Address P.O. Box 219 Batavia, IL 60510
Phone 800-452-1261
Fax 866-452-1436

Eddy’s Brake—Lenz’s Law Demonstration Kit

By: The Flinn Staff

Item #: AP7182

Price: $20.55

In Stock.

In the Eddy's Brake and Lenz's Law Demonstration Kit for physical science and physics, investigate how a changing magnetic field generates temporary electric current loops in conducting metals.

See more product details

Product Details

How can you quickly slow down a spinning wheel without touching it? With a magnet of course! A changing magnetic field generates temporary electric current loops in conducting metals. These current loops generate their own magnetic field, even if the metal itself is not magnetic. The magnetic fields from these induced eddy currents alternately repel and attract the external magnet in such a way as to slow down the spinning wheel-as if by magic! Once the wheel stops spinning, it is no longer magnetic. The principle is easy to demonstrate—simply spin the metal disk like a top and then hold the magnet over the rim. The disk will instantly stop rotating. Alternatively, a Bracken's Demonstration Spinner, available separately, may be used to show the continuous stopping power of the eddy currents. Detailed instructions, background information, and student worksheet are provided. Concepts: Electromagnetism, Eddy currents, Lenz's law. Time Required: 15 minutes Materials Provided: Metal disk, plastic lid, neodymium magnet, screw. All the materials are completely reusable! The Bracken's Demonstration Spinner is a recommended accessory but is not required for the demonstration.


Materials Included in Kit: 
Lid for chromatography centrifuge
Metal disk
Neodymium magnet, ½" x ⅜"
Screw, zinc-plated steel, 10-32 thread, ½" long

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Asking questions and defining problems
Developing and using models
Analyzing and interpreting data
Constructing explanations and designing solutions
Engaging in argument from evidence
Obtaining, evaluation, and communicating information

Disciplinary Core Ideas

MS-ETS1.A: Defining and Delimiting Engineering Problems
MS-ETS1.B: Developing Possible Solutions
HS-PS2.B: Types of Interactions
HS-PS2.A: Forces and Motion

Crosscutting Concepts

Cause and effect
Systems and system models
Structure and function
Stability and change

Performance Expectations

MS-PS2-4: Construct and present arguments using evidence to support the claim that gravitational interactions are attractive and depend on the masses of interacting objects
MS-PS3-3: Apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer.
HS-PS3-3: Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.