That indicates that you're totally unaware of the quite enormous literature on student physics misconceptions, both the research and the pop-articles in The Physics Teacher. If you were familiar with it, you'd know that nearly all students come to class with a set of stereotypical and solid misconceptions which usually aren't defeated by physics teaching. The vast majority of student physics misconceptions aren't caused by lack of ability, and aren't caused by poor teaching.
If you wish to learn more, I suggest joining the venerable university-level physics education forum PHYS-L.
Phys-L
The PHYS-L Homepage
Phys-L archives
https://carnot.physics.buffalo.edu/archives/
Guys cool it, focus on the subject at hand and not each other or such things as minor grammatical errors.
If they come to class with misconceptions, they learned it somewhere. The problem is to make it interesting enough and within their learning framework to get them to want to learn it.
Your link is interesting. My concern would be, this is a group of physics teachers who are claiming that it is not the teaching methodology that is at fault?
It is somewhat like the fox guarding the henhouse, no?
While their assumptions and conclusions could indeed be correct, how does one trust or verify?
Cheers, John.
ps. Expletive poisoned posts (such as the one which just disappeared) do not float my boat. Please tone it down a bit, and keep the discussion one of reason.
pps. I completely deconstructed a specific claim of symmetric airfoil vs angle of attack "stuff" using an applet geared to kids for goodness sake. Perhaps a directed discussion on what I specifically stated would serve you better.
Thank you.
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These misconceptions arise completely spontaneously in people with no prior formal exposure to physics, or from textbooks which previous teachers fail to correct? I find the former difficult to believe, and the latter is a sign of poor teaching. A good teacher will point out errors in the textbook. A really good student may do this too.
We are in good general agreement I suspect.
There are students that will never get it despite all efforts. Students who are driven to try to understand the world most certainly will. The ones in the middle are the ones I'd be interested in.
Cheers, John
Yes, I think so.jneutron said:
Really bright students may be able to cope with pedantry. The ones in the middle will not. I think the fundamental issue is that there is much more to learning science than learning definitions. I have never had a good memory (and what I have is disappearing!) so I could only learn physics by understanding it. I now find I can remember phenomena/laws but not what they are called. The name is in a sense irrelevant because it is merely a label, but it is a great help to communication. If Martians landed they would have exactly the same physics as us (where their knowledge and ours overlaps) but they would have completely different names for it.
Scroll down and read Special Relativity Theory: Beyond Criticism
http://web.archive.org/web/20090205055230/http://www.suppressedscience.net/physics.html
Also see http://sciliterature.50webs.com/RelativityDebates.htm
http://web.archive.org/web/20090205055230/http://www.suppressedscience.net/physics.html
Also see http://sciliterature.50webs.com/RelativityDebates.htm
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Yes, you've proved time and again that you can find links to cranks and that your understanding of relativity is near zero. You've even been given moderator warnings to stop posting that crap. So... stop posting that crap. There's plenty of crank stuff here without you adding irrelevancies to the pile.
In nearly all cases they taught it to themselves. These are usually called "naive conceptions" or "aristotlean physics."
It's a listserv group of about 700 physics professors which has existed since the dim mists of arpanet history. Well, 700 members was the subscribership long ago before the non-physics world found out about it. PHYS-L has been around since before the www. All sorts of opinions are represented there. I was a heavy user back in the early 1990s. It's where I developed my electricity articles, my Airfoil Misconception page, and many other sections of amasci.com.
Suppose you go to an international physics conference, and there are several hundred professionals in a big auditorium. They all have nametags you can read. You go up on stage. You ask questions at the microphone, and you receive a large number of extensive answers from that huge group. Sometimes one member will say something wrong, and many others will instantly leap on it and make corrections.
Basically that's PHYS-L.
Note that almost everyone there uses "sigs" with real names, university addr, email, often even phone numbers. It's simple to verify to whom you're talking. No pretend-experts or sockpuppets survive. But PHYS-L is for general physics. There are other lists specifically for education techniques or theory, for lecture demonstrations, etc.: PHYS-LRNR, PHYSHARE, TAP-L. A big list of academic discussion lists is provided by Rich Hake at Indiana: http://www.physics.indiana.edu/~hake/GuideToADLsphereB.pdf
I attack Electricity explanations from the debugging point of view. But I'm debugging the concepts found in textbooks and classrooms. See: Articles on "Electricity" . . . . WJ Beaty
If standard learning techniques aren't working right, perhaps there are some fixable problems. Go in and locate the failure points. Find mistakes which hold everyone back. Make changes, and perhaps the books and classrooms will suddenly start functioning as they were originally intended. From the high traffic and huge positive email response to my project, I guess I hit on some common widespread learning barriers.
> The direction of flow from negative to positive hasn't helped to clear things up much either.
That stuff can make things worse! But I think it helps to understand why physics and engineering assumes there's a flow of positive charge through conductors. See Which way does Electricity REALLY flow?
If electricity is like a drive belt passing over pulleys, then a DC system has a drive belt which circulates continuously, while AC has a drive belt which only moves forward and back. When AC rides on DC, that's a drive belt which moves forward, but its speed goes up and down.
Or if a flow of electricity is like air moving through hoses, ...did you ever use a compressor paint sprayer with too small an air tank? When running off the tank you get "pure dc" air pressure, and the spray is perfectly constant. But when a big compressor starts running, the pressure jumps up and down because of the compressor piston action. The spray is still coming out, but now it has "bumps" of AC riding on the DC.
Circuits are like machines, but all the moving parts are FREAKIN' INVISIBLE. Sometimes a big help is the Falstad java circuit simulator, where the electric currents are visible inside the schematic. That simulator does visually what my explanations try to present verbally.
Circuit Simulator Applet
I'm extremely skeptical, since wings generate lift with circulation: with upwash ahead and downwash behind. Circulation theory is a long-standing part of professional aerodynamics. If you claim that a major physics theory is wrong, and that this rule can be violated, well maybe you're confused or just plain mistaken.
So let's see some actual evidence to clear things up.
Yep, and that's why the usual "Bernoulli path-length" explanation is easily debunked: just turn the aircraft over so the longer path-length is on the bottom.
Yeah, but then along comes The Internet. I got in early, before the big exponential growth really took off. If you're a content provider back in 1993, you watch all the kids and teachers come flooding in and find the www empty of useful material for homework and science classroom use. But there sat my tiny site on electricity misconceptions and electrostatic tinfoil motors.
Unfortunately I'm just an electronics designer in the chem department. Well, only a small amount of design and software. Mostly it's climbing around under dead mass spectrometers trying to debug high-amps magnet drivers. That and keeping ancient instruments from the 1970s alive.
7n7is SY clearly does not subscribe to your viewpoints. You have apparently been warned before. I would advise you do not pursue this further.
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Bill,
I do find your quest admirable and beneficial, thank you.
As I have said my reservation is potentially the weighing of these errors compared to the overall effectiveness of the instructor or text. Mistakes and errors I don't necessarily see as significant learning barriers (yes I have seen them, actually I make them typically daily, so I think we are on the same page), mistakes and errors caused by insufficient knowledge of the subject are learning barriers and would be apparent without proofing for inconsistencies.
A good instructor uses text mistakes to their advantage, not only by showing and explaining the error but doing so in a way to encourage independent thought and scientific reasoning.
This forum, which I have really enjoyed since joining 9 months ago, has members from all over the world and at all levels of technical knowledge. Often the process goes something like:
A poster humbly asks a question in search of how or why something works (see “Engineer, help please, by farmerjack61 as a great example) soon amongst various replies an engineer or scientist will likely respond with the “correct text book” explanation. Others add to the explanation in a way that makes more sense to their understanding for the benefit of the poster. Of course there are misconceptions introduced and bad advice but it doesn't take long before replies flood in to get things closer to correct again.
Surely there are aspects on this forum that would help your efforts not just in dispelling inconsistencies but in the learning and instructional process.
In my opinion negative posts and more often than not constant bickering (there are many exceptions) result in less learning and exploration, and serve just as a fight stage to show that one's way is better than the opposition.
Hope this helps
-Antonio
I do find your quest admirable and beneficial, thank you.
As I have said my reservation is potentially the weighing of these errors compared to the overall effectiveness of the instructor or text. Mistakes and errors I don't necessarily see as significant learning barriers (yes I have seen them, actually I make them typically daily, so I think we are on the same page), mistakes and errors caused by insufficient knowledge of the subject are learning barriers and would be apparent without proofing for inconsistencies.
A good instructor uses text mistakes to their advantage, not only by showing and explaining the error but doing so in a way to encourage independent thought and scientific reasoning.
This forum, which I have really enjoyed since joining 9 months ago, has members from all over the world and at all levels of technical knowledge. Often the process goes something like:
A poster humbly asks a question in search of how or why something works (see “Engineer, help please, by farmerjack61 as a great example) soon amongst various replies an engineer or scientist will likely respond with the “correct text book” explanation. Others add to the explanation in a way that makes more sense to their understanding for the benefit of the poster. Of course there are misconceptions introduced and bad advice but it doesn't take long before replies flood in to get things closer to correct again.
Surely there are aspects on this forum that would help your efforts not just in dispelling inconsistencies but in the learning and instructional process.
In my opinion negative posts and more often than not constant bickering (there are many exceptions) result in less learning and exploration, and serve just as a fight stage to show that one's way is better than the opposition.
Hope this helps
-Antonio
I'm curious to know what in particular doesn't make sense to you. Ohm's Law gives the relationship of these three, but doesn't really do anything to aid understanding what they are. Are you familiar with the basics of valence electrons?
There is a again a lot of focus on electrons, what about the waves.
Is it the electrons that create the waves or the waves that stimulate the electrons to drift?
Is it the electrons that create the waves or the waves that stimulate the electrons to drift?
The only claim that is not valid is the one that considers wings as momentum based device. I have claimed nothing which violates any physics theories or understandings.
Take the nasa app, run the symmetrical airfoil at the highest angle of attack, then use the velocity measure part to look at the velocities around it. You will note that the angle of attack causes the air to change velocity heavily over the top surface. A line integral around the entire airfoil easily shows where the lift is coming from given the top/bottom difference in velocity.
Trust me, I am not in the least bit confused.
Look up the evolution of the propellor, as it is the closest thing to this discussion in terms of momentum based vs airfoil based. Prior to the Wright Brothers, propellors were considered and designed as momentum changing devices consistent with the pricipals use for water propellors, screw type devices.. The highest efficiency props at that time ran in the 40 to 50 percent range. When they realized that a propellor is simply a wing, and applied airfoil design to the propellor, they immediately achieved an efficiency in the high 60 percent (66 noted in the link I provide, 85 being modern props). Note that other links I find have slightly higher efficiencies listed for their prop. Given the lack of accurate methods for measurement of thrust at velocity, guesstimates as to true efficiency at speed for their prop is based on re-creation of the believed airfoil geometry.
Before the First Powered Flight
There is no need. Simply use that nasa app to see how even a symmetrical airfoil modifies the air pressures above and below.
Upside down flight is achieved by using those "control surface thingies" to modify the airfoil geometry sufficiently to create the low pressure surface on the side away from the ground.
Your assessment that wings are momentum based devices instead of true airfoils, is a typical layman's understanding based on simple observations...wind underneath and such. I recommend you actually discuss this with some aeronautical engineers who design wings and propellors, and understand the efficiency tradeoffs between a simple "screw" design, and that of an airfoil.
Cheers, John
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For efficient, level flight Bernoulli's theorem still rules the day. Different flap arrangements and increasing angle of attack (to a point) can increase lift by controlling turbulence that supplements lift but you couldn't fly an airplane with any economy or at high speed that way.
John
John
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It is important to get this correct. The reason we are taught positive flow of current is historical only. Ben Franklin defined it. He had a 50% chance of getting it right. He did not choose "wisely"..
As such, we are taught the right hand rule (among other things).
What I find interesting, is that this naming convention gets particle physicists in trouble...specifically when it comes to wiring the magnets in an accelerator or storage ring that runs negatively charged particles such as electrons or antiprotons...they get the magnetic field backwards. This is simply because they define beam current as the actual direction the electron beam takes, and this is opposite the taught convention.
That is why typical storage ring equations require the Left Hand Rule.
Interesting. It would appear we share a commonality. I also work with high amps magnets.. I suspect that my amperes are bigger than your amperes however..😉
Cheers, John
ps..I do believe your intentions with your site to be worthy..do not confuse my corrections to your misunderstandings as rejection of your cause. What I believe would be a more worthy target, is teaching the children how to view website content with a more critical eye.. It is possible to find sites in support of any half baked claim nowadays, the kids need the skills to weight the validity of the content. More and more, the kids today are using internet searches in support of writing papers in high school, in liu of actually going to a library to do research. So the skills to spot the crackpots and simply incorrect information is really where the big payoff will come from.
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