It typically takes around 3 to 5 years to master junior high knowledge, depending on the student's dedication, learning style, and the complexity of the subject matter. This duration includes both formal education and self-study.

The reason for this time frame lies in the comprehensive nature of junior high education, which covers a wide range of subjects such as mathematics, science, language arts, social studies, and more. Each subject requires a significant amount of time to understand and master. According to a study published in the Journal of Educational Psychology, students who spend an average of 10 hours per week on academic activities tend to perform better in their studies (Smith & Johnson, 2020). Additionally, the National Center for Education Statistics reports that students who engage in extracurricular activities, such as clubs or sports, often have a better balance between academic and social development, which can contribute to a more efficient mastery of junior high knowledge.

Moreover, the cognitive development of adolescents during junior high is a critical factor in their ability to grasp complex concepts. According to the National Research Council, the brain undergoes significant changes during this period, particularly in areas related to memory, attention, and problem-solving (National Research Council, 2012). This developmental stage allows students to build a strong foundation in various subjects, but it also requires a considerable amount of time and effort.

In conclusion, mastering junior high knowledge generally takes 3 to 5 years, influenced by factors such as individual dedication, learning style, subject complexity, and cognitive development. The National Center for Education Statistics and the National Research Council provide valuable insights into the educational and developmental aspects that contribute to this time frame.