Affect and Meeting the Needs of the Gifted Chemistry Learner: Providing Intellectual Challenge to Engage Students in Enjoyable Learning - Affective Dimensions in Chemistry Education - page 138

number of the millions of substances known to (and indeed often created by)
chemists are familiar to most young people from their everyday experience outside
the laboratory. Moreover, learning about even a tiny fraction of the vast number of
substances that are known is only made manageable by a range of categories and
typologies used to organise chemical knowledge. Some of these categories and
classes may be considered quite close to natural classes—the elements for example.
But others are more arbitrary or less distinct. Notions of which elements are metals
and which are nonmetals admit matters of degree. Categories such as acid and
oxidising agent are, to a large extent, classes of convenience, as evidenced by the
way chemists have been prepared to redefine membership based on new theoretical
approaches (and the availability of new reagents, such as superacids). This is
inherent in the abstract and complex nature of chemistry as a subject to be taught
and learnt.
The various descriptions of substance properties and behaviours observed in the
laboratory that make up the of chemistry at the macroscopic-

theoretical-descriptive level are to a large extent underpinned in modern chemistry
by explanatory models of the structure of matter at a scale far too small for direct
perception (Johnstone, 1982 ). So students are taught about molecules and ions,
about bonds and partial charges, about orbitals and electron clouds, about shifts in
electron density and about the expansion of octets and resonance structures and
hyperconjugation. Not all of this material is taught at once, and some is considered
more advanced, but there is a brave new world of submicroscopic particles with
their properties and behaviours to be imagined and understood and then to be used
as theoretical tools in building explanations about the formal descriptions (changes
of state, oxidations, precipitations, etc.) that are already one step removed from the
flashes and bangs and colour changes and smells which are the actual phenomena
directly available to learners (Taber, 2013 ).
Aspects of this account are well recognised. Johnstone ( 1982 , 1991 ) long ago
raised the issue of how new learners can suffer from information overload in being
asked to deal with the macroscopic and submicroscopic levels and the various
forms of symbolic representations used to think and talk about them. Moreover,
work in the Piagetian tradition highlighted how the abstract theoretical nature of
much in the secondary school curriculum did not seem to be aligned with the levels
of cognitive development of many learners of secondary school age (Shayer &
Adey, 1981 ).
However, Perry

natural history

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s work suggests there is another issue, related to the multiplicity
of much of what is set out as target knowledge to be learnt in chemistry. This has
been described as

'

(Carr, 1984 ), but it has not had the attention it
perhaps deserves as a major issue in teaching chemistry. Carr referred, for example,
to the issue that there are several models, and so definitions, of acids, that appear in
school and college curricula. In part this is a historical issue; as chemists make new
discoveries and propose new ideas, which can be tested empirically, they refine
their theories (Lakatos, 1970 ): yet in education such historical models are often
presented ahistorically, and indeed what gets presented is sometimes a hybrid

model confusion

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