4 shows a tsunami generator in action. Pushing the metal plate down into the water creates a wave that moves across the tub of water and onto the sandy beach.

With the Students

Figure 5 Copyright © Geoffrey Hill

Figure 5. Model house on toothpick stilts.

Divide the class into three groups (A, B and C). Each group will make a different type of house, using either tissue paper, cardstock or notebook paper and toothpicks. Students in each group need not sit together while they construct their model houses.
Provide each student with supplies according to his/her assigned group, as well as access to scissors and masking tape.

Demonstrate the construction of the buildings as shown in Figure 1 and on the diagram on the Model House Template. (This is a great time to point out to the students that they are working with geometric shapes.)

Provide time for each student to construct his/her type of building (tissue, cardstock or notebook paper) using scissors and tape.

Have the students who construct the buildings using notebook paper tape toothpicks to the four corners of theirbuildings so that the toothpicks work as stilts (see Figure 5).

Give the students time to decorate their houses using markers. They can label and decorate their model structures to represent a variety of community buildings, such as houses, schools, bank, grocery store, restaurant, police station, library,city hall, power plant, playground, factory, boat marina, etc. Explain to the students that the metal plate in the tsunami generator model demonstrates the sea floor movement causing huge ocean waves.

In four different trials, set up the buildings made by each group of students, and the brass buildings made by the teacher.

First, have the students who constructed their model buildings from tissue paper place them scattered across on the beach to create a paper model village (see Figure 6). Before the tsunami, have students predict what will happen to the village.

A tsunami hits! Using the metal plate, create a wave that swamps most of the land. Create several more waves and remind the students that there is usually more than one wave associated with a tsunami. Expect the waves to destroy most of the

Figure 6 Copyright © Geoffrey Hill

tissue paper buildings.

Figure 6. A tsunami wave moves towards the paper model village.

Ask the students what they thought of the tsunami hitting the tissue village. Is this what they expected? Why did the tissue buildings fail so easily? What else do you observe? Perform steps 8 – 10 again, this time with the students who built the cardstock buildings. In this scenario, students observe that some buildings move slightly, but overall the cardstock village survives better than the tissue village. Note: After several waves the sand erodes slightly, so build up the continental shelf and beach with more sand, as needed. Perform steps 8 – 10 again, this time with the students who built the notebook paper buildings with toothpick stilts. Make sure students just set the stilted buildings on the sand and do not push the toothpicks all the way into the sand (see Figure 7).

Figure 7 Copyright © Geoffrey Hill

Figure 7. A tsunami wave moves through the stilts of this paper model village.

Finally perform steps 8-10 again, this time placing on the beach the brass buildings the teacher made in advance of the activity (see Figure 8). Have several tsunamis wash over them.

Figure 8 Copyright © Geoffrey Hill

Figure 8. Brass model house village.

Conclude with a class discussion comparing results of the four trials. Talk with the students about their observations.

Which materials held up the best? Worst? Rank the types of model buildings in order from worst to best at surviving the tsunamis. How might engineers design a building or structure so it is able to survive a tsunami? What might be some disadvantages of these types of houses? How might you re-design your model buildings to improve their chances ofsurviving big waves? Conduct the summary assessment activities as described in the Assessment section.
Safety Issues

Students should not handle the brass houses since the edges are sharp.

Troubleshooting Tips

This activity can be messy, so it is best to set it up outside. To create more controlled and consistent waves, have the teacher operate the tsunami generator for each trial. It helps to practice creating waves before conducting this activity in class.

Assessment

Pre-Activity Assessment

Voting: Have the class vote yes or no on the following question:

Can engineers prevent tsunamis? (Answer: No. Tsunamis are natural events caused by earthquakes, landslides and volcanoes, over which people have no control. Since we cannot control or prevent tsunamis, engineers help us predict and survive them.)

Activity Embedded Assessment

Prediction: Have students predict the outcome of the activity before the activity is performed. Before hitting each village with a wave, ask the students: What do you think is going to happen to the village? (Students should start to realize that the buildings made from the lighter and more water absorbent materials are more susceptible to tsunami damage. The heavier buildings and those built up and away from the water are most likely to survive.) Have the students rank the houses from lightest to heaviest materials in their summary observations.

Post-Activity Assessment

Concluding Discussion: Ask the students and discuss as a class:

Describe the results of the four tsunami trials? How did they compare? What did you observe?
Rank the types of model buildings in order from worst to best at surviving the tsunamis.

How might engineers design a building or structure so it is able to survive a tsunami? (Possible answers: Build it out of concrete, stone or bricks [heavier, stronger materials]; build it on stilts so it is above the water flow; make sure it has a deep footing into the soil; or shape it so that water flows around it.)

What might be some disadvantages of these types of houses? (Possible answers: Buildings like this might cost more to construct, be more difficult to build, or be considered less attractive.)
How might you re-design your models to improve their chances of surviving big waves?

Re-Engineering: Ask the students how they might improve the buildings in their village. Have them sketch or test their concepts for tsunami-resistant buildings. What material would they use? How would they be shaped? What features
would they have? Where would they be located?

Activity Extensions

Have students research the house designs engineers have come up with to resist tsunamis. Look at this website to see what a group of engineers from Harvard and MIT are doing. Have them write a paragraph describing the building and what makes it unique.

Contributors

Geoffrey Hill, Malinda Schaefer Zarske, Denise Carlson
© 2006 by Regents of the University of Colorado

Filed under: Lesson Plans

Tags: Environmental Engineering, Ocean, Research on Learning