Changing student conceptions in a chemistry classroom after chemistry in context: - A research project within the framework of the "Didactic Reconstruction" model

The clear discrepancy between students' everyday explanatory models and specialised scientific concepts has been empirically proven many times. One of the reasons why learners find it difficult to use scientific concepts in everyday life and in other application situations is that these concepts are learnt in very narrow teaching contexts and remain attached to them; they are not associated with everyday concepts at all. The selection and treatment of substances, experiments and questions in chemistry lessons that are far removed from everyday life does not suggest a transfer to questions that are close to everyday life. This is one of the reasons why the Chemistry in Context concept (Chik for short) aims to teach specialised content and concepts embedded in authentic, student-relevant contexts.
Among the student conceptions relevant to chemistry lessons, ideas about substances, their properties and their structure from particles are of central importance. The interplay between the consideration of the material level and the level of interpretation in the model of the smallest particles is characteristic of the acquisition of knowledge in the subject of chemistry and is a prerequisite for further understanding. The above-mentioned discrepancy between pupils' ideas and the subject-specific concept has been well investigated in this area. The study aims to investigate changes in these perceptions within a teaching unit for initial lessons after ChiK.
The development of this teaching unit - as well as the follow-up units after ChiK - is based on the model of didactic reconstruction. This model provides for the development of so-called didactic structures, e.g. concrete teaching units, a consistent, reciprocal relationship between pupils' ideas and subject-related concepts. In order to capture the pupils' perspective, essential results of conceptual research from the field of ideas on the structure of substances were therefore compiled and categorised (the category system substances-particles). In addition, a basic concept of "substance-particle" was developed after analysing textbooks and the various framework guidelines. In addition, a basic concept of "substances-particles" was developed after analysing textbooks and various framework guidelines. On the basis of this didactic structuring, the context for the initial lessons was developed; its title is "The taster in grade - chemistry replaces the taster". When designing the lessons, methodological suggestions from conceptual change research to promote concept changes were also incorporated.

Aims and survey methods

Trials of the developed teaching units are empirically accompanied in the design of case studies. We report on the pilot testing of the "taster context", which was carried out in the 2001/2002 school year with a duration of 23 lessons at a grammar school in Lower Saxony.
The aim is to evaluate this teaching unit as a previous didactic structure with regard to the following research questions: Was it possible to support the incorporation of pupils' ideas by teaching according to ChiK? Could pupils' ideas in a ChiK lesson serve as a starting point for the introduction of specialised chemical concepts? Did the lesson content and the ideas addressed in it have an effect on ideas about other phenomena that were not the subject of the lesson?
Questionnaires - so-called learning support sheets - and videography were used as survey instruments. The learning support sheets were used before, during and after a unit. The questionnaires contained tasks relating to a specific everyday phenomenon (e.g. making tea) that had to be answered repeatedly. The pupils received their own answers back and were thus able to comment on their ideas, correct them if necessary and track their own learning progress. The corresponding tasks were not related to the context covered in class, but allowed the chemical content of the context to be applied and were always aimed at describing the students' own ideas. The recorded student formulations were analysed using the developed category system "substance level", "particle mixing concepts", "adequately discontinuous". Changes in conceptualisation could thus be identified as category changes.
In the next step of the research work, the video data was analysed. A comparison of the students' coded conceptions from the learning support questionnaires with those from the dialogues recorded in class showed that the questionnaire can serve as a valid instrument for recording students' conceptions. With the help of turn-by-turn analyses, we now describe the course of the dialogue and the student interactions depending on the respective teaching situation (work questions, methods, experiments). In this way, we attempt to identify more detailed statements about effective elements of the lesson. These provide new hypotheses for follow-up studies in which the previous didactic structure can be optimised.

Schmidt, S. Parchmann, I.; Rebentisch D (2003) Chemistry in Context for Lower Secondary Levels: Cola and Ketchup in the Beginning Classroom. CHEMKON 10(1): 6-16

Schmidt, S. Parchmann, I. (2003). Von "erwünschten Verbrennungen und unerwünschten Folgen MNU 56(4): 214-221.

Christiansen, D. Huntemann, H. Schmidt, S., Parchmann, I. : "Müll kann man nicht wegwerfen" in: NiU Chemie 14 (1) 2003, pp.11-15

Parchmann I.; Rebentisch, D. Schmidt, S. (2003). With chemistry in context to a substance quantity concept. PdN Chemie 52(7): 10-15.

Schmidt, S. Parchmann, I. (2003). Investigation of students' ideas in a lesson based on chemistry in context. Proceedings of the annual conference of the GDCP 2002. extracurricular learning in physics and chemistry. A. Pitton. Münster Hamburg London, Lit Verlag: 272-274

Parchmann, I.; Schmidt, S. :Chemie im Kontext - von sinnlichen Wahrnehmungen zu ersten Teilchenvorstellungen, Chimica didactica, i.D.

<tdwidth="257"></tdwidth="257">