Re: [Phys-L] Conservation of Energy vs Constant Energy

[John Denker <jsd@av8n.com>]

On 05/08/2015 08:15 AM, Paul Lulai wrote:

> Thanks John.

:-)

> I think it will come up again.

That's for sure.

> I was shocked that energy conservation =/= energy is constant was a 
> one vs the room debate.

I'm not surprised.  There is a lot of stuff in this 
category, i.e. widespread deep-seated misconceptions.

Note that as usual, the ideas that cause the most
trouble are the ones that get the right answer /some/
of the time.  (In contrast, completely crazy ideas
pose almost no threat.)  "Conservation=constancy" is
not completely off-the-wall crazy.  In some sense it's
completely wrong, but in another sense it's just an
oversimplification.

  By way of analogy:  "entropy=disorder".  In some
  sense that's completely wrong, but in another sense
  it's almost half right.  Just enough to cause trouble.

  By way of exception:  "Sig figs."  As far as I can
  tell, the whole idea is conceptually wrong and
  unnecessarily laborious ... yet still it gets taught.

  Oddly enough, a single correct idea is key to fixing
  both of the previous errors.  Hint:  There is no such 
  thing as a random number.  You can have a random
  distribution over numbers, but then the randomness 
  is in the distribution, not in any particular number
  that might be drawn from such a distribution.

> It seemed like some were slowly starting to wonder.

That's the magic word!  /Wondering/ is what sets powerful, 
useful learning apart from mere rote learning.  That's
the foundation of critical thinking:  Ponder each new
idea.  Mull over each new idea, to see in what ways it
is consistent (or inconsistent!) with previously-known
ideas.

This requires them to expend time and effort ... but if 
you can get them to do that -- to actually /think/ about
what's they're teaching -- everybody is tremendously better
off.  And then somewhere down the line they might start
asking their students to think for themselves......

If you want to quote an authority, quote Feynman about 
the perils of appeal to authority:

   “Your instructor was right not to give you any points,
   for your answer was wrong, as he demonstrated using 
   Gauss’s law.  You should, in science, believe logic 
   and arguments, carefully drawn, and not authorities. 
   [....]  I am not sure how I did it, but I goofed.
   And you goofed, too, for believing me.”
      http://www.feynmanlectures.info/flp_errata.html

Or quote James about the psychology of learning:
   Each of its associates becomes a hook to which it 
   hangs, a means to fish it up by when sunk beneath 
   the surface. Together, they form a network of 
   attachments by which it is woven into the entire 
   tissue of our thought. The 'secret of a good memory' 
   is thus the secret of forming diverse and multiple 
   associations with every fact we care to retain.
        http://www.uky.edu/~eushe2/Pajares/tt12.html

> Baby steps i guess.

Right idea, maybe not the best choice of words.  I know
"baby steps" is an idiomatic expression and an analogy ...
but these guys are not babies.  You're asking them to do 
something that is seriously hard.  So yes, take it one 
step at a time.  Each of the steps takes time and effort.
Useful proverb:
  You cannot make a flower grow faster by pulling on it.

Another useful proverb:
  People tend to overestimate the power of short-term change,
  and underestimate the power of long-term change.

I've seen things like this take years to sink in.
 Year 0:  I lose the argument, and lose ugly.
 Year 1:  I'm prepared with better arguments and diagrams
          ... but still get no perceptible traction.
 Year 2:  I rewrite the web page yet again.  A couple 
          people concede that the "new" idea might not
          be completely crazy.
 Year 3:  I don't need to make the argument at all.
          When the question comes up, /somebody else/
          offers the correct explanation.

As for the next step:  I reckon it will take 50 years before
the right answer starts showing up in textbooks.