Some basic electronics and unlearning the wrong

[SY]

You used it several ways. You also missed my point completely- "electricity" is a word that has many different meanings. If you use it to mean electrical charge, then use it to mean electrical current, don't complain that charge and current aren't the same thing.

And before you ask, no, I am not currently teaching. Yes, I have in the past and may again.

 

[abraxalito]

You also missed my point completely

And you missed his, completely -

why not just give evidence?

Please, just cut/paste an example.

 

[SY]

I've done that previously.

 

[Pano]

I asked a direct question - never got an answer. Bill?

Chemical energy in the battery is used to push the "electricity" to the bulb? Like a steam engine pushes something with rod. The rod is not the energy. Is that what you are saying?

 

[abraxalito]

I think that's what he's saying. The electrons are carriers of energy from the battery to the bulb/LED. Its like each one has a bucket and dumps whatever's in that bucket into the load then returns for more.

 

[sofaspud]

I'm feeling as Pano does.

Originally Posted by sofaspud View Post
Quote:
Originally Posted by wbeaty
Then I point out that electricity in a flashlight flows in a complete circle, going through the battery and through the bulb. It circulates over and over with none being gained or lost.
If electricity is charge, then this statement is incorrect, as it is indeed the charge in the battery that is being lost.
Oops, let's stop and clarify something.

Do you believe that a charged battery contains more electric charge, more Coulombs, than a discharged battery? If not, then please explain your statement above.

So if the net charge is always the same, then are you saying that a discharged battery contains the same electricity as a charged battery? If the scientific answer is yes, it certainly deserves qualifying. I asked "drained of what?" waaay way back and it was ignored. To be honest, this thread is beginning to appear as an egocentric Red Rover game.

 

[wbeaty]

Would using the word "neutralized" instead of "lost" allowed an answer? I believe that the net charge is always the same, whether charged or discharged.

That's a separate topic. First, please explain exactly what's wrong with my statement below. You say you see an error. What is it? Please? The more details the better.

Then I point out that electricity in a flashlight flows in a complete circle, going through the battery and through the bulb. It circulates over and over with none being gained or lost.

If electricity is charge, then this statement is incorrect, as it is indeed the charge in the battery that is being lost.

"It's incorrect" doesn't help me to see what you mean. What in particular is incorrect?

Perhaps you've changed your mind, and no longer think my statement is wrong?

Here's another version below.

Then I point out that electric charge in a flashlight flows in a complete circle, going through the battery and through the bulb. Electric charge circulates over and over with none being gained or lost.

Why is this incorrect?

I asked "drained of what?" waaay way back and it was ignored.

First please help me clear up my confusion. Why is it incorrect?

 

[wbeaty]

I asked a direct question - never got an answer. Bill?

Asked who? Go read your message question #66. You were asking sofaspud, right? Or asking the whole group in general?

 

[wbeaty]

You used it several ways.

Are you talking to me? Your message contains no clue as to who it's directed to.

In your post, you defined "electricity" (sometimes explicitly, sometimes tacitly) as current, energy, charge, flow of charge, and work done by the mains. Then complained that these were not consistent.

Again, 2nd time... If you think I'm misusing the word "electricity," why not just give evidence? What's the big deal with that? Please, just cut/paste an example.

You used it several ways.

Assuming you were talking to me in the above ...repeating the accusation doesn't change anything. Please show me where I used it several ways.

 

[sofaspud]

First please help me clear up my confusion.

Your confusion is in reading a question and being unable or (most likely) unwilling to provide an answer. Sorry, I cannot help you with that one.
"I asked "drained of what?" waaay way back and it was ignored."

First please help me clear up my confusion. Why is it incorrect?

"First" nothing. I've wasted enough time on this and gotten nowhere. I'll make better progress with the first textbook I get my hands on.

 

[abraxalito]

I defined "electricity" as meaning "charge."

Whereas the average user of electricity buys electricity in Joules (kWh to be precise) so I think that's one of the reasons for confusion here. Why would a colloquial word such as 'electricity' need to be defined in science, that's what I'm curious about? Surely scientists have more precise words like 'electric current' at their disposal.

 

[wbeaty]

Your confusion is in reading a question and being unable or (most likely) unwilling to provide an answer.

No, I honestly don't know why you accused me of being wrong.

I'm asking for clarification. Please help me understand your statement about me being incorrect. Here it is again:

I said this:

Then I point out that the Electricity in a flashlight flows in a complete circle, going through the battery and through the bulb. It circulates over and over with none being gained or lost.

You then said:

If electricity is charge, then this statement is incorrect, as it is indeed the charge in the battery that is being lost.

Again: why is my statement about the flashlight incorrect? No, I'm not trying to be disingenuous, or confuse you, or anything creepy. I'm asking you a simple direct question because I honestly don't understand what you mean. When charge flows through a resistor, the inflow exactly equals the outflow, and none builds up inside. When charge flows through a coil, same situation, and none builds up inside. When charge flows through a battery, same as with resistor and inductor: inflow equals outflow, and none builds up inside. These are simple very basic facts of circuit physics, and are required by the "complete circuit" rule for DC. You can visually demonstrate them using the Java simulator at Circuit Simulator Applet (Please try it out. It should help greatly.) So, which part of all these statements is incorrect?

 

[sofaspud]

You stated earlier that the battery is drained, and I asked "drained of what?" It was ignored, and later pointed out to you. And ignored again. Instead you choose to play what I perceive as confused innocent childishness. If you were actually confused, you should have said so then, not waited for patience to drain too.

Originally Posted by wbeaty, #48
Yet the battery is being drained, and soon it's dead.

Originally Posted by sofaspud, #49
Drained of what?

Originally Posted by wbeaty, #92
No, I'm not trying to be disingenuous, or confuse you, or anything creepy.

Sounds like The Official Truth.

 

[DF96]

The battery loses electrochemical energy, which is turned into electrical energy and then (mostly) heat energy. Energy, like charge, is conserved. I think I already said this.

Why would a colloquial word such as 'electricity' need to be defined in science, that's what I'm curious about?

It isn't. It's just wbeatty asserting that it is, as the same as 'electric charge'. As I and others have pointed out, this is not true. It is used as a general term for a range of phenomena. Failure to accept this is where he goes wrong.

So what 'is' electricity? I would say that it is the movement of electric charge, or a spatial arrangement of charge. The former is normally just called 'electricity' and the latter 'static electricity'. However, I would not wish to be pinned down by a pedant on the precise details of these definitions and what is included/excluded by them - I do not intend that sort of definition! Physics (and other sciences) is not about definitions but understanding. Note that 'electricity' is not a term which physicists use very much, we prefer to talk about charge or current or electrons etc. We use 'electricity' in a general sense when talking to non-physicists.

 

[SY]

I'm feeling as Pano does.


So if the net charge is always the same, then are you saying that a discharged battery contains the same electricity as a charged battery? If the scientific answer is yes, it certainly deserves qualifying. I asked "drained of what?" waaay way back and it was ignored. To be honest, this thread is beginning to appear as an egocentric Red Rover game.

You weren't ignored. I answered that for you- if one wants to define "electricity" as "electrical charge," the net electrical charge in a "charged" battery and discharged battery is the same- zero. The difference between the two states is the Gibbs free energy.

 

[Sheldon]

Any comments on the discussion about writing textbooks? Should an elementary book strictly avoid any 'untrue' statements, or is this impossible? My own view is that accuracy is important, but clarity may require some compromise. It helps, of course, if the writer is aware of when he is compromising so he needs to have a level of knowledge which exceeds the level of the book he is writing. Poor books can be written by people who don't realise when they are offering simplification or approximation, but people who are too advanced (or think they are) can also write bad books.

I once read of a physics teacher who reduced marks for pupils who wrote of light bouncing off mirrors, as in her view they should have said reflected. Unfortunately it may be that pupils who talk about bouncing have some understanding of what is happening (or at least the power of analogy) while the others may simply have learnt how to repeat a technical word. I'm glad my physics teacher wanted us to learn both the words and what they meant.

This is a real issue in communicating technical or scientific concepts. What is the appropriate level of detail, and what analogies are close enough and appropriate for the level of the subject? One attempt to address the issue:

Don't Be Such a Scientist

 

[DF96]

There is a difference between an elementary textbook and a popular science book. One is trying to transmit knowledge, the other is trying to transmit an impression and (perhaps) the appearance of knowledge. Very few people can do both. In the case of physics the test at the end is: can you calculate it, or just talk about it? There is more to physics than calculation, of course.

 

[Pano]

Asked who? Go read your message question #66. You were asking sofaspud, right? Or asking the whole group in general?

I was asking the man who says "A battery is a chemically-fueled charge pump."
That man is Bill Beaty. His work is the subject of this thread. The question was for him.

For: Bill Beaty.
(I have restated my question for clarity.)
Chemical energy in the battery is used to push the power to the bulb? Like a steam engine pushes something with rod. The rod is not the energy. Is that what you are saying? If not, please clarify.

The question above is for William J. Beaty.

 

[wbeaty]

Chemical energy in the battery is used to push the power

Nope, power isn't something that can move. You're using the word "power" to mean "electrical energy."

To prevent students from getting confused, or even to prevent them from acquiring misconceptions, it's vitally important that we stick to clear definitions. Here's Bohren:

"Lest you think that I am quibbling over minor points of language, I note that in my experience many of the misconceptions people harbor have their origins in imprecise language... Precise language is needed in science, not to please pedants but to avoid absorbing nonsense that will take years, if ever, to purge from our minds." - Dr. Craig F. Bohren, Physicist

Electrical energy can move from place to place in a circuit. And "Power" is a measure of it's flow rate. The joules can move around, and power comes in units of joules per second. If we carefully stick to clear usage, there will be no need to spend years trying to remove confusing nonsense from our heads. OK onwards.

Chemical energy in the battery is used to push the [electrical energy] to the bulb? Like a steam engine pushes something with rod. The rod is not the energy. Is that what you are saying? If not, please clarify.

No, instead the entire circuit is always full of movable electricity, of electrons. Every metal atom donates at least one mobile electron to the "sea of charge" inside the wires. The electron population inside wires is as densely numerous as atoms. That's why we say that, if wires are like water pipes, they are always FULL pipes, with no bubbles anywhere.

If you have a flexible hose full of water, and you hook the ends together, what do you get? You get an invisible wheel. The hose can remain unmoving while the water inside will rotate along like a liquid drive-belt. If we added a water pump in series with our hose-loop, then we could make the wheel start turning.

BICYCLE WHEEL ANALOGY
"Electricity" Misconceptions Spread By K-6 Textbooks

Batteries are charge pumps. The chemical corrosion reactions on the surfaces of the battery plates will pull positive charges out of the metal and drive them into the battery electrolyte. (These positive charges are the dissolved metal ions.) But the two plates must employ two different metals, and one plate is electrically a bit stronger than the other. Its force wins out over the force from the other plate. So there is a net driving effect. This forces charges to flow across the battery's electrolyte layer. But without a complete circuit, this flow is normally blocked, and it can only start up if the battery terminals are connected to a conducting pathway. A battery is a chemically-fueled charge pump. Since it puts out a constant voltage-drop, we could call it a "constant pressure pump." (Batteries and fuel cells are basically identical, but fuel-cells have their chemicals piped in from outside, while batteries store the fuel chemicals in their plates.)

 

[abraxalito]

Since we've having fun with pedantry here (and why not?) a quick point about the use of the apostrophe:

To prevent students from getting confused, or even to prevent them from acquiring misconceptions, it's vitally important that we stick to clear definitions.

Here we see one correct use of <it's> - the apostrophe being used to shorten <it is>.

Electrical energy can move from place to place in a circuit. And "Power" is a measure of it's flow rate.

And here's an example of an incorrect use of the apostrophe - to indicate the possessive together with the pronoun <it>.

Apostrophes | Punctuation Rules

See rule 9.