SummaryStudents examine the existence of sound by listening to and seeing sound waves while conducting a set of simple activities as a class or in pairs at stations. Students describe sound in terms of its pitch, volume and frequency. They use this knowledge to discuss how engineers study sound waves to help people who cannot hear or talk.
Biomedical engineers are especially interested in sound waves because they design devices such as hearing aids or computerized voices that help people who cannot speak or hear be able to create or identify these sound waves. Engineers also design many types of imaging devices that change ultrasonic and infrasonic sound energy into visual images. For example, some medical equipment uses sound energy to create screen images of what is going on, unseen, in the human body. And, ocean navigation equipment includes sound imaging equipment so ships can determine the unseen terrain of an ocean floor.
After this activity, students should be able to:
- Describe how sound is created by the vibration of certain objects. As the vibration changes, so does the sound.
- Relate that sound energy can be seen as well as heard.
- Describe sound in terms of volume, pitch and frequency.
- Explain how engineers use their knowledge of sound waves to create devices to help people hear.
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Each TeachEngineering lesson or activity is correlated to one or more K-12 science,
technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN),
a project of D2L (www.achievementstandards.org).
In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics;
within type by subtype, then by grade, etc.
Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.
All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).
In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.
Each student needs:
For each pair of students or activity station:
- Tuning Fork Station: tuning fork (available at a musical instruments store), cup of water (or ping pong ball)
- Milk Container-Reflector Station: cardboard milk container, scissors, tissue paper, tape, small mirror, flashlight
- Spatula Blade Station: spatula (metal or plastic)
- Rubber Band on Doorknob Station: rubber bands, doorknob on a door
- Boom Box Station: boom box, balloons, paper plate, small pieces of paper
We are going to explore three characteristics of sound energy today—pitch, volume and frequency. Volume is how loud a sound is (greater amplitude), pitch is how high a sound is (short wavelength = high pitch), and frequency is how fast a sound wave is moving (high frequency = short wavelength = high pitch). These three properties really help us describe sound energy.
Can you see sound energy? Can you feel sound energy? Well, let's find out! Everybody stand up! Now shake your body! Shake all your body parts as much as you can! When something moves back and forth, it is said to vibrate. Can you see your neighbor's body vibrating? Well, sound is made by vibrations that are usually too fast to see.
Have students hum their favorite songs while gently placing their fingers on their throats. What do they feel? (Answer: They are feeling the vibrations of their vocal chords, which vibrate to make sound.)
The vibrations you feel when you hum are how we make and hear sound. Biomedical engineers are especially interested in sound energy; they design devices that help people who cannot speak or hear be able to create or identify sound waves. You may be familiar with hearing aids, which are devices created by engineers. Using their understanding of sound energy, engineers create equipment to help people hear.
In today's activity, we are going to examine how we can see and feel sound energy using pitch, volume and frequency.
biomedical engineer: Engineers who solve medical problems in health care and medical services. They work with doctors and medical scientists to develop and apply the latest technologies, such as microcomputers, electronics and lasers. Also called bioengineers.
frequency: The rate of vibrations in different pitches. Low pitch sounds have lower frequencies (and longer wavelengths).
pitch: The highness or lowness of a sound. Related to the wavelength and frequency of a noise. Short wavelength equates to high frequency and subsequently high pitch.
sound energy: Audible energy that is released when you talk, play musical instruments or slam a door.
sound wave: A longitudinal pressure wave of audible or inaudible sound.
vibration: When something moves back and forth, it is said to vibrate. Sound is made by vibrations that are usually too fast to see.
volume: When sound becomes louder or softer. A measurement of amplitude.
wave: A disturbance that travels through a medium, such as air or water.
Before the Activity
- Gather the materials for each station.
- Make copies of the Seeing Sounds Worksheet, one per student.
- Decide whether to condcut the activity as an entire class demonstration or a student team activity. Either have the class perform each activity station together, or set up stations around the room and have students conduct each activity station in small groups.
With the Students
- Strike a tuning fork and place one of its tines against a cup of water or ping-pong ball.
- Discuss what happened to the ping-pong ball. Why did it move?
- Cut a large hole (~9 cm [3.5 inches] in diameter) in the side of a cardboard milk container.
- Tape a small mirror (sized smaller than the hole) on the middle of a piece of tissue paper.
- Tape the tissue paper (with mirror) taut across the hole.
- Have a student hold the milk carton as if s/he were pouring, and talk down into the open end of the carton while another student shines a flashlight on the mirror at an angle that reflects it on the wall. Talk in different voices: loud and soft, high pitch and low pitch.
- Discuss what happens to the light on the wall when the student is talking (creating sound waves).
- Place the tip of a spatula blade on a desk or table with the handle extending over the side.
- Pull the handle down and let go.
- Discuss what happens when the handle is let go? What does the spatula look like? Do you hear anything? Describe the volume, pitch and frequency of what you observe. These vibrations are similar to what goes on in your vocal chords when you talk.
Rubber Bands on Doorknob
- Fasten a rubber band to a doorknob, pull it taut, and pluck it.
- Discuss what happens when the rubber band is plucked? What does the rubber band look like? Do you hear anything? Describe the volume, pitch and frequency of what you observe. These vibrations are similar to what goes on in your vocal chords when you talk.
- Hold a blown-up balloon in front of a boom box speaker and turn up the volume.
- Observe what happens to the balloon when the volume is turned up.
- Place a paper plate with small pieces of paper on it on top of the boom box.
- Observe what happens to the pieces of paper as you turn up the volume.
Discuss with students what they have seen and felt. Come to a class consensus: Can you see and feel sound energy? Sound energy is a useful form of energy for sensing and detecting vibrations. Engineers use sound energy to help people see and feel things that they would not otherwise be able to, like what is going on deep inside a human body, far under the surface of the Earth, and deep below the sea to the ocean floor. Engineers also design medical devices, such as hearing aids, that help people hear things they may not be able to normally hear.
Remind the students that loud noises can damage their ears. They should be as quiet as possible, especially when experimenting with the boom box.
If the class period is too short to complete all the activities, just do one or two.
This activity may get loud. To avoid disturbing other classes, consider going outside.
Brainstorming: As a class, have 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:
- What is sound energy?
- In what places have you heard sounds?
- What creates these sounds?
Sound Drawing: After each student has drawn a picture of a noisy place they have been, have them describe all the noises to the class.
Activity Embedded Assessment
Worksheet: Have students use the Seeing Sounds Worksheet to guide them as they rotate through the activity stations and as a place to record their observations. Review their answers to gauge their mastery of the subject.
Class Definitions: As a class, or in small groups, come up with your own definitions of sound energy, volume, frequency and pitch. For each definition, include how this trait might help engineers trying to design a hearing aid for a person who could not hear.
Roundtable: Have the class form into teams of 3-5 students each. Ask the class a question with several possible answers. Have the students on each team make a list of answers by taking turns writing down ideas on a piece of paper. Students pass the list around the group until all ideas are exhausted. Have teams read aloud the answers and write them on the board. Ask the students:
- How many different things can you think of that use sound energy? (Possible answers: Radio, television, car horn, telephone, crosswalk signal, smoke alarm, oven timer, etc.)
Have student conduct an Internet or library search to learn more about ultrasound and infrasonic sound and the engineering products created from using these types of sound.
Have students describe the sound that comes from using various instruments such as a guitar or a drum. On a guitar, how do you make the sound change in pitch? Does it relate to the frequency of the sound wave?
- For lower grades, conduct these activities as a class demonstration, instead of individual stations. They are fun to do together.
- For lower grades, have students draw pictures of their observations.
Biomedical Engineering Society. "To promote the increase of biomedical engineering knowledge and its utilization." Accessed October 3, 2005. http://www.bmes.org/
ContributorsSharon Perez; Natalie Mach; Malinda Schaefer Zarske; Denise W. Carlson
Copyright© 2005 by Regents of the University of Colorado
Supporting ProgramIntegrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
The contents of this digital library curriculum were developed under grants 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.
Last modified: June 15, 2017