The purposes of this research were to develop and find the quality of the experimental set for studying the changing state of matter with smart learning media displayed through the IoT system. The data collection tools used in this research were 1) the accuracy percentage, 2) a suitability assessment form 3) a learning achievement test in “changing state of matter” and 4) satisfaction questionnaires. The statistics for analyzing the collected data were mean (), percentage, standard deviation (S.D.), and t-test dependent. The result showed that the Digital Thermo Sensor had 98.5% accuracy in 30 -100 compared with the standard thermometer. The experimental set was used to determine the melting points of pure substances, Naphthalene, Biphenyl, and water’s boiling point. The result found that the accuracy of melting point of Naphthalene and Biphenyl and the boiling point of water was 99.87, 99.75, and 99.99, respectively. The quality of the experimental set was also studied. Three experts evaluated the developed experiment set at a very good level. The experimental set successfully developed students’ understanding of a change of state concept. About 80% of students scored above the prescribed criterion of 70% of the total score. After learning, the scores of the students were higher than those before learning at a confidence level of 0.01. 30 grade-10 students evaluated the satisfaction evaluation at an excellent level. Therefore, the experimental set developed suitable for student learning in the topic of change of state effectively.