Two booklets were developed by the Learning in Science Project (primary)--LISP(P)--to help teachers adopt an approach to science teaching which would enhance children's understanding of floating and sinking; the strategy enables teachers to reconceptualize their teaching task from activity-driven, didactic teaching to conceptual-change teaching. The first booklet was written for more confident teachers, using a less-structured approach, and the second for teachers who might prefer detailed guidance. The booklets were initially tested to determine problems in their use. A second set of trials was conducted to examine: if actual classroom practices matched intentions of the authors in the booklets; ways in which teachers modified and amplified materials in the booklets during their implementation of suggested strategies; and features of the approach which presented difficulties for teachers or students and which could be clarified or revised. This paper includes: case studies focusing on teachers' preparation and planning, teacher/student classroom experiences, and evaluation of the teaching/learning experiences; comments about the trials related to the three evaluation objectives; and a discussion of two major issues which arose during the trials. Results indicate that the booklets can be re-written to convey a teaching sequence and strategies within the capabilities of teachers, provided they are not intended to stand alone. (JN)