Dr. Keith S. Taber
Publication:
Taber, K. S. (2003)
The atom in the chemistry curriculum: fundamental concept, teaching
model or epistemological obstacle?
Foundations of Chemistry, 5 (1), pp.43-84.
Abstract:
Research into learners’ ideas about science suggests that school
and college students often hold alternative conceptions about ‘the atom’.
This paper discusses why learners acquire ideas about atoms which are incompatible
with the modern scientific understanding. It is suggested that learners’
alternative ideas derive - at least in part - from the way ideas about atoms
are presented in the school and college curriculum. In particular, it is
argued that the atomic concept met in science education is an incoherent
hybrid of historical models, and that this explains why learners commonly
attribute to atoms properties (such as being the constituent particles of
all substances, or of being indivisible and conserved in reactions) that
more correctly belong to other entities (such as molecules or sub-atomic
particles). Bachelard suggested that archaic scientific ideas act as ‘epistemological
obstacles’, and here it is argued that anachronistic notions of the atom
survive in the chemistry curriculum. These conceptual fossils encourage learners
to develop an ‘atomic ontology’ (granting atoms ‘ontological priority’ in
the molecular model of matter); to make the ‘assumption of initial atomicity’
when considering chemical reactions; and to develop an explanatory framework
to rationalise chemical reactions which is based on the desirability of full
electron shells. These ideas then act as impediments to the development of
a modern chemical perspective on the structure of matter, and an appreciation
of the nature of chemical changes at the molecular level.