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The three types of knowledge in chemistry

By Steve Draper,   Department of Psychology,   University of Glasgow.

Alex Johnstone (see references below) pointed out that in Chemistry, students must learn in three different representations at once, and how to inter-relate each new concept or fact in all three domains:

  1. Macroscopic: descriptive and functional (e.g. how chemical phenomena appear to the senses, colour, smell, density, etc.).
  2. Formal or representational (the equations used to represent reactions).
  3. Molecular, "submicro", explanatory: the invisible but 3-dimensional world of molecules' shapes and their dynamic motions, interactions, and kinetics.

There are several points about this.


A.H. Johnstone (1982) "Macro- and microchemistry" School Science Review vol.64 pp.377-379

A.H. Johnstone (1991) "Why is Science Difficult to Learn? Things are Seldom What They Seem" Journal of Computer Assisted Learning vol.7, 75-83.

A.H. Johnstone (1993) "The development of chemistry teaching" Journal of Chemical Education vol.70 no.9 pp.701-705

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