The Invisible Force
Magnetism is a fundamental force of nature caused by the motion of electric charges. A magnet is any material that produces a magnetic field.
Properties of Magnets
Poles: Every magnet has two ends, called poles. One is the north pole and the other is the south pole.
Attraction and Repulsion: The basic rule of magnetism is that opposite poles attract, and like poles repel.
A north pole will attract a south pole.
A north pole will repel another north pole.
Magnetic Field: A magnet is surrounded by an invisible area of influence called a magnetic field. This field is represented by magnetic field lines, which emerge from the north pole and enter the south pole. The field is strongest where the lines are closest together, which is at the poles.
Cutting a Magnet: If you cut a bar magnet in half, you don't get one north pole and one south pole. You get two new, smaller magnets, each with its own north and south pole. Magnetic poles always come in pairs.
The Link to Electricity: Electromagnetism
For a long time, electricity and magnetism were thought to be separate forces. In 1820, a scientist named Hans Christian Oersted made a revolutionary discovery by accident. He noticed that when he turned on an electric circuit, the needle of a nearby compass moved.
This showed that an electric current produces a magnetic field.
This discovery unified the two forces into one concept: electromagnetism. It's the principle behind electric motors and generators.
Building an Electromagnet
You can easily create your own magnet using electricity. An electromagnet is a type of magnet in which the magnetic field is produced by an electric current.
How to Build One:
1.Take a piece of iron, like an iron nail. This will be your core.
2.Wrap an insulated copper wire tightly around the nail many times. This is your solenoid (coil of wire).
3.Connect the ends of the wire to a power source, like a battery.
How it Works: When the current flows through the coiled wire, it creates a strong magnetic field around the iron core. The iron core concentrates the magnetic field, making it much stronger. The nail is now a magnet!
Controlling the Magnet: The great advantage of an electromagnet is that you can control it.
It is a temporary magnet: If you disconnect the battery, the current stops, and the magnetic field disappears.
You can make it stronger by increasing the number of coils in the wire or by increasing the current (using a more powerful battery).