ABSTRAK
Penelitian ini bertujuan untuk: (1) mengetahui perbedaan prestasi belajar siswa menggunakan model pembelajaran Inquiry Based Learning (IBL) dan Problem Based Learning (PBL), (2) mengetahui perbedaan prestasi belajar siswa pada kemampuan matematik tinggi dan rendah, (3) interaksi antara model pembelajaran Inquiry Based Learning (IBL) dan Problem Based Learning (PBL) dengan kemampuan matematik siswa terhadap prestasi belajar siswa.
Penelitian ini menggunakan metode eksperimen dengan desain faktorial 2x2. Populasi dalam penelitian ini adalah siswa kelas XI MIA SMA Negeri 1 Sukoharjo tahun pelajaran 2015/2016. Sampel terdiri dari siswa 2 kelas yang diambil menggunakan teknik cluster random sampling. Teknik pengumpulan data yaitu dengan metode tes dan non tes. Teknik analisis data berupa uji hipotesis Anava 2 jalan dan Kruskal-Wallis dengan bantuan software SPSS 20. Untuk pengujian hipotesis pada aspek pengetahuan dan keterampilan menggunakan uji Anava 2 jalan, sedangkan aspek sikap menggunakan uji non parametrik Kruskal-Wallis.
Berdasarkan hasil penelitian pada materi termokimia kelas XI SMA Negeri 1 Sukoharjo tahun pelajaran 2015/2016 dapat disimpulkan: (1) tidak ada perbedaan prestasi belajar siswa pada aspek sikap dan pengetahuan namun pada aspek keterampilan ada perbedaaan dengan menggunakan model pembelajaran Inquiry Based Learning (IBL) dan model pembelajaran Problem Based Learning (PBL) , (2) tidak ada perbedaan prestasi belajar antara siswa kemampuan matematik tinggi dan rendah, (3) tidak ada interaksi antara model pembelajaran Inquiry Based Learning (IBL) dan model pembelajaran Problem Based Learning (PBL) dengan kemampuan matematik terhadap prestasi belajar siswa.
Kata kunci: Inquiry Based Learning, Problem Based Learning, Kemampuan Matematik, Prestasi Belajar, Metode Eksperimen.  
ABSTRACT
This research has aimed to : (1) known differences student’s learning achievement between Inqury Based Learning and Problem Based Learning models, (2) known differences student’s learning achievement between higher mathematic ability and lower mathematic ability, (3) known interaction between Inqury Based Learning and Problem Based Learning with mathematic ability towards student’s learning achievement. This research used experiment method with factorial design 2x2. Population of this research was all the XI grade SMA N 1 Sukoharjo in academic years 2015/2016. Sample consist of 2 class which used cluster ramdom sampling technique. Technique of collected data with tes and non-tes method. Technique of analysis data suched as hypothesis test are two-way anava and Kruskall-Wallis with SPSS 20. For knowledge and skill, hypothesis test used two-way anava meanwhile for attitude used non-parametric test is Kruskall-Wallis. Based on result of the research in termochemistry matter of XI grade SMA N 1 Sukoharjo in academic years 2015/2016 can be concluded are : (1) there isn’t differences student’s learning achievement for attitude and knowledge but there was difference for skill between usage learning models of Inquiry Based Learning and Problem Based Learning, (2) there isn’t differences student’s learning achievement between higher mathematic ability and lower mathematic ability, (3) there isn’t interaction between Inqury Based Learning and Problem Based Learning with mathematic ability towards student’s learning achievement. Keywords : Inquiry Based Learning, Problem Based Learning, Mathematic Ability, Student Achivement, Experiment method.