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Free eTextbook while your book ships Contract starts on the date of product shipment, not on date of purchase. The most basic question in philosophy is: What kind of being am I? The answer to this question about human nature will affect how you see others and how you live.
Psychologists have considered the question of whether humans are self-interested, or whether unselfish considerations can motivate. Sigmund Freud, for example, held that humans are essentially selfish and aggressive—a view that was also endorsed earlier by the English.
Mercer claims that introspection reveals that humans always act intentionally to benefit themselves. If you believe that humans are self-interested, this will affect how you interact with others. Manuel Velasquez's clear and engaging prose and the nontechnical primary source readings make complex philosophical concepts easier to understand, and carefully crafted built-in learning aids help you quickly master the material and succeed in your course.
An accelerating electric charge is known to emit electromagnetic waves according to the Larmor formula in classical electromagnetism. An orbiting charge should steadily lose energy and spiral toward the nucleus, colliding with it in a small fraction of a second.
The second problem was that the planetary model could not explain the highly peaked emission and absorption spectra of atoms that were observed. Quantum theory revolutionized physics at the beginning of the 20th century, when Max Planck and Albert Einstein postulated that light energy is emitted or absorbed in discrete amounts known as quanta singular, quantum. In , Niels Bohr incorporated this idea into his Bohr model of the atom, in which an electron could only orbit the nucleus in particular circular orbits with fixed angular momentum and energy, its distance from the nucleus i.
Bohr's model was not perfect. It could only predict the spectral lines of hydrogen; it couldn't predict those of multielectron atoms.
Worse still, as spectrographic technology improved, additional spectral lines in hydrogen were observed which Bohr's model couldn't explain. In , Arnold Sommerfeld added elliptical orbits to the Bohr model to explain the extra emission lines, but this made the model very difficult to use, and it still couldn't explain more complex atoms. While experimenting with the products of radioactive decay, in radiochemistFrederick Soddy discovered that there appeared to be more than one element at each position on the periodic table.
That same year, J. Thomson conducted an experiment in which he channeled a stream of neonions through magnetic and electric fields, striking a photographic plate at the other end.
He observed two glowing patches on the plate, which suggested two different deflection trajectories. Thomson concluded this was because some of the neon ions had a different mass. In Rutherford bombarded nitrogen gas with alpha particles and observed hydrogen nuclei being emitted from the gas Rutherford recognized these, because he had previously obtained them bombarding hydrogen with alpha particles, and observing hydrogen nuclei in the products.
Rutherford concluded that the hydrogen nuclei emerged from the nuclei of the nitrogen atoms themselves in effect, he had split a nitrogen. From his own work and the work of his students Bohr and Henry Moseley, Rutherford knew that the positive charge of any atom could always be equated to that of an integer number of hydrogen nuclei. This, coupled with the atomic mass of many elements being roughly equivalent to an integer number of hydrogen atoms - then assumed to be the lightest particles - led him to conclude that hydrogen nuclei were singular particles and a basic constituent of all atomic nuclei.
He named such particles protons. Further experimentation by Rutherford found that the nuclear mass of most atoms exceeded that of the protons it possessed; he speculated that this surplus mass was composed of previously-unknown neutrally charged particles, which were tentatively dubbed 'neutrons'. And as the technological, political, and social world around us changes, we come to new understandings of ourselves and our society; this, too, introduces change into the world of philosophy.
New technologies, for example, have forced us to rethink our views on euthanasia and the environment, and the proliferation of terrorism has led us to rethink our views on the proper responses to violence.
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