The Class: The labs we are designing are for the Science and Technology of Everyday Life class at Hope College. This is a class that is typically taken to fulfill a liberal arts science requirement. The students are usually education or non-science majors that are not enthusiastic about taking science classes due to their previous science experiences. Because of this, the class focuses on the "how" of science and technology rather than the "why". The class contains as little calculations as possible and instructions must be easy to follow. The labs for this class are designed to take some of the mystery out of everyday technology. Some labs include dismantling and reassembling a car engine, building an electric keyboard, making a simple AM radio and observing the components of a personal computer. These labs along with others help bring an understanding of how today’s technology works.

Summary of Work:

As we attempted to create a microphone lab for the Science and Technology of Everyday Life class at Hope College we stumbled on a potential new design for the speaker lab which had been a mainstay in the class for the past few years. The current lab was adequate, however we hoped to improve on the sound quality and ease of construction without sacrificing performance or cost to build. The students that take this particular class often have had either poor success or bad experiences in previous science classes. Therefore labs for this class should be as simple and unthreatening as possible. The current speaker design, although it functioned well, was often tricky to build and took a long time. Our new design uses a plastic cup as the enclosure, its lid as a diaphragm, and a straw to hold the coil. This new design is easier, less expensive and faster to build and yet implements the same conceptual ideas as the original lab.

Project Requirements:

For this lab to be affective it must meet several criteria. The speaker must:

1. Be compatible with today’s stereo systems. The hookup must be compatible and the resistance must be similar to that of a standard industry speaker.
2. Sound good.
3. Use parts that we can obtain on a regular basis
4. Have a total cost of parts ~$5 or less.
5. Be safe to use, free of the possibility of fire or electrocution during normal use.
6. Be reliable and consistent in its function.
7. Have an easy construction.
8. Promote the understanding of how a modern speaker works.

Circular Magnet: This magnet configuration is a modification of the magnet from the original speaker design. It utilizes two cylindrical ceramic magnets (gray) that create the field. The top two washers (dark gray) focus the north field towards the bolt in the center that acts as the south magnetic pole. This configuration focuses the field far better than the U-magnet configuration. This increased the output volume of the speaker and allowed us the leeway to make other modifications. This magnet design fit nicely into any cup we were testing with.

Results - This design was the answer to previous failures. The circular magnet increased the field to the point where the volumes of the 8ohm resistance coils were quite loud. This magnet configuration also fit and worked sufficiently in the store bought clear cups. Because of this, the design is not lost if the larger cups are unattainable.

The final design utilized the circular magnet configuration in the 16oz clear plastic cup along with the corresponding lid and a giant class straw. The coil is made from 18-20 feet of 36gauge insulated copper wire that has a total resistance similar to 8 ohms. The total cost of this lab is $2.43.

Full Cost Analysis