Joo Arthur Fortunato Porto Alegre, March of 2011 the physicist of positivista orientation Ernst call Mach conceived one co- nhecida experience in thought. Such was considered: ' ' perfect and completely equal frogs are two esfe situated next to the other and am bas far the sufficient to be excluded possible interactions between two and external existing objects to that binary mechanic. It is verified reality of a geometric difference between them, namely, that the equator of one of the spheres became elliptical while the equator of the other follows being circular' '. The existence of relative movement is assumed then as if a centripetal dynamic propensity existed that would modify geome tria of one of them. It is asked: if the movement is relative, because deformed one if and to another one not? The theory of restricted relativity was excited the pair to tir of assimetrias in the electrodynamics that if conserved in the change of a referencial ' ' in repouso' ' for a referencial ' ' in movement uniforme' '.