How to help teachers to design teaching plan for raising student’s competency at secondary school in laos is now of great concern. On the other hand, teachers teach sciences almost by lecturing theoretical only. They rarely explain the problems based on actual phenomena that occur in pupils’ daily life nor do experiment during the class. Thus, one of the vital concerns for lao’s science education is that the summative and formative assessment for science learning are both only focused on evaluating the pupils’ knowledge. To develop experimental competence, we developed and evaluated a practical science course “heat and temperature” with hands on activities and realistic application, using action research approach. For measuring experimental competence, the framework for practical assessment from some previous researchers was adapted and used. In this paper, we describe the process and experiences of how to develop the course with comprehensive worksheets and hands on equipment. We also interpret the way to gather evidence of experimental competence during the course. As a result, the course with hands-on activities and realistic application can significantly develop the following indicators of experimental competence: “make logical reasoning to find out what to investigate”, “identify which physics quantity should be measured or which phenomena should be observed”, “describe experimental design”, “collect experimental data”, “interpret experimental data”. 2019, Journal for the education of gifted young.