Module 15: Magnets and Magnetism

 

Module 15: Magnets and Magnetism

Introduction

Because the earth is a magnet, people have been intrigued by magnetism for centuries. In fact, it was found in the 19th century that magnetism and electricity are not two separate phenomena, but are closely linked. Now physicists refer to electro-magnetism as a fundamental force of nature. But you would never guess by playing with a magnet that it had anything to do with electricity.

Learning Objectives

Upon completion of this module, students will be able to:

  • Explain a magnetic pole.
  • Describe the earth's magnetic poles.
  • Define a permanent magnet.
  • Define an electromagnet.
  • Explain how a permanent magnet is created.
  • Describe a magnetic field.
  • Explain how a magnetic field affects not only magnets but also electrical charge in motion.
  • Explain the principles of electric motors, generators, and eddy currents, all of which involve the inter-relation of magnetism and electricity.
  • Explain the relationship between magnetism and electricity.
  • Describe the design an electric motor and generator.

To Do List

1. Watch the Video Lectures (links below)
2. Complete the Practice Problems (links below)
3. Take the Module 15 Quiz
4. Complete the Exam Practice Problems for Module 15

Lessons

Lesson 15.1 Magnets

The basics of permanent and electromagnets are explained, together with a description of the underlying cause of magnetism.

Lesson 15.2 The Magnetic Field and Magnetic Force

We've learned about gravitational fields and electric fields, now is the time for magnetic fields. In particular, there are surprising results about how moving charges are affected by magnetic fields, and also changing magnetic fields cause the motion of charges.

Lesson 15.3 Applications of Magnetic Field and Force

Using the fact that the magnetic and electric fields affect each other, we show how we can design an electric motor (or, the opposite, a generator). In addition, transformers are shown as way up stepping voltage up and down.

Quiz

Once you have watched the lectures and completed the practice problems, you should demonstrate your understanding by taking the Module 15 Quiz. Be sure to submit the quiz before its deadline.

Coming Up

In the next Module we will learn about Light Rays.