We present and discuss Carl Friedrich v. Weizsäcker’s historic 1948 derivation of the 5/3 law for energy dissipation in turbulence. His discussion assumes of a cubic volume filled with isotropic quasistationary turbulence, where he then introduces a systematic partitioning of that volume into ever smaller nested cubes. Weizsäcker’s dimensional analysis in real space parallels Onsager’s 1949 partly k-space and partly real space dimensional analysis, and foreshadows the fractal beta model. We compare several steps in Onsager’s and Weizsäcker’s approaches and then extend Weizsäcker’s dimensional analysis to the beta model. The more recent experimental violations of the assumption of homogeneity and isotropy are discussed. We end with a practical experimental measure for isotropy plus the consideration of the unstable vortex sheet in the ink droplet generation of an anisotropic and inhomogeneous branching cascade from large to small scales.