Development of a two-tiered diagnostic test to assess learners’ understanding of the particulate nature of gases

Abstract

The particulate nature of matter is a basic concept in chemistry. It serves as the foundation for higher chemistry concepts that can be applied to gas behaviors and must be understood by the learners during instruction. The study aims to develop a valid and reliable tool to assess the understanding of grade 11 learners on gas concepts as affected by temperature, pressure, and diffusion. Participants were STEM (n=96) and non-STEM (n=139), a total of two hundred and thirty-five (n=235) grade eleven (11) senior high school learners of an accredited private school. Classical Test Theory was used to analyze the initial form of sixteen (16) two-tiered items. Difficulty and discrimination indexes were used in the item analysis while the strength of association was determined using the Phi coefficient. Actions were made based on the combined results of those analyses, such as either selected, revisable, then selected, or deleted, resulting in ten (10) final forms with moderate reliability (r=.637). Learners' understanding of gas concepts was assessed, and alternative conceptions were revealed. The two-tiered tools can help teachers analyze learners’ understanding of the gas concepts and challenge learners to achieve higher-order thinking skills.