The aim of this research is to determine the effect of the use of guidance material based on the 5E model on students' conceptual understanding of a topic entitled "What is the earth's crust composed of?" The sample consists of 40 students from the 5th grade (experimental group 20, control group 20). A concept test, a drawing test, and semi-structured interview questions were used for data collection. In the experiment group, guidance material prepared according to the 5E model was used; the control group was conducted using the existing textbook. Student responses were examined in terms of the following categories: complete understanding, partial understanding, alternative concept, no response or irrelevant responses. The quantitative data obtained from the experimental and the control groups were compared by using the Mann-Whitney U-test. Content analysis was used to analyze students' drawings. In conclusion, it was determined that the guidance materials developed according to 5E model have a positive effect (U = 76.00, p<0.05) on students' conceptual understanding about the topic entitled "What is the earth's crust composed of?"