Normal Modes
About
Topics
- Oscillator
- Normal Modes
- Polarization
- Mass Spring System
- Frequency
- Amplitude
- Phase
Description
Play with a 1D or 2D system of coupled mass-spring oscillators. Vary the number of masses, set the initial conditions, and watch the system evolve. See the spectrum of normal modes for arbitrary motion. See longitudinal or transverse modes in the 1D system.
Sample Learning Goals
- Explain what a normal mode is.
- Explain what are the frequency, the amplitude, and the phase of a normal mode.
- Explain why different normal modes have different frequencies and why higher-numbered modes have higher frequencies.
- Identify how many normal modes a given system has and be able to sketch the individual modes qualitatively, for both 1D and 2D systems.
- Explain the distinction between transverse and longitudinal normal modes in a 1D system.
- Explain how adjusting the phase of a normal mode affects the motion of the system.
- Explain qualitatively how any arbitrary state of the system can be written as a sum of normal modes; that is, explain the superposition principle.
- Explain which properties of the system are set by the initial conditions, which properties are time-independent, and which properties are time-dependent.
- Explain why striking a metal plate in one spot raises the temperature of the plate.
For Teachers
Teacher Tips
Overview of sim controls, model simplifications, and insights into student thinking ( PDF ). |
Teacher-Submitted Activities
Title | Authors | Level | Type | ||
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How do PhET simulations fit in my middle school program? | Sarah Borenstein | MS | Other | ||
Alignment of PhET sims with NGSS | Trish Loeblein | HS | Other | ||
PHET Digtial Wave Lab | Martin Hofkamp | MS HS K-5 |
Lab HW |
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MS and HS TEK to Sim Alignment | Elyse Zimmer | MS HS |
Other | ||
Simulações no Ensino de Fisica | Carla Tavares | HS | Guided Discuss Lab HW Demo MC Other |
Translations
Related Simulations
Software Requirements
Windows | Macintosh | Linux |
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Microsoft Windows XP/Vista/7 Macromedia Flash 9 or later
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OS 10.5 or later Macromedia Flash 9 or later
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Macromedia Flash 9 or later
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Credits
Design Team | Third-party Libraries | Thanks To |
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