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.New York:Basic Books, 1993.This controversial book raises questions about the kind ofabstract theoretical directions that Brian Greene (see previous item) promotes.Like many books that challenge cutting-edge physics, it is easier to understandthan books by supporters.This could be a matter of oversimplification, or amatter of seeing through a certain amount of double-talk.Greene s and Lind-ley s books are worth taking a look at in tandem, exactly because they are inopposition.Suplee, Curt.Physics in the Twentieth Century.New York: Abrams, 1999.Pub-lished in association with the American Physical Society and the AmericanInstitute of Physics, this book has an almost equal balance between text andpictures.The captions to the pictures, which are often spectacular but res-olutely scientific, are often as informative as the text.For the general readerthis may be the most approachable book on twentieth-century physics yet pub-lished a bang-up job.Ferris, Timothy.Coming of Age in the Milky Way.New York: Morrow, 1988.Winner of the American Institute of Physics Prize, this remains, even a dozenyears later, the best introduction there is to the field of cosmology in general.Thuan, Trinh Xuan.The Secret Melody.New York: Oxford University Press,1995.Thuan is as much poet as scientist and therefore always a delight to read.His elucidation of the four fundamental forces, in terms of a storm in a smalltown, was the inspiration for the baseball analogy used in this chapter.Bodanis, David.E = mc2: A Biography of the World s Most Famous Equation.NewYork: Walker, 2000.Among the books listed here, this is the most recent, andperhaps the best, attempt to explain Einstein s famous equation in terms thatcan be easily grasped by the general reader.Bodanis lays out the earlier workby such nineteenth-century scientists as James Clerk Maxwell, which Einsteinbuilt on, and he includes entertaining historical and biographical material. c15.qxd 6/19/01 2:27 PM Page 150Chapter15What Is Light? Let there be light. (The First Book of Moses, called Genesis ) Nature, and Nature s Laws lay hid in Night: / God said, LetNewton be! and All was light. (Alexander Pope intendedepitaph for Isaac Newton)reation myths from the beginning of human his-tory have tried to account for the existence of light,Cand there are few great poets who have not cele-brated its presence, or lamented its absence.Long before therewas anything that could be called science, the human race recog-nized that light was a life giver.Nonetheless, it took a very longtime for light to begin to be understood scientifically, and evennow, some aspects of light remain deeply puzzling.In 1666, while Newton was formulating the three laws ofmotion and the universal law of gravity, he was also experiment-ing with light.Humans had always delighted in the colors of therainbow at the conclusion of a storm and, by Newton s time,were familiar with the multicolored effects that occurred whenlight shone through the prisms of chandeliers.Still, people as-sumed that the light itself was white, and that something aboutthe sky after a storm or the composition of glass added color to it.Newton would later write, In the year 1666 (at which time Iapplied myself to the grinding of optick glass or other figures than150 c15.qxd 6/19/01 2:27 PM Page 151What Is Light? 151spherical) I procured me a triangular glass prism, to try the cele-brated phaenomena of colours. (The spellings here are those inuse at the time.)The experiment Newton performed was simple but no onehad ever thought of doing it before.He admitted a narrow beamof light into his workroom by making a small hole in the shuttercovering the window.The light was white.Then he placed hisprism in front of the beam of light.On the opposite wall, a fullspectrum of colors appeared.Newton then took a crucial furtherstep.He used two boards, each with a very small hole in it.Heplaced one board between the prism and the window, furthernarrowing the beam of light.The second board was placedbetween the prism and the wall, so that only a single color wasable to pass through the hole in it to appear on the wall.He thenput a second prism in front of that hole, and saw that, again, onlythe single color was reflected on the opposite wall.The secondprism did not change the color of the light.He repeated thisprocess for each of the colors of the spectrum, and each time thelight that passed through the second prism was unaltered.Thus,the colors were not in the prisms, but in the light itself other-wise, the second prism should have produced all the colors, notjust the isolated one [ Pobierz całość w formacie PDF ]
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.New York:Basic Books, 1993.This controversial book raises questions about the kind ofabstract theoretical directions that Brian Greene (see previous item) promotes.Like many books that challenge cutting-edge physics, it is easier to understandthan books by supporters.This could be a matter of oversimplification, or amatter of seeing through a certain amount of double-talk.Greene s and Lind-ley s books are worth taking a look at in tandem, exactly because they are inopposition.Suplee, Curt.Physics in the Twentieth Century.New York: Abrams, 1999.Pub-lished in association with the American Physical Society and the AmericanInstitute of Physics, this book has an almost equal balance between text andpictures.The captions to the pictures, which are often spectacular but res-olutely scientific, are often as informative as the text.For the general readerthis may be the most approachable book on twentieth-century physics yet pub-lished a bang-up job.Ferris, Timothy.Coming of Age in the Milky Way.New York: Morrow, 1988.Winner of the American Institute of Physics Prize, this remains, even a dozenyears later, the best introduction there is to the field of cosmology in general.Thuan, Trinh Xuan.The Secret Melody.New York: Oxford University Press,1995.Thuan is as much poet as scientist and therefore always a delight to read.His elucidation of the four fundamental forces, in terms of a storm in a smalltown, was the inspiration for the baseball analogy used in this chapter.Bodanis, David.E = mc2: A Biography of the World s Most Famous Equation.NewYork: Walker, 2000.Among the books listed here, this is the most recent, andperhaps the best, attempt to explain Einstein s famous equation in terms thatcan be easily grasped by the general reader.Bodanis lays out the earlier workby such nineteenth-century scientists as James Clerk Maxwell, which Einsteinbuilt on, and he includes entertaining historical and biographical material. c15.qxd 6/19/01 2:27 PM Page 150Chapter15What Is Light? Let there be light. (The First Book of Moses, called Genesis ) Nature, and Nature s Laws lay hid in Night: / God said, LetNewton be! and All was light. (Alexander Pope intendedepitaph for Isaac Newton)reation myths from the beginning of human his-tory have tried to account for the existence of light,Cand there are few great poets who have not cele-brated its presence, or lamented its absence.Long before therewas anything that could be called science, the human race recog-nized that light was a life giver.Nonetheless, it took a very longtime for light to begin to be understood scientifically, and evennow, some aspects of light remain deeply puzzling.In 1666, while Newton was formulating the three laws ofmotion and the universal law of gravity, he was also experiment-ing with light.Humans had always delighted in the colors of therainbow at the conclusion of a storm and, by Newton s time,were familiar with the multicolored effects that occurred whenlight shone through the prisms of chandeliers.Still, people as-sumed that the light itself was white, and that something aboutthe sky after a storm or the composition of glass added color to it.Newton would later write, In the year 1666 (at which time Iapplied myself to the grinding of optick glass or other figures than150 c15.qxd 6/19/01 2:27 PM Page 151What Is Light? 151spherical) I procured me a triangular glass prism, to try the cele-brated phaenomena of colours. (The spellings here are those inuse at the time.)The experiment Newton performed was simple but no onehad ever thought of doing it before.He admitted a narrow beamof light into his workroom by making a small hole in the shuttercovering the window.The light was white.Then he placed hisprism in front of the beam of light.On the opposite wall, a fullspectrum of colors appeared.Newton then took a crucial furtherstep.He used two boards, each with a very small hole in it.Heplaced one board between the prism and the window, furthernarrowing the beam of light.The second board was placedbetween the prism and the wall, so that only a single color wasable to pass through the hole in it to appear on the wall.He thenput a second prism in front of that hole, and saw that, again, onlythe single color was reflected on the opposite wall.The secondprism did not change the color of the light.He repeated thisprocess for each of the colors of the spectrum, and each time thelight that passed through the second prism was unaltered.Thus,the colors were not in the prisms, but in the light itself other-wise, the second prism should have produced all the colors, notjust the isolated one [ Pobierz całość w formacie PDF ]