Imagine sitting in a room where a balloon is popped and you can hardly hear the sound, a room in which echoes do not exist because the walls absorb almost 100% of all sound energy. A room like this actually exists. The anechoic chamber, as it is called, is located at the Acoustic Research Center of the Armstrong World Industries company. The research center is devoted to research and discovery of new sound reduction materials.

Noise is any unwanted sound that has no pleasing quality. Noise can disturb our concentration and even cause physical pain when allowed to reach certain levels. Imagine trying to study sitting in the middle of a construction site or having to work at a desk with the drone of a loud machine in the background. It is the job of acoustical engineers to design spaces where noise will not disturb workers and good communications can take place.

The science of sound is called acoustics. Acoustics deal with the production, control, reception and effects of sound energy. In the activities that follow, you will have the opportunity to investigate the properties of sound energy and apply what you learn to a design problem. You will have the opportunity to experience what it might be like to be an acoustical engineer.

Design I Build I Apply Problem Statement

The store next to the library is being renovated into a "Teens Only" center by a community group. The plan behind the "Teens Only" center is to provide a place where teenagers can go to listen to music, hang out and just have some fun. A major concern for the library board is the level of noise that will be generated at the center and its impact on the atmosphere within the library.

You are an architect specializing in acoustic design who has volunteered to design and build a model for the proposed renovation. Your task is to research acoustical materials and their applications and use the data in your model. You will then make a presentation to the library board demonstrating how your design addresses the issue of keeping noise levels at an acceptable level.

Criteria

The store is 40 feet long and 40 feet wide with a 14 foot ceiling. The model must be built at a 1/2 inch = 1 foot scale.

The model must include two exits and a stage where the sound will be generated. The stage is 10 feet deep and 15 feet long.

The acoustic design of the model must reduce the decibel level of a sound source placed into the model by twenty-five percent (percentage may have to be adjusted by the instructor) when measured outside the model.

Testing Procedure

1. The sound source can be an alarm clock, radio, CD player, etc... Adjust the volume to approximately 100 decibels using a sound level meter placed three inches form the source.

2. When the model is complete, place the sound source in the model on the stage. Place the roof on the model. Using the sound level meter, check the decibel levels around the outside of the model. Calculate the reduction in sound level from the original levels.

Materials

modeling materials such as:

foam board corrugated cardboard assortment of fabrics wood

plastic

cardboard

acoustical materials ceiling tile foam rubber Styrofoam fabric packing material paper towel

Equipment

standard material processing tools and machines Radio Shack Sound Level Meter

sound source

Assessment

The following scoring guide will be used to grade your design solution to the above problem. Be sure to check the guide as you proceed through the activity

• 4- Accomplished: Your work demonstrates that you have mastered this portion of the activity.

• 3- Good Work: Your work fulfills all of the objectives, specifications and constraints of this portion of the activity.

• 2- Acceptable: Your work is acceptable but needs minor revisions, additions and some more investigation.

• 1- Unacceptable or missing: Your work is incomplete or requires major revisions, additions, and investigation.

A. Student Portfolio

Each portfolio must contain the following:

______ Sketches and drawings of design ideas

______ Data, notes and interpretations from experiments

______Daily log sheet reflecting the teams decisions, questions, remarks and

accomplishments

______Design changes

______ Research materials you gathered

B. Discovery Activities

______ Recommended procedures were followed

______ Accurate data was collected

______ Conclusion reflected the data collected

C. Construction and Testing of the Model

______ Sketches and drawings

______ Model reflects application of concepts developed in the Discovery Activities

______ Design reduces the decibel level outside the space by 25%

______ Model reflects quality and craftsmanship

D. Classwork

______ Team shows consistent effort

_____ Team worked cooperatively, demonstrating an "all sink or swim attitude"

_____ Suitable class conduct displayed