Hands-on Activity: Induced EMF in a Coil of Wire

Contributed by: VU Bioengineering RET Program, School of Engineering, Vanderbilt University

A photograph shows a circuit board.
Current travels from coil to conductor.
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Summary

Students use a simple setup consisting of a coil of wire and a magnet to visualize induced EMF. First, they move a coil of wire near a magnet and observe the voltage that results. Then they experiment with moving the wire, magnet and a second, current-carrying coil. They connect the coil to a circuit and the current from the induced EMF charges a conductor.
This engineering curriculum meets Next Generation Science Standards (NGSS).

Engineering Connection

To create MRI machines, engineers harness the power of radiation to produce images of the body while designing the equipment to protect patient and medical personnel from any dangerous side effects. To do this, engineers who develop MRI safety strategies must be aware of voltage changes occuring in metal objects within the magnetic field as result of the motion and strength of the field. At activity end, students consider this application with respect to MRI machines in the handout questions 1-3.

Learning Objectives

After this activity, students should be able to:

  • Describe the motional EMF produced when a coil of wire moves through a magnetic field or a magnetic field moves through a coil of wire.
  • Explain the induced EMF when a magnetic field through a coil of wire is increased.
  • Charge a conductor using current from an induced EMF.

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Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

  • Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Medical technologies include prevention and rehabilitation, vaccines and pharmaceuticals, medical and surgical procedures, genetic engineering, and the systems within which health is protected and maintained. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Technological innovation often results when ideas, knowledge, or skills are shared within a technology, among technologies, or across other fields. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
  • Results of scientific inquiry--new knowledge and methods--emerge from different types of investigations and public communication among scientists. In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge. In addition, the methods and procedures that scientists used to obtain evidence must be clearly reported to enhance opportunities for further investigation. (Grades 9 - 12) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Materials List

Each group needs:

  • 2 gilley coils*
  • rubber-coated NdFeB magnet
  • multimeter
  • 6V lantern battery or 5V DC power wupply
  • 1000-ohm resistor
  • 3 wires with alligator clip leads
  • several hookup wires
  • diode
  • LED
  • 100 μF capacitor
  • breadboard
  • Induced EMF in a Coil of Wire Handout, one per student

* Gilley coil induction sets are available online from a number of venders for ~$50. Improvise an easy alternative by winding a 2-inch diameter coil of 100 turns using 20 gauge magnet wire held together with duct tape.

Introduction/Motivation

We have learned that magnets can create a current in a wire. In this lab, we will experiment with this current and then use it to charge a capacitor. Learning more about the properties of magnetic fields will help us to better understand MRI machines so we can work to solve our MRI safety challenge.

Procedure

  1. Gather materials and make copies of the Induced EMF in a Coil of Wire Handout.
  2. If desired, divide the class into small groups of two or three students each.
  3. Distribute the materials and handout.
  4. Direct students to follow the handout instructions to explore the current that is created when a loop of coil is passed over a permanent magnet.
  5. Then have them follow the instructions to create a circuit and use this induced EMF to light a diode.
  6. Conclude the activity by giving students time to individually prepare summary lab reports, as described on the handout and in the Assessment section.

Attachments

Assessment

Post-Lab Assessment

Lab Reports: As directed on the Induced EMF in a Coil of Wire Handout, have students individually prepare summary lab reports that include answering the four application questions, listing their observations, and describing any problems or issues that occurred during the lab. Review their lab reports to gauge their depth of comprehension. If desired, lead a class discussion in which students share their results, conclusions and answers to the questions, paying special attention to conclusions that relate to the ongoing engineering grand challenge of the unit.

Contributors

Eric Appelt

Copyright

© 2013 by Regents of the University of Colorado; original © 2006 Vanderbilt University

Supporting Program

VU Bioengineering RET Program, School of Engineering, Vanderbilt University

Acknowledgements

The contents of this digital library curriculum were developed under National Science Foundation RET grant nos. 0338092 and 0742871. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.

Last modified: June 29, 2017

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