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Copper in health
 Introduction 
Photo of electric bell
Picture 1. An electric bell uses copper wires in its electromagnets.
Using electromagnets
An electromagnet is a magnet that works with electricity. It can be switched on and off. The coils are nearly always made of copper wire because it is such an excellent electrical conductor (see conducting properties).

Electromagnets have many uses. Here are some examples.

An electric bell The electromagnets make the hammer vibrate back and forth, ringing the bell.
An electric lock When the entryphone has been answered, the door can be unlocked from an upstairs flat. An electromagnet pulls the bolt open. Switch it off and the bolt springs back.
A crane

A scrapyard crane can lift a whole car. Move it into position, and switch off to let go.

A surgeon's tool An eye surgeon can pull scraps of steel out of a patient’s eye using an electromagnet. Turn up the current until it pulls just enough to gently remove the metal.

In this electronic resource (e-source), we'll look at how electromagnets work and how they can be made efficient.

Contents
This e-source has 4 pages:
  1. Introduction
  2. Magentic fields
  3. Solenoids
  4. Making them stronger

Using this e-source
There are a number of interactive features in this e-source:

A glossary of terms: any word with a glossary entry is highlighted. Clicking on the word will open a new window with a definition of that word.

Quick questions: at the end of each page is a quick question to test your understanding of that page. Type in your own answer then click on the button to see how well you did.

Quiz: at the end of each unit, there is a quick quiz to see how well you understand the ideas.

Roll over diagrams: many of the diagrams have highlights or sequences. You can see these by rolling your cursor over part of the picture or part of the text. The text has a roll over highlight.

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