Since PISA 2000, the performance of 15 year-old students from French speaking Community of Belgium (FWB) in science is largely below the OECD average (OECD, 2002, 2004, 2007, 2010 and 2013). This low level of performance is not really unexpected as it was already observed at grade 7 and grade 8 in TIMSS 1995 (Harmon, Smith & Martin, 1997). In mathematics and in reading, the average performance of the 15 year-olds do not significantly differ from the OECD mean. Can these differences in performance in comparison with the OECD means be partly attributed to the emphasis and importance of the respective intended and implemented curricula? Does the relative importance of science teaching differ between primary and secondary education? In this investigation, we make the assumptions that the problem already exists in primary education and persists in secondary education. Therefore, we will focus on primary education. Data will be mainly collected on opportunities to learn (OTL) for science education and on professional knowledge and teaching practices More precisely, these study intents to question teachers at grade 3 and grade 4 about their beliefs and practices in science. Do the primary teachers feel confident and comfortable with science knowledge and science teaching? What’s the effective learning time of our pupils in science? Can we identify patterns of teachers that current international research has shown to have a significant role in science education of pupils?