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Short Circuit Projects for Kids

An unwanted short in an electrical circuit occurs when an electrical connection is made where one should not be. This can be from wires touching when they should not, water or other liquids coming in contact with the circuit or overheating of the circuit. The short bypasses all, or part, of the circuit and results in damage to the components and can lead to electric shock or fire. Some electrical short circuits are intentional, such as a switch, and are designed to complete an otherwise "open" circuit.

Switches
- Switches turn on or off electrical circuits by "opening" or "closing" the circuit. When the switch is engaged, the wires on either side of the switch are shorted and electricity passes through. By breaking the connection, or putting the switch in the open position, a break in the circuit prevents the electricity from flowing. A simple circuit made from a power source, such as a 9V battery, a small switch and a 9V light or LED, can effectively demonstrate how the switch shorts the circuit causing the light source to illuminate.
Fuses
- Fuses prevent unwanted short circuits from damaging electrical components and causing electrical shock or fire. Fuses have metal links inside them that, when heated, melt and cause an open in the electrical circuit to prevent further current flow. To demonstrate how a fuse protects a circuit from shorts, add a switch and a fuse to the above circuit across the leads going to the light. When you close the switch, it will short circuit across the fuse and cause the fuse to blow.
Cicuit Breakers
- Most buildings, including homes, are wired through an electrical panel that uses circuit breakers rather than fuses. The circuit breaker is thrown open when a short occurs. You can tell when a circuit has been shorted by the position of the breaker in the panel and the red indicator in the circuit breaker window. Normally, a circuit breaker is in the "on" or "off" position. When a short circuit has occurred, the breaker will be in the center and the window next to it will show a red tab.
Electrical Components
- Some electrical components are designed to be "shorted" when the right conditions occur. A diode is an electronic component that allows electrical current to flow in only one direction. When the right conditions are met, the diode acts as a short circuit allowing the electrical current to flow down the circuit to the remaining components in the circuit. To demonstrate how a diode works, put it in line between the battery and one terminal on the LED in the first circuit. When connected correctly, the LED will light up indicating the diode is acting as a short circuit. If you reverse the diode's direction in the circuit, the LED will not light up.

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