The aims of this research were to find out the students activities and learning outcomes' differences between the students who were taught by STS (Science Technology Society) learning model and the students who were taught without STS learning model, and also to find out the influence of STS learning model toward learning outcomes the seven grade students of SMPN 1 Sengah Temila on the separation of a mixture material. The method of this research was quasi experiment and the design of research was Nonequivalent Control Group Design. The sample was taken by random sampling technique. Data were analyzed using U-Man Whitney test. The result of the students activity showed that Asymp.Sig (2-tailed) value is 0,038 (α = 5%), and the students learning outcomes showed Asymp.Sig.(2-tailed) value is 0,023 (α = 5%). This finding showed that the activities and students learning outcomes' differences between the students who were taught by STS learning model and the students who were taught without STS learning model. The use of STS learning model gave influence 21,57% to the improvement of the students learning outcomes.