This study aims to improve students' understanding of substance changes using household materials that are easily obtained. The concept of substance changes, which encompasses both physical and chemical changes, can be challenging for students to grasp when presented solely through lecture methods or visual media. Limited laboratory facilities in schools pose a significant challenge for many teachers, particularly at Abdi Pusaka Indonesia Private Junior High School, which has a limited number of students and resources. This study used the one-group pretest-posttest method with a subject of 10 students in class VIII. Materials used in the practicum included ice cubes, candles, paper, baking soda, and vinegar. The results showed an increase in student understanding, with an average pretest score of 60 to 85 in the posttest. The average gain score calculated is 0.63, which is included in the moderate category. In addition, student activity during the practicum increased significantly, and almost all students stated that this method was interesting and helpful in understanding the material. This study shows that the use of household materials in science practicum is effective in improving students' understanding of the concept of substance changes.