Preliminary field testing involved nine students in grade VIII of SMP Negeri 1 Wates, Kulon Progo who had different abilities. The group consisted of three high-ability, two medium-skilled, and three low-ability students. The result of preliminary field testing was expected to be a reference for whether developed worksheets could be used and understood by students with different abilities. The nine students involved in this test were randomly selected based on teacher input on the learner’s ability in class. The results of preliminary field testing of the learner response to the developed NGSS worksheet are presented in Table 6.