ABSTRACT
A more sophisticated model of an atom has a small central ball (the nucleus) surrounded by orbiting electrons. It’s also wrong, but the extra complexity enables people to explain more and to solve more problems. The cognitive differences between novices and competent practitioners underpin the differences between two kinds of teaching materials. A tutorial helps newcomers to field build a mental model; a manual, on the other hand, helps competent practitioners fill in the gaps in their knowledge. The counterpoint to formative assessment is summative assessment, which takes place at the end of the lesson. Summative assessment is like a driver’s test: it tells the learner whether they have mastered the topic and the teacher whether their lesson was successful. In order to be useful during teaching, a formative assessment has to be quick to administer (so that it doesn’t break the flow of the lesson) and have an unambiguous correct answer.
