Janice Musfeldt, age 14, of Buffalo Grove, I11., for her question:

WHAT DOES AN ELECTRIC FUSE DO?

Passage of electric current through wire produces heat because of electrical resistance. When the current is large enough, the wire gets hotter. All wires are in constant danger of suddenly being obliged to carry such heavy currents they will set fire to materials around them. A short circuit in a home may be caused quite easily by accident and could start a fire that might burn down the home. An electric fuse prevents this.
Wires in a fuse are of an alloy which melts at low temperature, and are made to carry only a certain amount of current. This amount is called the fuse's rating.When the current reaches a dangerous amount, the wire melts, or fuses, and the current is broken. A fuse may actually be considered a kind of circuit breaker.