Electricity and Magnetism

Author: Kurtis Smith and Dave Massey, Santee Alternative - Santee School District

Overview

An application of how magnetism and electricity are related, students observe the spinning of a coil of copper wire that is part of a circuit powered by a battery and attached to a spindle positioned over a magnet and are ask to discuss why the mechanism works in the manner that it does.

• Objectives: Students will demonstrate understanding of the relationship between magnetism and electricity by explaining how the model motor operates. Students will relate the model motor to larger generators used by power companies to generate electricity.
• Subjects: Physical Science
• Suggested Grade Level: 4th, 5th, and 8th grades
• California Standards Addressed
• Grade 4 Physical Sciences:
  • Students know how to design and build simple series and parallel circuits by using components such as wires, batteries, and bulbs.
  • Students know how to build a simple compass and use it to detect magnetic effects, including Earth's magnetic field.
  • Students know electric currents produce magnetic fields and know how to build a simple electromagnet.
  • Students know the role of electromagnets in the construction of electric motors, electric generators, and simple devices, such as doorbells and earphones.
  • Students know electrically charged objects attract or repel each other.
  • Students know that magnets have two poles (north and south) and that like poles repel each other while unlike poles attract each other.
  • Students know electrical energy can be converted to heat, light, and motion.
• Grade 8 Physical Science:
  • Students know a force has both direction and magnitude.
  • Students know when an object is subject to two or more forces at once, the result is the cumulative effect of all the forces.
  • Students know when an object is subject to two or more forces at once, the result is the cumulative effect of all the forces.
  • Students know that when the forces on an object are unbalanced, the object will change its velocity (that is, it will speed up, slow down, or change direction).
• Time: One Hour

Materials

Battery, small gage copper wire, 4 or 5 magnets, set-up to hold spindle with coil attached to it so that it is positioned above stack of magnets. (See attached photo. Several types of designs are available on the Internet. Check Exploratorium website. http://www.exploratorium.edu/

Preparation and Background

Students need to have an understanding of: how to make an electric circuit, that electric circuits create magnetic fields around them, how a switch works and how to construct a switch, and properties of magnets (like poles repel, unlike poles attract)

Procedure

1. Set up model motor where all students can observe.
2. Have students take notes on how the spindle is put into motion.
3. Ask students to draw the course of the electric circuit.
4. Ask students to discuss what forces are acting upon the spindle to keep it in motion.
5. Ask students why the spindle doesn’t just turn it’s opposing pole toward the magnetic field and stay there.

Discussion

1. Where in everyday life is this concept used?
2. What happens if a magnet is spun inside a coil of wire? Will the reverse happen in that an electrical current will be generated?

Extensions

This lesson is the perfect set-up to visit a local power plant so that students can see how the model they have observed is reversed and used on a much larger scale to generate electricity for their homes. In San Diego, we have the resource of the USS. Midway which offers a student trip into the generating stations that provided power for the ship while it was at sea. There are other such opportunities throughout the state.

Resources

• Exploratorium website: http://www.exploratorium.edu/