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Friday, July 2, 2010

Part II: The Current Debate

See Part I: The Current Debate under the May 2010 heading
See Part III: The Current Debate -The Electro Chemical Impulses of the Body under the July 2010 heading

Part II: The Current Debate
How Electricity Works at the Atomic LevelBy Robin Strom-Mackey

I started this project with a couple of different, seemingly simple goals in mind. To figure out how electricity works so that I could figure out what EMF detector to buy; so that I could more effectively hunt ghosts! Oh sure, it sounds simple. Little did I know that my simple premise would take me on a monumental quest through the pursuit of so many disciplines in order, only now, to start being able to connect the dots. The obvious place to start this search was in Ghost Hunting manuals, but while they offered a recommendation or two about models, not one of my fellow, yellow-bellied authors provided any real explanation as to how they worked, or why one model might be preferable over another. Since then I’ve perused chemistry textbooks to figure out how the atom works; Anatomy and Physiology texts to find out how electrical impulses worked in the body; Psychology texts, where I learned for the first time about how closely related all electro-magnetic energy really was; technology sites where I studied how household current works and why it’s different from DC current, which is the current in your cell phone battery or flashlight.

In this second article in my series I’ll explain the composition of the atom, how the atom works to create electricity, and how electricity actually works in the human body. In other words, this article is likely not only to excite your inner geek, but to have her braying Handel’s Messiah. So strap on the thinking caps, ghost hunters, because we’re goin in!

Ah, the Atom
I know, at this point you’re wondering, "if I’m not a chemist or biologist, why would I possibly care about the makeup of the atom?" (Or maybe you’re wondering, what in the bloody, blue blazes an atom even is?) The reason I discuss the atom at all, is because it all  starts from here. I will be brief and make this as painless as possible. So here goes. A working definition of an atom is that an atom is the smallest unit of an element that displays the properties of that element. So, for example, an atom of aluminum would be the smallest unit of aluminum you could have that would still display the properties of aluminum.
All matter is composed of atoms, and until recently, they were believed to be the smallest particles of matter. (Quantum physicists now believe the atom can be broken down further, but that’s a discussion for a different day.) Atoms are so tiny that you really can’t see them even with the strongest microscope. The atom itself is comprised of three particles, protons, neutrons and electrons. Protons are fairly large, (by atomic standards – which is to say that they’re really tiny) and fairly heavy and all protons have a positive charge. Neutrons are also rather heavy and all neutrons have a neutral charge – or no charge at all. Now the protons and the neutrons are fond of one another, and they reside in close proximity at the center of the atom which is called the nucleus.

Think of a baseball in the center of a football field. That baseball is the nucleus of the atom, residing in the center of the atom with all that space around it. And that space is inhabited by another type of particle, the electron. Electrons are small, light weight particles with a negative charge. They literally whir around the rest of the football field, pinging and poinging all over. Remember how magnets work, the positive end of the magnet is attracted to the negative end of another. Atoms work like magnets. The positive protons at the nucleus are what attract and hold the negative electrons which otherwise would just dance off into space.

Atoms prefer having a balanced charge. In order to be balanced the protons and the electrons are equal in number. For example, hydrogen, the lightest element, has one proton and therefore one electron; the positive proton being balanced by the negative electron. But, if everything were this simple and balanced we wouldn’t have electro-magnetic energy at all, nor would life be possible. So what happens to disturb the balance?
 
Well, it comes down to those pesky electrons. The electrons dancing around in the football field of our atom reside in what are called electron shells. The shells hold a certain number of atoms only, and according to how many electrons are in the electron shell (or cloud) determines how balanced an element truly is. Think of an apartment building with floors as an example of shells. The first floor (shell) has only one apartment and can house only two residents (electrons). Thus the first electron shell, the one closest to the nucleus, can hold up to 2 electrons. The second shell (or second floor of our atomic apartment building) can hold up to, and no more than 8 electrons.

Atoms are balanced when they have the maximum number of electrons in their electron shells, 2 in their innermost shell, 8 in their second shell or third shell. Therefore, hydrogen is extremely unbalanced because it only has one electron in its electron shell, instead of two. But helium, which has 2 protons and therefore 2 electrons, is extremely stable. In fact helium with its outer shell of 2 electrons won’t react with any other type of element – period. It’s one stable dude.


This carbon atom has 2 electrons in its innermost shell (first floor), but only 4 in its outer shell (second floor), thus it isn't stable (i.e. the super is looking to rent those other four apartments).

So what happens to atoms of elements that aren’t quite  stable? Well, those electrons whirring about their football field in an unbalanced number can do a couple of different things. If the electrons of an unbalanced element, such as hydrogen, meets up with another element that is unbalanced such as oxygen with its outer rings of 2 and 6, (remember oxygen really wants 8 electrons in its second shell, so it’s looking for two more electrons) they might agree to share an electron between them.

Now oxygen would have 7 electrons in its outer ring, so it’s still not happy - until it finds yet another hydrogen atom with whom to share an electron. Voila, we have a water molecule, where the oxygen atom is balanced with 8 in its second shell and the two hydrogen atoms are happy and balanced as well with 2 electrons a piece in their first shells. This is what is referred to as a covalent bond. Covalent bonds are very strong bonds, because the elements involved are all completely balanced. Water is an extremely balanced compound, those hydrogen and oxygen atoms just love to hang around together in the form of H2O. - which is short hand for saying 1 oxygen and 2 hydrogen atoms.
 
But sometimes this balancing act doesn’t go as well as that. Sometimes an atom with a positive charge will seduce an electron completely away from its nucleus. An ion, by the way, is an atom that has lost or gained an electron or electrons. It can go both ways. An atom can lose an electron or two in which case the atom takes on a positive charge – because now the protons outnumber the electrons.

Atoms can also acquire more electrons, so that the electrons outnumber the protons, in which case an atom would take on a negative charge. Atoms that are positively or negatively charged tend to be attracted to one another. They will hang in close proximity forming an ionic bond. But just like the dating couple that just can’t quite make it work, ionic bonds are loose bonds that can be dissolved pretty easily under the right circumstances.
 
Electrons are flighty creatures and can be induced to flit from one atom to another, to another to another. This is what we refer to as electricity. Electricity is defined as “the flow of electrons through a conductor (Malone & Dolter, 2010).” Metals make terrific conductors, in other words it’s not too difficult to get the electrons to move along from atom to atom via a metal element. Think of the wires in your house, encased by the outer plastic layer (plastic does not conduct electricity) is a metal wire.
 
As George Gamow put in his science-popularizing book, One, Two, Three...Infinity (1947), "The metallic substances differ from all other materials by the fact that the outer shells of their atoms are bound rather loosely, and often let one of their electrons go free. Thus the interior of a metal is filled up with a large number of unattached electrons that travel aimlessly around like a crowd of displaced persons. When a metal wire is subjected to electric force applied on its opposite ends, these free electrons rush in the direction of the force, thus forming what we call an electric current (Wikipedia, 2010)."
 
So when these wandering, feckless electrons are given a push they move from one metal atom to another, to another…down the wire. At the end of their journey into whatever device the wire runs, these tiny electrons expend their energy by lighting a light bulb or running the dryer. In order for electricity to work there needs to be a non-interrupted track (circuit) through which the electrons flow and they need a push to get going. If you for instance break the flow, say you flip off the light switch, the circuit is interrupted.

Electrons will stop flowing when an interruption occurs. In the case of a battery, the push comes from electrons moving away from the negative pole of the battery toward the positive pole of the battery. When all the electrons have been pushed through, the battery is dead. In the case of the electricity in your house, the push comes through by way of the electric generator – which was discussed in Article I. Your household electricity is running along the circuit to the ground wire, which is its positive pole. Remember our negative electrons are always seeking out more positive company with whom to hang.

Now a word to the wise. I've grossly condensed and simplified my atomic explanation of how electrons flow to create electricity because most of us are ghost hunters, not electrical engineers (although I ghost hunted for awhile with an electrical engineer (who would in all honestly probably break out in hives at my simplistic explanations). But there it is in an atomic shell, electricity is nothing but feckless electrons movin on down the road.

References
 
Hockenbury,D.H., Hockenbury, S.E., (2010) Psychology 5th Edition. Worth Publishers: NY, New York.
Malone, L.J, Dolter, T.O. (2010). Basic Concepts of Chemistry; Eighth Edition. Wiley and Sons, Inc.: Hoboken, NJ
Marieb, E.N., Hoehn, K. (2009) Human Anatomy and Physiology; Eighth Edition. Pearson Education, Inc.: San Francisco, CA.
Physics: Electric Current Through Various Media Downloaded July 2, 2010 from Wikipedia at http://en.wikipedia.org/wiki/Electric_current




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