In this lesson, students learn that sound is energy and has the ability to do work. Students discover that sound is produced by a vibration and they observe soundwaves and how they travel through mediums. They understand that sound can be absorbed, reflected or transmitted. Through associated activities, videos and a PowerPoint presentation led by the teacher, students further their exploration of sound through discussions in order to build background knowledge.

Students learn about the mathematical characteristics and reflective property of ellipses by building their own elliptical-shaped pool tables. After a slide presentation introduction to ellipses, student “engineering teams” follow the steps of the engineering design process to develop prototypes, which they research, plan, sketch, build, test, refine, and then demonstrate, compare and share with the class. Using these tables as models to explore the geometric shape of ellipses, they experience how particles rebound off the curved ellipse sides and what happens if particles travel through the foci. They learn that if a particle travels through one focal point, then it will travel through the second focal point regardless of what direction the particle travels.

Zmiany położenia cząsteczek i zmiany ciśnienia. Animacja pokazuje drgające cząsteczki fali podłużnej.

Students learn the connections between the science of sound waves and engineering design for sound environments. Through three lessons, students come to better understand sound waves, including how they change with distance, travel through different mediums, and are enhanced or mitigated in designed sound environments. They are introduced to audio engineers who use their expert scientific knowledge to manipulate sound for music and film production. They see how the invention of the telephone pioneered communications engineering, leading to today's long-range communication industry and its worldwide impact. Students analyze materials for sound properties suitable for acoustic design, learning about the varied environments created by acoustical engineers. Hands-on activities include modeling the placement of microphones to create a specific musical image, modeling and analyzing a string telephone, and applyling what they've learned about sound waves and materials to model a controlled sound room.

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 TeachEngineering 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.