A form of energy carried through wires and used to operate machines.
What is electricity?
To understand electricity, we first need to take a look at the atom.
Atoms are the building blocks of all matter. They are so small that you can't see them with the naked eye. Atoms contain three basic parts — protons, neutrons, and electrons. The electrons orbit like tiny little planets around the protons and the neutrons.
Electrons are negatively charged particles. Because electrons are constantly moving they sometimes move right off of one atom to join other atoms.
Some materials give up their electrons easily. You have probably seen this happen. It is called static electricity. That little spark you sometimes see when you pull towels apart after removing them from the dryer is an electron hopping through the air. Or the zap you get when you touch other people after walking across the carpet. That is static too. Lightning is just a much bigger version of this same thing.
Did You Know?
The first power plant in the United States was owned by Thomas Edison and opened in New York City in 1882.
There are currently over 100 nuclear power plants operating in the United States.
Arco, Idaho was the first community in the U.S. to get all of its power from nuclear energy. This happened on July 17, 1955. The Idaho National Laboratory has a first-hand account of the event by the people who made it happen.
Benjamin Franklin did not invent electricity. He just found out that lightning was actually a form of electricity.
Lightning is not just for rainstorms. It has been seen in volcanic eruptions and forest fires too.
Static is actually electricity. It is the energy created by moving electrons. It isn't very reliable, however. It comes and goes. It is dependent on the amount of moisture in the air and so many other things. It would be hard to power your computer by rubbing your feet across the carpet.
Current electricity refers to the electrons as they move through the wire, and it is the form of electricity we use for power. It is only when the electrons move that they provide electricity. When the movement stops, the electricity stops too.
Imagine being in a long line to go to a movie. When you get in at the end of the line and the front person goes in to see the movie, the line moves. But if no one goes in, then the line no longer moves. Electricity functions in a similar way. Electrons are being added to the end of the wire, while other electrons get off at the opposite end. This is current electricity. But it moves so much faster than the line at the movie. It moves at the speed of light — 186,000 miles per second.
Current electricity is generated in huge amounts and sent through wires to be used to power televisions, vacuums, lights — well everything that we use electricity for.
In order to make electricity useful, it must flow like a stream of water. That means it must always be available when we want it. We don't want to wait to watch television until someone creates some electricity and then run the risk that they didn't make enough to last to the end of our favorite show. We expect that when we flip the switch in a dark hall, the lights will come on. To ensure electricity is available when we want it, the power companies are always making it — and in huge amounts.
In the early 1800s scientists discovered that if a piece of copper was moved quickly past a magnet, an electric current can be generated. Electrons were being encouraged to move. From this discovery, the generator was created. Many modifications have been made to the original invention to make it work in today's world.
A generator is a coil of copper wire that is usually spun inside of a magnet using some other form of energy, such as water, wind, or nuclear power. The electricity that is created is then sent on huge wires to homes, schools, stores, factories, and any other place where power is needed. But the electricity is in such a huge, huge voltage that it would blow up your television, not run it. So the power company changes it before it reaches your home.
How Electricity is Generated Today
To drive the generator to spin, takes a lot of energy. This energy must come from some other source other than electricity. So how do power companies spin a generator?
Electricity is made in different ways depending on the resources available in the location where they are creating the electricity. Where rivers are plentiful, the energy of the flowing water is stored behind a dam. The pressure of the flowing water can be used to turn the turbines that spin the copper wire within the magnet.
In some areas, coal is burned to heat water and create steam to turn the turbine
Wind can turn huge blades on a windmill structure to turn the turbine. These are called wind farms.
And in still other locations, nuclear energy is powering the generators. The process of splitting atoms apart creates huge amounts of heat that can be used to power turbines.
Some matter gives up its electrons easily. These materials have the ability to conduct electricity. Copper is one of those materials. For this reason, it makes a good conductor. Copper is used in wiring for this reason. The wiring in your house and the cords to your appliances are copper.
Some matter does not give up its electrons easily, so it does not conduct electricity. These are called insulators. In some cases, they even work to stop the flow of electricity. Electricians use tools covered in special materials such as plastic or rubber to insulate them from electricity.
The word circuit is related to the word circle. For electricity to be able to perform the job of powering something — also called the load — it must move in a complete circle. Electrons move down a wire, then into, for example, a TV ("the load"), and then back out again. If you remember the line for the movie talked about above, as one person goes into the movie, another one gets in line. The process repeats over and over. That is why electrical cords have two prongs; one for in and one for out. Batteries have two terminals for the same reason.
A battery is a self-contained source of electricity. Usually, it has some sort of acid inside that reacts with a type of mineral in order to get the electrons moving. The electrons move out of the terminal of the battery marked with a minus sign, move into the load (the flashlight, the toy, the remote control, etc.), and then the electrons cycle back into the battery at the terminal marked with a plus sign. Remember, for electricity to work it must make a circle.
When electricity makes a complete circle, the circuit is called "closed," and electrons can travel the circuit. When some part of the circle is broken, then the circuit is "open," and the electrons cannot move. A switch can be the reason a circuit is broken. When you turn a light out, the connection in the wire creates a space in the circuit. When you turn it back on, then a complete circle is created. It works similarly to a door. Switches are only one reason a circuit can break. A severed wire, a burned-out light bulb, or a bad connection can also create a broken circuit.
Volts, watts, amps, ohms — it can be very confusing to understand the language of electricity. To explain these terms, it might be easier to compare water in a garden hose to electricity in a wire.
Amp or ampere — the amount of electrons flowing past a given point in a second — compare that to how much water is coming out of the garden hose.
Volt — the amount of push behind the electricity — like how much pressure is behind the water in the hose or here, behind these rocks
Watt — voltage times amps — a certain size of a garden hose is required in order to get so much water.
Ohms — resistance — think of this as drag or friction.
Series and Parallel
There are two basic types of circuits: series and parallel. In a series circuit, the loads are all lined up in a row on the circuit. Think about Christmas tree lights. They all light when the circuit is closed.
But if one of the bulbs burns out, then none of them might work. That is because the burned-out bulb has created an open circuit. It would be very inconvenient to wire your house in series. When you turned out the light in your bedroom, the television in the living room would shut off and so would the refrigerator in the kitchen.
So houses are wired in parallel. Even some Christmas lights have been made in parallel so you can find the burned-out bulb. In parallel circuits, the wire has a secondary possible route to let power move around each load. That way you can turn things on and off independently of one another.
As interesting as electricity is, be aware that it is also very, very dangerous. Our bodies run on electricity too. That is how our brain communicates with our nerves, and it is what makes our heart beat. If we mess with the amount of electricity that runs these vital processes in our body, we can really disrupt how they function.
The electricity found in your average bolt of lightning has killed many people. Lightning can have over 100 million volts. Compare this to the power in your home which is only 120 volts. People can die just as easily from the electricity in their house or in wires running from power lines overhead in the backyard.
Never play with electricity!! Doing science experiments under the supervision of your science teacher is not actually playing. But always follow directions for your safety. Here are some safety rules that will keep you and your family safe.
- Don't stick foreign objects in the outlets.
- Don't use electrical appliances in or around water.
- Stay away from power lines — watch kites and ladders.
- If you see frayed wires on a power cord, do not use the appliance, but have it repaired.
- Don't put rugs over the tops of power cords.
- Don't plug too many things into an outlet or power strip.
- Don't try to get things down that have gotten too close to a power line. Even if your cat gets stuck in a tree let the people from your power company or animal control help you.
Top 10 Questions
Thanks to John Gardner, Professor of Mechanical and Biomedical Engineering, Boise State University; and Kip Sikes, Operation Analysis and Development Manager, Idaho Power for the answers.
What amount of electricity does the average person in the U.S. use in a week?
We think of this in terms of horsepower. The average household uses 1.6 horses every second. It's like a constant horse riding around. That's how much electricity we are using all the time. (From Joel at Dalton Gardens Elementary School in Dalton Gardens)
How do clouds get electricity?
Lightning is a natural phenomenon that happens as the clouds move through the air. The atoms and molecules in the air and the water in the clouds have free electrons that get exchanged as the clouds move through the atmosphere. The electrons build up on the clouds and need a place to go. They'll usually go to the closest spot that's of a different charge level. That's usually why lightning will hit a tree. It happens in the atmosphere as a course of everyday events. (From Ryan at Dalton Gardens Elementary School in Dalton Gardens)
How does electricity travel?
There is more than one way electricity travels. Normally, we think of it traveling through a conductor, or a wire, where the electrons bounce and push each other through. Electricity can also be stored. A battery can be used for this. Overall, for electricity to flow, a circuit is needed that allows for a complete connection circle all the way around to the source. (From Megan at Valley View Elementary School in Boise)
When was electricity discovered?
We're not sure. A lot of understanding of electricity came about in Europe in the 1700s. Many of the scientists who made some of the discoveries have names that are associated with electric terminology. A volt came from the scientist Volta, and amps came from the scientist Ampere. It was over a period of hundreds of years that people studied or investigated electricity. In the 1800s, Thomas Edison created a grid that allowed the electricity to be sold to the people of New York City. (From Charlotte at Valley View Elementary School in Boise)
How does electricity end up in everyone's home?
Electricity is produced by a generator that has wires in it. It gets to your home through this series of wires, called a grid, that run between states or throughout your region. (From Tyler at Cynthia Mann Elementary School in Boise)
How fast can electricity travel through water?
If it's pure water, electricity won't travel through it at all. It can't, because the water acts like an insulator. Small impurities in the water, like tap or river water, conduct electricity. Impurities, like salt, are really good at conducting electricity. Impurities will allow more and more electricity to move through the water. When electricity flows, it flows at a speed close to the speed of light. This is very, very fast. (From Yoshi at Valley View Elementary School in Boise)
Why is it that when you rub your feet across the carpet, you make electricity?
It has to do with static electricity. When you rub your feet across the carpet, your shoes act as insulators. As electrons build up on your body, you get a charge of electrons that's different than somebody else. So, the more you rub, the more electrons transfer to you that you can't get off until you reach out and touch someone. Zap! That zap that you feel is a little mini lightning bolt and that's why it hurts. (From Owen at Dalton Gardens Elementary School in Dalton Gardens)
How does tidal power work?
Tidal power is similar to hydroelectric power that we are more familiar with in Idaho. The water is held up by dams and it gets higher and higher above the level of the river. We use gravity to move that water down to the level of the river. While it's on its way through, it spins a turbine that generates power. With tidal power, sometimes the tides will rise and fill the water behind a dam. They'll close the dam off, and then it looks like a hydro dam. Sometimes, if the tides are coming though a smaller area, like a river, they'll put propellers underwater, anchored to the floor of the river. The tide will move past the propellers and the flowing water moves the propellers, spinning a turbine that turns the generator. (From Kendall at Valley View Elementary School in Boise)
What creates the electricity in solar panels and lightning?
Solar panels are basically made of sand or silicon. As the sunlight hits them, the electrons get excited. Gates are used to let the electrons out in just one direction, which creates the current. The electrons then bounce out of the solar panels. Lightning is actually static electricity. As clouds rub against the atmosphere, charges build up that are different between the cloud and the earth. Once there's enough difference in the electrons, the positive and negative charges, the air is ionized. This creates that big zap that allows the electrons to go through the air and down to the ground to balance out the charges again. (From Ryan at Cynthia Mann Elementary School in Boise)
What properties of metal and bone make them great conductors of electricity?
Free electrons make a good conductor. A good conductor is something that is made of atoms that have a lot of electrons that can move from atom to atom without a lot of resistance, meaning they can move easily. If you have a piece of metal or bone, it doesn't mean electrons are moving through them constantly. It takes a difference in voltage to make them move. If you can push the electrons and they can move easily, that's what makes a good conductor. Something that's an insulator is where the electrons are bound very tightly together and don't move. Even if you push on the electrons, they are going to stay in place. (From Moses at Valley View Elementary School in Boise)