# Building Shaking —Variations of the BOSS Model

#### Summary

Building Oscillation Seismic Simulation, or BOSS Model, is an opportunity for learners to explore the phenomenon of resonance for different building heights while performing a scientific experiment that employs mathematical skills. They experience how structures behave dynamically during an earthquake. Can be done as a 5 minute demonstration, and/or a student lab.

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## Context

#### Audience

This activity could be done with introductory learners in upper elementary through early college. The demonstration can be used in conjunction with an Earth science unit or as a practical example of engineering design in an engineering or physical science unit. It can also work for informal education or public outreach venues as a demonstration or interactive.

#### Skills and concepts that students must have mastered

Learners should know what earthquakes are.

#### How the activity is situated in the course

This activity can largely stand alone once learners know what earthquakes are. However in a larger unit on earthquakes it should probably come later when the topic moves from understanding what earthquakes are to how they affect our society and address steps we can take to mitigate earthquake risk. Works well in conjunction with Build a Better Wall and Base Isolation for Earthquake Resistance.

## Goals

#### Content/concepts goals for this activity

Learners will be able to:

• Explain the relationship between building height and natural frequency
• Describe the phenomenon of resonance

#### Higher order thinking skills goals for this activity

• Perform an experiment to establish the relationship between the height of a structure and its natural frequency.
• Make claims based on evidence, synthesizing information from several sources.

#### Other skills goals for this activity

• Working in groups
• Using physical models
• Recording measurements, averaging, and graphing
• Making claims based on evidence

## Description and Teaching Materials

Why do buildings of different heights respond differently in an earthquake? All buildings have a natural frequency of oscillation. Shorter buildings have a different frequency than taller buildings. If a seismic wave has an extended rolling motion at the same frequency of a building, the structure will begin to sway back and forth with increasing amplitude. This effect is called resonance. The amplitude of building motion during an earthquake can increase to the point where the structural integrity of the building is compromised. Buildings can be engineered to withstand predicted oscillations without damage.

Building Oscillation Seismic Simulation (BOSS) is an opportunity for students to explore the phenomenon of resonance while performing a scientific experiment that employs mathematical skills. The students are intrigued by a discrepant event involving the BOSS Model, and are then set to work experimenting with the factors that affect the natural frequencies of structures.

#### Activity

See attached file for educator notes, NGSS alignment, links to supporting resources, and student exercise.

## Teaching Notes and Tips

• There are several different ways to build a BOSS Model. See above educator notes.
• The BOSS Model can be presented as a whole class demonstration, and/or used for a full student lab activity.
• Learners can get pretty vigorous and excited playing with physics models that shake and respond. You will need to demonstrate the level of shaking that is appropriate for the particular model you are using. This is true even for the more robust versions such as the the wooden dowels. We recommend keeping extra dowels on hand in case of breakage.
• Related activities that could be considered for extensions on this topic are:

## Assessment

The student lab handout, if used, serves as the summative assessment for the activity. In that case the instructor can use the answer key included above to develop a point scheme for grading the open-ended questions. However, some instructors may choose to just use this activity as a less formal activity. If that is the case or if one is working with an informal audience, formative assessment of learner understanding can be gathered from questions to and discussions with small groups or the whole group.