This thesis presents the effect of using computer simulations instead of laboratory equipment as teaching aids. The research was carried out at Tana Haik Secondary and preparatory School on grade 12A and 12B students who were chosen for the experiments. Students in these classes are randomly grouped into an experimental group (EG) of twenty students from grade (12A) and twenty control group (CG) students from grade (12B). In the experimental group they were given both lecture and computer simulation and the control group they were given both lecture and real lab by the same teacher on simple pendulum. In this thesis I had compared the two groups in achievement, attitude and group interaction after the experiments. I had carefully examined the experimental set up and other parameters by applying proper analysis method. I have observed that, there was no significant difference between the two groups in terms of their skills and attitudes. However, the experimental groups had better conceptual understanding and group interaction as compared to the control group.