UPAYA PENINGKATAN BERPIKIR KRITIS DAN HASIL BELAJAR SISWA DENGAN PENGGUNAAN STRATEGI PEMBELAJARAN KOOPERATIF PADA MATERI VIRUS DI KELAS X1 SMA NEGERI 2 MEDAN

This Classroom Action Research (CAR) was aimed to find out data of students critical thinking and achievement at virus concept, along with data of students individual activity observation and discussion using Think Pair Share. The research instrument were critical thinking test,cognitive tests, observation sheet and students respond questionnaire. Data was analyzed qualitatively and quantitatively. Research subject was class X th 1 that consist of 43 students. The result of the research showed increase of students critical thinking and achievement. The students who got completetion score in cycle I were 14 students, and in cycle II were become 18 students. Percentage of students score completetion in cycle II was 41 ,86%, this percentage was smaller than classical completetion standard in that school, 80%. At students critical thinking in cycle I was 34,88% and in cycle II was 37,2%. The result of students respond questionnaire by using cooperative learning with type Think Pair Share, obtained cooperative skill average in 91,97 with high level of category. From the explanation above, it can be concluded that this research can increase students critical thinking and achievement in cognitive aspect and affective aspect.