Summary
Frederick Soddy's "Matter and Energy" argues that mass and energy are fundamentally interchangeable quantities, proposing a new mechanics consistent with experimental facts like electron mass variation and radioactivity. The book posits that changes in a body's energy content directly correspond to definite changes in its mass, irrespective of the process involved. This leads to the conclusion that mass is a direct measure of a body's total energy, expressible by the equation m = E/V².
The central idea is the unification of mass and energy under a new system of mechanics. By postulating that radiation possesses mass and travels at the velocity of light, Soddy demonstrates how absorbing radiation increases a body's mass. The book seeks to reconcile Newtonian mechanics with these new observations by revising axioms, particularly the independence of mass from velocity, while upholding the conservation laws of mass, energy, and momentum.
Key concepts
- Conservation Laws — The book maintains the truth of the laws of conservation of energy, mass, and momentum, and potentially electricity, as foundational to a new mechanics.
- Relation of Mass to Energy — The book proposes that mass and energy are different names and measures of the same quantity, linked by the equation m = E/V².
- Mass Increase with Kinetic Energy — A new axiom replaces the Newtonian idea of mass being independent of velocity, stating that mass increases with kinetic energy.
- Mass of Radiation — The book postulates that a beam of radiation possesses mass and moves with the velocity of light, carrying momentum and energy.
From the book
LIX. A Revision of the Fundamental Laws of matter and Energy. By Gilbert N. Lewis . Ph.D., Associate Professor of Physical Chemistry, Massacussets Institute of Technology, Boston . R ECENT publications of Einstein and Comstock on the relation of mass to energy have emboldened me to publish certain views which I have entertained on this subject and which a few years ago appeared purely speculative, but which have been so far corroborated by recent advances in experimental and theoretical physics that it seems desirable to subject these views to a strict logical development, although in so doing it will be necessary to modify those fundamental principles of the mechanics of ponderable matter which have remained unaltered since the time of Newton. The recent experiments which indicate a…
Popular questions readers ask
- Lewis states his intention to "modify those fundamental principles of the mechanics of ponderable matter which have remained unaltered since the time of Newton." Explain in your own words what makes such a drastic revision necessary at this time, citing specific experimental and theoretical advancements mentioned in the text.
- The text suggests that phenomena like "a change in the mass of an electron with the speed" and "radioactivity" created doubt about "the exact validity of some of the most general laws of nature." How might these specific observations *appear* to challenge one or more of the "three great conservation laws" Lewis ultimately seeks to uphold?
- Lewis proposes to build a "simple system of mechanics" consistent with known facts and resting on the conservation laws. Articulate, as if explaining to a peer, the historical significance of *reaffirming* the conservation of mass and energy in 1908, given the scientific landscape described in the excerpt.
- Describe the phenomenon of light pressure and how its experimental verification, combined with the law of conservation of momentum, "inevitably leads" to the conclusion that a beam of light possesses momentum. Why is this particular insight crucial for Lewis's revision of fundamental laws?
- Considering Lewis's 1908 publication date and his reference to Einstein, how does this "revision of the Fundamental Laws of Matter and Energy" reflect the broader conceptual revolution in physics occurring at the beginning of the 20th century? What previously held assumptions about the nature of matter and energy are being challenged and potentially integrated?