The study aims to present how to apply a STEM activity in which physical computing principles and computational thinking processes are used as a differentiation practice to be used in the education of gifted students. In the activity, the students designed smart packaging that will provide healthy long-term storage of foods to solve the greenhouse gas emission problem caused by intensive plastic production. The activity was carried out with eight gifted students studying in 7th-9th grades. The students investigated the factors that would reduce greenhouse gas emissions and synthesized biodegradable polymers during the inquiry process. In the engineering design process, they determined the most suitable solution for packaging design in the polymer synthesis they carried out using different plant extracts with antibacterial properties. They developed a smart packaging design using physical computing in this process. During the STEM activity, the students used computational thinking, engineering design, and inquiry process.