Eugene Hecht - Academia.edu (original) (raw)
Papers by Eugene Hecht
American Journal of Physics, 2009
This paper explores the evolution of Einstein's understanding of mass and energy. Early on, Einst... more This paper explores the evolution of Einstein's understanding of mass and energy. Early on, Einstein embraced the idea of a speed-dependent mass but changed his mind in 1906 and thereafter carefully avoided that notion entirely. He shunned, and explicitly rejected, what later came to be known as "relativistic mass." Nonetheless many textbooks and articles credit him with the relation E = mc 2 , where E is the total energy, m is the relativistic mass, and c is the vacuum speed of light. Einstein never derived this relation, at least not with that understanding of the meaning of its terms. He consistently related the "rest energy" of a system to its invariant inertial mass.
American Journal of Physics
A book titled "MASS" promises all sorts of conceptual delights, and so I came to this work with g... more A book titled "MASS" promises all sorts of conceptual delights, and so I came to this work with great expectations. The concept of mass, though central to most, if not all of physics, is exquisitely subtle and still evolving. Anyone bold enough to take on the task of explaining the as yet unexplained deserves encouragement. Alas, I must apologize to the author, Jim Baggott, at the outset; having read the book twice in whole, and several times in part, I remain somewhat disappointed. Readers of AJP know and enjoy physics, and like me, no doubt come to a popularization expecting to find something insightful, perhaps some fresh explanation, or a novel synthesis, possibly a new perspective, or even an elegant historical account, but above all such a book must be scrupulously accurate. This book-i.e., at least its first 110 pages or so-seems not to have been written for the informed AJP subscriber. "MASS" has a friendly light style, even while admirably attempting to explain concepts that are extremely subtle and complex, such as general relativity and quantum field theory. Unfortunately, it too often rather casually says things about physics that are not rigorously true; if you are a reader of AJP those little lapses will be quite jarring. One thing seems certain, this book was neither written nor edited by a physics teacher. On the strikingly handsome black dust jacket the book proclaims itself to be about MASS, but the easily missed small-print subtitle, "The quest to understand matter from Greek atoms to quantum fields," is much closer to its true overly ambitious intent. The treatment begins under the banner of "ATOMS AND VOID" with the oftenirrelevant notions of the usual collection of ancient Greek scholars. The next chapter wanders around dropping names like Sixtus IV, Gutenberg, Spinoza, and Bruno; I love Giordano Bruno, he's one of my heroes, but not here in a book that's supposed to be about MASS. Continuing this aimless historical meandering, the author lists "mechanical philosophers" from Bacon to Descartes to Newton, (p. 21) inexplicably overlooking two pivotal figures, Isaac Beeckman (from whom Descartes learned what meaningful physics he had) and the great Robert Hooke. It is not until Chapter 3 that the word mass finally appears, and then it's done by quoting Newton's awkward Definition 1, from the Principia, as if this is when the concept first entered physics-it is not. Baggott paraphrases Newton: "So, an object has a certain intrinsic mass-the 'quantity of matter' in it-which is related
Tienda online donde Comprar Optics (Softcover) 5th Ed. al precio 72,78 € de Eugene Hecht, tienda ... more Tienda online donde Comprar Optics (Softcover) 5th Ed. al precio 72,78 € de Eugene Hecht, tienda de Libros de Medicina, Libros de Oftalmologia y Optica - Optica
Newtonian Mechanics. Density, Elasticity, and Fluids. Heat, Temperature, and Thermodynamics. Wave... more Newtonian Mechanics. Density, Elasticity, and Fluids. Heat, Temperature, and Thermodynamics. Waves. Electricity and Magnetism. Light and Geometrical Optics.
The Physics Teacher, 2017
The Physics Teacher
In recent years, there have been a number of articles published concerning whether or not potenti... more In recent years, there have been a number of articles published concerning whether or not potential energy (PE) as defined in mechanics is invariant under Galilean transformation. This essay addresses that issue in a different, more fundamental and elegant way than has been done thus far. It recognizes that a considerable change in the concept of PE has occurred over the last century, mostly as a result of both the special and general theories of relativity. We will show, by simple argument, that PE is Lorentz invariant, even if it is not a rigorously proper relativistic quantity. Although PE is an extremely important classical (i.e., pre-relativistic) theoretical device, it depends on the positions of the interacting bodies at any and every moment. Simply put, if the relative position of any constituent changes, the corresponding interactions must change instantly, and that violates special relativity. In general relativity, PE is not even a well-defined concept.
American Journal of Physics
European Journal of Physics
American Journal of Physics
The Physics Teacher
Anyone who has taught introductory physics should know that roughly a third of the students initi... more Anyone who has taught introductory physics should know that roughly a third of the students initially believe that any object at rest will remain at rest, whereas any moving body not propelled by applied forces will promptly come to rest. Likewise, about half of those uninitiated students believe that any object moving at a constant speed must be continually pushed if it is to maintain its motion. 1 That's essentially Aristotle's law of motion and it is so “obviously” borne out by experience that it was accepted by scholars for 2000 years, right through the Copernican Revolution. But, of course, it's fundamentally wrong. This paper tells the story of how the correct understanding, the law of inertia, evolved and how Newton came to make it his first law.
American Journal of Physics
A study of physics textbooks from the 1860s up to the present reveals shortcomings of our contemp... more A study of physics textbooks from the 1860s up to the present reveals shortcomings of our contemporary approach to teaching the concept of energy. In response, this paper offers a coordinated set of conceptual definitions of force, work, and energy, which can provide a somewhat more accessible grounding on which to develop the subject pedagogically.A study of physics textbooks from the 1860s up to the present reveals shortcomings of our contemporary approach to teaching the concept of energy. In response, this paper offers a coordinated set of conceptual definitions of force, work, and energy, which can provide a somewhat more accessible grounding on which to develop the subject pedagogically.
American Journal of Physics
The concept of gravity came into being in ancient times as a terrestrial concern associated with ... more The concept of gravity came into being in ancient times as a terrestrial concern associated with the practicalities of “weight.” A great leap forward came in the early 1600s with the important theoretical speculations of Johannes Kepler. This article focuses on his prescient theory of gravity which guided the later progress of a number of scholars including Roberval, Hooke, and Newton. And yet, Kepler's remarkable contribution to gravitational theory has been almost completely overlooked in the contemporary scientific literature.The concept of gravity came into being in ancient times as a terrestrial concern associated with the practicalities of “weight.” A great leap forward came in the early 1600s with the important theoretical speculations of Johannes Kepler. This article focuses on his prescient theory of gravity which guided the later progress of a number of scholars including Roberval, Hooke, and Newton. And yet, Kepler's remarkable contribution to gravitational theory has been almost completely overlooked in the contemporary scientific literature.
European Journal of Physics
This paper is an exploration of the concept of energy, illuminated by the transformative insights... more This paper is an exploration of the concept of energy, illuminated by the transformative insights of the special theory of relativity. Focusing on potential energy (PE), it will be shown that PE as presently defined is in conflict with the tenets of special relativity. Even though PE remains an indispensable theoretical device its actual physicality is questionable. Moreover its ontological status is quite different from that of both kinetic energy and mass, a significant point that is not widely appreciated. We will establish that PE is a theoretical concept as opposed to an empirical one; it is a descriptor of mass–energy without a detectable physical presence of its own. PE is a measure of energy stored, it is not the energy stored.
European Journal of Physics
The article 'Comment on 'Relativity, potential energy, and mass'' (2019 Eur. J. P... more The article 'Comment on 'Relativity, potential energy, and mass'' (2019 Eur. J. Phys. 40 028001) makes a number of unsubstantiated assertions regarding the 'reality' of potential energy (PE), the measurability of mass, and the ontological status of kinetic energy. This essay is a refutation of those assertions.
American Journal of Physics, 2009
This paper explores the evolution of Einstein's understanding of mass and energy. Early on, Einst... more This paper explores the evolution of Einstein's understanding of mass and energy. Early on, Einstein embraced the idea of a speed-dependent mass but changed his mind in 1906 and thereafter carefully avoided that notion entirely. He shunned, and explicitly rejected, what later came to be known as "relativistic mass." Nonetheless many textbooks and articles credit him with the relation E = mc 2 , where E is the total energy, m is the relativistic mass, and c is the vacuum speed of light. Einstein never derived this relation, at least not with that understanding of the meaning of its terms. He consistently related the "rest energy" of a system to its invariant inertial mass.
American Journal of Physics
A book titled "MASS" promises all sorts of conceptual delights, and so I came to this work with g... more A book titled "MASS" promises all sorts of conceptual delights, and so I came to this work with great expectations. The concept of mass, though central to most, if not all of physics, is exquisitely subtle and still evolving. Anyone bold enough to take on the task of explaining the as yet unexplained deserves encouragement. Alas, I must apologize to the author, Jim Baggott, at the outset; having read the book twice in whole, and several times in part, I remain somewhat disappointed. Readers of AJP know and enjoy physics, and like me, no doubt come to a popularization expecting to find something insightful, perhaps some fresh explanation, or a novel synthesis, possibly a new perspective, or even an elegant historical account, but above all such a book must be scrupulously accurate. This book-i.e., at least its first 110 pages or so-seems not to have been written for the informed AJP subscriber. "MASS" has a friendly light style, even while admirably attempting to explain concepts that are extremely subtle and complex, such as general relativity and quantum field theory. Unfortunately, it too often rather casually says things about physics that are not rigorously true; if you are a reader of AJP those little lapses will be quite jarring. One thing seems certain, this book was neither written nor edited by a physics teacher. On the strikingly handsome black dust jacket the book proclaims itself to be about MASS, but the easily missed small-print subtitle, "The quest to understand matter from Greek atoms to quantum fields," is much closer to its true overly ambitious intent. The treatment begins under the banner of "ATOMS AND VOID" with the oftenirrelevant notions of the usual collection of ancient Greek scholars. The next chapter wanders around dropping names like Sixtus IV, Gutenberg, Spinoza, and Bruno; I love Giordano Bruno, he's one of my heroes, but not here in a book that's supposed to be about MASS. Continuing this aimless historical meandering, the author lists "mechanical philosophers" from Bacon to Descartes to Newton, (p. 21) inexplicably overlooking two pivotal figures, Isaac Beeckman (from whom Descartes learned what meaningful physics he had) and the great Robert Hooke. It is not until Chapter 3 that the word mass finally appears, and then it's done by quoting Newton's awkward Definition 1, from the Principia, as if this is when the concept first entered physics-it is not. Baggott paraphrases Newton: "So, an object has a certain intrinsic mass-the 'quantity of matter' in it-which is related
Tienda online donde Comprar Optics (Softcover) 5th Ed. al precio 72,78 € de Eugene Hecht, tienda ... more Tienda online donde Comprar Optics (Softcover) 5th Ed. al precio 72,78 € de Eugene Hecht, tienda de Libros de Medicina, Libros de Oftalmologia y Optica - Optica
Newtonian Mechanics. Density, Elasticity, and Fluids. Heat, Temperature, and Thermodynamics. Wave... more Newtonian Mechanics. Density, Elasticity, and Fluids. Heat, Temperature, and Thermodynamics. Waves. Electricity and Magnetism. Light and Geometrical Optics.
The Physics Teacher, 2017
The Physics Teacher
In recent years, there have been a number of articles published concerning whether or not potenti... more In recent years, there have been a number of articles published concerning whether or not potential energy (PE) as defined in mechanics is invariant under Galilean transformation. This essay addresses that issue in a different, more fundamental and elegant way than has been done thus far. It recognizes that a considerable change in the concept of PE has occurred over the last century, mostly as a result of both the special and general theories of relativity. We will show, by simple argument, that PE is Lorentz invariant, even if it is not a rigorously proper relativistic quantity. Although PE is an extremely important classical (i.e., pre-relativistic) theoretical device, it depends on the positions of the interacting bodies at any and every moment. Simply put, if the relative position of any constituent changes, the corresponding interactions must change instantly, and that violates special relativity. In general relativity, PE is not even a well-defined concept.
American Journal of Physics
European Journal of Physics
American Journal of Physics
The Physics Teacher
Anyone who has taught introductory physics should know that roughly a third of the students initi... more Anyone who has taught introductory physics should know that roughly a third of the students initially believe that any object at rest will remain at rest, whereas any moving body not propelled by applied forces will promptly come to rest. Likewise, about half of those uninitiated students believe that any object moving at a constant speed must be continually pushed if it is to maintain its motion. 1 That's essentially Aristotle's law of motion and it is so “obviously” borne out by experience that it was accepted by scholars for 2000 years, right through the Copernican Revolution. But, of course, it's fundamentally wrong. This paper tells the story of how the correct understanding, the law of inertia, evolved and how Newton came to make it his first law.
American Journal of Physics
A study of physics textbooks from the 1860s up to the present reveals shortcomings of our contemp... more A study of physics textbooks from the 1860s up to the present reveals shortcomings of our contemporary approach to teaching the concept of energy. In response, this paper offers a coordinated set of conceptual definitions of force, work, and energy, which can provide a somewhat more accessible grounding on which to develop the subject pedagogically.A study of physics textbooks from the 1860s up to the present reveals shortcomings of our contemporary approach to teaching the concept of energy. In response, this paper offers a coordinated set of conceptual definitions of force, work, and energy, which can provide a somewhat more accessible grounding on which to develop the subject pedagogically.
American Journal of Physics
The concept of gravity came into being in ancient times as a terrestrial concern associated with ... more The concept of gravity came into being in ancient times as a terrestrial concern associated with the practicalities of “weight.” A great leap forward came in the early 1600s with the important theoretical speculations of Johannes Kepler. This article focuses on his prescient theory of gravity which guided the later progress of a number of scholars including Roberval, Hooke, and Newton. And yet, Kepler's remarkable contribution to gravitational theory has been almost completely overlooked in the contemporary scientific literature.The concept of gravity came into being in ancient times as a terrestrial concern associated with the practicalities of “weight.” A great leap forward came in the early 1600s with the important theoretical speculations of Johannes Kepler. This article focuses on his prescient theory of gravity which guided the later progress of a number of scholars including Roberval, Hooke, and Newton. And yet, Kepler's remarkable contribution to gravitational theory has been almost completely overlooked in the contemporary scientific literature.
European Journal of Physics
This paper is an exploration of the concept of energy, illuminated by the transformative insights... more This paper is an exploration of the concept of energy, illuminated by the transformative insights of the special theory of relativity. Focusing on potential energy (PE), it will be shown that PE as presently defined is in conflict with the tenets of special relativity. Even though PE remains an indispensable theoretical device its actual physicality is questionable. Moreover its ontological status is quite different from that of both kinetic energy and mass, a significant point that is not widely appreciated. We will establish that PE is a theoretical concept as opposed to an empirical one; it is a descriptor of mass–energy without a detectable physical presence of its own. PE is a measure of energy stored, it is not the energy stored.
European Journal of Physics
The article 'Comment on 'Relativity, potential energy, and mass'' (2019 Eur. J. P... more The article 'Comment on 'Relativity, potential energy, and mass'' (2019 Eur. J. Phys. 40 028001) makes a number of unsubstantiated assertions regarding the 'reality' of potential energy (PE), the measurability of mass, and the ontological status of kinetic energy. This essay is a refutation of those assertions.