By Contributor Updated Mar 24, 2022
The electric motor is a foundational technology that powers everything from household appliances to space‑craft. Though its operation is governed by the elegant principles of electromagnetism, the components required to create a working model are surprisingly basic. With a nine‑volt battery, a few wires, and a bar magnet, you can construct a miniature motor that demonstrates the core physics in a hands‑on way.
Place a clean bar magnet on a flat surface. Attach two stripped electrical wires to either side of the magnet, leaving a small loop at the top of each wire to act as a cradle. The bottom ends of the wires should protrude slightly; these will later connect to the battery.
Wrap each of the bottom wires around one pole of the nine‑volt battery, ensuring a snug contact. Secure the connections with a short strip of electrical tape. Position the battery flat on the work surface so the wires are ready to contact the magnet.
Take a length of enameled wire and strip a short section of insulation from one side. Cut the wire into three pieces: one long segment and two shorter ones. Coil the long segment around your finger until it forms a tight circle. Attach the two short segments to opposite ends of the coil, aligning the stripped ends so that they face downward and will connect with the battery wires.
Place the completed rotor onto the magnet cradle. When the stripped ends of the rotor touch the battery connections, a current flows, generating a magnetic field that interacts with the magnet’s field and sets the rotor spinning. Observe the motion and feel the principles of electromagnetism in action.
While the current from a nine‑volt battery is relatively low, the wires can heat up after prolonged use. Handle stripped sections with care and avoid prolonged contact with bare skin to prevent burns.
