The principle of magnetism states that any object that contains charged particles produces a magnetic field when those particles move. Magnetic materials, such as iron, nickel, and cobalt, have certain atomic properties that allow them to be magnetized more easily than other materials. When these materials are magnetized, their magnetic domains align in the same direction, creating a larger magnetic field. The magnetic force between two objects is proportional to the strength of their magnetic fields and the distance between them. The principle of magnetism has many practical applications, including electromagnets, electric motors, MRI machines, and compasses.
