Developing Assessment Instrument to Measure Physics Problem Solving Skills for Mirror Topic

Abstract

The Problem solving skills are needed to students in physics learning. Physic problem can be seen in
 daily, such as mirror topic. Student who has problem solving skills can solve question of mirror topic
 not only by equation, but also use concepts and principles what he know. This research aimed to
 develop a valid physics assessment to measure problem-solving skills for Senior High School
 Students grade XI. The development stages include: (1) determination for general purpose, (2)
 conceptual definition, (3) operational definition, (4) establishment for indicators, (5) construction for
 grid questions, and (6) determination for test form. The development stage includes: (1) the content
 validation by experts, (2) revision of the instrument, (3) the prepation for research (4) trial and
 empirical validation. The disseminate stage was publication of journal. Subjects of this research was
 55 students of Senior High School 2 Yogyakarta. Students as subjects of this research was chosen
 who had learned mirror topic. According the result of the content validation and the empiric
 validation, assessment instrument was valid to measure physics problem solving skills in mirror
 topic. The content validation has 0,96 for all items, while the empirical validation has 0,97 ± 0,18 for
 Infit MNSQ, it means all items are in accordance with PCM model. the assessment instrument has
 value of goodness of fit un range -0.94 to 1.12 and has level of item difficulty in range -0,94 to 1.12,
 those mean all items in the assessment instrumen are good. Futhermore, the assessment instrument
 is valid in the content validation and the empirical validation and able to measure physics problem
 solving skills. Categories problem-solving skills of subjects obtained of low, medium and high
 category