One of the problems in science education research is obtaining evidence that particular teacher support of learning helps achieve better academic results for students. Classroom ecology involves many variables that are difficult to control and, moreover, many results can only be seen in the medium term. The purpose of this case study on an expert science teacher is to identify the main variables that characterise the teachers' suport on learning and to obtain evidence that really helps to improve the students' scientific literacy. The scientific literacy level of students has been assessed by some 2000 and 2003 PISA items. The findings show that explicit teaching by metacognitive strategies and the implementation of communication skills, accompanied by a warm, firm caring atmosphere in class, is a powerful educational tool to improves students' learning, particularly students with low to medium academic achievements.