School science is seen as providing a pre-professional training and acts essentially as a sieve for selecting those who will enter academic science and the professions that have a scientific base, or follow courses of scientific vocational training. Consequently, the principal focus of any GCSE course should be on developing ‘scientific literacy’ rather than on training future scientists. This does not mean that the school science neglect the process of preparing student for careers in science. The science curriculum should provide access to more advanced courses, in both pure and applied science, for those who wish to take them. (Millar and Osborne 1998).This is why the programme of study for Key Stage 4 has two versions, one for ‘double science’ taking up to 20% of curriculum time and one for ‘single science’, taking up to 10% curriculum time. The NC does not preclude schools offering what has become known as ‘triple science’ (i.e. biology, chemistry and physics taught as separate subjects) in the 14-16 age range. The minimum requirement is that pupils are taught single science. A significant feature of the national curriculum was that science had to be taught in primary schools. There had been a steady increase in the number of primary schools teaching science prior to the introduction of the national curriculum, but from 1989 it became compulsory. Pupils now entering secondary school in Year 7 have already six years of science teaching. This has profound implications for the secondary curriculum.In England, the new National curriculum programme of study of key stage 4 (ages 14-16) from 2006 recognises the breadth of aims of the science curriculum, perhaps for the first time. It has been designed to provide the flexibility needed to address the multiple purpose of the science curriculum and the diversity of student needs and interests.