How Does Electricity Work?
Ask Science talks about electricity: what it is, how it works, and why you need it to turn on a light bulb.
When I was a kid, one of my favorite movies was Breakin’ 2: Electric Boogaloo.
The movie had nothing to do with electricity, and not very much to do with boogaloo either. While the movie didn’t do much for my horrible dance skills, it did give me occasional thoughts about how cool it would be to open up a community center for teens.
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You might be wondering what this has to do with science. Is this a science of dance episode? Unfortunately, it’s just a rather paltry attempt to use humor in introducing the subject of this week’s episode: electricity.
What Is Electricity?
What most people call “electricity” is what scientists call “electric current.” If the first thing that comes to your mind when you hear the word current is a swiftly flowing river or undersea stream of water pushing boats along their course, you’re not far off. Electric current is a stream of charged particles.
There are a few different types of charged particle carriers, but usually when we talk about electricity, we’re talking about electrons. If you remember my episode about atoms, you’ll remember that electrons are the little negatively charged particles that float around the nucleus of atoms.
See also: What Is Static Electricity?
Despite what you may have learned by watching Jimmy Neutron, electrons don’t orbit around atomic nuclei like planets in a miniature solar system. Instead electrons to spend most of their time in specific areas around the nucleus called atomic orbitals. These orbitals have various shapes, depending on how many electrons an atom has, and a couple of other factors.
These atomic orbitals are arranged in layers around the nucleus. For the purposes of electricity, the only electrons we really care about are those in the outer shell, which are sometimes called the valence electrons.
When electrical current flows, what’s really happening is that these valence electrons are moving from atom to atom.
Shields Up
Imagine for a moment that you’ve got a length of wire that is one atom thick in diameter. If you push an electron into one end of that wire (say from a battery), it’s going to try and jump into the valence shell of the first atom it encounters. When this new electron comes in, it pushes one of the valence electrons out of the atom, which moves into the next atom, and the process continues all the way down the length of the wire.
See also: Why Doesn’t Static Electricity Kill You?
You probably know that conductors conduct electricity, while insulators don’t. What you might not know is what makes the difference between an insulator and a conductor, is how their valence electrons behave.
In most insulators, the nucleus of the atom excerts a strong enough pull on the valence electrons that it is hard for them to get pushed out of position. Since the electrons aren’t moving, we don’t get any electrical current.
There are a few different factors that can determine whether something is an insulator or a conductor. One of the reasons that the valence electrons of atoms like copper and silver can flow so freely from atom to atom is that they have so many electrons in their inner shells, that the valence electrons are shielded from the pull of the nucleus. This allows the valence electrons to hop willy nilly from atom to atom whenever a new electron comes to push them aside.
Let There Be Light
Electrons moving around wires are great, but what if we want to use electricity to do something useful, like turn on the light? Well once again, it’s the electrons that are the stars of the show here.
In the case of incandescent light bulbs, as electrons move into the filament, they excite the atoms in the filament causing them to vibrate. This vibration causes some electrons to get transferred to a higher energy shell, but this change is only temporary. After a short time, the electron falls back to its previous level, releasing its extra energy in the form of a photon, or particle of light.
Conclusion
So now you know more about electricity, what it does and how it does it. You also know what makes some things conductors versus insulators.
If you liked today’s episode, you can become a fan of Ask Science on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at everydayeinstein@quickanddirtytips.comcreate new email.
Electricity image, Filter Forge at Flickr. CC BY 2.0. Atom image courtesy of Shutterstock.
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About the Author
Dr. Lee Falin earned a B.S. in Computer Science from the University of Illinois, then went on to obtain a Ph.D. in Genetics, Bioinformatics, and Computational Biology from Virginia Tech.
