Electromagnet attracts paper clips when current is applied creating a magnetic field, loses them when current and magnetic field are removed

When current flows through a wire it makes a magnetic field around the wire. Usually this field is very weak, so a single wire won't make a magnetic field strong enough to pick up metal objects. In this picture "I" is the current and "B" is the magnetic field.

Electromagnets are temporary and artificial magnets. They are magnets that are only magnetic when there is a coil of wire with electricity running through it. The coil of wire is called a solenoid. The strength of the magnet is proportional to the current flowing in the circuit. The electricity running through the wire is called a current. The current is the flow of electrons, which are negatively charged particles. Electromagnets are used for a variety of purposes. In a simple example, an electromagnet can pick up pieces of iron, nickel, and cobalt.