This action research explored the effectiveness of the Spark-Test-Act-Reflect-Think (START) activity in enhancing the understanding of science terminologies among Grade 5 learners at Magatos Integrated School, Division of Davao del Norte. The study employed a quantitative-descriptive approach involving 32 students. Quantitative data were collected through pre-test and post-test assessments based on four science topics: Processes that Shape Earths Surface, Weather Disturbances, The Moon, and The Stars. Descriptive results revealed an increase in learners mean scores from M = 38.28% (Very Low) in the pre-test to M = 67.19% (Average) in the post-test. On the other hand, inferential statistics showed that this difference was statistically significant, t(31) = 43.60, p < .001, with a very large effect size, Cohens d = 7.70. Qualitative insights from student interviews further validated the interventions impact, revealing four key themes: enhanced awareness of scientific vocabulary, increased engagement and motivation, development of independent study strategies, and improved confidence in science learning. The results align with recent literature emphasizing the role of scaffolded, reflective, and vocabulary-focused instruction in promoting science comprehension. The study concludes that the START strategy is a practical and effective approach to improving science terminology understanding in elementary education and may serve as a model for similar interventions in other contexts.