Do you ever feel left out, you have missed a trick or if only you had known something sooner ? Well, I spotted something on Twitter recently and when I read the link it felt that a lightbulb went on ! The article in question was about the theory of the chemical triplet. Ask any chemist about triplets and their first response will inevitably be based around NMR and splitting. But this theory is fundamental to the teaching of chemistry and was introduced by Johnstone in 1991. It identifies the idea that there are three levels when teaching chemistry – macroscopic, sub-microscopic (is that nanoscopic then ?) and symbolic which can also be referred to as descriptive, explanatory and representational. (Diagram from RSC)
I found an excellent research paper on this theory ( I’ve attached the link below). It looks at three teachers with different experience and levels of knowledge of triplet theory. One of the teachers believes that the topic dictates which teaching triplet is most important, for example the macroscopic level to teach acids or symbolic to teach equilibrium. Another believes that the topic should always be introduced through macroscopic everyday examples. One of the teachers believes that particle theory, particle models, particle diagrams are the essences of the microscopic level of triplet relationship. I found this interesting as recently I tried a different approach to teaching redox. I asked the pupils to carry out simple experiments such as displacement and burning magnesium which they would be confident completing.
Instead of asking for observations which would be an intrinsic part of a normal practical I asked them to draw diagrams showing electronic representations of the atoms/ions of the reactants and products to see if they could work out what was happening before embarking on constructing the symbol equation representations. Little did I realise at the time I was moving between all three levels. Whether it improves their understanding will be seen with their topic test.
Triplet theory holds resonance with me as I have always felt that chemistry involves a leap of faith – we are asking our students to relate macroscopic observations which they can see to sub-microscopic behaviour that they can’t. This is probably one of the largest hurdles a chemistry teacher has to overcome but it is a journey they have to make on their own. Pedagogic content whilst training is for the most part generic and does not focus on subject mastery. Continuing professional development is also very much linked to the school’s development plan leaving little focus on subject mastery. The importance of social media and organisations such as the RSC and ASE cannot be underplayed as they reach out to teachers and provide material and ideas to develop their subject mastery.