With this resource, your students will dive into the fascinating world of friction, gravity and air resistance as they conduct an engaging zipline carrier investigation.   Students become engineers as they construct two zipline carriers with distinct criteria. One carrier will aim to achieve maximum speed, while the other will strive for minimum speed. Focusing on material selection based on their understanding of forces, students will apply their knowledge to design carriers that meet the performance criteria.   The resource includes comprehensive worksheets for planning, analysing and evaluating the investigation, scaffolding students to develop their science inquiry skills. Two versions of the observations page help to provide differentiation for your students. When you have decided which version to give to which students, print it along with the rest of the sheets, gather a range of zipline carrier creation equipment and start the activity.   Prepare for an unforgettable hands-on experience as students put their creations to the test. With safety as a priority, use a long piece of string to set up a secure classroom zipline.   This resource is part of our Physical Sciences Year 4 UNIT PLAN.