Hobbies And Interests
Building a Circuit
Construct a simple circuit by connecting two wires from the positive and negative terminals of a battery to a simple electrical component such as a light bulb or a small fan. The electrical component should display clear signs to demonstrate whether or not current is passing through it, so that the children can easily tell whether or not the circuit is functioning. A nine-volt battery or lamp battery works well as a power source. You may also purchase a battery holder which will allow you to use several AA batteries instead.
Creating a Short Circuit
A short circuit can be introduced by stripping a short section of each wire of insulation and laying a screw driver across both bare wires. The screwdriver should have a plastic or rubber handle to prevent a shock. If a short circuit is caused without a fuse in the system, it can cause damage to the electrical component and the battery, and will cause all components in the circuit to heat up considerably. As this could cause the battery to split or corrode, a short circuit should never be caused without a fuse or breaker between the power source and the short circuit.
Building a Fuse
While commercially available fuses are cheap enough to use in this experiment, modern fuses tend to be very small, which makes it difficult to see how they function. A more visible fuse may be built by including a thin strip of aluminum foil between the power source and the wires to be short-circuited. When the short circuit is created, the foil will heat rapidly and break, stopping the flow of current to the rest of the circuit. This will allow the audience to clearly see the function of the fuse in the circuit.
Explanation
Create a map of the circuit, showing the flow of electricity through all the components. The map should also show what happens to the flow of electricity when the short circuit is introduced. Finally, the map should show what happens to the flow of electricity when the fuse fails. Discuss what would happen to the circuit if the short circuit occurred in a system without a fuse, and the electrical components were allowed to heat up beyond the failure point of the fuse. Describe the ways in which fuses and electrical components are utilized in household electrical systems.