Investigation of the requirements and argument qouality of decisions of the science teaching candidates on the various socio-scientific issues: Classroom discussion used with youtube support

In this research, it is aimed to examine the decisions, reasons and the quality of written arguments of pre-service science teachers about some socio-scientific issues. The study group consisted of 26 pre-service science teachers (18 females, 8 males) studying in the 3rd grade in a state university designated according to purposeful sampling method. In this study, a case study is adopted from qualitative research designs. The data source of this research is composed of media-social media questionnaire, sugar loading during pregnancy, raw/open milk and processed/closed milk, written arguments for SSI, pre-service teachers logs, researcher notes and semi-structured focus group interviews. The data obtained from the research were analyzed according to descriptive, content and continuous comparative analysis techniques. At the end of research, it was determined that pre-service science teachers spent a good part of their times using the social media fort he purpose of more information and communication. Before the implementation, pre-service science teachers expressed their opinions as agree, disagree and irresolute. It was determined that some of the pre-servsce teachers changed their minds and some of them did not change their minds after the YouTube supported classroom discussion. The preservice teachers' expressed the reasons of their decisions taking the social/cultural, ethical/moral, political, economical, environmental and scientific aspect in to account. Pre-service science teachers' social/cultural, ethical/moral, scientific dimensions about the loading of sugar during pregnancy are decided by the SSI; In the context of raw/open milk and nuclear power plant issues, they explained the scope of SSI in all dimensions. It was determined that the pre-service science teacher' the quality of the examining written arguments after class discussion increased positively during the application. At the end of the research, it was determined that pre-service science teacher' awareness about the SSI developed their scientific process skills and life skills such as decision making, hypothesis forming, discussion, analytical thinking. Key words: Socio-scientific Issues, Argumentation, Decision Making, Pre-Service Science Teachers, YouTube.