This article presents an experience that allows determining the restitution coeficient in collisions using spectrum of the sound emitted by successive impacts of a sphere in a plane surface. The data are acquired through PC sound card, with times of resolution of order of 22 mus and sampling rates of up to 44 KHz and that allows to obtain results with a good precision as it can be seen through the results obtained in this work. The spectrum of the sound is analyzed with shareware software that presents the sign in the graphic form of frequency versus time and that has many resources. The equipment used in this experiment is found easily, as well as the software to analyze the sound sign.
