The concept of matter, especially its particulate nature, is acknowledged as being one of the key concept areas in learning science. Within the framework of learning studies and variation theory, and with results from science education research as a starting point, six lower secondary school science teachers tried to enhance students' learning by exploring what must be learnt in order to understand the concept in specific way. It was found that variation theory was a useful guiding principle when teachers are engaged in pedagogical design, analysis of lessons, and evaluation of students learning, as well as a valuable tool for adapting research results into practice.