It's not linked to electron movement except at the point of flashover. Before that point, the electrons in the plastic are quite tightly bound- there's no conduction band.
So the tighter they are bound the higher voltage would have to be for the flash over to take place. So what creates the bond is this the pull between the center of the atom and the electrons?
Or the molecular bond of the material?
What are your thoughts on free electrons in conductors?
Regards
M. Gregg
Not exactly. Dielectric strength is an interesting and complex area, but very far off topic here. It's destruction, not conduction. If you want to open another thread to discuss it, feel free.
As I said before, the free electron gas model for conduction in metals is a pretty good approximation. Like all approximations, it has limits, but it works surprisingly well in normal circumstances.
'Resistance' is a term normally used of conductors, to characterise how good/bad they are at conducting. I assumed you were giving a false description if how resistance arises. Are you now saying that, instead, you were attempting to describe dielectric breakdown but misnaming it resistance?M Gregg said:
I am sorry you are wrong! Resistance is a value that can be used across any conducting or "Non" conducting material.
EG insulation resistance value, Resistor value, conductor value which creates volt drop based upon current drawn. One other is Earth fault loop impedance which is also a resistance value including the ground you stand on!
Regards
M. Gregg
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I did not say resistance cannot be used of non-conductors, just that it is normally used of conductors. For non-conductors we are usually more interested in breakdown voltage, or surface leakage currents, because the resistance is so high it can usually be ignored.
In any case, you used the word resistance while apparently attempting to describe something else. The energy required to move an electron from one atom to the next is related to ionisation and insulation breakdown, not resistance. Resistance relates to a shortage of conduction electrons or the obstacles they face.
In any case, you used the word resistance while apparently attempting to describe something else. The energy required to move an electron from one atom to the next is related to ionisation and insulation breakdown, not resistance. Resistance relates to a shortage of conduction electrons or the obstacles they face.
Yep, there are plenty of innocuous mistakes which have no bad effects. My fascination is with the few rare mistakes which create actual learning barriers. And my central fascination is with my own major unsuspected physics misconceptions, and whether others suffer from the same ones I do. I can cure myself, and perhaps this can help others with similar problems. It's definitely my obsession. The un-learning of wrong ideas is the other half of physics teaching and learning. It's a topic which was almost entirely unexplored until the last twenty years or so. I think the majority of physics instructors still haven't encountered it. It's still too much concealed in niche research journals.
Since I first stumbled on the topic during science museum work, I've had amazing personal experiences with it. That's the real cause of my obsession.
Losing a long-held misconception is like finding you've been wearing distorting glasses all your life. They're glasses you didn't know were there. Take them off and parts of simple physics suddenly look different. They becomes sane and understandable for the first time. The well-known equations suddenly fit the visual-intuitive picture. (The equations were always right of course, it was my misconception-filled intuitive picture which needed repair.)
Exactly right. The game of Insult And One-Upmanship seems to be required as part of introduction on many forums. The current users jump in to play "insult the newcomer," but subtly so moderators miss it. But should newbies play the game? Or ignore it? As a long time list moderator I automatically ignore it. But I'm always experimenting, so this time I intentionally went the other way. Maybe went too far!
You also need to see it from the point of view of long time forum members. A least once a month an "expert" pops up on the forum who has vast knowledge & experience. The expert then goes on to preach and prove everyone else wrong.
Usually these self professed experts wilt quickly under the strong light of reason and logic. This applies equally to experts with practical, scientific or mystical expertize. The forum can be a tough playground because there are so many here with great depths of knowledge across many disciplines.
Remember, you are not the first and won't be the last. If you can back up your arguments you will be warmly welcomed to the community. It's that simple.
Usually these self professed experts wilt quickly under the strong light of reason and logic. This applies equally to experts with practical, scientific or mystical expertize. The forum can be a tough playground because there are so many here with great depths of knowledge across many disciplines.
Remember, you are not the first and won't be the last. If you can back up your arguments you will be warmly welcomed to the community. It's that simple.
I'm still not getting my point across. Obviously. 🙂
The problem is that the public is greatly confused about the nature of "electricity." Why is this? This thread demonstrates the problem! Different people have totally different ideas about the "true" nature of electricity, and the disagreement seems to have no possible solution.
One major source of confusion is traditional and widespread conflation of different electrical concepts in pop literature and in K6 textbooks: charge versus energy versus power versus voltage. All are mixed together and labeled "the electricity." This happens when some authors state that electricity is one particular thing: it's the flowing motion of electric charges ...then other authors state that it's a different particular thing: electricity is a form of energy. Essentially the general public is being taught that amperes are watts. Both are supposedly "the electricity." Smart techies know how to pull the correct meaning from syntax. But the general public doesn't know about this. They honestly think that "an electricity" exists; a single entity which has confusing contradictory behavior.
One way to clear up the mess is to go back to using "electricity" with its original scientific meaning. (Nobody but me is trying to do this. Obviously!)
Another way has already been tried: abandon the term "electricity." Just stop using it in instructional materials. This hasn't worked. Many older references still contain the original scientific usage (I have a thick folder of examples somewhere, but offhand I only recall CRC handbook and SI physics standards.) People still ask what electricity is, and our answers confuse them.
Probably the reason this hasn't worked is because we never declared electricity to be an unscientific term. Instead, the scientific and engineering communities silently stopped using it. It was abandoned with no discussion. Nobody bothered to tell the K6 science education community that "electricity" is an unscientific term. K6 educational materials still use "electricity" quite heavily, and treat it as a scientific term with narrow meaning.
Exactly: confusion is spread when grade school textbooks universally use electricity as a precise 'scientific' term. (Perhaps you simply don't believe this. I can go check out a stack of these books from our education library and quote passages where they do it.)
Which model? What are you talking about?
Where is this coming from? What model?
The hydraulic model of a resistor is a component providing fluid friction: an extremely narrow pipe, or better, a pipe with a filter cartridge or perhaps a plug of fine sand.
Yes, extensively, For example there's Scott Eberhardt, a fluid dynamics guy here at Aero/Astro UW dept, and his co-author David Anderson, a Fermilab physicist. They became misconception-fighters, and from that came their pop edu paper, their textbook, and indirectly an entire set of web pages at NASA GRC. The controversy grew and made the news, in the NY Times, NPR, Discover mag, Plane&Pilot, even XKCD comic. Online it's in How Stuff Works, About.com, and The Straight Dope. The counter-infection spreads! See links on The Airfoil Misconception in K-6 Textbooks
Not an error. A rotating cylinder has no edge, is not an airfoil, and the one can't somehow "disprove" the other. Lift is created by circulation plus relative motion. Circulation can be created by a rotating cylinder, but it also can be created by the "Kutta Condition" using an airfoil. Kutta condition is produced by the down-tilted trailing airfoil edge of cambered airfoils or positive-attack-angle airfoils at high Reynolds number. Undergrad fluid dynamics texts have complete details, or see Airfoils and Airflow [Ch. 3 of See How It Flies]
I don't see how this is grossly incorrect, unethical, confusing, etc. It may be broadly applied, but it still fits with Gilbert's electriks in my mind.
No, they honestly think that the electricity exists, and think very little of its behavior.
I'll commend you for battling textbook errors for students, but if you want the general public to start using scientific terms I would find that a rather futile exercise.
The snag is you can jump to the conclusion that someone is confused just because they see things differently from you. People may differ because they are seeing things more clearly than you. You may feel you have had a rough ride here, but accusing a physicist of not knowing the difference between charge and energy is hardly likely to win friends and influence people!wbeatty said:
We are generally kind to newbies, but experts (whether genuine or self-appointed) can expect vigorous debate. Some welcome that; others are offended by it.
You have claimed that the trailing edge must be downward aiming to generate lift.
That is incorrect. Entities without a trailing edge can generate lift.
An absolute statement which is disproven once, is broken. Name dropping does not negate an incorrect statement.
You obviously missed my inference on the line integral and the symmetrical airfoil.
And, a reference to an equation involving the stagnation of airflow on the trailing edge is still, not a negation or proof in support of an incorrect assertion.
Fix your page.
Cheers, John
ps. I can't seem to get your website at this time, I was going to cut and paste exactly where you are incorrect..
Ah, it works now.
Your "wrong picture" says no lift.
Your link to "How it flies", diagram 3.5, middle wing in particular, shows the exact same geometry and says it produces lift. You say it does not.
Your links and your "mythbusting" are not consistent.
You clearly show the bottom surface of the wing at zero degrees, the linked 3.5 has that at 5 degrees angle of attack..your pic ignores the chord line angle, and assumes that zero angle of attack is bottom horizontal.
Honestly, you should just link to 3.14 of the how it flies..your verbage doesn't help much, as your attempt to explain it correctly is inconsistent with the link explanation section 3.14.
Thanks for the link to that page, his explanations are internally consistent, well written, and enjoyable to read.
Your page, in my humble opinion, does not present well. The reader walks away thinking you have a chip on your shoulder..
Cheers, John
Your "wrong picture" says no lift.
Your link to "How it flies", diagram 3.5, middle wing in particular, shows the exact same geometry and says it produces lift. You say it does not.
Your links and your "mythbusting" are not consistent.
You clearly show the bottom surface of the wing at zero degrees, the linked 3.5 has that at 5 degrees angle of attack..your pic ignores the chord line angle, and assumes that zero angle of attack is bottom horizontal.
Honestly, you should just link to 3.14 of the how it flies..your verbage doesn't help much, as your attempt to explain it correctly is inconsistent with the link explanation section 3.14.
Thanks for the link to that page, his explanations are internally consistent, well written, and enjoyable to read.
Your page, in my humble opinion, does not present well. The reader walks away thinking you have a chip on your shoulder..
Cheers, John
Fascinating topic, but start a separate thread for this? It's quite a threadjack from "unlearning wrong basic electronics."
Hmmm, good thing that I didn't claim to be an expert. 🙂 No education PhD, not even physics degree, no teaching experience. Just vast amounts of on-the-job learning. A lowly amateur scientist, a "research engineer," Job: Research Engineer - YouTube I'm out to understand physics from the perspective of a 5yr old. I'm also out to help the little guy: I take the wall of math that keeps people from understanding electricity, and try my best to knock it down. It had its uses over the years, but it was also an intentional barrier, like doctors in 1700 all speaking Latin. Instead, why not describe EM physics without any equations at all? Instead, let's remove all the "Latin" and have my daughter and my grandmother understand the same things that previously were only accessible to those with multiple PhDs.
Actually you've hit on the secret that both Einstein and Feynman based their success upon: always remain a student. Approach science like a little kid who knows nothing. Do it that way because, the moment you think of yourself as "an expert," your learning slows, perhaps even halts entirely. After all, you've arrived at the top! the passion flickers out. There's nothing left to do except a bit of straightening up, and collecting the accolades.
Instead, if you're a little kid who knows nothing, then your task is to learn how to learn. After many years you acquire many self-teaching tricks, and your learning rate redoubles. But still you know nothing, so you keep always goosing it upwards. After all, on an exponential hill, you're always near the bottom no matter how long you've been climbing.
On this article below, the graph should have had "amateur" and "expert" swap places. Change the title: "How to be an Amateur!" It's the experts who hit a ceiling.
Creating Passionate Users: How to be an expert
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