Engineering Outreach @Berkeley
What is Sound?
Why do a trumpet and a flute playing the same note sound different? How do noise canceling headphones work? Why does a siren sound different moving towards you than it does moving away from you? This module provides an intuitive explanation for many aspects of the sounds around us including pitch, amplitude, the Doppler Effect, and interference and includes an introduction to the relevant mathematical theory. The module includes a presentation with numerous animations to aid the explanations, a slinky demonstration illustrating the different types of waves found in nature, and a simple activity done on a chalkboard to demonstrate the Doppler effect. In addition, we have a number of computer-based activities demonstrating wave interference, the waveforms and spectra of human speech, and the basic workings of pitch correction software such as Auto-Tune.
The complete set of materies required to conduct this module, including videos, PowerPoint presentation, and MATLAB software, is available as a zip file here (300MB). Individual components are described below.
The instructional videos below demonstrate and describe the key steps for using the components included in the zip file link above with the module materials.
We have developed a short (approximately 10–15 min) multimedia PowerPoint presentation that includes many videos, animations, and thought-provoking slides. The slides are annotated with instructor notes providing suggestions for implementation. The presentation is intended to be a stimulating introduction providing background for the hands-on activities.
Due to the presentation's emphasis on concepts and abundance of media, the presentation can be tailored to a wide range of students. We have successfully conducted this module with students from third grade up to high school seniors.
Below are the primary videos that we use to convey the ideas of wave as the movement of particles. The videos below include comparison of high and low amplitude, and high and low frequency.