What is electricity?
To understand electricity, we first need to take a look at the atom.
Atoms are the building block 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 the electrons are constantly moving they sometimes move right on off of the 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 a huge 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. Click here for more Information.
Benjamin Franklin did not invent electricity. He just found out that lightning was actually a form of electricity.
Lightning is not just saved for rainstorms. It has been seen in volcanic eruptions and forest fires.
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 is how we use the electrons as they move through wire. It is only when the electrons move that they provide electricity. Whenever the movement stops, we have no power.
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, that the lights will come on. So 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, then an electric current can be generated. Electrons were being encouraged to move. And 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 energy. The electricity that is created is then sent to homes, schools, stores, factories and any other place where power is needed on huge wires. 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 to work in 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 reaction of splitting atoms apart creates huge amounts of heat that can be used to power turbines.
Some matter gives up its electrons easily. These things 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 electrons easily and so they do 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, into the tv (load) for example, and then back out again. If you remember the line for the movie talked about above, one goes into the movie, 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 they have some sort of acid inside that reacts with a type of mineral to move electrons. The electrons move out of the terminal of the battery marked with a minus sign, move into the load (the flashlight, the toy, or the remote control) and then the electrons cycle back into the battery at the terminal marked with a plus sign. Remember, for it to work it must make a circle.
When a circuit makes a complete circle, it 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 for a circuit to be 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 similar to a door. Switches are only one reason for the circuit to be broken. A broken wire, a burned out light bulb, or a bad connection can 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 use water in a garden hose as a comparison 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.
Watts – 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. Learn more about how electricity is measured here.
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, for example has killed many people. Lightning can have over 100 million volts. Compare this to the power in your home which is only 220 volts. People can die just as easily from the electricity in their house or in wires running from power lines overhead in the back yard.
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 power company or animal control help you.
Check out this site for a fun way to learn about electrical safety. Click here.