Do you like storms? Some people dislike storms, because they fear bad weather will damage their property or health. Others love to watch storms roll in and stand amazed as Mother Nature unleashes her powerful forces of weather upon Earth.
There's one thing, though, that most everyone dislikes about storms: losing power. When the thunder booms and the lightning lights up the sky, most of us wait anxiously for the lights to flicker. When power goes out and we're all left in a dark and quiet world, a collective groan can be heard across entire households, neighborhoods, and even cities!
It's at these times of quiet and darkness that many of us realize how dependent we are upon electricity…and how much we take it for granted. If we were pioneers from a century or more ago, we would be unfazed. Today, though, we often feel lost, unable to do anything but wait for power to be restored.
Although we use and depend upon electricity for most, if not all, of our daily activities, many of us don't have a solid understanding of exactly what electricity is and how it works. In fact, many people's knowledge of electricity begins and ends with a mental image of Ben Franklin flying a kite during a thunderstorm.
Despite not understanding electricity very well, most of us are awestruck when we realize its power and prevalence. Electricity is all around us. In addition to running through the wires of our homes, it's in the clouds in the sky, in the static sparks in our flannel pajama pants, and even running through our bodies in our hearts, brains, and nervous system.
Electricity is a form of energy caused by those tiny, negatively-charged particles known as electrons. When electricity builds up in one place, scientists call it static electricity. When it moves from one place to another, it's called current electricity. Electric currents are what we depend on to power all of those electronic devices we can't seem to live without.
To form an electric current, electrons must flow steadily along a closed path known as a circuit. Circuits usually consist of electrical components connected with wires. The wires and other parts of a circuit are usually made of metals, such as copper or aluminum, which are good conductors of electricity.
Metals conduct electricity because their atomic structure is such that they have free electrons that allow electricity to flow easily through them. Materials with atomic structures without free electrons don't allow electricity to flow freely. Scientists call these materials insulators. Rubber is a good example of an insulator.
Current electricity can be further divided into two types depending upon how it moves around a circuit. If the electrons always move around the circuit in the same direction, that's called a direct current (DC). On the other hand, if the electrons constantly reverse direction at the rate of 60 times per second as they travel around the circuit, that's known as alternating current (AC).
Batteries produce a direct current. Electricity always flows the same direction between the positive and negative terminals of the battery. In general, batteries produce a current at a fairly low voltage, which is a measure of the force pushing the electrons around the circuit.
By way of comparison, the electricity that flows from a power plant to the outlets in your house is alternating current. Alternating current can be generated at extremely high voltages and transmitted over large distances. A series of transformers lowers the voltage of the electricity before it gets to your outlets, so it can be used by the large appliances and electronic devices in your house.
In the late 19th century, Thomas Edison promoted direct current, because he thought alternating current was too dangerous. One of his former employees, Nikola Tesla, promoted alternating current instead, and it was the technology that eventually won out. Despite the fact that it can indeed be dangerous when misused, alternating current revolutionized the world to the point where we can't live without it today!