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Classical Physics-Modern Physics

  1. Jan 31, 2010 #1
    Hi All,

    I'm not sure exactly what is considered classical physics.

    I always thought it was everything before Einstein's Theory Of Special Relativity but recently I read that it is everything other than Quantum Mechanics.

    Please clarify this for me.

    Thank you,
  2. jcsd
  3. Jan 31, 2010 #2


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    Science Advisor

    From what I gather, there are two distinctions, depending on the context in which you are talking about classical vs. modern physics. You pinpoint both of them very nicely.

    For an undergraduate course in classical physics, it's probably everything before 1900. However, I often hear General Relativity referred to as a classical theory, especially when it's juxtaposed with a theory of quantum gravity. So, depends on the context.
  4. Jan 31, 2010 #3
    I think classical physics is all physics that models Nature as deterministic and in principle predicts that all outcomes of an experiment are knowable exactly, Newton's Laws, Maxwell's equations, Einstein's theory of relativity. Non-classical physics predicts only probabilistic outcomes of experiments and models Nature as probabalistic rather than deterministic. Quantum mechanics when first proposed said that there is no possibility of a precisely predicted outcome of an experiment and that the underlying physical processes were fundamentally probabalistic. Now a days I am not sure that this is still true.
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