What is the difference between chemistry and physics

Chemistry procedures are reproducible, and all theories or hypotheses are tested in order to verify reliability of the hypotheses. Chemistry deals with the chemical composition and reaction of matter. The science of physics also involves the study of matter and energy and how they interact with each other, but physicists are generally looking for the base answer as to why or how matter reacts the way it does.

Don't worry about the electrons? That is about all I worried about in organic chemistry, were are the electrons going and what are they doing. And, of course, if you go to a large enough condensed matter system, it just becomes mechanics The Born-Oppenheimer BO approximation is ubiquitous in quantum chemical calculations of molecular wavefunctions.

It consists of two steps. The electron-nucleus interactions are not removed and the electrons still "feel" the Coulomb potential of the nuclei clamped at certain positions in space. This first step of the BO approximation is therefore often referred to as the clamped nuclei approximation.

This second step of the BO approximation involves separation of vibrational, translational, and rotational motions. This can be achieved by application of the Eckart conditions. The eigenvalue E is the total energy of the molecule, including contributions from electrons, nuclear vibrations, and overall rotation and translation of the molecule. The exceptions to Born-Oppenheimer are themselves interesting, including some genuine Chemistry on surfaces, and some molecular biology.

I'm not claiming that organic chemists don't know anything about nuclear structure or atomic spectroscopy-- that would be foolish. The claim is that their primary concern is with things at a higher level of abstraction. It's the same with my own field of atomic physics. There are plenty of people working in atomic physics who have an excellent understanding of nuclear physics.

I've worked with several of them. Their primary concern as atomic physicists though, is with the arrangement of the electrons in the atoms, and not with how the protons and neutrons are arranged in the nucleus, except insofar as that affects things like the hyperfine structure and internuclear interactions.

Atomic physicists should certainly know something about nuclear physics, in the same way that nuclear physicists should know something about spectroscopy, and particle physicists should know something about band structure. But the study of atomic physics can be defined, roughly, as being that part of physics that cares primarily about the study of individual atoms and their behavior.

Good point. It's mechanics, then geology, then planetary science, then astronomy, then cosmology. Where, Chad, do you put exotic atoms i. And where do they go in the Periodic Table? The recently detected molecule dipositronium belongs to which discipline? A physicist hands you a paper describing the answer.

A chemist hands you a vial containing the answer. A social advocate demands legislation condemning the question. Easy to derivatize as a lyotropic liquid crystal for spinning into miles of supercon wire. Shouldn't somebody do the chemistry and find out? Jonathan 8: rather than adding epicycles to the model, we can set aside anything hard-to-categorize and call it "interdisciplinary". Sic transit astroparticle physics, cosmochemistry, plasma physics, exotic atoms, biogeochemistry, and so on.

In my field, organic chemistry, most people usually do not have to calculate anything. It is not that they would be lazy but it is extremely difficult to model things accurately. It is sufficient in most cases to use qualitative explanations, to get the work done.

There is a computational branch, people working on chemical calculations of simplified systems ab initio but it is very hard thing and not very useful - real life problems get out of hand quickly.

Just taking in account the influence of a solvent is non-trivial. While chemistry is very advanced today, it doesn't use mathematics too much. Physics is about the research of all aspects of Nature that are sufficiently "simple" or "fundamental" so that we may describe their behavior by accurate enough mathematics and the laws that govern this observable behavior may be translated to very accurate mathematical equations, too.

It's a different motivation, different strategy, and different methodology. When systems become too complex or "composite", such as some particular complicated molecules, we usually don't expect physics to study these things that fail to be fundamental although they may have very important applications in industry or chemistry.

In the case of atoms, physics still studies the objects using the traditional physical concepts such as position, velocity, acceleration, forces, energies — applied to electrons, atoms, and molecules.

It actually wants to translate all these things to real numbers. We find out that to do so, classical mechanics must be replaced by quantum mechanics and deal with things like "wave functions" instead of positions but it still deals with real or complex functions of real or complex variables which include time.

Chemistry is much more practically oriented discipline that mostly studies the qualitative differences between compounds and how they change in the reactions. Of course, there is a boundary between physics and chemistry. It is probably not easy to divide the subdisciplines that exist near the boundary but they include physical chemistry, quantum chemistry, chemical physics, and so on.

These terms are actually different from each other and the practitioners may talk at length when they're working on physical chemistry and chemical physics but at the end, it's usually the same researchers, anyway.

When it's physics, it's about the mathematical laws of Nature which matter. When it's chemistry, it's about the compounds and reactions. Just to give you a simple analogy, physics is like "constitution" of a nation. Chemistry is a set of "laws", governing one particular types of affairs of the nation. Any law of chemistry must be "constitutionally valid". Please don't bring amendments here, though Physics is the "foundation".

In rough terms at the very fundamental level, it mostly deals with energy, mass, and electric charge. As mentioned by "Lubos", it studies both things at atomic scale, and things at galactic scale. Its ultimate aim, though not everyone would agree with that is to find an equation that would explain everything. Radical Edward 9 posts. Sayonara 9 posts. JaKiri 21 posts. YT 14 posts. Chemistry - The science of the composition, structure, properties, and reactions of matter, especially of atomic and molecular systems.

Physics - used with a sing. The study of the natural or material world and phenomena; natural philosophy. To say Chemistry is a subset of physics is just belittleing chemistry which is hardly surprising coming from a physicist.

Physics is in turn a subset of maths, namely the mathematical models that correlate with what we can empirically measure, with a few extra axioms and the like thrown in for measure. Well, most things in chemistry are explained using physical models.

HOwever, i would not consider this belittleing at all. I think that people that would take this as an insult are not quite secure in the fact that they are chemists -- perhaps they really wanted to be physicists? Anyway, why is this not an insult? Because, the chemist chooses to investigate a particulare aspect of "physics" in great detail.

SO much detail, in fact, that all other aspects of physics must be almost excluded. Of course this all depends on what you are doing in chemistry. A physical chemist will know almost as much nuclear chemistry as a nuclear chemists. By the same measure, a nuclear physisist might know a great deal about moleculare orbital theory. The point being that "chemistry" is just a short hand way of saying , "i specialize in the physics of interactions between molecules, wich mostly has to do with the interaction of outershell electrons with other outershell electrons and the formation of moleculare orbitals, yadda yadaa yadda.

Refferring to things other than Physics as stamp collecting shows an inability to appreaciate anything other than what you do. But sometimes that is what happens when you are involved in something that the world really reveres.

If we lived about years ago, people would have scoffed at you if you were a physicsist -- chemistry was where it was at then.