Re: [Phys-l] Learning barriers: was Physics first

[Rick Tarara <rtarara@saintmarys.edu>]

Consider that there are three generations of scientists out there using the 
terms oxidation and reduction.  You, of course, could teach your students 
using 'loss of electrons' or 'gain in electrons' and then your students 
wouldn't be confused UNTIL they hit the outside world and heard people 
saying oxidation and reduction.  They would be confused for a while, then 
they would realize these are just different terms for what old LK called 
'loss/gain of electrons".  They might curse you under their breadth for 
leaving them ignorant of this common nomenclature and, if they then go off 
to teach, will almost certainly return to these old words.

It would be wonderful if we really had a clean slate and could rework all 
the pedagogy without regard to common practices, common nomenclature, 
historical documents and developments.  I'm sure Jim Green would love to 
rewrite all the intro text book thermo sections.    ;-)

You could maybe start a movement towards more descriptive nomenclature by 
teaching 'loss/gain of electrons" but also clearly identifying that others 
call this oxidation and reduction, but that you hold such words confuse 
rather than clarify the physics/chemistry.  Maybe your students then will 
spread your teachings.

Rick

***************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
******************************
Free Physics Software
PC & Mac
www.saintmarys.edu/~rtarara/software.html
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----- Original Message ----- 
From: "Ludwik Kowalski" <kowalskil@mail.montclair.edu>
To: "Forum for Physics Educators" <phys-l@carnot.physics.buffalo.edu>
Sent: Thursday, November 16, 2006 12:32 PM
Subject: [Phys-l] Learning barriers: was Physics first


> What takes away pleasure from learning? One of the factors is confusing
> terminology, giving new meanings to words which already refer to
> something in common use. This has been discussed in some of our
> debates. Below is an illustration, pasted from Wikipedia; the law of
> conservation of charge is not even mentioned.
>
> If "oxidation" is loss of electrons then why don't they call it loss of
> electrons. And if "reduction" is gain of electrons then why don't they
> call it gain of electrons. By the way, reduction (for example in
> weight) is usually accomplished by loosing something, not by gaining
> something.
>
> Ludwik Kowalski
> Let the perfect not be the enemy of the good.
>
> Oxidation and Reduction
> The elements involved in an electrochemical reaction are characterized
> by the number of electrons each has. The oxidation state of an ion is
> the number of electrons it has accepted or donated compared to its
> neutral state (which is defined as having an oxidation state of 0). If
> an atom or ion donates an electron in a reaction its oxidation state is
> increased, if an element accepts an electron its oxidation state is
> decreased.
> For example when sodium reacts with chlorine, sodium donates one
> electron and gains an oxidation state of +1. Chlorine accepts the
> electron and gains an oxidation state of −1. The sign of the oxidation
> state (positive/negative) actually corresponds to the value of each
> ion's electronic charge. The attraction of the differently charged
> sodium and chlorine ions is the reason they then form an ionic bond.
> The loss of electrons of a substance is called oxidation, and the gain
> of electrons is reduction. This can be easily remembered through the
> use of mnemonic devices. Two of the most popular are "OIL RIG"
> (Oxidation Is Loss, Reduction Is Gain) and "LEO" the lion says "GER"
> (Lose Electrons: Oxidization, Gain Electrons: Reduction).
> The substance which loses electrons is also known as the reducing
> agent, or reductant, and the substance which accepts the electrons is
> called the oxidizing agent, or oxidant. The oxidizing agent is always
> being reduced in a reaction; the reducing agent is always being
> oxidized.
> The gain of oxygen, loss of hydrogen and increase in oxidation number
> is also considered to be oxidation, while the inverse is true for
> reduction.
> A reaction in which both oxidation and reduction is occurring is called
> a redox reaction. These are very common; as one substance loses
> electrons the other substance accepts them.
> Oxidation requires an oxidant. Oxygen is an oxidant, but not the only
> one. Despite the name, an oxidation reaction does not necessarily need
> to involve oxygen. In fact, even fire can be fed by an oxidant other
> than oxygen: fluorine fires are often unquenchable, as fluorine is an
> even stronger oxidant (it has a higher electronegativity) than oxygen.
>
>
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