The purpose of this research is to see what physics misconceptions students have regarding heat material. This study employs a three-tier diagnostic exam designed to identify students' physics misunderstandings. 150 grade VII students from five Lamongan district state junior high schools were included in the study. Creating a closed-ended the students' responses to the cognitive conflict instruction are used to create a three-tier instrument (CCI). The findings of the research revealed that the CCI is a viable and reliable tool for detecting misunderstandings. The findings of the detection of misconceptions in participants revealed that 45 % of pupils met the mastery criteria, 35 % met the misconception criteria, and 10% met the guessing requirement.