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This week's LabZone activity
Sept. 20, 2006
Reducing Noise Pollution
Materials: shoebox; scraps of paper, cardboard, wood, plastic, ceiling tile; alarm clock; meter stick; optional—decibel meter (speech and hearing teachers may have one)
Procedure:
- Place the alarm clock in the shoebox.
- Set the alarm and let it ring. Walk away from it until you can no longer hear the ringing. Measure the distance.
How far away were you when you could not hear the sound?
- Now fill the shoebox with the paper scraps.
- Place the clock in the paper and measure the depth of the paper below and above the clock.
- As before, let the alarm ring and measure the distance at which you can no longer hear the ringing.
How does this distance compare to the distance at which you heard the alarm before? Why is it different?
- Vary the material in the shoebox. Use cardboard, wood, and plastic. Repeat the activity with each of these materials.
- Record the distance from the shoebox where you couldn't hear the sound with each material.
- Arrange the materials from most effective sound absorber to the least effective sound absorber.
Why do some materials reduce noise levels more than others?
What contribution does distance from the sound source make?
What if you put a sound source in a thermos? Could you hear it? Why or why not?
- If you can obtain a decibel meter, measure the decibel level of the alarm with each material in the box. Graph the decibel level for each material.
From Creative Sciencing: Experiments for Hands-on Learning by Gerald H. Krockover and Alfred DeVito. Copyright © 2001 by Good Year Books. Used by Permission of Good Year Books, Tucson, AZ. To order, visit our online store www.goodyearbooks.com or call us toll free at (888) 511-1530.
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