This chapter outlines methods of planning secondary-science units and lessons based on a constructivist framework. The planning document that science teachers use in their schools is the science curriculum or syllabus, which is the mandatory document devised by a government body associated with the relevant state or territory authority. The whole-school plan ensures all concepts are addressed and directs teachers to the topics and key ideas they will address when planning units of work. The problem may be localised to an area surrounding the school: Scientists are trying to sustain the long-term health and resilience of the Great Barrier Reef. A context-based approach is when the context or application of the science to a real-world situation is central to the teaching of the science. A unit of work is a series of science lessons that teaches the concepts in a topic outlined in the science curriculum.