The particulate nature of matter

AuszugThe historic Particle Concept in chemistry and the Kinetic Molecular Theory deal with particles of matter. Experience and literature show that most students do not have mental models that all substances are built of small particles, they also are mixing very often the continuous view and the particulate (discontinuous) view - even after instruction. To contribute towards the conceptual reconstruction of scientific mental models a new teachinglearning strategy is suggested: Tetrahedral - in - Zone of Proximal Development (T-ZPD). This T-ZPD instructional strategy was introduced in an experimental group and compared with the traditional (conventional) approach as a control group on the effects of students’ misconceptions and conceptual reconstruction. The research was carried out with a mixed research paradigm: Dominant - Less dominant, Sequential research design. Pilot and main study have been conducted in junior high school chemistry classes in Addis Ababa, Ethiopia; the participants of the main study included a total of 366 students. The Particulate Nature of Matter - Concept Inventory (PNM-CI) was administered to both groups as pre and post tests followed by interviews with selected students. The results of the independent t-test on students’ post test scores on PNM-CI show that the T-ZPD group students’ conceptual reconstruction towards the scientific concept is statistically significantly better compared to the Traditional group students in all contexts investigated. Moreover it is recommended to apply the Particulate Nature of Matter to structural models and model drawings in all future chemistry lessons to develop a better scientific understanding of substances and chemical reactions.