Hands-on Activity What Soundproofing Material Works Best?

Learning Objectives

After this activity, students should be able to:

• Demonstrate and explore which materials absorb sound.
• Demonstrate and explore which materials reflect sound.
• Communicate testing results with their classmates.
• Apply their knowledge of sound to real-life situations.

Educational Standards

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.

NGSS: Next Generation Science Standards - Science

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

Assign each group to use one type of material such as fabric, wood, plastic, paper, metallic, stone or polymer. 

Each group needs:

• roll of tape
• glue
• scissors
• shoebox or tissue box with the top removed (note: each group’s boxes should be roughly the same size, so have the students determine this during the Decibels and Acoustical Engineering lesson)
• one type of material from the list below:
• 8 felt pieces
• 1 bag cotton balls
• 8 fleece pieces (10 cm x 15 cm)
• 4 toothpick boxes
• 2 popsicle stick packs
• 1 packing peanuts box
• 1 bag of Styrofoam plate
• 1 bag of Styrofoam cups
• 8 note cards (10 cm x 15 cm)
• 1 newspaper
• 2 copy paper sheets (20 cm  x 27 cm; standard 8.5 x 11 in)
• 1 box of aluminum foil
• 1 package of plastic plates
• 1 package of plastic cups

To share with the entire class:

• portable speaker and two smart phones (for decibel testing and sound generation)
• Two apps from the App store:
• Tone Generator
• Decibel X: dB, dBA Noise Meter

Worksheets and Attachments

Pre-Req Knowledge

Students should complete the Decibels and Acoustical Engineering lesson prior to doing the activity.

Introduction/Motivation

(Reintroduce the Decibels and Acoustical Engineering Presentation that was used in the associated lesson as an opener to this activity. Slide 11 provides an overview of this activity and group material assignments and slide 12 gives some tips and tricks for creating a soundproof shoebox.)
 
In the previous lesson we learned about the properties of sound. We know sound travels in waves and that it can be absorbed or reflected. We also discussed the nature of acoustical engineering and how this discipline contributes to designing instruments and structures that harness sound. Acoustical engineers use their knowledge of sound to design buildings and rooms so that we can hear the sounds we want to hear as well as those sounds that we don’t want to hear. Think for a moment about what kind of rooms are or should be soundproof? (Answers may include: a movie theater, a music practice room, school classrooms, libraries, recording studios, etc.)

Today, you will take on the roles of acoustical engineers! Your task: to design a soundproof room using one type of material. Your room should absorb the most amount of sound, so that the room’s noise does not disturb the other rooms. (Show the Decibels and Acoustical Engineering Presentation, slide 11.) Each group will get a shoebox and one type of material to explore. (Show slide 12.) To measure which group’s material helped decrease sound the most, we will use a speaker within the shoebox and an app to measure the sound decibels from outside your test box.

Procedure

Background

The associated lesson, Decibels and Acoustical Engineering should provide students with sufficient background knowledge to perform the activity. As a summary, the teacher may reinforce the concept that sound is energy and has the ability to do work. Students need to know that sound is produced as a result of a vibration, which occurs when an object or molecule moves back and forth. When a vibration occurs, it produces a sound. When the vibration stops, the sound stops as well. Sound travels in waves from one place to another, which might be compared to when a person drops a rock in a pond. The impact of the rock on the surface of the water produces a ripple effect; sound waves “ripple” through a medium such as air in a similar fashion. Sound waves need a medium to travel through. This medium can be a solid, liquid, or gas. When a sound hits a specific medium it can either be absorbed, reflected, transmitted, or a combination of these things. When a sound is absorbed, a material takes in the impact of the sound waves and causes the sound to dissipate. When a sound is reflected, the waves bounce off the material and comes back to the person or object making the sound. When a sound is transmitted, it is passed through one medium to another; the sound may also be either amplified or dampened during transmission.

Before the Activity

• Download two apps from the App store:
• Tone Generator
• Decibel X: dB, dBA Noise Meter
• Purchase all necessary materials.
• Set up materials into groups; it helps to have each type of material in piles so groups can easily gather their assigned material.
• Optional: you can assign groups in the main part of the activity, or ahead of time during the Decibels and Acoustical Engineering lesson.

With the Students

1. Introduce the activity and explain that each group will be testing a different material to see how well it acts in soundproofing (Refer to slide 11 of the Decibels and Acoustical Engineering Presentation).
2. Review with students how to set up their boxes (Refer to slide 12 of the Decibels and Acoustical Engineering Presentation).
3. Place students into groups of three or four students (about six groups total, depending on class size).
4. Test the decibel reading for each groups’ box without any material to record baseline data by going to each station. Make sure the room is quiet while testing to avoid background noise. Have students write the decibel reading on Soundproofing Material Handout. 

1. App to test: Tone Generator, found at the (App Store for free)
2. Decibel meter: Decibel X: dB, dBA Noise Meter (App store for free)
3. Test with the boxes facing down on the table.
4. Put one phone inside the box with the Tone Generator on; place the box face-down on the table.
5. Use Decibel X outside the box to measure the sound generated from the Tone Generator.

5. Assign each group a different material to test. Each group will cover the inside of their box with one layer of their material.

1. Group 1: fabric
2. Group 2: wood
3. Group 3: Styrofoam
4. Group 4: paper
5. Group 5: metallics
6. Group 6: plastic

6. Repeat step 4 to test the decibel reading for each groups’ box WITH material to get data. Have students write the decibel reading on Soundproofing Material Handout. 
7. One student from each group will write their change in decibel data on the board or in a Google doc to share with the class.

1. Subtract their original decibel reading from the decibel reading after materials were added

8. Students will fill out their data and other groups’ data from the board or Google doc in the (Soundproofing Material Handout, page 1).
9. Guide the class into filling out a bar graph by graphing which material had the largest change in decibels from testing on the Soundproofing Material Handout.

1. y-axis = decibel reading (in amps)
2. x-axis = material used
3. Title: For example, “Decibel readings of different materials” (can create with class)
4. Change in decibel reading; subtract the initial reading of an empty box from a reading with a box that contains material.

10. Have students analyze the data present on the graph to answer the following analysis questions. Teacher can have students answer the questions within groups, individually, or with the entire class in the Soundproofing Material Handout.

Vocabulary/Definitions

absorption: The process by which a material, structure, or object takes in sound energy when sound waves are encountered, as opposed to reflecting the energy.

acoustic: The branch of physics that deals with the study of all mechanical waves in gases, liquids, and solids including vibration, sound, ultrasound, and infrasound.

decibel: A unit of measurement used to express the intensity of a sound, or the power level of an electrical signal by comparing it with a given level on a logarithmic scale.

medium: A material substance that can help move energy waves (such as sound) along. Also known as a transmission medium.

oscillation: The repetitive variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. The term vibration is precisely used to describe mechanical oscillation.

reflection: The change in direction of a wave at the fact of a medium so that the wave returns to where it originated.

sound: A vibration that manifests itself as a wave of pressure and can be perceived by humans (depending on the frequency) via the ear. Humans can hear soundwaves when the frequency lies between 20Hz and 20 kHz.

Assessment

Pre-Activity Assessment        

Pre-quiz: Administer the Soundproofing Pre-Quiz to determine what students gained from the associated lesson.

Activity Embedded Assessment

Handout: Students complete the Soundproofing Material Handout. Ensure each group shares their data with the class; students may work independently or in groups.

Post-Activity Assessment

Rubric: Use the Soundproof Rubric to grade students on their work during the activity. Focus on Topics that include Soundproofing Material Handout data table and Group Consideration.

Investigating Questions

1. Why did a groups’ designs work really well at absorbing sound? (Possible answers include: they used materials that absorb sound well, their materials were thicker, etc.)
2. Why did other groups’ design fail at absorbing sound? (Possible answers include: they used materials that reflect sound, they used materials that transmit sound, etc.)
3. What materials work really well at absorbing sound? (Possible answers include: cotton, felt, Styrofoam, etc.)
4. What materials work well at reflecting sound? (Possible answers include: plastic plates, foil, etc.)
5. What materials work well at transmitting sound? (Possible answers include: newspaper, printer paper, etc.)

Safety Issues

• Remind students about the importance of using scissors properly in the classroom.

Troubleshooting Tips

• Ask students and teachers to collect boxes prior to the activity.
• Have materials store set up prior to starting the activity with materials labeled.
• Teacher will be the official “tester” (place the phone flat on the side of the box; choose the exact same orientation for each test to reduce the variables added into testing).
• Use two phones; one to play the Tone Generator and the other to measure the decibel reading.

Activity Extensions

Lead a class discussion using the following questions. If time permits, have students explore the questions by using different shaped boxes or by swapping materials between groups and then repeat testing the decibel reading of their boxes.

• How would different sizes and shapes affect results?
• How would different materials affect results?
• What places will this design be useful?
• What are other factors besides sound that go into architect design?

Activity Scaling

• For lower grades: simplify the rubric when grading the soundproof room challenge. Complete the bar graph of data and results as a class instead of individually. Go over post-activity assessment questions orally as a class.
• For higher grades: have students take multiple test readings (5-10 tests recommended) and figure out the mean, median, mode and range.

Copyright

Contributors

Supporting Program

Acknowledgements

This material is based upon work supported by the National Science Foundation under grant no. EEC 1405869—a collaborative Research Experience for Teachers Program titled, “Inspiring Next Generation High-Skilled Workforce in Advanced Manufacturing and Materials,” at the University of Dayton, Central State University and Wright State University in Ohio. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.