In this activity about electricity, learners explore what happens when you blow a fuse. Learners short-circuit a battery using copper wire (a good conductor with very low resistance) and thin iron wire. Learners will discover that when they connect the clip to the iron wire, the voltage of the battery pushes electrons through the circuit against the resistance of the iron wire, causing the iron wire to heat up. Note: the wire gets very hot! Use this activity to introduce learners to basics of electricity including conductivity, resistance, and currents as well as electronics safety and circuit breakers.