One of the most important goals of science education is to help students get good at applying knowledge, ie solving unfamiliar scientific problems. To do that, we need a clear idea of what that involves. There is a whole body of research on how expert understanding (the outcome) differs from novice understanding (what students often have). Novices may have a lot of knowledge, it is relatively disconnected. Whereas experts organise their knowledge in a hierarchical way around fundamental principles, or big ideas. This is what helps them identify situations and use their knowledge to solve problems. And it is what students are increasingly required to do in exams. The Blueprint 5-year plan is organised around a structure of knowledge.
‘Big ideas’ are at the heart of the structure. They are the broadest, most transferable ideas in science. They can usually be summarised in 2-3 words, for example, ‘forces predict motion’ and ‘species are interdependent’. Big ideas can’t be taught directly. Students construct them over a long time and many exposures by connecting concepts together. We identified 14 big ideas in science that connect to all the knowledge students need for secondary science.
Figure 1: 14 big ideas
Figure 2: How all the knowledge about the big idea can be organised.
Key concepts are central components of the big idea. They are the complex ideas that what we want students to understand in one unit. There are 3 kinds of concepts we use in science:
- Generalisations express patterns that link together two or more concepts. E.g. ‘some metals react with acids to produce hydrogen’. It links the concepts of ‘metals’ and ‘acids’ and identifies characteristics about them. It is general because it applies to many different examples.
- Principles are also conceptual relationships. They are cause and effect links, correlations and laws – how one thing influences another. E.g. ‘tuberculosis is caused by the tubercle bacillus’, or ‘for every action there is an equal and opposite reaction’. The knowledge is not just to know it is a fact but how the relationship works.
- Models & theories A theory is a set of conceptual ideas to explain phenomena, and a model is a simplified representation of how a process or system works.
According to Erickson (2013) concepts are also: timeless, universal, one or two words, and abstract to different degrees. Concept understanding is the most important focus of each unit, and takes time. This is why we have limited units to 2-3 concepts.
These are more specific concepts that students need to properly grasp and connect if they are form the key concept. E.g. for the key concept of ‘balanced & unbalanced’ forces, students need to understand the concept of ‘equilibrium’. We need to give students sufficient experience and time to construct these concepts.
Much of the content in science only needs superficial understanding. For instance, at year 7, students only need a few details about each part of a cell such as the mitochondria and cytoplasm. So although in more advanced biology they could be learned as concepts, in year 7 we treat them as factual knowledge, and give them lower priority.
A major reason why many students don’t become experts in understanding is that the syllabus is overstuffed with knowledge. This tends to encourage a ‘coverage’ approach. The syllabus becomes the curriculum, as teachers basically work their way swiftly through the content as a set of items to teach, giving each one roughly equal time.
The trouble with the coverage approach is that it does not give enough time to the key concepts. They take a long time for students to fully understand, but are crucial if we want students to develop expert understanding. Given the amount of content exceeds the time available, the only solution is to prioritise.
A structure of knowledge makes prioritisation easier. Blueprint units are structured around key concepts. Each has a 5-stage learning pathway to ensure there is enough time for students to grasp it. Concepts are given more curriculum time, and knowledge that we have defined as ‘key words’, is given less time.
Curriculum (p135-141) from Chapter 9: Designing Curriculum, Instruction, Assessment, and Professional Development (2002) National Research Council
Working with the big ideas of science education (2015)Association for Science Education