This type of research is Classroom Action Research (CAR) carried out in 2 cycles, each cycle consisting of 4 stages, namely (1) planning (2) implementation of actions (3) observation (4) reflection. This study aims to improve learning outcomes, namely attitudes, skills and knowledge of students on additives and addictive substances using the Discovery Learning model. The subject of this research is the eighth grade students of As Shiddiqiyah Junior High School in the first semester of the 2018/2019 academic year with a total of 30 students, consisting of 9 male students and 21 female students. Data analysis was carried out with quantitative descriptive techniques. Based on the results of the study, it was found that the attitude of students increased, as evidenced by the results of observations in the first cycle that the class average was 68.15 including the good category experienced an increase in the second cycle to 81.14 including the excellent category. The skill area of students in the first cycle obtained an average value of 71.36 including the good category, which increased in cycle II to 84.11 with a very good category. The area of knowledge of students also experienced an increase that the average yield in the first cycle was 59.61 in the second cycle increased to 81.07. The percentage of classics in the first cycle is 30.76% with a category that is less and has increased in the second cycle to 82.14% with a very good category. Based on the results of this study, the indicator of success has exceeded 75%, it can be concluded that the increase in science learning outcomes of eighth grade students of SMP As Shiddiqiyah is in a very good category. Keywords: Discovery Learning, Attitudes, Skills, Knowledge, Additives and Addictive Substances.