Copper wire is a good conductor. Materials that do not allow electricity to pass through them are called insulators. Plastic is a good insulator. What is an electric current? To produce an electric current, three things are needed: a supply of electric charges electrons which are free to flow, some form of push to move the charges through the circuit and a pathway to carry the charges.
The pathway to carry the charges is usually a copper wire. The flow of electricity can be likened to a flow of water through a pipe. Water comes from the dam and is forced through a pipe by a pump or by gravity. The supply of water is the dam, the push is the pump or gravity and the pipe is the pathway. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. Key concepts Electricity Conductor Insulator Introduction Electricity powers many of the devices you use every day.
Materials Flashlight one you can take apart Batteries for your flashlight Three pieces of wire that can be cut and stripped See Procedure for more information. You might have a junk drawer full of old cell phone chargers—those will work great. You can also purchase wire at hardware or some craft stores. Cut three pieces of wire, each at least 10 centimeters long.
Have an adult use scissors or a sharp knife to shave about one centimeter of insulation off the ends of each wire, exposing the metal inside. There is also a special tool to do this called wire strippers. You or an adult can use those if they are available.
Disassemble your flashlight. Remove the batteries. Caution: Electricity from wall outlets is very dangerous and can be deadly. Never cut into a wire or open an electronic device while it is plugged into a wall outlet. Procedure Examine the inside of your flashlight and try to trace the circuit. Remember that electricity requires a closed circuit to flow.
Can you find the circuit? Your first goal is to use two wires to connect the battery compartment directly to the bulb. This might take some tinkering on your part—not all flashlights are the same. Is it difficult to create your own new closed circuit? Use electrical tape to attach one end of a wire to the metal parts on each end of the battery compartment. Make sure to squeeze the wires on firmly so they make good contact.
Tip: If the batteries just slide into the flashlight body—rather than being held in place by clips or springs—use rubber bands to hold them together end to end when you remove them from the flashlight. Now search for two metal contacts on the bulb housing and connect the other ends of the wires to those with electrical tape. Tip: Sometimes the entire inside of the flashlight case is metal, and this serves as one of the contacts.
Were you able to create a circuit and make the bulb light up? If you made the contacts correctly, this should cause the bulb to light up. If the bulb does not light, don't worry!
There are a few things you can check: You might have an LED flashlight. If you have two pieces of a material of the same thickness but one is shorter than the other, the shorter one will conduct better because the shorter piece has less resistance, in much the same way that it's easier to force water through a short pipe than a long one. Temperature also affects conductivity. As temperature increases, atoms and their electrons gain energy. Some insulators like glass are poor conductors when cool but good conductors when hot; most metals are better conductors when cool and less efficient conductors when hot.
Some good conductors become superconductors at extremely low temperatures. Sometimes conduction itself changes the temperature of a material. Electrons flow through conductors without damaging the atoms or causing wear. Moving electrons do experience resistance, though. Because of this, the flow of electrical currents can heat conductive materials. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile.
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