TE Activity: Controlling Sound
Contributed by: Integrated Teaching and Learning Program, College of Engineering, University of Colorado at Boulder
Summary |
Engineering Connection |
| Acoustical engineers study sound and design buildings that reflect and absorb sound to create the desired acoustics. In this activity, students are acting as acoustical engineers as they use design headphones using sound-absorbing materials. |
Contents
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| Grade Level: 3 (3-5) | Group Size: 2 |
| Time Required: 30 minutes |
Activity Dependency  :None |
Expendable Cost Per Group
:
US$ 2 |
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| Keywords: sound waves, acoustics, absorption | |
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Related Curriculum
:
| subject areas | Physical Science |
| curricular units | Sound and Light |
| lessons | To Absorb or Reflect… That is the Question |
Pre-Req Knowledge (Return to Contents)
Lessons 1-5 of the Sound and Light unit: Longitudinal, Transverse Waves (Lesson 1), Wavelength and Amplitude (Lesson 2), Frequency (Lesson 3), Sound Waves (Lesson 4), Acoustics (Lesson 5).
Learning Objectives (Return to Contents)
After this lesson, students should be able to:
- Explain that some materials absorb sound, while others reflect it.
Materials List (Return to Contents)
For activity demonstration:
- One pair of working headphones (the kind that covers the entire ear)
- Bells, small buzzer, CD player, or other noise-making items
Each group/individual needs:
- Various materials such as cloth, sponges, foam, cotton balls, cotton batting, small carpet samples, and any other materials that will absorb sound
- Something to hold the earpieces together, such as old headphones without the earpieces or a piece of material that will bend without breaking (vinyl strips from a mini-blind or inexpensive plastic headbands)
- Dixie cups (work well as earpieces and can be stuffed with sound-absorbing materials)
- Rubber bands
- Duct Tape
- Masking tape
- Scissors
- 2 copies of Headphone Planning Sheet
Introduction/Motivation (Return to Contents)
Let's take a look at the ceiling and floor of your classroom. Do you see acoustic tiles on the ceiling and carpet on the floor? What would happen if the floor was made out of hard tile and the ceiling had the same material? (Answers: There would be a lot of echoes, sound waves would not be absorbed quickly, it would be noisy.) Acoustical engineers have noticed this phenomenon and design special tiles for the ceiling that absorb sound. And, they know that material absorbs sound, so they usually put carpet on the floor when they are designing a classroom!
We have been learning about acoustics and acoustical engineers, and now you are going to have the chance to act like an acoustical engineer. I am going to break you into teams of two, and your engineering team will use some sound-absorbing materials to design a set of headphones.
Here is a pair of real headphones (see Background section). Let's have a volunteer put them on and see if they can hear the noises that I am going to make. (Have a student put on the headphone; ask the student to raise her/his hand if they s/he hears the noises). It looks like whoever designed these headphones did (or, possibly, did not do) a good job! Now you and your teammate are going to have a chance to design your own headphones. Once you are done, you can test them using these same noises.
Before you can begin building, there is a box on your Headphone Planning Sheet that you need to have checked off by me or another adult helper. Even real engineers need to get their designs checked before they build them! One more thing… remember to listen to each other's ideas and work as a team!
Procedure (Return to Contents)
Background
In this activity, students need to use substances that absorb sound. Materials that absorb sound send back few or no sound reflections or echoes. These types of materials can be found in classrooms, offices and other places to help reduce sound.
Have a pair of working headphones available for students to inspect. (These should be the type that completely covers the ear. Prior to starting this lesson have one student put on the headphones and another without. Have several objects that make noise, such as bells, buzzer, CD player, etc.), and have students identify if they are able to hear them while wearing the headphones. They need to design and make their own headphones to quiet these sounds.
Before the Activity
- Gather materials
- Copy Headphone Planning Sheet (one per group, or one per student if working individually)
- Write the list of materials on the board (so students know how to spell them for their worksheets)
- It may be helpful to set up several "construction stations" on various desks throughout the room so that the students can easily access the materials
With the Students
- Divide students into teams of two.
- Pass out materials and Headphone Planning Sheet.
- Students should work as a team to create and write down their design on the Headphone Planning Sheet. Remind students to get their design checked off before beginning to build. Encourage students to make their design as detailed as possible.
- Give students time to build their design.
- Students should test their headphones to see how they work, by using the bells and/or buzzers provided.
- Encourage students to try each other's headphones, and talk with each other about ideas that work well.
- Have a class discussion about the headphones. Which ones worked best and why? Talk about how engineers design, then build, and finally test their ideas. Engineers often have to redesign, rebuild and retest many times before they perfect their creation.
Safety Issues (Return to Contents)
Assist students with scissors as needed.
Troubleshooting Tips (Return to Contents)
Be sure to encourage students to periodically test their headphones as they build. If time allows, let students redesign and rebuild their headphones in order to make them even better.
Investigating Questions (Return to Contents)
- How many types of headphones are there?
- What are some of the different uses for headphones?
- Who uses headphones for their jobs?
Assessment (Return to Contents)
Pre-Activity Assessment
Absorb or Reflect?: Make a list on the board of materials that reflect sound and another list of materials that absorb it. Tell the students that today they are going to be using absorbent materials to create headphones that absorb sound. When would we want to use materials that reflect sound? (Answer: When we want something to be very loud, such as cymbals or bells).
Activity Embedded Assessment
Engineering Design Check-off: Since students need to get their designs checked off, use this time to talk with them about the features of their designs. Encourage students to add as many details to their designs as possible, including labeling the various parts. Make sure that students understand they are using materials that absorb sound.
Post-Activity Assessment
Best Features: As a class, talk about which features of the various headphones worked the best and why. Review how these absorbent materials "soak up" or absorb sounds.
Activity Extensions (Return to Contents)
As a class, design a room that will absorb sound. Create a miniature model of the room and discuss what features contribute to its acoustics.
Take a field trip to a radio station and talk with the disk jockeys about the importance of headphones (and microphones) in their work.
Activity Scaling (Return to Contents)
- For upper grades, limit either the amount of materials, time available or both. Talk about engineering constraints and how engineers work under deadlines and under budgets. Also discuss the importance of collaboration, teamwork and learning from others in engineering.
- For lower grades, activities should still be appropriate.
Contributors
Teresa Ellis, Frank Burkholder, Abigail Watrous, Janet YowellCopyright
© 2007 by Regents of the University of Colorado. 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. 0226322. 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.Supporting Program (Return to Contents)
Integrated Teaching and Learning Program, College of Engineering, University of Colorado at BoulderLast Modified: September 26, 2008