The kids at primary school De Singelier learn about STEM in a fun and engaging way. They build rockets from PET bottles using 3D printed parts and launch them using water pressure. As the children go through multiple iterations to arrive at a working design, they learn about the nature of design and development; about identifying the flaws in preceding versions, learning from it and improving the rocket accordingly. Read on to find a comprehensive lesson plan to incorporate this project into your school's educational program.