scientific literacy implies that student should have some understanding of the goal of scientific enquiry which is to generate reliable knowledge about the natural world. Data collected and obtained by observation experiment, either in the laboratory or in the field, lead to the development of models and explanatory hypotheses that enable predictions that can then be tested experimentally. New ideas, however, commonly build on previous knowledge. Scientists themselves rarely work in isolation and are members of research groups or teams that engage in extensive collaboration with colleagues both nationally and internationally. New knowledge claims are always perceived to be provisional and may lack justification when subjected to critical peer review-the mechanism which the scientific community has established to ensure the objectivity of scientific knowledge. Hence science have a commitment to publish or report their findings and the methods used in obtaining the evidence. Doing so enables empirical studies. At least in principle, to be replicated and results confirmed or challenged. Measurements, however, can never be absolutely precise. Rather, they all contain a degree of error. Much of the work of the experimental scientist it, therefore, devoted to the resolution of uncertainly by repeating measurements, collecting larger samples, building instruments that are more accurate, and using statistical techniques that assess the degree of confidence in any result.