Sound Visualization Stations
Figure 1. A student places oobleck on a speaker.
Students learn about sound and sound energy as they gather evidence that sound travels in waves. Teams work through five activity stations that provide different perspectives on how sound can be seen and felt. At one station, students observe oobleck (a shear-thickening fluid made of cornstarch and water) “dance” on a speaker as it interacts with sound waves (see Figure 1). At another station, the water or grain inside a petri dish placed on a speaker moves and make patterns, giving students a visual understanding of the wave properties of sound. At another station, students use objects of various materials and shapes (such as Styrofoam, paper, cardboard, foil) to amplify or distort the sound output of a homemade speaker (made from another Teach Engineering activity). At another station, students complete practice problems, drawing waves of varying amplitude and frequency. And at another station, they experiment with string (and guitar wire and stringed instruments, if available) to investigate how string tightness influences the plucked sound generated, and relate this sound to high/low frequency. A worksheet guides them through the five stations. Some or all of the stations may be included, depending on class size, resources and available instructors/aides, and this activity is ideal for an engineering family event.
Engineers must understand how sound behaves in order to design sound equipment such as stereos, speakers, phones and radios. In order to design hearing aids and implants for hearing-impaired people, biomedical engineers also require an excellent understanding of sound energy and how our brains perceive sound. In this activity, students learn about sound waves and sound energy. In the discussion following the activity, students relate their knowledge of sound waves to engineering applications.
After this activity, students should be able to:
- Provide evidence that sound is a wave.
- Define amplitude, wavelength and frequency.
- Explain how sound energy travels as waves, interacts with the eardrum and is perceived as sound.