sentence: Electromagnets are used for a variety of purposes.
sentences_before: They are magnets that are only magnetic when there is a coil of wire with electricity running through it. This 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.
sentences_after: In a simple example, an electromagnet can pick up pieces of iron, nickel, and cobalt.
concept_name: electromagnet
headings: Electromagnet
categories: Tools Electromagnetism