Now a days learning is at the heart of teaching learning process. Traditional teacher centered approaches are in transformation phase to learner centered ones. Constructivism and constructivist approaches are the buzz words of educational arena. Today more and more students are alienating themselves from pursuing basic science. The reasons attibuted by students are like they find the subject boring, difficult and generally unnecessary for non-science-oriented careers. Many researchers feel that this difficulty stems from the passive role the students play in a traditional class (Zoller, 2000). If this is the case, then there is need to modify the way of teaching in order to develop students who are enthused about science and who really understand the material. Improving science achievement through the use of more effective instructional strategies, promoting the active role of the learner, and promoting the facilitative role of the teacher has long been an aspiration of science educators. Present book enlighten the scope of constructivist instructional approaches with special reference to 5 e Model in secondary level science classrooms. With the help of Biological Science Curriculum Study (BSCS) a reliable formula has been defined to view constructivism. The process is defined as five "E"s. These 5 Es represent the verbs engage, explore, explain, elaborate and evaluate. Present book also provides an insight into how 5 E Model can be used in science classrooms and its effectiveness on evaluate.