Lesson: The Energy of MusicContributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Educational Standards :
Learning Objectives (Return to Contents)
After this lesson, students should be able to:
Introduction/Motivation (Return to Contents)
Have the students close their eyes and sit quietly for 30 seconds. What did you hear? (Have a few students describe the different sounds they heard.) These are all sounds and we will be learning about sound energy today.
Now tap on your desk. How would you describe that sound? Can you tap on your desk louder? Now, really softly? What do we call this change in sound? We call this characteristic of sound, volume. Now, tap on your desk using a pencil. What is this sound like? Is it a higher sound? We call this characteristic of sound, pitch. You have just learned two of the three important characteristics of sound energy that we will discus today — sound volume and pitch.
Have you noticed how the noise of a speeding vehicle, like a motorcycle, car, train or plane, seems to be constant as it approaches you; then as it goes past, the noise drops or falls in pitch, to a lower note? As the vehicle moves toward you, it travels a small distance closer between sending out each sound wave. So for you, the sound waves are squashed closer together and make a high sound. As the vehicle passes, it travels a small distance away between sending each sound wave; so the sound waves are more stretched out, and make a lower sound (see Figure 1). This change is called the Doppler Effect after the man who first described it in 1842.
To travel, sound energy must vibrate molecules. These molecules move in a sound wave. Sound frequency is how much a sound wave is vibrating. Frequency is the third characteristic of sound that we will discus today. Let's see what this looks like!
Classroom demonstration: Use a large spring or slinky to demonstrate the characteristic of frequency. Expand the slinky and have students hold each end. Make sure the students stand very still and do not shake the slinky.
What are our three characteristics of sound energy again? That's right, volume, pitch and frequency! Frequency, or the vibrating of sound waves, clearly shows us that sound is a form of energy. By moving molecules and making them vibrate, sound waves are doing work. How do we use sound energy? How do engineers use sound energy?
We use sound to communicate, learn and express ideas, and to make plans, either face-to-face or with a telephone. Musical and natural sounds, such as a bird song, affect our emotions, influencing us to be happy or sad, worried or relaxed. We hear many sound frequencies, but because of the way our ears work, we do not hear all of the sounds around us. Our ears pick up a wide range of frequencies. However, some animals hear frequencies that are too high-pitched for our ears to detect. These frequencies are called ultrasounds. Other creatures detect frequencies known as infrasonic sounds that are too low for our ears to detect.
To detect what our ears cannot hear, engineers design instruments that are able to "listen" to ultrasound and infrasonic sounds. Ultrasound can detect tiny flaws in metals, plastics and other materials used to make parts — from bridge bolts to airplane wings. Ultrasound used in medical sensing equipment helps us "see" the development of a baby inside its mother's womb. Ships use sonar, a type of ultrasound, to search for undersea objects such as wrecks, submarines, rocks, icebergs, whales and shoals of fish. Sonar can also measure the water depth so it is useful for ocean navigation and mapping the seabed.
Some electronic equipment built by engineers turns ultrasound or infrasonic sound signals into electrical signals, and further into sounds of lower pitch, which we can hear as "pings," or into visual patterns of lines and colors that we can see on monitor screens.
Lesson Background & Concepts for Teachers (Return to Contents)
Every sound, whether it is from a rubber band twanging or a loud speaker cone, is created by vibration. You cannot hear sound in a vacuum because sound reaches your ear as vibration, and there must be something to vibrate. Usually, the medium that vibrates is air. When the sound source vibrates back and forth, it pushes the air around it back and forth. The sound travels through the air as it is pushed back and forth in a chain reaction that is being alternately stretched and squeezed. This moving stretch and squeeze is called a sound wave.
Vocabulary/Definitions (Return to Contents)
Associated Activities (Return to Contents)
Lesson Closure (Return to Contents)
What is sound energy? (Answer: It is the energy produced when sound is created.) What are three characteristics of sound energy? (Answer: Volume, pitch and frequency.) We may not be able to hear every sound that exists, but engineers use all types of sounds to create devices that help people. Engineers have designed instruments that can "hear" ultrasonic and infrasonic sound that humans cannot hear with their ears. Sound is a type of energy that we use every day, especially when our families, friends and our teachers talk to us.
Attachments (Return to Contents)
Assessment (Return to Contents)
Know / Want to Know / Learn (KWL) Chart: Before the lesson, ask students to write down in the top left corner of a piece of paper (or as a group on the board) under the title, Know, all the things they know about sound. Next, in the top right corner under the title, Want to Know, ask students to write down anything they want to know about sound. After the lesson, ask students to list in the bottom half of the page under the title, Learned, all of the things that they have learned about sound.
Brainstorming: As a class, have the students engage in open discussion. Remind them that in brainstorming, no idea or suggestion is "silly." All ideas should be respectfully heard. Take an uncritical position, encourage wild ideas and discourage criticism of ideas. Ask the students:
Vocabulary Review: Review the vocabulary terms with the students. Ask them:
Lesson Summary Assessment
KWL Chart (Conclusion): After the lesson, ask students to list in the bottom half of the page under the title, Learned (or on the board), all of the things that they have learned about sound.
Wave Game: To determine whether the students understand the concepts, have each show you both types of waves (longitudinal and transverse) and demonstrate a high- or low-frequency wave (fast or slow vibrations). Turn this into a game. Pick a type of wave and have a student team demonstrate the wave. If the team demonstrates the wave appropriately they get a point. If not, the next team has an opportunity to demonstrate the wave type and earn a point.
Engineering Design: The local city wants a new theme park. Have student teams design a theme park around sound using what they have learned in this lesson.
Bingo: Provide each student with a sheet of paper containing a list of the lesson vocabulary terms. Have each student walk around the room and find a student who can define one vocabulary term. Students must find a different student for each word. When a student has all terms completed s/he shouts "Bingo!" Continue until two or three (or most) students have bingo. Ask the students who shouted "Bingo!" to give definitions of the vocabulary terms.
Lesson Extension Activities (Return to Contents)
Conduct the attached Sound Lab: Simple Instruments activity. Have the students make a variety of simple instruments, and explain how their instruments make the sounds they do and why. Have the students use their instruments to perform a song.
Ask students to research and prepare a descriptive poster on an electronic device or product that makes, stores or detects sound. Have them explain to the rest of the class how the device works. Possible devices include: CD player, tape cassette, microphone, phonograph, loudspeaker, etc.
Divide the class into pairs of students to create their own latitudinal and longitudinal waves using a slinky, string or their bodies. As you walk around the classroom, have each group show you a wave and tell you if it has a low or high frequency.
There is a tremendous amount of physics and engineering that goes into the design of a baseball or softball bat, especially the new high-tech aluminum and composite bats. Have students research the sound energy related to this topic, starting with Professor Dan Russell's Physics and Acoustics of Baseball and Softball Bats, http://www.acs.psu.edu/drussell/bats.html.
References (Return to Contents)
Dictionary.com. Lexico Publishing Group, LLC. Accessed October 3, 2005. (Source of vocabulary definitions, with some adaptation.)
Energy Quest, Energy Education, California Energy Commission. http://www.energyquest.ca.gov/index.html Accessed October 3, 2005.
Farndon, J., James, I., Johnson, J., Royston, A., Steele, P. and Walters, M. Giant Book of Questions and Answers. Italy: Dempsey Parr, 1998.
Graham, I., Taylor, B, Farndon, J. and Oxlade, C. Science Encyclopedia, 1999, pp. 78-90.
Kids Zone. U.S. Department of Energy. http://energy.gov/ Accessed October 3, 2005.
Lowery, L. The Everyday Science Sourcebook. CA: Dale Seymour Publications, 1985, pp. 232-233.
Russell, Daniel A. Longitudinal and Transverse Wave Motion, Acoustics and Vibrations Animations. Updated 2001. Applied Physics, Kettering University, Flint, MI. http://www.acs.psu.edu/drussell/Demos/waves/wavemotion.html Accessed October 3, 2005. (Excellent animations of wave motion)
Russell, Daniel A. Physics and Acoustics of Baseball and Softball Bats. Updated June 20, 2005. Applied Physics, Kettering University, Flint, MI. http://www.acs.psu.edu/drussell/bats.html Accessed October 3, 2005.
ContributorsSharon Perez, Natalie Mach, Malinda Schaefer Zarske, Denise Carlson
Copyright© 2005 by Regents of the University of Colorado.
Supporting Program (Return to Contents)Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Acknowledgements (Return to Contents)
The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.