The current research aims at investigation The effectiveness of the model of " thelen" in achievement development at the fourthgrade students of primary school in social studies. The sample of the research consists of two groups of students (control and experimental) was (76) students, the number of students in the control group (38) students, and the number of students in the experimental group (38) students. To fulfill the aim of the research, the researcher prepared tool( Achievement test) to measure the academic achievement of scientific knowledge among the students of the fourth grade of primary education, After analyzing the data ,the Research concluded the following results: There is a statistically significant difference between the mean scores of control and experimental groups students on academic achievement test in favor of the experimental group. Accordingly, the researcher set a number of recommendations benefit increased attention to the model of " thelen" in the teaching process through the training of teachers and urged them to use it, through providing them with assistance and support needed for that.