Eddy Currents

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In this activity related to magnetism and electricity, learners discover that a magnet falls more slowly through a metallic tube than it does through a nonmetallic tube. Use this activity to illustrate how eddy currents in an electrical conductor create a magnetic field that exerts an opposing force on the falling magnet, which makes it fall at a slower rate. This activity guide also includes demonstration instructions involving two thick, flat pieces of aluminum to illustrate the same principle.

Quick Guide

Preparation Time:
Under 5 minutes
Learning Time:
10 to 30 minutes
Estimated Materials Cost:
$1 - $5 per group of students
Age Range:
Ages 8 - 18
Resource Types:
Activity, Demonstration
Language:
English

Materials List (per group of students)

  • A cow magnet or neodymium magnet
  • A nonmagnetic object, such as a pen or a pencil
  • One 3 foot (90 cm) length of aluminum, copper, or brass tubing (do not use iron!) with an inner diameter larger than the cow magnet and with walls as thick as possible
  • One 3 foot (90 cm) PVC or other nonmetallic tubing
  • (Optional) 2 thick, flat pieces of aluminum (available at hardware and home-repair stores, optional)
  • (Optional) cardboard
  • (Optional) Masking tape
  • (Optional) Rubber bands or cord

Keywords

Subjects

  • Physical Sciences
    • Electricity and Magnetism
      • Electric Charges and Currents
    • Motion and Forces
      • Gravity
  • The Nature of Science
    • The Scientific Process
      • Conducting Investigations

Audience

To use this activity, learners need to:

  • see
  • touch

Learning styles supported:

  • Involves hands-on or lab activities

Other

This resource is part of:

Access Rights:

  • Free access

By:

Rights:

Funding Sources:

  • National Science Foundation
  • California Department of Education
  • NEC Foundation of America