Experiment & Explore
|11+||Medium||About 60 minutes|
I bet you love playing with magnets and their invisible forcefields able to pick up metal things and make magnets snap together or fly apart. In this Experiment and Explore activity, you will discover the hidden relationship between electricity and magnetism, how electricity creates a magnetic field, how to make this field stronger and explore ways engineers put this fact to work to solve real-world problems.
You can share your experiments with the world at #nextengineersdiy.
While any reasonably thin but insulated copper wire can be used to create an electromagnet, best results are obtained when using 30/32 gauge enameled copper wire.
If you don’t want to buy new wire, you can often find such wire in old power supplies for mobile phones, laptops, and desktop computers.
You will also need the following items to do some additional investigations.
If you connect a piece of wire to a battery it might not seem like anything is happening but looks can be deceiving. In fact, the electric current through the wire generates a circular magnetic field around the wire. If you wrap the wire into a coil, all the fields around each turn of wire add up and make a stronger magnetic field that has the same shape as the field around a bar magnet with a clear North pole on one side of the coil and a South pole on the other. Reversing the direction of the current flips the poles around. You should see this when you bring a magnet near to each side of the coil.
If you disconnect the coil from the batteries, the magnetic field disappears. Therefore, you can turn the magnet ‘on and off’ by connecting and disconnecting the circuit. We call this an electromagnet.
The more turns of wire the coil has, the more magnetic fields there are to add together and the stronger the whole magnetic field gets. You can pick up more pins.
If you wrap the coil around a ferromagnetic material like iron or steel, the magnetic field gets concentrated in the material and the overall magnet is even stronger than before, even with the same number of turns.
We call coils of wire that are used to make electromagnets solenoids.
If you want to learn more about electromagnets and how they work watch the video called How does an Electromagnet Work? (2:55)
The region around a magnet or moving electric charge within which the force of magnetism acts.
A type of magnet where the magnetic field is produced by an electric current flowing through a wire.
A material, such as iron (ferrum in Latin), that can easily be magnetized by other magnets or by the magnetic field around a current carrying wire.
A coil of wire (usually copper) that acts as an electromagnet when current flows through it.
Image of a solenoid by Zureks is released into the public domain.
Knowing what you now know about electromagnets and how to make one, try these experiments yourself to see which ones produce a stronger electromagnet. Measure the strength of the magnetic field by counting how many pins the electromagnet can pick up. Remember to keep some notes.
Electromagnets are fun to play with, but do you think we can use then to solve real-world problems? Consider these possibilities.
Watch these videos to learn even more about electromagnets and their amazing properties.
Students create their own small electromagnets and experiment with ways to change their strength.
Learn more about the basic concepts in magnetism, including magnetic poles, magnetic fields, and electromagnets.
Electromagnetism is one of the four fundamental forces of nature. Learn more.