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11.12.2014

JCF-Weihnachtsvorlesung: "Misconceptions in Chemistry"

JCF-Weihnachtsvorlesung:

Das JungChemikerForum (JCF) wird auch das Jahr 2013 mit der traditionellen JCF-Weihnachtsvorlesung ausklingen lassen. Die Vorlesung beginnt am 11. Dezember um 17.15 Uhr im großen Hörsaal.

Für den Vortrag konnten die Jungchemiker in diesem Jahr Prof. Hans-Dieter Barke von der Universität Münster gewinnen. 

Structure of matter – diagnosis of misconceptions and challenge

In teaching science we differentiate two kinds of misconceptions: preconcepts which young students are bringing from home or from every-day-life: their special images about the burning process, about gases and their properties, about substances and their changes. On the other hand we know about “school-made” misconceptions which are caused by inappropriate teaching methods or by complexity: equilibrium, acids and bases, redox, energy.     
   
Salts and salt solutions are not easy to teach because students know the idea of atoms and molecules, but do not accept the idea of ions. Like on Organic chemistry they are thinking of molecules: “NaCl molecules” in sodium chloride, even of “Cl-Ca-Cl molecules” in solid calcium chloride or in aqueous solutions. The same with acids and bases: students often are thinking of “HCl-molecules” in hydrochloric acid or “NaOH-molecules” in sodium hydroxide solution if only formulae like HCl and NaOH are written in equations – and not hydronium ions and hydroxide ions which react to water molecules, also not the remaining ions which do not react.
   
If one introduces a Periodic Table which shows the atoms and ions as basic particles of matter, students may better accept the ions and their charge number – even without the atomic nucleus-shell model. When additionally beaker models are drawn showing the involved ions of salt solutions, of acids and bases, the world-wide stated misconceptions should be challenged.
   
In every case misconceptions should be diagnosed and discussed in chemistry lectures. One idea for diagnosis is to show key experiments and to ask students about their explanation or their mental models: one answer may be the scientific one, other answers are misconceptions. The students discuss these models with the help of the teacher and will come to the scientific idea. Another useful strategy is offering Concepts Cartoons: They show four or five pictures of students, one with the scientific answer for the written question, the others with well known mis-conceptions. The discussion of students may come up with the scientific answer; afterwards students are also aware of mistakes if they have discussed the shown misconceptions.

Im Anschluss an den Vortrag lädt das JungChemikerForum alle Hörer der Weihnachtsvorlesung zu einem kleinen Umtrunk ein.