Two years after the end of a two-year intervention program set within the context of science learning intended to promote formal operational thinking, achievement of students (n=234) was tested by their results on British National examinations taken at age 16. Male experimental subjects achieved an average of 40 percent more grades of C or above…

Attempts to show that not only can density be taught to lower ability pupils but that by doing so, there is the possibility of assisting pupils to develop their reasoning powers. Lists teaching activities that help in this process. (CW)