What Is Electricity? An Introduction To Scientific Magic
Electricity is an amazing thing, and it is more amazing that we are able to direct it in such wondrous ways. We can direct it and use it in massive quantities, driving electrical power across the entire globe, and yet at the same time we can harness its same power into millions of little tiny logic gates in a one inch processor. Electricity is behind some of our most powerful machines, and its behind all of our modern “thinking” machines, being those that can calculate. The funny thing to me, is that we can’t really experience electricity except as side effects. What I mean by this is that we might be able to see a lightning strike, or feel electricity course through our flesh (hopefully not killing us) but we can’t really hold, or touch, electricity say in our hands as a “physical” object. This is partly because electricity works on such a microscopic level, truly between atoms and the things that make up atoms, and partly because electricity is a form of energy. When you think of energy, you might be inclined to think of vibrational energies of consciousness, or feel good energy from a musical performance, but what I mean by energy is that which can manifest in a force. A big anvil suspended in mid air about to fall has a lot of potential energy, yet that energy isn’t something we can, again, see, hold, or touch. When a car goes from zero to sixty in three seconds, it’s expending a lot of energy to move its huge metal body, and although we can see the car move, we can’t see, hold, or touch the energy acting upon it. In this sense, energy, and much of the elements that make up a study of electricity, are both concretes and abstractions. It is a concrete in the sense that it does exist in our physical world, to a degree, but abstract in the sense that we have to construct an understanding of it in our minds since it is invisible.
This is somewhat difficult for me personally, because I have attuned and trained myself to deal with many things purely as abstractions. Understanding something where the relationships between the abstractions are mitigated by their placement and function in a physical space, their nature, has proven somewhat, well, hard for my brain to grok. The reason my ideas of how abstractions work and connect to each other is such this way is because I’ve spent my life learning and understanding systems of computer programming. In computer programming everything is an abstraction, and no particular abstraction has any “real life” counterpart other than, what programmers term as “physical”, written expressions of code. Understanding the relationship between completely abstract things, being purely abstract relations, is easy for me. Understanding and learning the relationship between abstract concepts where the relations are determined in physical reality is a new experience.
However, I want to build electronic devices not only to be autonomous entities such as robots, but to “augment” to a degree my normal human functioning. If I want to build a robot, I’m going to have to learn how electricity and circuits work, particularly integrated circuits and such. If I want to build my own eye tracking augmented reality headwear, knowing how to connect diodes in circuits and displays to microcontrollers is going to be a necessity. So, I’ve decided to endeavor here to explain how electricity works from the perspective of someone who is learning it for the first time. I hope I’m able to somewhat succeed.
Ancient people were scant aware of electricity as we are aware of it today. The closest they came to experiencing or identifying anything as belonging to category of what we’d call “electric” were lightning and the shocks from electric fish. Though the connection between lightning and these eels and such was weak, the Egyptians did refer to these creatures as “Thunder of the Nile” in texts dating back to 2750 BCE. However, the Arabs made a more direct connection linguistically before the 15th century where the word for lightning (رعد) was applied to the electric ray. However, of most import was the Greeks and other cultures around the Mediterranean who observed that amber, rubbed with fur, possessed strange properties. This strange property was of course static electricity and its mild magnetic effects, and was studied by Thales of Miletus. However Thales failed to ascertain the electrical background present in this phenomenon.
It was until the 1600s that electricity was identified or even coined as a word, funny enough, since the word has greek roots. William Gilbert of England also studied much the same phenomenon that Thales studied, but was able to ascertain that there were two effects present: the lodestone effect and what we now know as static electricity. It was Gilbert that coined the word electricus (deriving from the Greek word for amber ἤλεκτρον, pronounced electron.) In 1646 the word was “canonized” in the work Pseudodoxia Epidemica by Thomas Browne, and now we have the words electric and electricity.
First Steps: Charges
The first step towards understanding electricity is to understand what I call charge. Other people call it charge to, but sometimes the word is used in another context. In this context I’m simply describing a measure that something can have. Charge exists on a continuum between two poles: positive and negative. In the middle, there is no charge:
In general, these two charges hole a special relationship with each other, and themselves. The idea here is that opposite charges attract, and like/same charges repel. This true in electricity, the structure of an atom, and magnetism, which are also all related. You can picture this relationship in the following diagram:
So in essence, things, particularly particles, have a charge. That charge is either no charge, positive charge, or negative charge. Differing charges, being opposite on the continuum, attract each other, and like or similar charges repel each other.
Historically this was discovered and codified by Charles-Augustin de Coulomb. A conductive ball suspended from a string can be charged by touching it with a charged glass rod (achieved by rubbing it with a cloth). If a similar ball is charged by the same rod then both balls have the same charge, and when brought close to each other they repel each other. However, if one of the balls is charged in a similar fashion with an amber rod, both balls move towards each other. In essence, the “opposite” charge from the amber causes the balls to attract. This inspired Charles to declare that charge comes in a opposite facing continuum, as we have shown, and the axiom that “like-charged objects repel and opposite-charged objects attract.” In fact, there is a mathematical construct known as Coloumb’s Law that describes the forces that are affecting these balls in relation to their charge. This force, that attraction of repulsion, is also called electrostatic force. I hope to cover Coloumb’s Law and static electricity in another article.
Understanding charge can help us understand the medium of electrical current, that is, atoms, and the particles that make up those atoms.
Electricity as we know it has its origins in atoms. To understand how electricity as a force flows or exerts any kind of force, we must understand the medium, or material, through which electricity operates. Atoms have a long history dating all the way back to the ancient Greeks and Indians. Way back in these days philosophers were still trying to figure out what exactly were the physical things in our universe made up of? The “physicists,” or as commonly known, pre-socratic philosophers rejected mythological explanations of natural occurrences, and broke off from the theologians of the time. They wanted to answer questions about natural reality through rationality and asked many questions including, “Where does everything come from?” and “How is everything composed?”
Thales, the father of Greek philosophy, declared water to be the composer of all things, but Anaximander later came to assume an undefined unlimited substance without qualities from which opposites emerged, such as hot and cold. Anaximenes decided air made up all things, thickening and thinning to form material objects. Heraclitus of the Ephesian school decided all things existent were in perpetual flux, connected by a pattern known as Logos. To him, fire was the primary element of this pattern. Then came Empedocles, asserting that there were multiple elements at play being air, earth, fire, and water. Anaxagoras decided that all these were ordered by reason, or a kind of divine mind. You can see the struggle was real.
Finally a man named Leucippus and his pupil Democritus came along and decided that matter was made up of atoms. Atoms comes from the Greek ἄτομον meaning indivisible. These atoms were philosophically to appear in an infinite variety of shapes and sizes, but their distinct characteristic was their indestructibility and immutability. They were surrounded by a void of nothingness, and in this void they collide with other atoms or combined to form clusters. Philosophically brilliant, and scientifically very close, this was the doctrine of atomism. It should be noted as well that Democritus should not be the only person accredited with atomism, there were many schools in ancient India as well that were arriving to such conclusions including the Jain, Ajivika, Carvaka. The Nyaya and Vaisheshika schools later developed these notions to include the combinations of atoms into more complex objects. There were thoughts of atomism as well in Islamic history, such as in the Asharite school of theology. Atomism is not necessarily the sole domain of greek philosophers, but Democritus was one of the earliest historical figures to really capture the idea in whole.
The dark ages saw a rejection of atomism philosophically, and unfortunately, the theory and its works were almost lost entirely were it not for a few men responsible for the rebirth of atomism in the 16th century. Such famous scientists and philosophers as René Descartes, Pierre Gassendi, and Robert Boyle advocated and entertained atomism. It’s funny really, the Northumberland circle which revived the classical form of atomism was considered part of the avant-garde, and not necessarily totally accepted. Francis Bacon became an atomist in 1605 but later rejected some of its claims. Galileo became an advocate of atomism in his 1612 discourse on floating bodies, and later offered more information and elaboration on atomism in The Assayer where he proposed a corpuscular theory of matter.
Further philosophical work continued on atoms until the seed of what we now know as the atomic theory, which is evidence based, was proposed by John Dalton in 1808. He had attempted to gain empirical evidence on the composition of matter and noticed that distilled water became hydrogen and oxygen in the same proportions. This was empirical evidence of earlier mathematical theories proposed by Roger Boscovich who built upon the ideas of Newton and Leibniz. Dalton’s work was controversial through the 19th century up until the 20th century with the rise of atomic physics.
Joseph von Fraunhofer was studying spectral lines, omissions or additions in a continuous light spectrum resulting from emissions or absorptions of light in a narrow frequency range, and his work led to the development of the Bohr atom model and the birth of quantum mechanics. From there, scientists have revised and developed the atomic and quantum models of matter to form what we have today. It is fascinating to see how man was able to intuitively devise and “see” a framework for matter in philosophy and even spirit, only to have it “come true” so to speak with much greater evidential analysis.
So what makes up an atom? Atoms, in the simplest sense, are a collection of charged particles consisting of electrons, protons, and neutrons. What exactly a particle consists of, or how it behaves, as a mass or a wave, is a whole other topic, but for now you can imagine them as I do when I think of atoms: little tiny itty bitty balls of mass-energy. Electrons are negatively charged particles, while protons are positively charged particles. Neutrons have, as far as we know, no charge.
The idea here is that an atom has a nucleus made up of protons and neutrons, and “orbiting” around them (they make more figure eight paths really), are the electrons, much like a miniature solar system. In fact, electrons form multiple shells around the nucleus, meaning, that in one layer (shell) one or two electrons may be orbiting, and in a further outer layer (shell) six or eight might be doing the same. There are very specific rules to how many shells an atom might have, and how many electrons they contain, and is offered as interesting further reading.
A usual atom in balance has equal amount protons as electrons. This means that the atom is electrically neutral in that the charge of the electrons equals the charge of the protons. The electrons of an atom “left alone” are considered to be in a ground state, being that they are not “excited” and have only what I consider the minimum necessary amount of charge. It’s possible for electrons to gain additional energy from light, magnetic fields, collisions with other particles, and enter into an excited state. Electrons populating a particular shell are in a bound state as well, which is different than ground state. However, the state is so named because you can actually cause an electron to exit its shell by applying an amount of binding energy, thus exciting it and at the same time causing the atom to be ionized (the process in which an atom itself in whole is considered to have a positive or negative charge through the loss of a balancing electron or proton.) Electrons in the outermost shell, those “furthest” away from the nucleus, are considered valence electrons, and the number of electrons in the outermost shell is sometimes referred to as the atom’s variance. This characteristic and information is very useful in chemistry, but have a big of significance to electrical current as we’ll read soon.
You can imagine electrons, protons, and neutrons composing an atom as a bit like the following diagram:
There are many materials and substances in the field out there today. The question becomes what is the smallest indivisible portion of these substances? Answering this question gives rise to understanding exactly what that substance is composed of, no more or less. Some substances are “pure” so to speak, and are composed of a single atom. The atom becomes the smallest indivisible piece of matter still identifiable as that substance. For example, hydrogen is reducible to one atom consisting of one proton and one electron. Oxygen is another substance that is reducible to one atom consisting of 2 protons, 2 neutrons, and 2 electrons. Something that is reducible to a single atom is known as an element. More than 100 elements have been identified. Elements can be categorized on a number of different characteristics, but the most popular categorization is a table of increasing weight (protons and neutrons give an atom most of its weight), which groups them as well into families having similar properties. You may have heard of this table as the periodic table of elements.
Some substances, in their smallest form, are made up of multiple atoms, or elements. The simplest and most accessible example is water. There is no “water” element, or atom, instead water is made up of three atoms: 2 hydrogen atoms and one oxygen atom. The atoms are bound together in such a way to form what we know as water. This multiple atom composition, in it’s irreducible form, is known as a molecule. On a side note, when whole molecules are combined or separated from another it is referred to as a physical change. Where as when molecules of a substance are altered to form new molecules it is known as a chemical change. What’s interesting here is that most chemical changes involve positive and negative ions and thus are electrical in nature. In this way, you could say that all matter is electrical in nature. In many ways, we ourselves are electric. That’s a thought.
One of the central ideas of electricity that we deal with on a constant basis in our modern lives is that of electrical current. When people think of electricity, this is generally what they are referring to. Lightning, sparks, what shoots through your body when you stick a knife into a power socket (don’t do that!), what occurs in a large scale circuit such as a lightbulb, or a tiny integrated circuit, is all electrical current.
Electricity in this paradigm or view might be defined as the “force that moves electrons.” This is an interesting definition because it does well to describe an effect, but it fails to truly describe the force. To make this last sentence clear, imagine if we defined a car engine as the “force that moves a car”. We have said nothing about the engine, only what the engine does, likewise we have said nothing about the electromotive force, only what the force does. There are many treatises, particularly in quantum levels, on what exactly this force is, but they’re out of the scope of this article.
This hasn’t stopped a whole cadre of people from determining and observing how this force operates under various number of conditions. Although one may not necessarily understand the force, by understanding how it behaves, or what effects it has, you can harness its power in tremendous fashions without knowing its true identity. Also, for now, we don’t need to worry about where this force manifests or comes from, for now simply imagine its source such as a battery as a black box that produces this force.
When we apply this force to a given substance, let us say a pure element, the idea is that electrons in the outer orbit, or what we identified earlier as the valence electrons, are pushed out of orbit and proceed along the “direction” of the current. Although there are conditions in which protons might move, it is not usually the case, because protons are very heavy in comparison to the lighter electron. The proton in hydrogen for instance is 1,850 times heaver than its corresponding electron. We know that when an atom loses an electron it becomes ionized (losing an electron causes it to become positively charged, otherwise known as a positive ion.) We call this newly unbound electron a free electron. Electrical current has a path, usually a circuit, that establishes a direction for the free electron to move, however, in all cases the free electron moves from one atom to another. This chain of atoms being continually ionized and then de-ionized as electrons move from one atom to another is known as electrical current. This model of electrical current is known as the electron flow model. You might picture this process as the following diagram:
Different substances have different atomic compositions. I the substance is an element, it’s smallest component is a single atom, in which case the greatest variance lies in the number of valence electrons present. Substances that reduce to molecules are much more complex. The general idea is that the more valence electrons there are, the harder it is to move a single electron out of that shell, causing it to become a free electron. In this way, substances can be classified in regards to electricity as conductors and insulators (otherwise known as poor conductors, or nonconductors).
Conductors are substances that allow an easy flow of a large number of electrons. In copper for instance each electron moves from one atom to the next atom forcing another electron out of orbit, repeating the process over and over. The greater the number of moveable electrons in a material under a given force, the better the conductivity of that material. Another way to imagine this is that the material has low opposition to electron flow. Another factor in conductivity is a material’s dimensions, but we won’t worry about that for now. Good example conductors include silver, copper, aluminum and so on.
Insulators on the other hand have a high opposition to electron flow. On an atomic level this may be due to an increased number of valence electrons, making it harder to “pop” an electron free. Examples of good insulators include rubber, glass, wood, bakelite, and such. In order for electron flow to occur in a substance that is known as an insulator a much larger amount of electrical force must be spent than when compared to a conductor.
Since electron flow is known to exist in all matter to one extent or another, no matter how small, there is no actual dividing line between conductor and insulator. Really, it simply is a measure of conductivity. The idea for most electricians is to use the best conductors to carry the electrical current in a circuit, and insulators say around those conductors to protect the flow from being diverted.
Electron flow isn’t the end of the story when it comes to electricity. Electrical current is related to some other phenomenon including the production of heat (which James Joule studied mathematically in 1840), and the “production” of magnetic fields as observed by Hans Christian Ørsted in 1820. Electrical current, and electricity in general’s relationship to magnetic fields and magnetism is very important and will be the subject of another article. It’s quite complex, and deserves more space to be expanded.
This was an introduction to the core aspects of electricity as most people conceive of it. Electricity has many aspects that I hope to expand upon in future articles including charge, current, magnetism, fields, potentials, chemistry, and power. The electron flow model is, I believe, the easiest to understand model of electrical current, but it is a simplistic model. Current efforts in understanding the nature and identity of electricity has led researchers to think of electrical current more in terms of fields of charge, but starting from there would prove too complex for an introduction to electricity.
I hope you were able to find this article useful and thanks for reading!
This article is part of a larger list known as “Electricity: Scientific Magic“
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