<![CDATA[This research was aimed to describe the practicality, effectiveness, and effect size of discovery learning model to improve the ability of the students flexibility thinking of solution electrolyte and non electrolyte topics. This research used poor experimental method with one group pretest-posttest design. Students of SMAN 6 Metro for 2016/2017 academic years at X.8 class was used as sample which it was obtained by using cluster random sampling. The results shown that the practicality and effectivity of discovery learning model had high criteria, n-gain average in the ability of the students flexibility thinking was 0.54 and effect size was 0.95. Based on them, discovery learning model was practical, effective, and big effect size to improve the ability of the students flexibility thinking of solution electrolyte and non electrolyte topics.Penelitian ini bertujuan untuk mendeskripsikan kepraktisan, keefektivan dan ukuran pengaruh model discovery learning dalam meningkatkan kemampuan berpikir luwes siswa pada materi larutan elektrolit dan non elektrolit. Penelitian ini menggunakan metode poor experimental dengan one group pretest-posttest design. Siswa SMAN 6 Metro tahun pelajaran 2016/2017 di kelas X.8 digunakan sebagai sampel yang diperoleh dengan menggunakan cluster random sampling. Hasil penelitian menunjukkan bahwa kepraktisan dan keefektivan model discovery learning berkriteria tinggi, nilai rata-rata n-gainkemampuan berpikir luwes siswa sebesar 0,54 dan ukuran pengaruh sebesar 0,95. Berdasarkan hal tersebut, model discovery learning praktis, efektif dan memiliki ukuran pengaruh yang besar dalam meningkatkan kemampuan berpikir luwes siswa pada materi larutan elektrolit dan non elektrolit.Kata kunci: discovery learning, elektrolit dan non elektrolit, kemampuan berpikir luwes]]>
