Abstract. The authors in this paper draw attention to the importance of an instrument that can analyze student's misconception.This study described the kind of the misconception in acid-base theory, and the percentage students' misconception occur in every subconcept of acid-base theory. The design of this study is a descriptive method, involved 148 of 11 th grade science students from Senior High School, which divided into two classes are high cognitive and low cognitive. Further analysis of using Modified Certainty of Response Index (CRI) as a diagnostic instrument is used to explore misconception which in that test included evaluating only content knowledge with considering the reason behind the students' choice of response and their certainty of response in every question. The result of data analysis has shown that misconception occurred in high cognitive class, gained 43,86% and misconception occurred in low cognitive class, gained 24,63%. Based on the diagnostic interview has shown that misconception occurred in students due to students does not understand the concept well and they related the one concept to the other concepts with partial understanding, the result students make the failed conclusions. The type of misconception occurred is a conceptual misunderstanding. According to the data analysis showed that Modified Certainty of Response Index (CRI) is effective used to analyze students' misconceptions and the diagnostic interview is effective used to know the reasons that caused students which having misconceptions.

This research aims to validate multiple representations instruments for measuring student's multiple representations skill of electrolytes and nonelectrolytes. This research uses quantitative descriptive method with nonexperimental approach. This research applies stratified sampling method with total 94 students who respond to 40 items multiple choices that cover macroscopic, microscopic, symbolic, and mathematical aspects. Rasch model in this research analyzes the instruments such as determining the unidimensionality, reliability, item map, item measure, item fit, and test information function. Data analysis shows that the finding of good category of validity and reliability of the instrument can be used as a diagnostic tool in the assessment of student's multiple representation abilities.

Pembelajaran IPA merupakan salah satu kajian ilmu pengetahuan yang berisi tentang berbagai teori dan konsep ilmiah yang dapat dibuktikan melalui serangkaian kegiatan penelitian.  Kegiatan penelitian dalam pembelajaran IPA dapat dilakukan melalui laboratorium IPA atau di tingkat SMA/Sederajat dibagi menjadi tiga laboratorium, yaitu laboratorium kimia, fisika dan biologi. Laboratorium merupakan tempat yang digunakan untuk pengamatan, percobaan, serta pengujian konsep pengetahuan dan teknologi yang dilengkapi berbagai fasilitas alat dan bahan untuk menunjang pembelajaran. Laboratorium IPA yang baik adalah laboratorium yang memiliki sarana, prasarana, serta manajemen yang baik dan teratur. Akan tetapi, beberapa sekolah belum melakukan manajemen laboratorium secara maksimal, sehingga dapat menyebabkan pembelajaran IPA dalam rangkan membuktikan konsep ilmiah mengalami beberapa kendala bahkan tidak jarang menimbulkan bahaya reaksi bahan kimia tertentu. Oleh karena itu, sangat penting diadakan manajemen laboratorium di sekolah dengan baik agar dapat menunjang proses pembelajaran dan terhindar dari bahaya reaksi kimia tertentu. Tujuan penelitian ini yaitu menganalisis secara kualitatif manajemen laboratorium kimia dan biologi di SMAN 1 Geger Madiun. Metode penelitian yang digunakan adalah kualitatif. Pengumpulan data dilakukan dengan wawancara terhadap narasumber dan data yang didapatkan dianalisis secara deskriptif kualitatif. Hasil penelitian menunjukkan sebagian besar Laboratorium di SMAN 1 Geger memenuhi standar manajemen laboratorium yang baik.

As one of the sciences, some students consider chemistry complex and abstract, so many misconceptions arise. One of the chemistry topics that cause many misconceptions is hydrocarbons. A misconception is an understanding of concepts in students' minds that are contrary to scientific concepts. This research aimed to identify the student’s understanding and misconception of hydrocarbon. The study was qualitative descriptive research. Qualitative descriptive research was used to identify student misconceptions using the four-tier test. The sample of the research was 24 students. The instruments used in this research are four test levels which include (1) multiple-choice, (2) confidence rating of the answer beliefs, (3) reason for the answer, and (4) confidence rating of the reasoning. The result shows that 24,7% of students well-understood hydrocarbon concepts, 32,1% do not understand, and 43,2% have misconceptions. Misconceptions in this research are divided into three categories: low, moderate, and high. The students experience misconceptions with high criteria on the concept reaction of hydrocarbon (66,7%), moderate criteria on the concept of determining hydrocarbon compound (31,3%), the nomenclature of hydrocarbon compound (56,3%), types atom carbon (37,5%), Physical and Chemical Properties (45,8%), isomers (47,9%) and low criteria on the concept of characteristics of carbon atoms (16,7%).