Creating a Pressure-like wave in a Coaxial Cable

Highlights of the activity

1. This kinesthetic activity is designed to give upper-division undergraduate students an intuitive understanding of non-dispersive wave propagation inside a coaxial cable.
2. Students form two lines and act as electrons while a voltage wave propagates through a coaxial cable.
3. The whole class discussion focuses on how a voltage (“force”) wave is measured as compared to how the charges are moving (“displacement” wave) and the difference between material velocity and the propagation speed of the wave.

Reasons to spend class time on the activity

The activity gives students a tangible way of thinking about what is happening in a coaxial cable, which they will use for the Wave Propagation in a Coaxial Cable lab. It helps them to understand how voltage waves relate to how charges are moving, as well as to disambiguate material velocity (how fast the electrons move) and the speed of wave propagation.

Reflections

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Instructor's Guide

• Wiki version