Tuesday, April 28, 2009

Science Fair: Homopolar Motor

Isaac told me last night he has the opportunity to participate in a science fair this year. Here is my write up to guide him through a potential project.

The experiment teaches the principal of electro-magnetism in a simple motor allowing many options for creative design.

I. Design

a. The only parts needed are a battery, copper wire, and a circular magnet (I had ordered some magnets during the weekend if you want to use those).

b. See this video for the operation of the simple motor, and the variety of design options.

II. Explanation of Electro-magnetic principals

a. Basically explained by using force vector diagrams, where the interaction between the force in the electrical circuit and the magnetic force of the magnet create a tangent force perpendicular to the magnet giving the torque (spinning to the copper wire).

i. See the second half of this article for demonstration and illustration

ii. Here’s another explanation in Wikipedia

III. History

a. A similar experiment creating rotation from electro-magnetism was created by Michael Faraday in 1821

IV. Additional questions and experiments for Isaac

a. How can you make the wire spin faster?

b. What happens when adding a bigger battery, or stronger magnet, or alternative shaped wires?

c. How does this apply to other types of motors? DC, AC, etc.

1 comment:

Anonymous said...

Good job, son. Mom