When, and how much, 'simplification' is justified in teaching science?

I've copied this from the physics teachers' list (PTNC - apologies
for those on both lists): the old 'chestnut' of finding the optimum
level of simplification is still going strong.

Keith


>
>in biology we use an 'onion skin' perspective at different levels, and as
>you get 'higher up' you get more of 'the truth'. And admit that sometimes
>at lower levels we have "simplified" (never lied, of course not) because the
>truth is too complex at the previous level.
>
>Mind you, introducing quantum chromodynamics at Y7 could be interesting...
>
>Cheers
>Graham
>
>-----Original Message-----
>From: Physics Teaching News and Comments
>[mailto:PTNC@...]On Behalf Of Gren Ireson
>Sent: 23 September 2003 13:39
>To: PTNC@...
>Subject: Re: LH and RH rules
>
>
>Not as easy as it appears this!
>
>Why do we bother to teach ... seems a rather strong term and could be
>applied to so much physics; why bother to teach the Bohr model of the atom
>and a model based on charge probability density?, why bother to teach a
>version of the Dirac Sea model for anti-matter which can't be used with
>bosons and not the Klein-Gordon equation?, Why bother with a study of
>electromagnetism other than one which includes Maxwell's equations?
>
>Of the 30 000 ish physics A-level students only about 2400 go on to an
>undergraduate course in physics and hence I would argue that:
>
>1. school physics at GCSE and A-level should be accessible to the 30 000
>(and no A-level spec includes cross-products, or dot-products, in its
>mathematical requirements - perhaps the development groups thought this
>through) where the LH and RH rules do allow the students to make predictions
>regarding physical phenomena.
>
>2. university students do not need to 'unlearn' school physics but rather to
>be shown how their current understanding can be extended to include a more
>sophisticated (and often more mathematical description).
>
>3. knowledge of vector and/or scalar products (or other mathematical
>devices) by students and the ability to solve numerical problems using them
>DOES NOT in general indicate they UNDERSTAND - much research shows this to
>be the case.
>
>Gren
>
>"If we want things to stay as they are, things will have to change"
>(Di Lampedusa, The Leopard, 1957)
>
>Dr Gren Ireson CPhys MInstP ILTM
>Matthew Arnold Building
>Loughborough University
>Leicestershire
>LE11 3TU
>UK
>
>+44(0)1509 222784
>----- Original Message -----
>From: "Elizabeth Parvin" <emp4@...>
>To: <PTNC@...>
>Sent: Tuesday, September 23, 2003 12:24 PM
>Subject: Re: LH and RH rules
>
>
> > Speaking from the university point of view, I could not agree more. One of
> > the first things we have to do for new undergraduates is to 'unteach' all
> > the stuff about RH and LH rules and teach vector cross products and the
>> right hand rule. Everything can be done using the one rule then.
>>
>> Liz Parvin
>> Warwick University
>>
>>
>>
>> PTNC@... writes:
>> >Can someone explain : why do schools bother with LH and RH rules for
>> >motors and generators. Why not use a simple RH coordinate system rule
>> >throughout, F = qv x B (as in z = x cross y) : F is the first finger, v
>> >is the second finger and B is the thumb.
>>


--

Dr. Keith S. Taber
http://www.educ.cam.ac.uk/staff/taber.html
University Lecturer in Education
University of Cambridge Faculty of Education
Homerton College site
Hills Road
Cambridge CB2 2PH


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