The present preliminary research work was intended to measure the scientific attitude, scientific aptitude and scientific knowledge of secondary school students in the selected schools of two districts in Tamilnadu, India. The normative survey method was applied and a total of six null hypotheses(gender, studying class, medium of instruction, board of affiliation, locality and type of management) were framed. The sample consisted of 76 secondary school students from seven different schools in Chennai and Thiruvallur districts. The standardized tools were used in the study. The data were collected, recorded and analysed using Statistical Package for Social Sciences (SPSS-19.0 version), IBM Corporation. The measuring scores (low, average and high) were prepared using Normal Probability Curve (NPC) method. The most statistically significant results were obtained for all selected variables except board of affiliation (State and Central Board of Secondary Education) towards scientific attitude and scientific knowledge. Hence the present study concluded that the samples drawn from the selected schools were standardized for conducting further experimental study. Keywords: Attitude, Aptitude, Secondary school students, Normal probability curve.