Can you explain electricity?

Anyone, please correct me if I missate something:

Electricity is the movement of charged particles, usually electrons, from one molecule to another over a conductive material. Lightning is an electrical discharge from ions in the air created by friction of air molecules in a storm.

Electrical generation is caused by moving a loop of copper wire or a copper disc around a magnet. The movement of the copper around the magnet is done by a turbine spinning by way of falling water, or spun by a windmill, or by an engine that burns fuel. Thus one form of energy causes something to generate electricity, transforming kinetic energy into electricity.

(Solar cells are activate by the sun to excite the chemicals in the panel and release electrons to generate a current.)

So the wind spins the mill in Kansas, excites electrons, and starts the passing of electrons as a current through the wires to Illinois, into your house and into your toaster, which runs through the tiny wires in your toaster and heats them up which toasts your bread.

Your toast that is made from electricity in Kansas that makes it to your pad in Illinois via the connected grid. The grid being the electrical cables that span the nation.

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Thanks, @zenvelo. That was a good jumping in place. I’m here.
I don’t know how I went through HS as an honors student and 4 years of college without learning some of this. Likely I knew enough terms to pass the test without a real understanding. At least I’m not alone…no one that I asked in RT was able to help at all.

Thanks, @kritiper. I have transmission questions, big time, but I’m trying to get a basic understanding first.

Too much, @ARE_you_kidding_me. That volume of information is likely the reason I’m ignorant on the topic.

There is a program on PBS that might air in your area. “The Mechanical Universe” explains the electricity fundamentals very well. That and get yourself on book on the basics of electricity.

Electricity 101:

Start with too many electrons in one place and not enough in another place.

Build a path (wiring) between the two places, but make sure to slow down immigration by putting some sort of restriction (a load, be it a motor, light bulb, toaster or what-have-you) along that path to make those electrons do useful work as they migrate.

Failure to restrict that electron flow will allow unrestricted migration which will cause the path (wiring) to set on fire. A toaster is a restricted flow of electrons that generates just enough heat to toast bread but hopefully not enough to melt itself or burn down your house in the process.

Electricity 201 – Generation and storage:

Any time you have a conductor, a magnetic field, and relative motion between the two, you generate an electrical current. Electrical generators can be spun by an engine, steam turbine, waterfall, bicycle… or a windmill. With a little engineering, you can take any two of those things to make the third. For instance, electric motors take conductors and a magnetic field and make relative motion.

Electricity can also be generated by various chemical reactions. Certain combinations of chemicals allow for electricity to be stored rather than generated. Solar panels often use batteries to store energy during the day for use at night when solar panels don’t produce power.

Electricity 202 – Distribution:

Electric wiring has inherent resistance, so the further you have to transport it, the more voltage (electrical “pressure”) you need. Regular household 120 can go through a 100’ extension cord just fine, but it won’t make the many-hundreds-of-miles trip from the power plant to your outlet; there is too much resistance. That is why long-distance transmission lines pump it up to 50,000 volts or more.

But while high voltage is great for long distance transmission, it’s a little unsafe and requires special precautions, as well as more expensive poles and wires. Normal power lines are just fine in a 20-foot pole or in an underground pipe, high high-voltage lines have a different set of requirements. And if someone slams a car into a utility pole and gets a power line across their roof, you’d really rather it was 440 volts than 44,000 volts!

The best compromise for safety and cost is to utilize step-down transformers at substations that are near where the power is going to be used. Many utility poles have their own stepdown transformers to knock the voltage down further just before sending power to a home.

Excellent, @jerv! I was hoping you’d jump in when I wrote the question.

When you apply electricity to a line/wire, is the entire line immediately energized, or is there travel time?

@ibstubro There is no travel time. What electrons enter the wire, others are immediately displaced along the wire to the end, at the speed of light. (or darn close to it!)
The voltage, as already stated, is the pressure that drives the electrons. The resistance to the flow is measured as ohms, the practical units of resistance, being the resistance of a circuit in which a potential difference of one volt produces a current of one ampere. Amperage is the strength of a current (flow of electrons) of electricity measured as amperes or amps.If I remember my basic electricity classes right, you can’t have current flow if you take away one of these three items: No (ohms) resistance = direct short, circuit fried, fuses blown, no electron flow. No voltage, no pressure, no electron flow. No amps, no electron flow.

@ibstubro Here’s some more stuff for you:
Rules of Current Flow
1. Current always returns to it’s source.
2. Current is never used up or lost in any circuit.
3. Current follows all paths.
Also: Ohms Law; E = I x R, I = E/R (I = E over R), R = E/I (R = E over I)
(E = volts, I = amps, R = ohms)
And then there’s Mhos law, the opposite of Ohms law; Watts law, that deals with horsepower as with electrical motors.

No travel time is what I’d been given to believe, @kritiper, thanks.
The rest is above my current level of understanding.

For anyone thinking this is a silly or stupid or vacuous question, I have asked the same question of several men that I personally know, aged 17 to 70, and none have been able to articulate an answer. All were unafraid of electricity and competent at wiring.

The 17 yo college student told me today that he didn’t believe there was any travel time across wiring because “if you’re holding the end of an electric fence in one hand and you plug it in with the other hand, you’re immediately shocked. Lots of practical experience here in the Midland, little book learning.

I started this out by trying to understand why electricity is so impossible to store.

@kritiper Pretty close. In fact, it may be dead-on and I’m jsut reading it wrong.
Amperage is the amount of electrons being pushed; 1 Amp(ere) = 1 Coulomb of charge (6.2415093 * 10^18 elementary charges, generally electrons) passing a given point per second. Ohm’s Law is accordingly slightly expanded with the addendum:
I = Q / t , where Q equals Charge and t equals time.
As for no resistance, that is basically trying to divide by zero, which allows infinite electron flow… until something gives… which often involves some combination of smoke, funny smells, and pyrotechnics. Read how John Wayland earned the nickname ‘Plasma Boy’ either for more details or just for a laugh. In any event, one of the things I learned in my training is that all short circuits eventually become open circuits, so saying a short circuit leads to no electron flow isn’t wrong.

@ibstubro For practical purposes, it’s instantaneous; the speed of light (186,000 miles or 983,571,056 feet per second) is fast enough to go around Earth about 7½ times every second, or to the Sun in a little over 8 minutes. Given that many circuits are considerably shorter, generally the entire circuit is energized in a micro-second or less, and that’s close enough to “instantly” for a layperson. Assuming about a ten-foot cord, your fence-grabbing friend may have had 0.00000001 seconds at most between plugging in and getting belted.

* * * * *
Now for an explanation of another old saying about electricity, “It’s not the volts that get you; it’s the amps!”. This statement is educational, and quite true. Lets see how;

Scuff your feet across the rug and you’ll build up a little bit of a static charge. It may be 30,000–75,000 volts worth, but mere microamps as the charge is so small and is only a relatively few electrons. E is going to be high enough to actually bridge a small air gap with a spark despite the high resistance® of air, but the amperage (I) will be pretty low simply because there just aren’t enough electrons; once you touch that doorknob, charges are equalized and the most you’ll feel is a little zot.

Now imagine grabbing a high-voltage transmission line. The voltage will be about the same, somewhere around 30–50 kilovolts, but there is one huge difference; until the breaker is tripped or you pull the fork out, the electrons will just keep coming. Power plants and hydroelectic dams have PLENTY of electrons to give, so the total amount of electrons that will go through your fork and your body on their way to electrical ground is limited not by how many you picked up as you scuffed your feet across the carpet, but rather only by the resistance of your body.

How does this really affect you though? Remember what I said earlier about unrestricted electron flow heating up wiring? What if those wires are your muscles and nerves? And since most of the time people are touching the ground with their feet, odds are that those electrons will travel along your arm, through your torso, possibly including your heart, and down your leg on their way to complete the electrical circuit. The human body can handle a little bit of that. The actual effects of electricity on the human body is complex and non-linear, but the simple version is that anything in the micro-amp range (static shocks) is harmless, things in the milliamp range (tasers; stun guns) will cause muscle issues, possibly screwing up the heart’s rhythm, and anything above half an amp for an instant (lightning strike) or one-tenth that (50 milliamps) for more than a second (holding a fork in a wall outlet) will generally cause permanent physical damage… though there is a possibility that you won’t live long enough to see the damage it does.

Too many amps isn’t just bad for people though. Since everything (except superconductors; more on them later) has at least a tiny bit of resistance, that means that anywhere current flows, there is waste heat. That is why there is a minimum thickness of wire that must be used to wire up buildings that plan to comply with fire codes. If you try putting 15 amps through a hefty 14-gauge wire and the resistance is low enough that you’ll be fine. Try skimping and using 18-gauge wire and things will get a little warm. Possibly warm enough to melt plastic… like the insulation on the wires… which could lead to a short, which generates a lot more heat… inside your wall with all that flammable stuff around.

Understanding how electricity works can allow you to mess around safely or do otherwise dangerous things safely. High-voltage, low-amperage electricity is great for freaking out electrophobes who would never handle ArcAttack’s music. You’ll understand how much rubber can help and how much water can hurt, and why.

A common way of giving a feel for electricity is to present an analogy with water. The analogy is far from perfect (check the link to the problems with it), but I think it gives a good intuition for things like voltage, amperage and resistance.