# What is the difference between physics and chemistry? **URL:** \ **Category:** Factual Questions\ **Created:** [May 1, 2011, 10:35am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375 "2011-05-01T10:35:12Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![NineToTheSky](https://avatars.discourse-cdn.com/v4/letter/n/b5a626/32.png) [@NineToTheSky](https://boards.straightdope.com/u/NineToTheSky)\ **Post date:** [May 1, 2011, 10:35am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/1 "2011-05-01T10:35:12Z")
I’ve always thought that physics deals with the very small, from strings and quarks, up to atoms. At that point chemistry takes over until you reach the biggest living things. Then physics takes over again, dealing with anything as big, or bigger, than planets. Is there any truth in this? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [May 1, 2011, 11:19am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/2 "2011-05-01T11:19:58Z")
Don’t tell that to the quantum chemists. The problem is you’re talking about several different fields that tend to get lumped together under the same name. In most general terms, chemistry is the study of matter and how it changes. Once you start dealing with subatomic particles you don’t really have matter any more, and the reason this stuff (quantum mechanics and string theory, etc.) gets put under physics is primarily because it was physicists who began investigating it. Physicists were looking at this stuff because they wanted to understand how forces like electromagnetism and gravity worked. But it’s really all the same stuff: investigating how the universe works. [This helpful chart](http://xkcd.com/435/) illustrates how the fields relate to one another. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [May 1, 2011, 11:26am UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/3 "2011-05-01T11:26:33Z")
Burning a piece of wood is chemistry. Sawing it in half is physics. ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [May 1, 2011, 12:43pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/4 "2011-05-01T12:43:16Z")
Chemistry is applied physics. In particular, chemistry is the application of Quantum Electro-Dynamics to the interaction of atoms. Chemists use a host of tools to study the complexity of what arises, and many of these tools came from physics too. Once you get past a dozen odd atoms interacting the QED basis becomes too complex to manage and approximate techniques come into play. But at its heart, chemistry is atoms rattling around as dictated by QED. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 1, 2011, 12:49pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/5 "2011-05-01T12:49:49Z")
Physics is the study of matter, and chemistry is the study of the elements and their interactions. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [May 1, 2011, 1:10pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/6 "2011-05-01T13:10:41Z")
In rough terms, chemistry explores (and attempts to predict) what happens when you mix A and B or set C on fire. Physics tries to determine why it happens the way it does, i.e. figuring out the underlying rules of the universe. [QUOTE=friedo] [This helpful chart](http://xkcd.com/435/) illustrates how the fields relate to one another. [/QUOTE] As one of my physics teachers liked to quip: “So as you see to figure out we should [perform complex string of mathematical operations], but since we’re not mathematicians we’re going to approximate like pigs and call it a day.” ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [May 1, 2011, 1:31pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/7 "2011-05-01T13:31:38Z")
> [@Napier](#): > > Physics is the study of matter, and chemistry is the study of the elements and their interactions. Chemistry is usually defined as the study of matter and its changes. (That’s even the subtitle of a popular chemistry textbook I used back when I taught the subject.) I would define physics as the study of energy, forces, and motion. FWIW, I also taught an introductory physics course for a couple of years. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 1, 2011, 3:13pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/8 "2011-05-01T15:13:05Z")
Chemistry is the physics of electron valences. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 1, 2011, 3:45pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/9 "2011-05-01T15:45:47Z")
chemistry was the study of matter and its changes. then when atoms were discovered, chemistry often had been defined as what happens with the electrons of atoms. then when the nucleus was found to be changable then you had nuclear chemistry (the nuclear reaction area of this). physics and chemistry also overlap in the areas of physical chemistry and chemical physics and quantum chemistry. also molecular biology and biochemistry have areas of overlap. depends on where you’ve been and where you might be going. ---
**Author:** ![mac\_bolan00](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@mac\_bolan00](https://boards.straightdope.com/u/mac_bolan00)\ **Post date:** [May 1, 2011, 11:46pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/10 "2011-05-01T23:46:06Z")
physical science both. hardly any difference (same as with engineering) but the depth and width of knowledge and methods for either justify marking each as a special discipline. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 2, 2011, 12:47pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/11 "2011-05-02T12:47:48Z")
Googling “chemistry” and “study of matter” together gives 281,000 hits. Googling “physics” and “study of matter” together gives 723,000 hits. The terms “chemistry” and “physics” by themselves both generate almost 2 million hits with counts differing by a couple percent. I think if we want to award a winner for which one is the “study of matter” it would have to be physics, but we sure couldn’t say that chemistry _wasn’t_ the study of matter. ---
**Author:** ![Markxxx](https://avatars.discourse-cdn.com/v4/letter/m/5daacb/32.png) [@Markxxx](https://boards.straightdope.com/u/Markxxx)\ **Post date:** [May 2, 2011, 1:01pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/12 "2011-05-02T13:01:26Z")
Physicists shave and chemists say “Oh you cut yourself” 🙂 ---
**Author:** ![mac\_bolan00](https://avatars.discourse-cdn.com/v4/letter/m/b3f665/32.png) [@mac\_bolan00](https://boards.straightdope.com/u/mac_bolan00)\ **Post date:** [May 2, 2011, 1:12pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/13 "2011-05-02T13:12:24Z")
how could i forget: physicists treat mass and weight differently while chemists don’t bother. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [May 2, 2011, 1:13pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/14 "2011-05-02T13:13:57Z")
> [@Napier](#): > > Googling “chemistry” and “study of matter” together gives 281,000 hits. Googling “physics” and “study of matter” together gives 723,000 hits. The terms “chemistry” and “physics” by themselves both generate almost 2 million hits with counts differing by a couple percent. I think if we want to award a winner for which one is the “study of matter” it would have to be physics, but we sure couldn’t say that chemistry _wasn’t_ the study of matter. Careful with google polls. “Physics is the study of matter” and “physics is not the study of matter” will both generate a hit on the same search words. ---
**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\ **Post date:** [May 2, 2011, 6:44pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/15 "2011-05-02T18:44:56Z")
Wasn’t there an old quip that went something like: “Sociology is applied psychology, which is applied biology, which is applied chemistry, which is applied physics, which is applied math.”? The real answer seems to be that the division is rather socially constructed, similar to the border of chem and bio, for example behavior of specific drugs on bodily systems. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 2, 2011, 7:18pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/16 "2011-05-02T19:18:21Z")
Chemists think a mole is a unit, while we’re on the subject. And math is applied philosophy. And philosophy is applied sociology. ---
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [May 2, 2011, 7:24pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/17 "2011-05-02T19:24:50Z")
I can get an A in chemistry. Yes, it’s all about me. ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [May 2, 2011, 7:33pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/18 "2011-05-02T19:33:22Z")
> [@Kobal2](#): > > Careful with google polls. “Physics is the study of matter” and “physics is not the study of matter” will both generate a hit on the same search words. Googling the former (without quotation marks) just returned 43.2 million hits. The latter, done the same way, returned 49.8 million. ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [May 2, 2011, 7:34pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/19 "2011-05-02T19:34:33Z")
> [@Napier](#): > > Chemists think a mole is a unit, while we’re on the subject. > > And math is applied philosophy. And philosophy is applied sociology. Can you explain the claim that math is applied philosophy? Because it strikes me as bullshit, but I’ve been wrong before. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [May 2, 2011, 8:44pm UTC](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375/20 "2011-05-02T20:44:03Z")
> [@Skald\_the\_Rhymer](#): > > Can you explain the claim that math is applied philosophy? Because it strikes me as bullshit, but I’ve been wrong before. Math is applied logic, and logic is a field of (or, perhaps, a form of) philosophy. [Next page](https://boards.straightdope.com/t/what-is-the-difference-between-physics-and-chemistry/580375.md?page=2)