Chapter 3: Physics and Other Sciences – Connections

Physics and Other Sciences – Connections , "The Relation of Physics to Other Sciences," establishes physics as the most fundamental and encompassing discipline, tracing its lineage back to natural philosophy. It explores the deep connections physics shares with related fields, starting with chemistry, where theoretical principles are ultimately governed by quantum mechanics, explaining the structure and relationships found in the periodic chart, although the precise prediction of complex reactions remains challenging. The application of statistical mechanics, which addresses the behavior of massive collections of jiggling atoms, is essential for understanding thermodynamics and physical chemistry. In biology, physics underlies cellular processes, such as the electrical activity of nerves likened to a wave of penetrability passing down a tube, and the energy transfer mechanisms involving molecules like GTP. The central assumption in understanding life is that all biological activity can be explained by the wiggling of atoms. Key biochemical discoveries rely heavily on physical techniques, such as using different isotopes to trace complex metabolic pathways like the Krebs cycle. The blueprint of life, DNA, is a structure of twisted chains that self-reproduces using complementary base pairs, while the machinery of life, the enzymes (complex proteins), lower the activation energy of necessary chemical reactions. Moving outward, astronomy was the initiator of physics, and modern physics uses spectroscopy to confirm that distant stars are composed of the same atoms found on Earth, aiding the analysis of stellar interiors and understanding how nuclear burning converts hydrogen into heavier elements, forming the matter we are made of. In the earth sciences, geology faces major unsolved physical problems, notably the causes of vulcanism, earthquakes, and the theoretical properties of matter under extreme internal pressure. Similarly, meteorology is hindered by the lack of a satisfactory theory for turbulent flow and fluid instability. Finally, in psychology, though less studied from a fundamental physical perspective, the core problem is understanding the physical mechanism of memory—how the atomic structure of the nervous system changes when learning occurs. Ultimately, the division of knowledge into distinct sciences like physics, biology, and geology is for human convenience, as nature itself maintains a unified coherence.