Development of an Assessment Instrument Based on Science Process Skills for Convex Mirror Material for Eighth Grade

This study aims to provide practical and effective assessment instruments for science teachers to evaluate students' science process skills and to encourage the improvement of science education quality in schools. The science process skills referred to in this study are the basic science process skills of students, which include observing, measuring, classifying, predicting, concluding, and communicating. The method used in this study is the DDR (Design and Development Research) method developed by Richey and Klein. The development model that forms the basis of this study refers to the model developed by Alessi and Trollip. This model consists of three stages: (1) Planning, (2) Design, and (3) Development. The completed product is then validated by experts. The expert validation stage is conducted to determine the feasibility of the developed product and to identify weaknesses, shortcomings, or aspects that need to be reduced or added in the product that needs to be revised. The results of the expert validation show that the developed assessment instrument is valid (feasible) for assessing the achievement of science process skills indicators. The validity (feasibility) of the development results is consistent with the experts' opinion, stating that the assessment instrument is valid (feasible).