The discovery and implementation of electricity in our lives is an amazing thing which has greatly increased our quality of life. But to many Americans, it is nearly as mysterious as when it was first introduced. What is electricity? How to we produce it? Why does it shock us? Demystifying this wonderful phenomenon is a great way to better appreciate the engineering responsible for so many of our modern comforts.
- What is Electricity?
Electricity is the flow of electrons. If you will remember your high school sciences classes, matter is made up of three basic particles. This is an over simplification, and we have identified smaller particles which make up these three major ones, but the model still works fairly well. Protons, neutrons, and electrons. Protons and neutrons make up most of the mass of an atom, while electrons are miniscule particles with a negative electric charge. This electric charge is how they interact with other particles. In metals, these electrons end up flowing freely in what is known as a sea of electrons. The protons and neutrons stay in the same place, but the electrons are able to move. We are able to make electrons move, by subjecting them to electromagnetic fields. If you take a magnet and run it the length of a wire, electrons will tend to be pushed along by the electromagnetic field around the magnet. If they don’t have anywhere to go, they will return to their original positions. But, if you create a circuit, you can create flow of electrons, where they are constantly moving down the wire. This movement can then be captured by electrical engines. Just how a turbine can capture the movement of water or wind and turn it into energy, the same is true for electrical motors and the flow of electrons.
- Why does it shock us?
Electric shocks are the product of two separate properties of electricity. The first, is that electricity (like all other natural things) naturally seeks its lowest energy state, and will take the path of least resistance. This is why water flows downhill. Because gravity is acting on it, it has lower gravitational potential energy if it is at the bottom of the hill than the top. This means that when electrons are flowing, they will always take the path of least resistance to a lower energy state. An electric shock is caused when the path of least resistance happens to be through a human body. If you touch a wire, and the electricity can flow through you to a ground, it will. The damage is done by the high amount of energy present in the electricity. This is why a battery is much less dangerous than a bolt of lightning. The amount of energy present in each (and thus able to flow through you) is very different.
- What are those electrical words?
A layman has almost certainly heard words like current, voltage, amperage, or resistance before. But very few laypeople understand what they mean. There are often misconceptions surrounding them as well, such as the idea that one (current or voltage) is more dangerous than the other. So here is a quick breakdown of these terms. Current (measured in amps) is related to the amount of electron flow in a circuit. If we are to use the analogy of a river, current is the amount of water which is flowing. Voltage, on the other hand, is the difference in electrical potential between one side of the circuit and the other. This will determine how quickly the electrons flow. In our river example, this would be the steepness of the grade. In order to receive a harmful shock, there will need to be a enough voltage and current for the electricity to jump through you, and be harmful. Finally resistance is a measure of the amount a wire will push back against the flow of electrons. A high resistance means that more energy will be needed for the electrons to flow. The natural resistance of our skin can help to protect us from lower energy shocks: this is why you generally wont get a shock by touching two sides of a battery simultaneously.
Mastery of these natural forces is the driving force behind most of our modern comforts. Travel, communication, entertainment, food production, safety, medical procedures, and scientific research all rely on our taming of this powerful natural force. I hope that this article was able to better explain some concepts which you may not have understood beforehand. With that said, this was just a brief overview, and to truly understand the principles and mathematics involved, you would need a much more in depth explanation. Next time you plug something in, take a moment to appreciate the intricate design involved with that simple act.