Activity 3

Activity Title: 

Understanding Sound Measurement

Unit Title: 

Feel The Noise

Estimated Duration: 

2 Days

Setting: 

Classroom

Materials:

Worksheets, graphing calculators (optional), sound meter or sound meter app, app such as Dog Whistle (free), Tone Generator app (free), or a method of generating sound of a given frequency. Examples of sound deadening material such as insulation, drywall, cardboard, empty egg cartons, foam, etc, should be acquired beforehand.  Various tapes and hot glue guns should be available for assembly of the boxes.

Worksheet: Design Your System

Worksheet: Materials for sound deadening

Worksheet: Materials for sound deadening

Teacher Advance Preparation:

The teacher should familiarize themselves with the concepts of sound and the measurement of sound in watts/ square meter converted to the decibel scale.  Measuring the decibel level inside the box is challenging.  The meter for measuring sound can be zeroed and placed into the box.  The sound can be generated outside the box, and then the monitor inside the box can be removed and read.  I plan on having a camera monitoring the meter inside the box in real time.  My camera has a light on it and can be placed inside the box via a USB cable. 

Author: 

David Macmorine

Date: 

July 2014

Activity Objectives

Students will design a box to eliminate or reduce sound.

Capture 2

Here is an example of a decibel meter.  Peak is the highest sound monitored regardless of length of time. Max highest decibel reading over a given time period (depending on the specific meter).  Average is the average over the time period the decibel meter has been monitoring sound. 

Guiding Questions
  1. Now that we have studied sound and how sound travels through the air, what sources produce excessive sound?
  2. Is there any reasonable way of avoiding these sounds in the urban environment?
  3. Since we can’t really avoid most of these sounds in the city, what can we do to reduce the intensity of these sounds?
Academic Standards

HS-PS4-1. Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media.

HS-PS4-5. Communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy.* 

Activity Procedures
  1. Ask the students about the sounds all around us.
  2. Have examples of stereo speakers, headphones, amplifiers, or point out any public address speakers in your classroom.
  3. Generate a 60 dB sound at a frequency of 2000 hz. 
  4. Zero the dB monitor and place it inside the box.
  5. Measure the dB level inside the box.
  6. Examine the difference in dB level.
  7. Have the students design a box to reduce the dB level to 50 dB inside.
Differentiation

Students may have not given sound measurement much thought.  Sound measurement in decibels is taken over time so when students read a decibel meter and see Peak giving a higher number than Max emphasize the difference being Peak is the highest dB level instantaneously whereas Max is the average highest dB level over time.