The aim of this research is to determine the ideas of Turkish prospective physics teachers about the factors influencing the velocity of a wave propagating on a non-distributed and homogeneous rope. The sample of the study is 147 prospective physics teachers attending at a state university in Turkey. The answers to an open-ended question and three multiple - choice questions relating to the subject, and the interview notes constitute the data of this study. A qualitative discussion of the data revealed that prospective physics teachers haven’t really understood what a wave is. Because of the fact that students don’t think waves differ from matter, they can’t improve a proper physical model to explain the wave propagation. Students’ different ideas using to explain wave propagation are identified and described in this research. Finally, some implications were discussed to improve instruction.