The 5th Professional Development Seminar of the Argumentation Based Science Inquiry Project, founded by the Scientific and Technological Research Council of Turkey (TÜBİTAK) and Turkish Ministry of Education, and run by TED University, was held in Coral Hill Hotel, Kuşadası, on 2-6 July, 2012. There were teachers from 21 different provinces and the representative of Turkish Ministry of Education attended the seminar. The activity was organized and implemented by our faculty Associate Professor Murat Günel, and managed by Nezir Ünsal, Director of Professional Development at Turkish Ministry of Education.