Learn to manipulate magnetic forces!
- Carefully review the general safety advice on the back of the box cover before starting the experiment.
- Read the “Magnets and electricity” section of the safety guidelines carefully before proceeding. Do not let children under 8 years old handle small magnets.
- Read the “Working with batteries” section of the safety guidelines carefully before proceeding.
- Disassemble the setup after the experiment.
- Dispose of used batteries in accordance with local regulations.
- Dispose of solid waste together with household garbage.
A magnet is an object that creates an invisible magnetic field around itself. A magnetic field is an area where a magnet spreads its influence: attracting or repelling other magnets and pulling on certain metals. This interaction between magnets and other materials decreases with distance.
Magnetic fields are invisible, but can be detected with a device called a compass . Compasses react to the external magnetic fields of nearby magnets and align accordingly. In the absence of such, however, compasses “feel” the Earth’s magnetic field, which is pretty weak but still detectable. That’s why a compass usually points North!
In this experiment, you used the metallic disc, which is a permanent magnet—it always features magnetic properties. A magnet with a magnetic field originating from electric energy is a different story. This is called an electromagnet.
A good example would be a metal wire connected to a battery, which forces electrons to flow through the wire from the “–” pole to the “+” pole of the battery . This electric current creates a magnetic field around the wire , which in our case is relatively weak. However, twist the wire into a spiral—and the fields of each curve accrue into one stronger magnet.
Metals that magnets can pull on are called ferromagnetic materials. What is so special about them? They become magnets themselves when subjected to a strong enough external magnetic field. See for yourself! When a paper clip is pulled on by a magnet, it can then pull on other paper clips.
Where are ferromagnetic materials utilized? They are mostly used to enhance the magnetic field of electromagnets. As mentioned above, electromagnets are magnets with a magnetic field that originates from electricity flowing through it. A simple example would be a wire coiled around a rod made of solid ferromagnetic material. Here, the magnetic field of the electromagnet turns the ferromagnetic rod into a magnet with its own magnetic field. Both fields add up to create a stronger resulting magnetic field.