CONCLUSION
These overviews present us the ideas that IBL and PBL have suggested new perspectives and have contributed to deal with some limitations of science instruction like the needs of raising question, problem solving, producing a product. However, it is obvious that IBL is the main framework of PBL. The two have to include IBL, yet the opposite of this idea cannot be claimed because IBL performs the function of corresponding learners learning necessities during the knowledge construction. Although IBL includes transference of knowledge into different areas, this process is carried out in later stages. Upon taking account knowledge transference, IBL gives its position to PBL overtime. Mainly, IBL focuses on knowledge construction. The main principles of IBL and PBL derive from different historical context, stress different social and educational needs and have different theoretical considerations. Therefore, in teaching practice, in order to apply these methods effectively and efficiently, practitioners should take these questions in mind: who the learners are, what their current level of proficiency is, and the circumstances in which they will be using science in the future, and so on. Science teachers also could implement all of these teaching methods in organization of activities as appropriate for learners to achieve in the future. In conclusion, no single method could guarantee successful results.