Volume in nature is a foundation of present-day physics. The volume dynamics, VD, is implied by evident properties: invariance of the speed of light and zero rest mass of volume The VD includes: - the existence and reality of volume portions, VPs - change tensors of VPs, including electromagnetic waves - the differential equation describing change tensors, form of wave packets, formation and propagation of VPs - real quantities are identified via the Hacking criterion The VD implies and explains present-day physics, e. g. - gravity and transmission of gravitational interaction - curvature of spacetime - general relativity as a semiclassical and averaging approximation - universal formation of quanta, a generalized Schrödinger equation, the postulates of quantum physics - the Schrödinger equation as a nonrelativistic approximation - an improved and generalized version of quantum field theory, including nonlocality & causality, without infinity – as expected, as real volume inside the light horizon cannot cause a real infinity The VD implies, explains and clarifies properties of space, e. g. - VD implies density of volume in our heterogeneous universe - VD provides the time evolution of the Hubble constant (front cover), this solves the Hubble tension - real VPs represent the wave function and its generalization - VD clarifies real zero-point-oscillations, real Casimir force and real VPs and solves the cosmological constant problem - causality with nonlocality is clarified - formation of matter has been derived - the era of cosmic ‘inflation’ has been derived and clarified - the elementary charge, the electroweak couplings and many elementary particles have been derived and explained - the cosmological parameters have been derived fundamentally Thus, the VD clarifies, generalizes and unifies present-day physics. All results are in precise accordance with observation. Thereby, no fit has been executed, and no hypothesis has been introduced. We derive all findings in a systematic, clear & smooth manner. We summarize our results by definitions, propositions & theorems. We are classes from grade 10 or higher, courses, research clubs, enthusiasts, observers, experimentalists, mathematicians, scientists, researchers …