This study focused on determining the extent to which students failed to solve problems on the concept of motion through the mis-use or non-use of the different stages of a model as well as the variation of the difficulties across sex and mathematical background of students. Two achievement tests were used. Sixty-eight SS2 students from four comparable schools in Ankpa and Idah Local Government Areas of Kogi State made up the final sample. Analysis of students’ papers and pencil written protocols showed that students were not systematic in following the various stages of the model being used by their teacher in the class; students had greatest difficulty in selecting information from memory; boys had consistently greater cumulative errors than girls though was inconsistent when all the stages were considered separately and students without additional mathematical background had greater errors for all stages separately and cumulatively. The educational implications of the findings were discussed also.DR EMMANUEL EDOJA ACHO
