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The Good, the Bad and the Electromagnet

Using plastic straws, wire, batteries and iron nails, student teams build and test two versions of electromagnets—one with and one without an iron nail at its core. They test each magnet's ability to pick up loose staples, which reveals the importance of an iron core to the magnet's strength. Students also learn about the prevalence and importance of electromagnets in their everyday lives. Electromagnets are temporary magnets that are created by running a current through a coil of wire wrapped in a loop. Typically, this loop is wound around a piece of metal such as iron or an iron compound. Electromagnets act just like regular magnets except that they lose their magnetic properties once current ceases to flow in the wire.

Weblink address (URL): 
The Good, the Bad and the Electromagnet

Standards & Objectives

Learning objectives: 

After this activity, students should be able to:

  • Describe what an electromagnet is.
  • Explain how current produces a magnetic field.
  • Describe the interconnection of electricity and magnetism.
  • Identify how an iron core affects the characteristics of an electromagnet.

Lesson Variations

Blooms taxonomy level: 
Understanding
Extension suggestions: 

Engineering Connection:
Great minds such as Maxwell, Faraday and Gauss made discoveries that continue to shape our modern world. It's a fact that electricity and magnetism affect every modern industry, including communication, entertainment, medicine, warfare and manufacturing. Engineers design electromagnets into uncountable electronic products, home appliances, vehicles, medical equipment and power plants. This activity is based on one of Maxwell's equations, Faraday's law of induction, the principle behind electric generators. The importance of the concept of induction is critical since this serves as the basis for electricity generation to power our homes and businesses.

Helpful Hints

Materials
Each group needs:

  • plastic drinking straw
  • high-gauge wire (28, 30 or 32 gauge), 2 ft (.6 m)
  • iron nail
  • loose staples
  • 9V battery
  • alligator clips
  • scissors
  • wire strippers
  • The Good, the Bad and the Electromagnet Worksheet, one per student
  • For the post-activity assessment: paper clips, and more wire and batteries

References

Contributors: 
Virginia Cooter
Originator: 
Ayers Institute for Learning & Innovation