Iron, steel, nickel and iron oxide are magnetic materials.
Magnets have a north&south pole.
Like poles repel&opposite poles attract.
Space around a magnet where its magnetic force works is called a magnetic field.
The magnetic field is stronger closer to the magnet.
Because we can't see magnetic fields we use iron filings. The tiny pieces of iron line up in a magnetic field.
When an electric current flows in a wire it creates a magnetic field around the wire.
By winding the wire into a coil we can strengthen the magnetic field. Electromagnets are made from coils like this.
We can make an electromagnet stonger by: wrapping more coil around the iron ore, adding more turns to the coil or increasing the current flowing through the coil.
Magnetic fields of electromagnets can be turned off and on.