It is aimed in this research to measure via knowledge hierarchy the things regarding exhibit themes learned by the visitors of the exhibits and compare them with the purpose that the exhibits are designed for, thereby realizing a summative evaluation of the exhibits by knowledge hierarchy method. The research has been conducted in a children's science museum with totally 12 middle school students, nine of which are in the sixth grade and three of which are in the seventh grade. Semi-structured interview forms have been used to make interviews with those students before and after the visit, and based on these interviews their knowledge levels have been identified. It has been found out that the students at the lower levels of the knowledge hierarchies of the exhibits have moved up to the higher levels after the visit. An accumulation of the students has been observed at higher levels and the exhibits meet the purpose of the visit.