Teachers' desire to maximise students' grades is, however, only part of the reason why this is happening. There are several other aspects of the assessment process which dissuade teachers from developing a wider range of investigations.
There are four skills which have to be assessed at key stage 4 in science: the ability to plan an experiment; the skill of obtaining evidence; the analysis of results; and evaluating the investigation.
When a science teacher develops a new practical experiment to use in assessment a detailed mark scheme has to be developed for each separate skill. The exam board criteria which have to be followed are complex and not always clear-cut. Hence we often need to rewrite each mark scheme after it has been tried out with students.
The teacher also needs to create a student work sheet, a technician guide sheet, and will have spent considerable time making sure the procedure is workable.
Exam boards have produced little exemplar material for teachers to use. In fact the last example I received related to a topic which one year previously had been removed from the syllabus. It is impossible to purchase off-the-shelf developed materials and so we are all reinventing the wheel and not travelling very far.
There are also limits on practical equipment and technician time. Class size is also an issue - it is not a good idea to have 26 Bunsen burners all raging at the same time in an average-sized laboratory.
The criteria set by the exam boards need to be simplified and, as Professor Osborne points out, we could look at other ways of assessing science skills.
Perhaps local authorities could second experienced teachers to work on the development of exciting practicals. We need to address this issue if we are to motivate and inspire science students of the future.
Mrs M Griffin
Hitchin girls school