In this study, students' conceptual change processes related to the sound concept were examined. Study group was comprises of 325 fifth grade middle school students. Three multiple-choice questions were used as the data collection tool. At the data analysis process "scientific response", "scientifically unacceptable response" and "no response" categories were used. While about the concept of sound before instruction scientific answer rate was very low, after instruction the rate of misconceptions has decreased. At students "the sound is not spread in solid and liquid phase" and "sound spread velocity does not depend on the phase" misconceptions were encountered. After instruction students' scientific answer rate has been increased. Experimental based instruction process has been effective in changing students' ideas about the concept of sound. Different studies can be done for investigating in this age group students' ideas about the concept of sound.