Introduction

The Energy Story

  Energy Is Born
  Energy Types
  Energy Changes
  Energy Generation

The Energy Problem

  Conservation of Energy
  Aging of Energy
  Finite Resources
  The Oil "Crisis"
  Energy Pollution
  Discussion Topics

The Energy Solution

  Conserving Electricity
  Appliance Efficiency
  Heating Conservation
  Renewable Energy

Web Links

Teacher Guide

About the Author


Secret Lives Title - The Energy Story


agif - compass
The Ten Types
Magnetic Energy


Magnetic and electrical energy are closely related to one another. When electrons move through a wire, a magnetic field is created around the wire. If the wire carrying the electrons is wound around a a metal bar of iron the iron will become magnetic and is called an electromagnet. The magnetic energy generated can be used to attract other metal parts and is used in devices like the magnetic hoists used to lift old cars into the car compactor.
electromagnet graphic
 

spinning electron graphic

Certain materials, mainly metals such as iron, nickel, and cobalt, can be permanently turned into magnets. This occurs when groups of atoms in the metal have their electrons all spinning in the same direction causing them to become little electromagnets. We have seen and used magnets to hold papers on refrigerators as one example and compasses to help us find our way.
 

The earth itself generates a magnetic field. This is caused by the rotation of the earth and the fact that the earth has a mainly liquid metallic core. This magnetic field helps protect us from being bombarded by particles and radiation from space. Many planets and stars also have magnetic fields.

 

Electromagnets can be designed to do more complicated jobs. A few examples are:

Door Bell - By turning an electromagnet on and off, a metal arm (or object) can be attracted over and over to the electromagnet causing the arm to hit a bell.

Solenoid - A solenoid is an electromagnet designed so that a plunger or metal object can be pulled or pushed back and forth. The starter in your car is basically a large solenoid. When you turn the key, the solenoid pushes the gears of the starter into the gears of the engine, causing the engine to turn and start. Once the engine is running on the burning gasoline, the solenoid pulls the gears back apart.

For more information on magnets, electromagnets, and their applications, see the web links below.

Learn.Co.UK Magnetism and a lot more.
Buzzer and Bell This explains how doorbells work.
Solenoid What is a solenoid?
Earth's Magnetic Field
Auroras Paintings in the sky.
Electromagnets How electromagnets work.

And here are a few experiments that you can run at home with a simple battery and some wires to explore how electromagnetism works.

Experiment 1 Wires exert a force on each other.
Experiment 2 This is how your doorbell works.