Firstly they can be switched on and off. Complete an electric circuit and a current passes to produce a magnetic field. Switch off the current and the magnetism disappears (provided the iron forms a temporary magnet). Also, their magnetic strength can be changed. The strength of the magnetic field around the solenoid can be increased by: Increasing the number of coils (or turns) of wire.
Increasing the electric current through the coil.
Placing a magnetic material inside the solenoid coil.
In the home, by far the most common use of electromagnets is in electric motors. Think of all of those bits of electrical equipment with some kind of electric motor: vacuum cleaners, refrigerators, washing machines, tumble driers, food blenders, fan ovens, microwaves, dish-washers, hair driers.
The list is a long one, and when you start thinking more widely about electric motors in cars, lawn-mowers and a whole host of industrial applications, it becomes obvious that this application of electromagnets is extensive and extremely important to our daily lives. The question of how electric motors work builds on the basics of magnetism introduced here, and is usually worked on in later years.
