BOSS Lite - Building Resonance

Description

Describe the impact of building resonance when assessing Earthquake Hazards

Audience

All Audiences

Time

10 - 15 Minutes

Objective

1. Describe the impact of building resonance when assessing Earthquake Hazards

Supporting Resources

Hubenthal, M. (2006) Revisiting the BOSS model to explore building resonance phenomena with students. The Earth Scientist, 22(2), 12-16.

The BOSS Model: Building Oscillation Seismic Simulation contained within: Federal Emergency Management Administration (FEMA) and American Geophysical Union (AGU), Seismic Sleuths: Earthquakes: A Teacher's Package on Earthquakes for Grades 7-12. Washington, DC, 375pp, 1994.

Michael Hubenthal - IRIS Education Specialist (hubenth@iris.edu)
Time: 10-15 Minutes
Target Grade Level: 9th (But can be used effectively with a range)
Content Objective: (Students will be able to)
1. Describe the impact of building resonance when assessing Earthquake Hazards.

Navigation

Teacher Background
Concept Map
Building the Boss Lite Model
Teacher Instructions
References/Acknowledgments
Alignment with Standards

Teacher Background

When building a house of cards, one quickly realizes that it is easy to build a sturdy house of one or two floors. However, this sturdiness quickly decays as the number of floors in your card house increases. Our experience tells us that the slightest bump of the table easily sends a tall house of cards tumbling down. Based on the simple building experience described above, many people form a naïve mental construct that taller buildings are “less safe” or “more likely to collapse” during the shaking as a result of an earthquake.

Realizing the role that simple experiences like these play in the development of our understanding of the world is crucial to providing effective science instruction. In the late 1800’s Johann Herbart laid the groundwork for this concept; recognizing that previously existing knowledge served as the starting point for the development of new concepts (DeBoer, 1991). My personal experience teaching this subject matter and using this model with many classes of students and many workshops of in-service educators has provided me with significant anecdotal evidence to support the presence of the naïve misconception described above. Unfortunately no literature exploring student misconceptions of building resonance phenomena could be located to further substantiate this claim.

Building on the role of pre-existing knowledge; discrepant event demonstrations, such as the BOSS Model Lite (described below) seek to challenge existing knowledge and motivate students to seek and formulate new explanations for the observed phenomenon (Chiappetta & Koballa, 2002). In the BOSS Lite demonstration the instructor presents five cardboard “buildings,” of varying heights and asks the students to identify the one they would prefer to be in during an earthquake. As a result of student’s naïve preconception, most select the shortest building. The when shaken across a spectrum of frequencies, the model presents and unexpected result; all heights of buildings shake. This occurs because of the building’s natural resonance frequency; the largest vibration of the building due to the enhancement of the energy at a special frequency to the building (Stein & Wysession 2004).

Tall buildings have a low natural resonance and respond to low frequencies, while short buildings have high natural resonances and respond to higher frequencies (Pratt). Seeing all the buildings shake violently during the simulated earthquake causes a cognitive disequilibrium for the observer since it was unexpected. To satisfy this disequilibrium the observer is predisposed for new learning as the teacher uses the students’ observations of the model to guide them to the conclusion that all buildings are “at risk” of earthquake damage. Once this new solution has been identified, the learner establishes a new cognitive equilibrium (Piaget, 1971). Examining the damage resulting from the 1985 Mexico City earthquake can further reinforce the new cognitive equilibrium. During this event intermediate height buildings (10-14 stories) were damaged while shorter buildings and skyscrapers were relatively undamaged (Bolt, 2004).

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Building Resonance Concept Map


click image to enlarge.

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Building Oscillation Seismic Simulation

Note: This model is an adaptation of the original BOSS Model (FEMA & AGU 1994)

Materials

  1. Manila file folder (a fresh one works best)

  2. Small binder clips

  3. Blocks of wood .5in wide x .5in high x 10in long

  4. Bolts 3in long

  5. Wing nuts to fit bolts

Tools

Drill
Ruler
Scissors
Pencil

 

Assembly

A. Create “buildings” from the manila file folder.   Measure out the following lengths of 1in wide strips (2) 4 inches long
(2) 5 inches long
(2) 6 inches long
(2) 7 inches long
(2) 8 inches long
B. Place the two equal length strips together and clip at one end with the binder clips.
C. Label each building A thru E 

Fig. 1 - The BOSS Lite model assembled for use

D. Drill in each end of the two blocks of wood large enough for the bolts to pass through.

Fig. 1 - BOSS Lite model assembled for use

E. Pass one bolt through each end of the blocks of wood and begin to tighten using wing nuts.

F. Place all five “buildings” equally spaced, between the two wood blocks and tighten the wing nuts until secure.

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Teacher Instructions

Objective(s)

SWBAT: Demonstrate the role of building resonance when assessing earthquake hazards.
Step 1:
Hold the model up and move around the room for all students to see.  Describe that each lettered strip represents a building.  The binder clips on the top of each strip represent air-conditioning/ventilation units on the top of the building.

Taxonomy

Question

Answer

Application

Which building would you prefer to be in during an earthquake?

Answers will vary

Application

Why did you select that building?

Think-Write-Pair-Share

Answers will vary

Step 2:

Now that students have predicted which building is the most likely to survive an earthquake, begin to create an “earthquake” by oscillating the base of the model at a low frequency. At low frequencies the tallest building will respond with an amplified displacement of the top of the building.  Now progress through the spectrum of frequencies towards higher frequencies.  As you do, students will notice that the tall building no longer responds, but progressively the small and smaller buildings do! 

*NOTE: It is important that you keep the amplitude of the oscillations as consistent as possible for all frequencies.

Taxonomy

Question

Possible Answers

Knowledge

What did you observe during the demo?

All the buildings shook

Analysis

How did this compare to your prediction?

Different – I predicted that building X would respond less than the others, while the model showed that all buildings responded.

Comprehension

Was there a pattern in the shaking of the buildings?

Yes, first the tallest progressing to the smallest.

Application

What controlled which buildings shook when?

You are likely to get vague answers like… “How you shook your hand.”  If so, run the demo again, and instruct the students to watch for more details about the movement of my hand.

Application

What controlled which buildings shook?

A variety of answers may occur at this point that may involve terms like how “fast”,  “quickly”, or “much” you moved your hand during the demo.  Using questioning and perhaps another run of the model, guide students to develop the concepts that the amplitude of the shaking was constant with only the frequency changing

Analysis

Therefore, if the frequency of shaking is important can anyone propose a relationship between frequency of shaking and building height?

Tall buildings shake the most at low frequencies while shorter buildings respond at high frequencies.

Comprehension

Lets revisit our original question.  Are any of these buildings more or less likely to be damaged or collapse during an earthquake?

No, they are all at risk.  The determining factor is the frequency of the seismic waves that reach the building.

Comprehension

How might this relationship impact the construction of buildings?

Answers will vary, but one basic concept to get across is that the frequency of seismic waves decreases rapidly with distance as a result of attenuation.  

Step 3:

Reinforce these concepts using a reading on the damage resulting from the1985 Mexico City Earthquake.

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Alignment with AAAS Benchmarks

Supports

The Physical Setting

F. Motion - Grades 9 through 12

Waves can superpose on one another, bend around corners, reflect off surfaces, be absorbed by materials they enter, and change direction when entering a new material. All these effects vary with wavelength. The energy of waves (like any form of energy) can be changed into other forms of energy.

Reinforces

The Physical Setting

C. Processes that Shape the Earth  - Grades 6 through 8

Some changes in the earth's surface are abrupt (such as earthquakes and volcanic eruptions) while other changes happen very slowly (such as uplift and wearing down of mountains). The earth's surface is shaped in part by the motion of water and wind over very long times, which act to level mountain ranges.

F. Motion - Grades 6 through 8

Vibrations in materials set up wavelike disturbances that spread away from the source. Sound and earthquake waves are examples. These and other waves move at different speeds in different materials.

Common Themes

B. Models – Grades 6 through 8

Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly, or that are too vast to be changed deliberately, or that are potentially dangerous.

Standard 1 – Analysis, Inquiry, Design

Scientific Inquiry - Key Idea 2: Beyond the use of reasoning and consensus, scientific inquiry involves the testing of proposed explanations involving the use of conventional techniques and procedures and usually requires considerable ingenuity.

Engineering Design – Key Idea 1: Engineering design is an iterative process involving modeling and optimization (finding the best solution within given constraints); this process is used to develop technological solutions to problems within given constraints.

Standard 4 - Understanding and Application of Scientific Concepts, Principles, and Theories of the Physical Setting.

Key Idea 2.11: The lithosphere consists of separate plates that ride on the more fluid asthenosphere and move slowly in relationship to one another, creating convergent, divergent and transform plate boundaries.  These motions indicate Earth is a dynamic geologic system.  (Earthquakes and volcanoes present geologic hazards to humans.  Loss of property, personal injury, and loss of life can be reduced by effective emergency preparedness.)

Standard 6 - Interconnectedness, Common Themes

Models – Key Idea 2: Models are simplified representation of objects, structures, or systems used in analysis, explanation, interpretation, or design.

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References/Acknowledgments

Many thanks to Larry Braile (Prudue University) who originated the design of the Boss Lite Model

American Association for the Advancement of Science. (1993) Benchmarks for Science Literacy.  Accessed online 3/10/05 at http://www.project2061.org/tools/benchol/bolintro.htm

Barker, Jeff, Building Resonance. Accessed online 4/1/05 at http://www.geol.binghamton.edu/faculty/barker/demos/demo8.txt

Bolt, Bruce, Earthquakes, (5th Edition), W.H. Freeman and Company, New York, 378pp., 2004.

Chiappetta, E.L, and Koballa, T.R., Science Instruction in the Middle and Secondary Schools, (5th Edition), Merrill Prentice Hall, Columbus, Ohio, 2002.

DeBoer, George, A History of Ideas in Science Education, Teachers College Press, New York, 269pp., 1991

Federal Emergency Management Administration (FEMA) and American Geophysical Union (AGU), Seismic Sleuths: Earthquakes: A Teacher's Package on Earthquakes for Grades 7-12.Washington, DC, 375pp, 1994.

Piaget, J. (1971), Biology and knowledge. Chicago: University of Chicago Press

References cont.

Pratt, Thomas, Frequencies, periods, and resonance.  Accessed online 4/1/05 at http://faculty.washington.edu/tpratt/frequencies.htm

Stein, S. and Wysession, M. An Introduction to Seismology, Earthquakes and Earth Structure, Blackwell Publishing, Malden, MA, 498pp., 2004.

The University of the State of New York, State Education Department. Physical Setting/Earth Science Core Curriculum. Accessed online 3/10/05 at http://www.emsc.nysed.gov/ciai/mst.html

 

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