An electromagnet is a type of magnet in which the magnetic field is produced by the flow of electric current. The magnetic field disappears when the current is turned off. Electromagnets are used in motors of electric fans, electric blenders, electric drill and in toy cars. It is also a component of generators, loud speakers, doorbells and radios. Powerful electromagnets are used for picking up and moving heavy iron objects.
The relationship between electricity and magnets can be shown using electromagnets. Before you ask the students make a simple electromagnet, it is best to show them examples of devices where electromagnet is used. In the Philippines, electricity and magnets are studied in Grade 5.
The short presentation below shows how to make a simple electromagnet. Notice that a hard plastic drinking straw instead of simply a nail wrapped with the enamel wire is used. Straw is better so students can insert different core material inside the straw to investigate what core material is best to use in an electromagnet. The labelling of the number of turns is also important for the follow-up activity on investigating how the number of turns affects the strength of an electromagnet.