A research approach to developing teacher subject knowledge: the case of dissolving

1. A research approach to developing teacher subject knowledge: the case of dissolving John Oversby & Anna Hedderly University of Reading j.p.oversby@reading.ac.uk ESERA: Istanbul, Turkey, September 2009

2. Overview • Previous knowledge • Research questions • Methodology • Data • Interpretation • Knowledge claims • Implication for teaching • References

3. Previous knowledge • Subject matter knowledge • Ideas about solutes, solvents and solutions • Practical work and safety • Modelling i.e. representing of sub-microscopic and symbolic levels • Pedagogical content knowledge • Standard alternative conceptions • Standard experiments • Resources available. including practical work • Nature of knowledge progression and difficulties • Methods of questioning • Methods of explaining

4. Research questions • What is the nature of the student teachers’ understanding of certain chemistry ideas? • What is the nature of the student teachers’ views regarding any aspects of the subject that might pose challenges to learners?

5. Methodology • Topic of dissolving chosen because it is accessible at different levels, it has been well-studied by researchers, and it is intensely practical and theoretical. • Two classes of science beginning teachers, including graduate chemists • Interview tutor about learning intentions and learning achievements (AH) • Use on-going questionnaire with BTs during thee session • Interview selected BTS after session • Collect field notes during the session (AH)

6. Characteristics of chemistry N=34 • Practical aspect (18), including incidence of practical work (14), safety/danger/risk element (7) • Models (3) • Formulae/equations (4), symbols (1) • Quantitative/mathematical aspect (5) • Relationship between submicroscopic and macroscopic levels (3) • Submicroscopic level in general and/or for specific submicroscopic areas/topics (9) • Difficulty in visualizing/involving the unseen (3) • The macroscopic level in relation to chemistry (2) • Abstract nature (2), other sciences seem more real (1) • Tangible nature (1) • Visually pleasing/colourful reactions (4) • Social representations (4), relates to everyday life (5) • Many concepts (3), involves recall (3)

7. Potential problematic areas of chemistry I N=34 • Mathematical aspect (12) including balancing equations (6) • Associated with recall/rote learning/little understanding (8) • Issues relating to practical safety/instruction (7) • Problems with understanding what is happening in reactions (5) • Abstractness (5) • Word equations (5) • Issues concerning visualization (5) • Specific mention of the term ‘sub-microscopic’ or ‘microscopic’ (2) • Use of scientific terms/language (3) – language includes symbols (1) • Issues concerning nature of substances (3) • Issues relating to modelling (2): • Not relevant to everyday life (2) • Spatial awareness (1) • Aspects of organic chemistry (4), physical chemistry (1)

8. Potential problematic areas of chemistry II N=34 Themes and topics • Atomic structure, particles (14) • Bonding (8), mole(2), conservation of matter and/or energy (2), periodic table (1), energy (1), stereo-isomerism (1), equilibrium (Le Chatelier’s Principle) (1), oxidation states (1), nitrogen/carbon cycle (1), energy transfer in reactions (1), electrolysis/rates of reactions (1), chemical processes (1)

9. Dissolving sequence: ideas to be illustrated Formation of iodine vapour • Structure and bonding of solid and vapour Diffusion • Draw a representation of what you think is happening at the particulate level: a. at the edge of the crystal and b. some way out from the crystal (in the liquid) Heat of vaporization of heptane/water: Melting of sodium chloride v dissolving in water of sodium chloride Temperature change and colour change of ionic solids upon dissolution in water: sodium chloride, anhydrous copper (II) sulphate, anhydrous copper (II) chloride • Interactions between ions and water dipoles Conductivity of solutions • Conductivity measurements of copper sulphate and cobalt chloride solutions

10. Major features of the responses for the formation of iodine vapour strand N =22 Explanation level: • Macroscopic only (8) • Containing some sub-microscopic element (albeit brief/vague) (13) Incidence of sub-microscopic terms: • In reference to vapour – “molecule” (8), “particle” only (4), none (10) • In reference to solid: “molecule” (3), “particle” only (5), none (12), “atom” (2) Bonding model: • Vapour – no (10), yes (12) – includes incidence of symbol “I2” (5) • Solid – no (20), yes (2) – includes incidence of symbol “I2” (1) – but they possibly changed “I solid particles” to I2 solid particles” • No clear indication of two components for both vapour and solid (9) • Packing in solid – regular lattice with touching components (14), Incidence of ideas relating to the type of process involved: • Sublimation: Use of term (11) - without term (5) • Evaporation (2) or dissolving (1) • Some form of chemical reaction (5) –gas.

11. Diagrams for iodine vapour

12. Melting sodium chloride N = 23 • Bonding model: • Ionic model (4, 2): Equivocal – due to lack of information (3) • Molecular (11) – includes explicit use of word “molecule” (6) • Atomic (2) – includes explicit use of word “atom” (2) • Incidence of ideas in annotations/labels regarding behaviour of particles and structure of liquid: absent (13), present (10) • Incidence of ideas in annotations/labels regarding heat or energy input: absent (14), present (9) such as idea of particles absorbing/gaining energy (2), heat exciting electrons of sodium chloride (1), implied/explicit idea of involvement of energy in breaking, overcoming bonds (7), implied/explicit idea that much energy is required because bonds are strong (5), use of term ‘lattice energy’ (1), explicit idea of reversible reaction (1)

13. Melting sodium chloride pictures

14. Data • Initial questionnaire indicates general confidence in personal SMK • Interactions in session suggest much hesitant basic chemistry about dissolving, even from the chemists. • On-going questionnaires demonstrate much faulty basic chemistry. • Pre-interview with tutor indicates joint interest in improving basic knowledge and an interest in developing pedagogical techniques e.g. in modelling. Tutor also promoted a metagogniitive-rec0nstructive approach. • Post interview with tutor suggests only a moderate level of success. • BTs focus on expected pupil activity raher than their own learning.

15. Interpretation I • These BTs will teach chemistry in the compulsory 11-16 age range • Problems in moving between macroscopic, symbolic and particulate levels • Inappropriate chemistry e.g. for iodine dissolving in heptane considering that HI is formed, despite there being no change in colour of the iodine.

16. Interpretation II • Sodium chloride indicated prevalence of molecular, not ionic, model • The video and presentation uncovered many serious problems of subject knowledge • The video and presentation uncovered many serious problems

17. Knowledge claims • Beginning Teachers have many alternative conceptions that are parallel to those of thir pupils or even below. • These alternative conceptions are difficult to change. • Pedagogical decisions about choosing appropriate levels of explanation may be impossible. • Prior learning, such as degrees and A levels are not certain indication of sufficient understandiing

18. Implications for teaching • Passive methods of learning subject knowledge are largely ineffective • Deep and challenging methods of learning SMK are needed for change (for pupils and for BTs)‏ • Challenging BTs' personal knowledge has a negative affect. • Developing a reflective attitude is not as common as we believe • Action-orientated goals are not as significant as metacognitve-reconstructive goals

19. References • Aguirre J.M, Haggarty SM and Linder CJ (1990) Student teachers’ conceptions of science, teaching and learning – a case study in pre-service science education International Journal of Science Education 12 (4) 381-390 • Gess-Newsome J and Lederman N, (1993) Preservice biology teachers’ knowledge structures as a function of professional teacher education: a year long assessment Science Education 77, 25-45 • Lederman NG., Gess-Newsome J and Latz MS (1994) The nature and development of preservice science teachers’ conceptions of subject matter and pedagogy Journal of Research in Science Teaching 31(2) 129 - 146 • Lederman NG and Latz MS, (1995) Knowledge structures in the preservice science teacher: sources, development, interactions and realationships to teaching Journal of Science Teacher Education 6 (1) 1-19