Science simulations are popular among educators as such simulations afford for multiple visual representation and interactivity. Despite the popularity and abundance on the internet, our literature review suggested little research has been conducted on the use of simulation in elementary school. Thus, an exploratory pilot case study was conducted to address this research gap. In this study, an open source energy simulation was remixed for use in elementary school targeted at the Grade 4 & 5 students as an after-school enrichment program. We proposed 3 stages: design, customization and implementation, to provide useful insights with the aim to allow other educators to conduct their own remixed simulation lessons. The simulation design principles (e.g., learning outcomes and colour coding) with the corresponding TPACK construct that emerged from the design and customization stages were reported. Such simulation design principles would be useful to interested educators and researchers who wish to adapt and use simulation or teach others how to remix simulation. Data from the multiple sources (e.g., field observations, surveys, design notes and existing simulations) indicated that students enjoyed learning with the remixed energy simulation.