Electric Motor
Electric Motor is a machine that uses magnets and electric current to spin a shaft.
A bar magnet sits inside a coil of wire. When current flows through the wire, it pulls and pushes the magnet. The magnet spins to chase that push and pull. That spin is how a motor turns electric power into motion.
Explaining electric motor by grade level
When you send power from a battery through a wire near a magnet, the wire moves. That push comes from the magnet and the flowing power working together. Wrap the wire in a loop, and it spins round and round. That spinning loop is the heart of a motor.
Projects that explore electric motor
A nail wrapped in wire becomes an electromagnet, and two magnets mounted on opposite sides of a cork provide the rotating force. When the cork spins, each magnet passes the reed switch and triggers a magnetic push. That repeating push keeps the shaft turning — the same principle that drives every electric motor. The cork runs on as little as 1.5 volts, with six volts giving more reliable operation as long as the battery has charge.
Every DC motor converts electric current into rotational motion through magnetic force, but some energy is always lost fighting internal friction. To measure how much, you run four DC servomotors with no load, ranging from 30 watts to 100 watts. You measure the voltage and current going in, then switch off the power and time how long each motor takes to stop. From the input power and stopping time, you calculate the friction loss. Bigger motors have bigger moving parts — and the results show they lose more energy to friction rather than producing useful rotation.