<![CDATA[This research aimed to know the effectiveness of laboratory based learning on student science process skills (KPS) and scientific attitudes. The design was pretest-posttes non equivalent group by purposive sampling so those class VII H and VII I were choosen as subject. The quantitative data was KPS that analyzed by t test and U test. The average value of pretest and posttest with pretest average of 39,09; posttest average of 73,85; and an average gain of 0,16. The average increase in all KPS aspects that were observed had moderate criteria (34,52). The qualitative data were obtained from observation and questionnaire, analyzed descriptively. Observation result of KPS had high criteria (81,67), the observation of a scientific attitude had a very high criteria (89,77) and from students questionnaire data showed nearly all students have a scientific attitude. Thus, it can be concluded that laboratory based learning is effective in improving students KPS and scientific attitude.Penelitian ini bertujuan untuk mengetahui efektifitas pembelajaran berbasis praktikum terhadap keterampilan proses sains (KPS) dan sikap ilmiah siswa. Desain yang digunakan adalah pretes-posttes kelompok non ekuivalen dengan purposive sampling sehingga kelas VII H dan VII I diambil sebagai subjek. Data kuantitatif berupa KPS siswa dianalisis dengan uji t dan uji U. Diperoleh rata-rata pretes 39,09; rata-rata postes 73,85; dan rata-rata gain 0,16. Rata-rata peningkatan KPS dalam semua aspek yang diamati berkriteria sedang (34,52). Data kualitatif berupa KPS dan sikap ilmiah siswa diperoleh melalui lembar observasi dan angket yang dianalisis secara deskriptif. Hasil observasi KPS memiliki kriteria tinggi (81,67), sikap ilmiah memiliki kriteria sangat tinggi (89,77) dan dari data angket sikap ilmiah siswa menunjukkan hampir semua siswa memiliki sikap ilmiah. Dengan demikian, dapat disimpulkan bahwa pembelajaran berbasis praktikum efektif dalam meningkatkan KPS dan sikap ilmiah siswa.Kata kunci : fotosintesis, keterampilan proses sains, pembelajaran berbasis praktikum, sikap ilmiah]]>
