Re: A list of textbook misconceptions

[William Beaty <billb@eskimo.com>]

On Wed, 11 Feb 1998, LUDWIK KOWALSKI wrote:
> This message ("The Physics of Flight: It's Newton not Bernoulli") may be
> appropriate for starting a list of common misconceptions that we, teachers,
> propagate on the basis of what is in our textbooks. So let us start the
> list. Please add your own item (but keep it short, elaborate in a separate
> message) and repost the list.

I've added some from my K-6 TEXTBOOK MISCONCEPTIONS page.  What grade
level should be the cutoff?  Feel free to edit out inappropriate entries. 
(But some of my examples appear in K-12, not just K-6) 

Note that I've changed the "airfoil" wording.  Bernoulli and Newton are
compatible.  The problem really involves false claims that airfoils
REQUIRE assymetry to function, that the ratio of upper/lower airfoil
surface is of prime importance, and that they operate only via pressure
difference and need not deflect any air. 

Also note the "speed of light in glass" entry, #18.  Photons always
propagate at c, but this is sometimes "mutated" into a belief that
macroscopic optical wavefronts never change speed, that optical fibers
cannot delay light pulses, etc.


                  A LIST OF TEXTBOOK MISCONCEPTIONS
                *************************************
 
 1) The Physics of Flight: It's air-deflection, not wing shape
 
 2) The green house effect: suppression of convection is the main factor.
 
 3) Capacitors in series: the equilibrated charges are not equal in dc 
    the circuits.
 
 4) Melting of ice under skating blades is due to high pressure.
 
 5) Gravity in space is zero (or very small, e.g. NASA's 'microgravity')

 6) Filled and empty balloons directly demonstrate air's weight

 7) Friction is caused by surface roughness (interlocking asperites)

 8) Infrared light is special, it is "heat"

 9) Ben Franklin's kite was struck by lightning

10) Clouds, fog, etc. are made of vapor (rather than droplets)

11) The Earth's "N" pole resides in the northern hemisphere

12) Light from the sun is perfectly parallel

13) Laser coherence is caused by atoms' in-phase emission

14) Sound travels much better through solids and liquids than through gas

15) For every motion there is an equal and opposite motion

16) Reentering spacecraft are heated only by frictino

17) Salt water contains molecules of NaCl

18) Light propagates at c even when in transparant media

(I'm not listing "electricity misconceptions" or "electrostatics
misconceptions" here.)
 

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