A naturalistic case study on the way primary school would-be teachers explain physics was conducted in Science and Technology Education. The study dealt with explaining physics phenomena (mechanics, thermodynamics, optics and electricity) at the beginning and at the end of the course on physics. Although the students used everyday and scientific knowledge their explanations also offered mixed information that comprised both types. When using scientific knowledge the most advanced justifications were found in the issues concerning mechanics and electricity related phenomena. The students mainly used everyday expressions discussing the cases of light and heat.
This study gives detailed information about primary school would-be teachers’ ways of explaining physics phenomena. The would-be teachers explained physics phenomena using different types of knowledge including everyday knowledge, everyday knowledge with scientific concepts, scientific sounding knowledge with everyday concepts and scientific knowledge. Scientific knowledge seems to be necessary in order the would-be teacher succeed in explaining everyday phenomena. The explanations in everyday topics also gave a different picture of the students´ knowledge, from what the exam had given. The analysis of the explanations can thus give other information on the results of learning. No difference was observed in the nature of the explanations given by different students. If a primary school would-be teacher did explain one question well, s/he did not necessarily do well in other questions. No specific coherence between the students and their responses was found. The would-be teachers possibly have different experiences of everyday life and also due to school science and different mental images of different topics.