Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Physics and Chemistry relationship

  1. Oct 24, 2012 #1
    Hi, I'm no expert and I'm still in high school, but I'm curious about the relationship between physics and chemistry. As far as I know Chemistry is based on atomistic theory, right? Well, I'm wondering does physics support atomistic theory entirely or there are some parts of this theory that are not welcomed in physics? And are physicists trying to come up with a theory that will prove atomistic theory wrong?
  2. jcsd
  3. Oct 24, 2012 #2
    atomic theory is extremely well accepted and not up for debate in any way.

    here's the difference between chemistry and physics:

    chemists care about the properties of materials at the length scale from micrometer to angstrom - the size of a bacteria to the size of an atom. this is the length scale that quantum mechanics starts to dominate, and in my opinion more importantly, where behavior is significantly influenced by thermal fluctuations. This is the scale where everything in chemistry happens: solvation, foaming, reactivity, diffusion, self assembly, protein folding, crystallization, etc. Chemists apply this knowledge to design things that require molecular, nano or micro level precision - new nanomaterials, thin films, medicines, sensors, semiconductor processing techniques, medical implants, etc.

    Most of the "easy" theory in chemistry is already taken care of. The "hard" theories remain but they're not things that beginners would even understand why it is a problem. These are things like the biopolymer folding problem, abiogenesis, the scaling problem (why do molecules of foams, micelles, proteins, etc. assemble into higher level structures and how do we predict the transition point?) which are extremely specific and hard to answer. For example we have surfactants that, at low concentrations, just dissolve into water. but at higher concentrations, they start forming micelles, and then assemble into surface foams. How do we predict, without doing any experiments and just using a computer and theory, what that critical concentrations are and what the entire mixture looks like at any given point? Or, how do we predict, without doing any experiments, what the structure of any arbitrary protein is?

    physics care about ALL length scales, and ALL properties, not just those of materials. for example physicists study black holes. that's on the kilometer-light year length scale and a black hole is not made of any material. they also care about far smaller things like quarks, which are useless in chemistry.
  4. Oct 24, 2012 #3
    When did theories become facts?
  5. Oct 24, 2012 #4


    User Avatar

    Staff: Mentor

    Physicist is happy when he can prove argon and nitrogen are gases behaving in the same way. Chemist is happy when he can prove argon and nitrogen are gases behaving in a different way.

    While physicists and chemists concentrate on different areas and different applications, there is no single property/area where they would use contradicting theories to describe the reality. It wasn't always this way, but the differences has its source in the fact we did not understood the reality. Once we start to really understand what is going on, it is not difficult to falsify incorrect theory and once it is falsified it is usually dropped as useless.

    Sometimes those falsified theories are still used if they are much simpler - but then we know their limitations and use them only where they work.
  6. Oct 24, 2012 #5
    you know the theory of gravity? you can debate it if you want. the point is that gravity keeps working. atomic theory works because you drive a car. if it didn't, the crude oil that got out of the ground could not be refined to gasoline.
  7. Oct 24, 2012 #6
    I'm not argueing the soundess of atomic theory, I am saying questioning science is how knowledge is gained. Not challenging theories stifles progress, without it we could still be stuck in the Caloric.

    If anything is 'not up for debate' it is this.
  8. Oct 25, 2012 #7


    User Avatar

    Staff: Mentor

    While in general you are right, it is exactly this argument that is abused by crackpots stating "theory X is wrong".
  9. Oct 25, 2012 #8
    most chemistry have already been proven beyond doubt. most of the rest only has niche application. chemistry is currently an applied science where the known theories are applied, either with experimental or computational methods. Indeed the vast bulk of science is applying known theories to unknown situations where those theories are known to exist and using that knowledge to design useful products.
  10. Oct 25, 2012 #9
    Again, I am not argueing the soundness of these theories. What I am saying is statements like this have no place in science, for someone of your background I would expect better.

    I am sure that is frustrating and I certainly have seen this on the forums (including many cleanups involving yourself Borek), but crackpots have a tendency to be easy to pick out.

    Questioning our understanding helps science bear more fruit, it's too important to bypass even if you have to deal with the occasional nut. Without it we would probably still be stuck in the Aether.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook