Experimental data sometimes fails to render the expected truth, such as high-speed bullets smashing into pieces on a water surface cannot verify the water's hardness. By re-examining the essence underneath quantum phenomena and analyzing their relevance to universal classical theory, this study has thoroughly revealed the classical counterpart of spin. From now on, almost all quantum concepts (e.g., wave particle duality, quantum entanglement, and magnetic moment anomaly) can be understood classically, just as prominent physicists such as Planck, Einstein, and Schrödinger longed for back then.