Lesson 2 Page 3
Explore - Electricity + Magnets = Electromagnets
Electricity and magnets are linked.
- You can use magnets to create electricity.
- You can use electricity to create magnets.
Video
Watch the BrainPop video Electromagnets.
Electromagnets have big advantages over permanent magnets.
- Electromagnets can be turned off and on.
- Electromagnets can be made stronger or weaker by changing the current.
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1. The magnetic field is stronger, the closer you are to a wire.
2. An increased current and an increased number of times the current flows makes an electromagnet stronger. Note: a wire with too much current gets too hot and energy is wasted because it becomes heat energy.
Digging Deeper
Here are some uses of electromagnets that have helped people and saved lives.
Electromagnetism shows magnets and electricity are related. One example is use in a junkyard. Iron is one of the most useful metals on the planet. Iron can be recycled, so old objects can be crushed and have their iron removed, melted, and re-used. How can many tonnes of iron be moved and separated from a mixture of metals and scrap? Magnets to the rescue!
Magnets have been called "iron detectors" because they strongly attract only iron and a couple of other metals. The only problem is, when iron is stuck to a magnet, how do you get it off? This is where electromagnets are so useful.
Electromagnets do all the same things that permanent magnets do but only if electricity is flowing through them. That is because, when electricity flows through a wire, it produces a magnetic field.
Have you ever heard of an MRI machine? At the heart of this amazing medical machine is a very powerful electromagnet. This electromagnet produces a magnetic field that allows medical technicians to take very detailed pictures of the inside of the body. Thanks to MRI machines, many ailments have been treated successfully and lives have been saved.
How can you make a strong electromagnet?
Materials
- Electricity Kit Items: thin copper wire, battery holder, small bar magnet
- Additional Items needed: 2 AA batteries, iron nail, paper clips, (possibly sandpaper, wide rubber band), tape
Video
Watch the ADLC Digital lesson: Building Electromagnets to help you set up this experiment.
Check Your Answers
Once you have completed this activity, check your answers below.
Electromagnet Strength Table |
| Type of Electromagnet | Observations |
| Test A: AA size battery, 
20 coils of wire | The number of paper clips picked up will depend on the exact materials you used to make your electromagnet, but the electromagnet should pick up one or two paper clips. |
| Test B: AA size battery, 40 coils of wire | The number of paper clips picked up will depend on the exact materials you used to make your electromagnet, but the electromagnet should pick up two or three paper clips. |
| Test C: TWO size AA batteries, 20 coils of wire | The number of paper clips picked up will depend on the exact materials you used to make your electromagnet, but the electromagnet should pick up three or four paper clips. |
| Test D: TWO size AA batteries, 40 coils of wire | The number of paper clips picked up will depend on the exact materials you used to make your electromagnet, but the electromagnet should pick up four or five paper clips. |
Conclusion: If you did this activity correctly,
you should have found by coiling more copper wire around iron, you can make an electromagnet stronger. Flowing electricity in a wire creates a magnetic field; therefore, more wire means
a greater magnetic field. Adding another loop is like putting another electromagnet next to the first one.
You should also have discovered that using more batteries increases the strength of the electromagnet. More batteries means more energy to increase the flow of electrical current. This means a stronger magnetic field.