<![CDATA[This study aimed to develop an air-pressure-based teaching aid for projectile motion and conduct a limited evaluation of its technical performance, expert-assessed validity, user responses, and student learning outcomes. The study employed a modified 4D development model restricted to the Define, Design, and Develop stages, without proceeding to Disseminate. The apparatus was designed to allow controlled variation of launch angle and applied air pressure and to enable direct measurement of horizontal range and maximum height. Technical testing showed that horizontal range increased toward a maximum at approximately 45° and subsequently decreased, whereas maximum height generally increased with elevation angle. Higher applied air pressure also produced greater measured range and height. Expert validation was conducted by four university lecturers and one physics teacher and yielded an overall score of 81.2% (mean item score = 4.06/5), meeting the predetermined “very valid” criterion. A limited classroom trial involved 18 Grade XI students and one physics teacher at SMA Plus Muhammadiyah Merauke during the 2023/2024 academic year. The teacher response was 43/50 (86%), categorized as “very effective” according to the predetermined response criteria, while the student response was 56.72/75 (75.6%), categorized as “effective.” The post-instruction learning-outcome test produced a mean score of 83.33, with 17 of 18 students (94.4%) meeting the minimum mastery criterion of 70. These findings indicate that the developed apparatus is technically functional, judged suitable by experts, positively received during limited classroom implementation, and accompanied by high post-instruction mastery. Because the study did not include a pretest or comparison group, the findings should not be interpreted as causal evidence of improved learning outcomes.]]>
