Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Many common electric devices, such as doorbells, contain electromagnets. If they have moving parts, they are likely to have an electric motor. An electric motor is a device that uses an electromagnet to change electrical energy to kinetic energy. Answer: electromagnets
What do electric motors use to change electrical energy into kinetic?