The purpose of this study was to compare working memory, saliva cortisol hormone, and problem solving skill between students in two different contexts: Open Inquiry and Conventional Learning. The participants were consisted of two classes of 86 10th grade students, from one school during the 0211 academic year. A pretest - posttest control group design was used in the experiment. The tools were consisted of1) salivary cortisol assay 0)The computerized assessment battery test 3)problem solving skill test. The collected data were analyzed by arithmetic mean, sd., t – test, and Hotelling T2. The findings revealed that: after intervention 1) student's saliva cortisol hormone in Open Inquiry group was lower than Conventional group at .05 level of significance 2) student's working memory in Open Inquiry group were higher than students in Conventional group at .05 level of significance, but unable to proof about the difference of student's problem solving ability.