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The difference between physics and chemistry?

  1. Dec 5, 2015 #1
    What is the difference between physics and chemistry? I asked my Science teacher (who teaches Physics in senior years) and he said that chemistry was basically applied physics.
     
  2. jcsd
  3. Dec 5, 2015 #2

    dextercioby

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    Fundamental (or quantum) chemistry is applied quantum mechanics (the latter being a theory of physics). Then once you've described matter at the level of atoms and molecules (so-called chemical compounds), chemistry parts ways with physics and is interested in describing interactions between atoms and molecules (the so-called chemical reactions). From this everything else in chemistry follows.
     
  4. Dec 5, 2015 #3

    Ygggdrasil

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    Obligatory XKCD reference:
    purity.png
    On the other hand, physicists like to say physics is to math as sex is to masturbation. (https://xkcd.com/435/)​

    In some respects, there is not much difference between chemistry and physics. Both are essentially the study of matter, though chemistry focuses mainly on thinking about matter at the atomic and molecular levels (while physicists also study matter on larger or smaller scales). One could say that chemistry is just applied physics (though physicists are notorious for trivializing any other field of study), but many aspects of chemistry are too complex to be modeled from first principles (as is the approach of physics). In many subfields of chemistry (e.g. organic, inorganic, biochemistry), the principles are more often heuristics worked out from experimental observations rather than derived from Schödinger's equation. However, what physical chemists learn is not much different from what is taught in quantum, atomic, and condensed matter physics.
     
    Last edited: Dec 5, 2015
  5. Dec 5, 2015 #4

    symbolipoint

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    No. Not at all.
    The basic meaning for Physics is the study of matter and energy. A way to take the basic meaning of Chemistry is, the study of materials, their identities, transformations reactions and properties.
     
  6. Dec 5, 2015 #5

    FactChecker

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    I wouldn't read too much into your teacher's statement. There are so many types of chemistry and physics that general statements are more misleading than constructive. Physical chemistry is not the same as organic chemistry and nuclear physics is not the same as astrophysics.
     
  7. Dec 6, 2015 #6
    @Ygggdrasil
    Nice cartoon! :smile:
    I wonder if we could really put Maths together with the other disciplines, though.
    I always considered Maths a form of philosophy, because it deals with purely abstract concepts, whereas all other sciences deal with physical entities (from fundamental particles all the way up to atoms, molecules, cells, organisms, societies).
    Having said that, I think I recall reading something in R. Penrose's book 'The Road to Reality' to the effect that Mathematics is just as inherent in reality as physics or chemistry are, i.e. it's not an artificial construct disconnected from reality, but something that would necessarily and automatically stem from the observation of our physical world whenever an intelligent being decided to put its mind to it.
    Who knows - we can't tell now because we already do have Maths. The counterproof would be to discover another intelligent life form somewhere in the Universe that managed to evolve into a complex society without knowing any Maths.
    Sorry, maybe a bit off topic, but interesting, I think.
     
  8. Dec 6, 2015 #7
    Physics studies mass, force, and energy.

    Chemistry studies substances and materials.

    A Chemist would be interested in what something is made of. A Physicist would not be interested. A Physicist would be more interested studying how much torsion force it can handle and then coming up with an equation to describe it I guess.
     
  9. Dec 7, 2015 #8
    Chemistry is the physics of atoms and molecules.
     
  10. Dec 7, 2015 #9

    symbolipoint

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    This is the "Physical Chemistry" point of view.
     
  11. Dec 7, 2015 #10
    What your teacher said is true, but if you want to go that far than literally everything except math is physics, and even that could be said to be a result of biology like psychology was in that picture above. They're different fields for a reason, of course nature doesn't care about our distinctions, but to argue about which field is more pure or all encompassing or fundamental is childish and stupid, and I'm astounded to have seen actual scientists have legitimate, angry arguments about this.
     
  12. Dec 7, 2015 #11

    symbolipoint

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    Some people, even if scientists, do not like messy things, and some others like the diversity found in messy things. Many (not all) people who really want to study Biology, want to understand some part of the diversity found in Biology, and do not mind the mess too much. They are not always trying to find an exact mechanism at the finest physical level. There's a difference between Biochemistry and Predator-Prey relationships.
    ...
     
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