This study compares the learning results of three groups of secondary two (grade eight) students of a similar academic standard who participated in a teaching intervention involving different pedagogies. One hundred and forty-nine Hong Kong secondary students were chosen and divided into three groups, "whole-class teaching approach", "group work with no specific strategies" and "group work with effective strategies", to study the "space travel" unit in their science curriculum. The first group was exposed to traditional whole-class instruction, and the latter two practised collaborative group work, with the third adopting four effective strategies derived from a UK-based quasi-experimental project. Analyses of the pre- and post-diagnostic assessments and audiotaped discussions revealed that group work comprising effective strategies not only raised students' test scores, but also enhanced their joint construction of conceptual knowledge in science. The findings suggest that the effective strategies adopted in this study are contributory factors to superior student accomplishments and a stronger desire to seek clarification accruing from shared cognitive activities.