Earthquakes can destroy buildings and bridges within seconds. Because of this destructive power, modern architects and structural engineers employ some of the fundamental principles of physics and mathematics to create buildings that can absorb, disperse and withstand strong seismic forces. These design ideas have not only found their way into buildings, but also bridges, highways, automobiles and many load-bearing objects.
In this lesson, students will explore the design principles which are needed to make a structure seismically safe and how architects apply those formulas to their works.
- Identify, describe, and explain earthquakes and their causes
- Experiment with, design, and test structures that can withstand earthquakes
Grade Level: 9-10
- One Class Period
Note: The list features multimedia resources with life science, physical science, and Earth and space science content.
Key: LS = Life Science resource
PS = Physical Science resource
ESS = Earth and Space Science resource
- Predicting Earthquakes QuickTime Video (ES)
(Per Group of 2 - 3 students)
- One Box of Tooth Picks (approx. 200 toothpicks)
- Soft clay or Play dough
- "Shake Table:"
- Two covers from a hard-covered binder
- Four small rubber balls
- Eight large rubber bands
- One roll of scotch tape
Before the Lesson
This lesson should be done after the students have been introduced to the idea of earthquake wave propagation.
Create Shake Tables:
- Place one binder cover down on a table
- Place one of the four small rubber balls at each corner of binder
- Carefully place second binder cover on top and secure with two rubber bands along each side
Part I: Getting Ready to Rumble
1. Assign groups and roles by telling students that they will be working in small groups (2 to 3) of "architects" and that they will be designing structures that can withstand earthquakes. There are many different roles that you can assign the members (Recorder, timekeeper, etc.) Since there will be only 2 to 3 students in the groups, it may be good to assign students with multiple roles, or if you have a larger classroom, you may increase the size of the groups as you see fit.
2. Inform the students that the activity will be a competition that will determine which team can construct the "best" earthquake-proof structure and that individually the members of the group will answer the questions:
- What do you think engineers and architects build into their structures to minimize the damage caused by earthquakes?
- What factors do they consider? (List at least two)
At the end of the activity, groups will share their responses. Before they begin, inform them that they need to consider the following four factors:
- Distribution of weight
- Variation in shape
- Variation in height
- Composition of materials
Part II: The Blueprints
3. On a blank piece of paper, students work together to sketch out a basic design for their structure and be prepared to give a rationale for the design decisions that they make and be prepared to answer questions at the end. The design must meet only two requirements:
- Must be four levels of toothpicks high, point to point.
- Students MUST use a combination of the clay and the toothpicks
Remember: Students are not building walls for the structure, but merely a wire frame. Consider a radio tower as an example. Students should have at least twenty minutes to sketch and build their structures before they are ready to test their strength. Have tow teams bring their structures next to each other so that they have exposure to different designs. One group's structure will be labeled design "a" and the other design "b." To test the structures, place them on top of the shake tables and secure them to the top of it using the scotch tape. One person on the team will be responsible for producing the "earthquake." To induce shaking, grasp the bottom portion of the binder and gently, but deliberately move it back and fourth to produce a steady level of oscillation. Time each "quake" for thirty seconds and record observations. One team will being their shaking while all students will observe for the thirty seconds, then the second team will induce the earthquake of their own. If a structure withstands the entire length of the thirty seconds, continue shaking until the structure no longer stands.
4. Record observations.
Part III: Check for Understanding
5. After the shaking has been completed. Have the students answer the following questions individually:
- Which structure withstood the quake better? Why?
- What part of the structures sustained the most damage?
- Where were the breaks (if any) in the structures?
- Explain how you might consider the "four factors" when building a structure in an earthquake prone area like Northern California. How heavy or tall should a structure be? What shape and what kind of materials?
- What kind of building would you not want to build in the Bay Area of California?
- How would you improve your structure if you were to build it again?
If the students are unable to complete the questions in the time available, assign whatever remaining questions as homework.