Students learned the principles and practice of photometry through project-based learning. They addressed the challenge of measuring the unknown concentration of a colored substance using a photometer they were required to design, build, and test. Then, they used that instrument to carry out the experiment and fulfill the challenge. A photometer was designed and built by students consisting of a green laser pointer as the light source and a lux meter as the detector and readout. Using this photometer students have determined the concentration of the unknown sample of KMnO 4 solutions. The concentration of this sample solution was calculated to be (4.62 ± 0.06) × 10 −4 M; this value agrees within 6% of the expected value from the measurement using the commercial spectrophotometer which was calculated to be (4.96 ± 0.005) × 10 −4 M. The experiments fit well into an analytical chemistry course and take a standard (1 h) lab period. This project has facilitated improved student understanding of the photometry concepts and increased the creative problem-solving. In general, the students' response to this laboratory was positive.

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Quick and real-time plotting equations using the Winplot software can be employed to create accurate hybrid atomic orbitals without complicated scripting. Performing this task on their own, students can more easily understand and remember hybrid atomic orbitals, in terms of shape and orientation.

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Creative thinking skills have an important role to face the challenges of the 21st century. This study aims to improve the creative thinking skills of junior high school students through a project-based learning model for processing cassava peel waste. This research method is quasi-experimental, non-equivalent pre-test-post-test control group design. The sample in this study was class VII students of SMPN 1 Purbolinggo, who were determined using a purposive sampling technique. The number of students in the control and the experimental classes was 32 people each. The instruments in this research are the Creative Thinking Skills Test and Performance Assessment. The results showed that the average N-gain for creative thinking skills in the experimental class was in the medium category (0.58), while on the control class, it was in the low category (0.29). Cohen's d coefficients for each indicator of creative thinking skills fluency, flexibility, originality, and elaboration; were 0.62, 0.58, 0.72, and 0.72, respectively, all in the medium category. However, Cohen's d coefficient effect size for the average N-gain overall creative thinking skills is 2.40, belonging to the very large category. Based on these results, it can conclude that the project-based learning model is effective with a very large effect on improving students' creative thinking skills.

The Effectiveness of POGIL Learning Model to Increase Problem Solving Ability in Hydrolyzing Salt. This research was aimed to describe the effectiveness of the Process Oriented Guided Inquiry Learning (POGIL) learning model to increase problem solving ability in hydrolizing salt topic. The method of this research was quasi experimental with pretest-posttest control grup design. The population of this research were all students of XI MIA one of Senior High School in Lampung Selatan. The samples were taken using purposive sampling technique and obtained XI MIA 1 as experiment class and XI MIA 4 as control class. The t test were used as data analysis. The result showed that the average n-gain of problem solving ability applied by POGIL learning model was higher than the average n-gain of problem solving ability with conventional model. The concluded in this research was the POGIL learning model was effective to increase problem solving ability in hydolyzing salt topic.Abstrak : Efektivitas Model Pembelajaran POGIL untuk Meningkatkan Kemampuan Pemecahan Masalah pada Materi Garam Menghidrolisis. Penelitian ini bertujuan untuk mendeskripsikan efektivitas model pembelajaran Process Oriented Guided Inquiry Learning (POGIL) untuk meningkatkan kemampuan pemecahan masalah pada materi garam menghidrolisis. Metode penelitian yang digunakan adalah kuasi eksperimen dengan pretest-posttest control grup design. Populasi penelitian ini adalah seluruh siswa kelas XI MIA salah satu SMA di Lampung Selatan. Sampel penelitian diambil menggunakan teknik purposive sampling dan diperoleh kelas XI MIA 1 sebagai kelas eksperimen dan kelas XI MIA 4 sebagai kelas kontrol. Analisis data menggunakan uji-t. Hasil penelitian menunjukkan bahwa rata-rata n-gain kemampuan pemecahan masalah yang diterapkan model pembelajaran POGIL lebih tinggi daripada rata -rata n-gain kemampuan pemecahan masalah dengan model pembelajaran konvensional. Berdasarkan hasil penelitian dapat disimpulkan bahwa model pembelajaran POGIL efektif untuk meningkatkan kemampuan pemecahan masalah pada materi garam menghidrolisis.Kata Kunci: garam menghidrolisis, kemampuan pemecahan masalah, model POGIL.

Students had been challenged to build a simple distillation apparatus by using project-based learning. In these project of the apparatus, they were applied their knowledges and skills to look for an alternative replacement tools, plan, build, and test the functioning of the apparatus. A simple distillation apparatus was designed and constructed by students where some tools could be replaced with used goods, such as: (1) a bunsen burner could be replaced with an spirit-wall lamp; (2) a soft drink glass bottle replaces a Pyrex flask as a distilling flask; (3) a modified plastic bottle with alumunium tube and plastic hoses replaces a glass tubing as a condenser, and (4) a modified dynamo from car toys was used as aerator with source of electric current from battery, power bank, or electric using phone charger. The apparatus already could be used to purify sea water that modeled by saline solution. The distillates were clearer and colorless compared to saline solution and did not conduct electricity. Based on that, the project was improved students’ understanding and creative thinking skills on the distillation concepts.