By grade 12, students should be able to • Construct their own explanations of phenomena using their knowledge of accepted scientific theory and linking it to models and evidence. • Use primary or secondary scientific evidence and models to support or refute an explanatory account of a phenomenon. • Offer causal explanations appropriate to their level of scientific knowledge. • Identify gaps or weaknesses in explanatory accounts (their own or those of others). In their experience of engineering, students should have the opportunity to • Solve design problems by appropriately applying their scientific knowledge. • Undertake design projects, engaging in all steps of the design cycle and producing a plan that meets specific design criteria. • Construct a device or implement a design solution. • Evaluate and critique competing design solutions based on jointly developed and agreed-on design criteria.