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Chemistry misconceptions – diagnosis, prevention and cure

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Teachers in Germany �(differences in our 16 states)

Five kinds of teachers:

Elementary school
Middle school (Junior high school)
Gymnasium (Junior and Senior high school)
Vocational school or Technical college
School for children with learning difficulties

All teachers have to have two subjects.

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Chemistry teachers for Middle schools at Chemistry-Didactic Institute, University Muenster

Bachelor studies (3 years):

General-, Inorg.- and Organic chemistry and Labs at our

institute of chemistry didactics, lectures integrated with

chemistry didactics (see following round cake chart)

Master studies (2 years)

Seminars on students misconceptions, inquiry learning,

problem solving, food chemistry, chemistry in context,

history of science, air pollution and climate change,

laboratory for school experiments with presentation,

one semester teacher training at school.

Hans-Dieter Barke - University of Muenster Germany

Structural units and chemical formulae

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Chemistry teachers for Gymnasium (grade 5 – 13) at University of Muenster

Bachelor studies (3 years):

General-, Inorg.- and Organic chemistry and Labs in the institutes of Inorganic, Organic and Physical Chemistry

Master studies (2 years)

Seminars on Chemistry Education at our Institute for Didactics of Chemistry.

One semester teacher training at Gymnasium under the supervision of an experienced Chemistry teacher

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Chemistry teacher training at school and teacher training seminar (1 – 1.5 years)

Teachers are employees for 1, 1.5 or 2 years at school and at teacher training seminar,
they give prepared lectures under supervision of an experienced chemistry teacher,
their lectures are critizised and judged by supervisors with goal „student-oriented lessons“
by good records they will be taken as employees of state for life time,
they get the full salary (during teacher training time half of the salary).

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Barke‘s 3-level concept (1986):�phenomena – structural models – chemical symbols

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Johnstone´s triangular concept (2000)

This graph can also be taken as the basis of „System Thinking“:

Teacher gives the full system of three basic kinds of particles: atoms, ions and molecules for interpreting chem. reactions.

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Example for Submicro level: „beaker model“ of particle arrangements for neutralization reaction

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Challenge of misconceptions by System Thinking:�Early introduction of atoms, ions and molecules �(German textbook for grade 7, Braunschweig 2016)

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Didactical Periodic Table (see www.educhem.eu):�Combine ions mentally to an ionic lattice, write ionic formulae:�Na⁺Cl^-, Ca²⁺(Cl^-)₂, (Al³⁺)₂(O^2-)₃ , shorten them to NaCl, CaCl₂, Al₂O₃ .

Hier steht der Titel der Präsentation

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Barke, H.-D. et al: Misconceptions in Chemistry. Heidelberg 2009 (Springer)

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Preconcepts and school-made misconceptions

Preconcepts: brought by children through careful observation in their every-day life: - combustion („something is going away“), - transmutation of substances („copper changes

from red to green, iron from grey to black“),

- gases are substances? („they have no mass“), etc.

School-made misconceptions: developed by inappropriate teaching on the representational level: - chemical equilibrium („reactants and products show same concentration, same amount of substance“),

- weak acids („they have a pH of 3 or above“),

- redox reactions („oxygen is always involved“), etc.

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Structural units and chemical formulae

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Contents in Chemistry text books for Secondary-I schools (grade 7 – 10)

Substances and their properties: sensory perception, states of matter, density, melting and boiling temperature, solubility, etc.
Mixtures and separation, pure substances, particle model of matter, dissolution, diffusion, according model drawings, etc.
Chemical reactions, combustion, elements and compounds, energy transfer, law of conservation of mass, gas laws, etc.
Dalton‘s extended atomic model, models for regrouping of atoms during chemical reactions, model drawings to develop mental models, mole idea, stochiometry, calculations, etc.
Air, water, metals, nonmetals, redox reactions, nucleus-shell-model of atoms and ions, covalent and ionic bonding,
Acids, bases and neutralization, chemistry and every-day life, chemistry in industries and technology, organic chemistry.

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Reaction of black iron oxide with silvery aluminum to form molten iron and white aluminum oxide

Procedure: Put a filter paper in the flower pot to close the opening. Fill half of the pot with mixture of iron oxide and aluminum powder. Take an iron bowl filled with sand and place it under the opening. Ignite a sparkler and put it with the burning end into the mixture.

Caution: 2000 degree hot iron melt is running out of the pot!

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Sphere packing models to visualize reactions of metal oxides and metals, develop mental models�Example: copper oxide(s) + iron(s)

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Contents in Chemistry text books for Secondary-II schools (Gymnasium grade 11 – 13)

Chemical structures (giant and molecular structures), chemical bonding, instrumental analysis,
Rate of reaction, kinetics, principle of Le Chatelier, chemical equilibrium, equilibria in every-day life,
Energy, enthalpy, entropy, Gibbs-Helmholtz equation, thermodynamics, energy in every-day life,
Donator-acceptor reactions, acids and bases, weak acids, buffer solutions, redox and complex reactions,
Electrochemistry, electrolysis, Galvanic cells, batteries combustion cell, corrosion,
Organic chemistry.

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�

Contact:

Prof. Dr. Hans-Dieter Barke

University of Muenster

Institut fuer Didaktik der Chemie

Corrensstr. 48

48149 Muenster

phone: 0049 - 251- 6743489

e-Mail: barke@uni-muenster.de

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