By Don Lincoln, Ph.D., University of Notre Dame
Perhaps, modern life is so entangled with electricity that the whole matter is taken for granted. People switch on lamps and other electric devices, thinking once the circuit is connected, one electron jumps from the switch to the lamp at the speed of light, and the lamp is on. They are very wrong.
How does electricity work? In simple words, electricity is the result of a string of electrons moving in place and pushing the other electrons, hitting them against the next. However, the common belief is that electrons actually zoom around, move from one place to another, and carry the electric charge. To understand this, you should first learn about myths about electricity.
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The Speed of Electrons
In the example of turning on the light, there is no delay between flipping the switch and getting the light from the lamp. Even though some people believe electrons move at the speed of light, but that is not supported by science.
If electrons want to move in a wire, they have billions of barriers ahead: other atoms and electrons. For example, a copper wire is a string of copper atoms sitting in place and not moving that much. Some electrons around each atom can move around freely and jump from one atom to the next. These electrons make the electrical current happen. When a battery is inserted in a circuit or a lamp is switched on, the electron moves forward but immediately gets hit by the next atom and is deflected. This keeps happening, so the electron cannot move forward easily. Thus, the speed of an electron in a typical household wire is less than a tenth of a millimeter per second. In other words, it takes ten seconds for an electron to move one millimeter.
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In a simple six-inch flashlight, an electron has to travel 12 inches, or 30 centimeters, to make a whole-circuit trip. That will take 50 minutes. In a normal room, the electron has to move around ten meters, and this will take 28 hours. Still, electric devices work immediately.
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How Current Is Created
In a battery, the current is created with the movement of electrons towards the wire. However, as explained in the previous section, electrons cannot move quickly because of all the wire atoms.
When the electron moves outside the battery, it hits another free electron in the wire. The newly-hit electron moves forward and bumps into the next electron, and so on. Thus, the current is the result of electrons moving in place and hitting their neighbors. This means all the electrons in the wire remain where they were, and no electron is actually thrown out of the chain.
So, why do circuits work so fast? An example will make it easy to answer. If a train carrying 100 cars and an engine in the back starts moving, it takes a long time for the engine to get where the first car is. However, the first car starts moving almost as soon as the engine does, because the push from the engine is transferred through all the cars to the first. The same thing happens in a circuit with electrons.
The electricity in a battery is different from that of the house. The battery always pushes electrons out of the negative side. But in a house, the electricity is pushed and pulled back all the time over and over again. In the United States, electricity is pushed and pulled into a house 60 times per second. In Europe, it happens 50 times a second. Other countries use one of these standards.
Regardless of the type of electricity – battery or commercial – what happens is that the electrons do not run around the wires and circuits. They just send the movement energy to the first electron in the, and the current is created.
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Common Questions about How Electricity Works
Electricity is made at a generating station by huge generators. The generated current is then pushed through wires to the smaller networks of houses. When a lamp is switched on, this is how electricity works: the electrons start shaking in place, and, consequently, create the current.
Electricity is the result of movements in a string of electrons. Despite common belief, an electron does not move all the way on its own to make the current, since it keeps bumping into the surrounding atoms and is pushed back. However, the movements go all the way to the end of the line, create the current, and make electricity work.
Electric charge is the result of excess or insufficiency of electrons compared to protons. Electrons are referred to as the negative charge and protons as positive. Currents are created in circuits as a result of this imbalance of negative and positive forces. Electric charge is the fundamental explanation for how electricity works.
Benjamin Franklin discovered the electric charge and named the positive and negative charges. Even though his famous kite experiment is scientifically impossible, his other experiments did result in the discovery of charge in the 18th century. Based on the definitions of charge, how electricity works can be explained.