Knowledge building is about getting learners to focus on ideas and improving ideas. On the other hand, classroom teachers have to organize learning activities which are tangible and engaging for students. Would the use of different task structures influence the ease of facilitating students engagement in knowledge building? In this contribution, the author will describe her experience in facilitating knowledge building through design projects linked to the high school Physics curriculum. In autumn 2003, the teaching of heat was conducted in parallel to an intra-class solar cooker design competition. In spring 2004, the teaching of mechanics was conducted in parallel to an inter-school design competition on flight devices that can stay the longest in the air within a defined touch-down area. A lot of the research literature on science education has documented the robust alternative conceptions in these two topic areas, heat and mechanics. An important aim in getting the students to engage in knowledge building using Knowledge Forum to support the group based design work was to see if this would lead to improvements in their understanding of the difficult, abstract concepts involved.

The results suggested that the KF work had a significant effect on the students learning outcomes. However, the task design and the teachers facilitation from are important factors influencing the learning process. In particular, the author will present the mathematical discourses the students had in relation to the alternative conceptions and how the students understanding improved through social context of the learning process. The outcomes of this academic years experience will help us in improved planning for our science curriculum as well as in improving mathematical teaching methods for teachers in elementary schools.