# Do atoms really exist? **URL:** \ **Category:** Factual Questions\ **Created:** [March 27, 2004, 8:26am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714 "2004-03-27T08:26:58Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![EllisDee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ellisdee/32/4531_2.png) [@EllisDee](https://boards.straightdope.com/u/EllisDee)\ **Post date:** [March 28, 2004, 3:42am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/41 "2004-03-28T03:42:44Z")
> [@Libertarian](#): > > “It is possible for it to rain outside.” [makes] a massive ontological commitment [by] saying that that there must be some world — some circumstance, context, or contingency — in which it is not possible that it is not raining outside. Really? Clearly I have killed way too many brain cells over the years, because I can’t grasp that concept. Could you either elaborate or link to a straightforward explanation for me? How does saying “X is possible” require that there be a reality in which “X is not possible”? If that is true, did the agnostics kill god? ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [March 28, 2004, 4:12am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/42 "2004-03-28T04:12:30Z")
> [@Lumpy](#): > > After Dalton proposed the first modern atomic theory at the beginning of the nineteenth century, the question of whether atoms are real was roundly debated through most of that century. Dalton proposed that chemical combination only occurs in fixed proportions by weight, and that all chemical reactions will consistantly behave in a manner explainable by presuming irreducable units of different “elements”, which he labled atoms. A century of investigation in chemistry confirmed this (although many of Dalton’s original postulates were discovered to be oversimplifications). In addition, the classical physics of the nineteenth century discovered more and more phenomena could be explained by “atomic theory”: heat could be considered the random motion of atoms and molecules; stereoisomerism (two substances apparently identical except for how they polarize light) by presuming mirror versions of molecules; crystallography could account for all possible crystal symmetries in terms of three-dimensional arrangements of atoms; and many others. > > Still, there were some holdouts. They said “all the above simply shows that matter behaves _as if_ it were atomic. But are there really tiny spheres of a definite size and weight?” A proof of the reality of atoms was produced by none other than Albert Einstein at the end of the century. > > Earlier, the phenomenon of Brownanian motion had been discovered. Tiny particles suspended in liquid will continually jiggle and bounce around, and the smaller they are the more they’ll move. This was eventually interpreted as caused by random thermal movement of molecules in the liquid: atoms are so small that a macroscopic object is struck by effectively identical numbers of them on all sides. But a very small object might be struck by, say, one million on one side and one million and one on the other, jiggling it about a little. An even smaller particle might be hit by ten thousand on one side and ten thousand and one on the other, being jiggled more strongly; and so forth. > > What Einstein did (in addition to Relativity and the photon theory of light) was to produce a mathematical analysis that exactly predicted how Brownanian motion would diffuse small suspended particles throughout a liquid, presuming that the molecules of the liquid were a certain finite mass. In fact, his paper produced the first method of directly calculating exactly what a molecule actually weighed. > > Of course, all this was done just as classical physics collapsed, but leaving out quantum physics: yes atoms are real, as real as anything is. I couldn’t agree with your last statement more, but just to be perverse, Brownian motion could be caused by pixies (invisible just like atoms are) with a malicious sense of humor. In fact, pixies can explain anything. The reason we rule them out, I think, is that you need a special pixie for each purpose and the atomic theory allows just one generalization to replace a plethora of pixies. Occam’s Razor and all that. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [March 28, 2004, 4:25am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/43 "2004-03-28T04:25:41Z")
I also believe atoms exist, but given that between measurements they behave as a wave I would have to say their existence is of a somewhat different nature than that of a keyboard–micro versus macro. > [@](#): > > I’m still learning QM, but I think it’s related to the probability of wave orientation that is being passed by the filter. I bet I’ve got the physics mucked up but it’s still a terrific field demonstration. It’s most definitely due to the wave nature of quantum particles. You may find it interesting that you can get the same effect with a taut string and sets of parallel bars. ---
**Author:** ![MonkeyMensch](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@MonkeyMensch](https://boards.straightdope.com/u/MonkeyMensch)\ **Post date:** [March 28, 2004, 4:27am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/44 "2004-03-28T04:27:27Z")
> [@David Simmons](#): > > I couldn’t agree with your last statement more, but just to be perverse, Brownian motion could be caused by pixies (invisible just like atoms are) with a malicious sense of humor. In fact, pixies can explain anything. The reason we rule them out, I think, is that you need a special pixie for each purpose and the atomic theory allows just one generalization to replace a plethora of pixies. Occam’s Razor and all that. **David S** , I believe you’re just a smidge off there. It is, of course, brownies that cause Brownian motion. Pixies, as is well known, cause pixelation. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [March 28, 2004, 6:11am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/45 "2004-03-28T06:11:07Z")
> [@MonkeyMensch](#): > > **David S** , I believe you’re just a smidge off there. > > It is, of course, brownies that cause Brownian motion. > > Pixies, as is well known, cause pixelation. I got a C in brownies, so you could be right. And I got an A in pixies. So obviously I would much rather talk about pixies. ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [March 28, 2004, 12:52pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/46 "2004-03-28T12:52:30Z")
> [@Ellis Dee](#): > > Really? Clearly I have killed way too many brain cells over the years, because I can’t grasp that concept. Could you either elaborate or link to a straightforward explanation for me? > > How does saying “X is possible” require that there be a reality in which “X is not possible”? If that is true, did the agnostics kill god? Wikipedia has a pretty good overview of the concept: > **[Modal logic](https://en.wikipedia.org/wiki/Modal_logic)** > > Modal logic is a type of formal logic primarily developed in the 1960s that extends classical propositional and predicate logic to include operators expressing modality. A modal—a word that expresses a modality—qualifies a statement. For example, the statement "John is happy" might be qualified by saying that John is usually happy, in which case the term "usually" is functioning as a modal. The traditional alethic modalities, or modalities of truth, include possibility ("Possibly, p", "It is poss... ---
**Author:** ![Liberal](https://avatars.discourse-cdn.com/v4/letter/l/848f3c/32.png) [@Liberal](https://boards.straightdope.com/u/Liberal)\ **Post date:** [March 28, 2004, 12:56pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/47 "2004-03-28T12:56:54Z")
As to this in particular: > [@](#): > > How does saying “X is possible” require that there be a reality in which “X is not possible”? Something got truncated in that. Saying that X is possible (along with committing X ontologically) requires that there be a reality in which **NOT X** is not possible. In other words, X must exist somewhere. ---
**Author:** ![Epimetheus](https://avatars.discourse-cdn.com/v4/letter/e/c4cdca/32.png) [@Epimetheus](https://boards.straightdope.com/u/Epimetheus)\ **Post date:** [March 28, 2004, 1:45pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/48 "2004-03-28T13:45:13Z")
Lib, you have hit a new low, pimping out your ontological/modal logic in a debate about atoms, you are falling off the deep end old boy. ---
**Author:** ![Jon\_the\_Geek](https://avatars.discourse-cdn.com/v4/letter/j/bbce88/32.png) [@Jon\_the\_Geek](https://boards.straightdope.com/u/Jon_the_Geek)\ **Post date:** [March 28, 2004, 1:52pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/49 "2004-03-28T13:52:23Z")
> [@Ring](#): > > I also believe atoms exist, but given that between measurements they behave as a wave I would have to say their existence is of a somewhat different nature than that of a keyboard–micro versus macro. Actually, everything behaves as a wave between measurements. Jupiter has a wavelength (which is some fraction of a nanometer larger than the diameter of Jupiter, so it’s mostly safe to think of Jupiter as being where we think it is). It’s just more noticeable the smaller you get, so that electrons and photons tend to behave more like waves than particles (because their wavelengths are considerably larger than the size of their particles). ---
**Author:** ![xash](https://avatars.discourse-cdn.com/v4/letter/x/c6cbf5/32.png) [@xash](https://boards.straightdope.com/u/xash)\ **Post date:** [March 29, 2004, 7:13am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/50 "2004-03-29T07:13:42Z")
> [@Epimetheus](#): > > Lib, you have hit a new low, pimping out your ontological/modal logic in a debate about atoms, you are falling off the deep end old boy. **Epimetheus** , please watch your comments. You are in GQ. - **xash** General Questions Moderator ---
**Author:** ![vasyachkin](https://avatars.discourse-cdn.com/v4/letter/v/c5a1d2/32.png) [@vasyachkin](https://boards.straightdope.com/u/vasyachkin)\ **Post date:** [March 29, 2004, 8:12pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/51 "2004-03-29T20:12:20Z")
whether or not something exists is not a question that can have a good answer imho. as far as i know there is no evidence that theory about atoms is wrong, that means to the best of our knowledge they _exist_ a more relevant question would be - what ARE they ? when you say that your keyboard exist what you really mean is you can interact with it, like bang it on your monitor. well you can also interact with atoms similarly, you can move individual atoms. that doesnt explain what they are though too well. ---
**Author:** ![Star\_Was](https://avatars.discourse-cdn.com/v4/letter/s/9d8465/32.png) [@Star\_Was](https://boards.straightdope.com/u/Star_Was)\ **Post date:** [March 30, 2004, 12:08am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/52 "2004-03-30T00:08:43Z")
Wow. What a clear answer. With all your fancy book learning I assumed you could answer this in a clear way. Just kidding. 😉 However, I am now even more confused. I don’t think I should have used the word “exist” in my question. Maybe a better way to ask my question is: Can an atom be observed directly like a “keyboard” or an “apple”? ---
**Author:** ![rowrrbazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rowrrbazzle/32/414_2.png) [@rowrrbazzle](https://boards.straightdope.com/u/rowrrbazzle)\ **Post date:** [March 30, 2004, 12:30am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/53 "2004-03-30T00:30:54Z")
Member [js\_africanus](http://boards.straightdope.com/sdmb/member.php?action=getinfo&username=js_africanus) currently has this as his sig: > [@](#): > > In terms of quantum electrodynamics, it is unclear whether a hydrogen atom even exists. --Rothman & Sudarshan ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [March 30, 2004, 4:21am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/54 "2004-03-30T04:21:31Z")
> [@Star Was](#): > > Wow. What a clear answer. With all your fancy book learning I assumed you could answer this in a clear way. > > Just kidding. 😉 > However, I am now even more confused. I don’t think I should have used the word “exist” in my question. Maybe a better way to ask my question is: > > Can an atom be observed directly like a “keyboard” or an “apple”? You can only see objects that are larger than the wavelength of visible light. So that’s about 10[sup]-6[/sup]m. An atom is about 10[sup]-10[/sup], so no you could never “see” an atom. You can “see” them if you use X-ray diffraction but that’s a complicated process. ---
**Author:** ![Ring](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@Ring](https://boards.straightdope.com/u/Ring)\ **Post date:** [March 30, 2004, 4:25am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/55 "2004-03-30T04:25:21Z")
> [@Jon the Geek](#): > > Actually, everything behaves as a wave between measurements. Jupiter has a wavelength (which is some fraction of a nanometer larger than the diameter of Jupiter, Given that the DeBrogie wavelength = h/p I’m curious as to how exactly you came up with the above? ---
**Author:** ![Jojo](https://avatars.discourse-cdn.com/v4/letter/j/ecd19e/32.png) [@Jojo](https://boards.straightdope.com/u/Jojo)\ **Post date:** [March 30, 2004, 4:51am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/56 "2004-03-30T04:51:22Z")
According to the Bill Bryson book I’m reading at the moment though _A Short History of Nearly Everything_: The common idea of an atom is of a central nucleus with electrons spinning round it like planets orbiting a sun but this is actually wrong. Due to the uncertainty principle, the electrons are everywhere all at the same time so if you could see an atom it would look more like a fuzzy tennis ball. You wouldn’t see the nucleus just the outside shell - the spinning electrons. Another interesting thing he says is that nothing ever really touches anything else. Although you think you are sitting on a chair you aren’t really. The negatively charged electrons of the atoms on your bottom are repelling the negatively charged electrons of the atoms of the chair and vice versa - they are repelling each other. So you are actually levitating above the chair. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [March 30, 2004, 6:02am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/57 "2004-03-30T06:02:54Z")
Nice article that’s kinda sorta related to the OP [The World on a String Physicist Brian Greene explains what may turn out to be a unifying theory of everything in the cosmos](http://www.msnbc.msn.com/id/4609826/) ---
**Author:** ![vasyachkin](https://avatars.discourse-cdn.com/v4/letter/v/c5a1d2/32.png) [@vasyachkin](https://boards.straightdope.com/u/vasyachkin)\ **Post date:** [March 30, 2004, 6:46am UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/58 "2004-03-30T06:46:32Z")
google for “IBM logo flypast” you will find a short mpeg movie showing an image of an IBM logo created by pushing around individual atoms. it was created at an IBM research center. the 3-D flypast motion is simulated but the basis for it is the actual microscope image. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [March 30, 2004, 4:54pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/59 "2004-03-30T16:54:17Z")
> [@vasyachkin](#): > > google for “IBM logo flypast” you will find a short mpeg movie showing an image of an IBM logo created by pushing around individual atoms. > > it was created at an IBM research center. > > the 3-D flypast motion is simulated but the basis for it is the actual microscope image. In order to forestall any misconceptions, the picture of the atoms that IBM “pushed around” to spell “IBM” isn’t an optical microscope picture of atoms. It is a pseudo image made by using the tunneling current from a probe very, very, very close to the surface to vary the intensity of the beam of a cathode ray tube or similar device. ---
**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\ **Post date:** [March 30, 2004, 5:13pm UTC](https://boards.straightdope.com/t/do-atoms-really-exist/236714/60 "2004-03-30T17:13:44Z")
> [@MonkeyMensch](#): > > Well I detect the presence of my keyboard with the interaction of EM fields. (I ain’t going QM 'cause I just am not conversant with it, yet.) And the way that humans interact with keyboards _is_ far removed from particle physics. But the rules and participants are the same in both cases. Again, I think you oversimplify and walk right into scientific realism which, in fact, suggests that no atoms exist, even though the scientific theory says they do. Neat, huh? Anyway, my problem is with your insistence that you detect the presence of your keyboard with the interaction of EM fields–you don’t. You touch it. You explain the sensation of touching, scientifically, with EM fields–which are just as speculative as atoms themselves. You believe that science is explaining what is “really” happening, so you suggest that there is an equivalence between the two. I find that to be a dangerous assumption. The answer to the question, “How do you explain these experimental results?” is, “With atoms”–we both agree here, it seems. At least, this is definitely my answer. To get to “atoms exist” we need to suggest that scientific explanations are a true picture of reality. To get to “keyboards exist” we need to suggest that “perception gives a true picture of reality.” Depending on how one qualifies that second remark, one arrives at my own position. Generally speaking, we do not disagree with science (if we did, why would we do it?), so it is safe to say that we’ve long since stopped questioning whether atoms exist and simply act as if they do. If this is the only requirement of existence, then atoms exist–simple as that. This is my original response. > [@](#): > > The alpha particle reference was a nod to Ernest Rutherford, the Kiwi physicist who shot 15" shells at a piece of tissue paper and noticed that some of them bounced back. The alpha particle is a helium nucleus. Helium, of course, comes in atoms. Using an atom to prove the existence of atoms is not very impressive. 😛 [Previous page](https://boards.straightdope.com/t/do-atoms-really-exist/236714.md?page=2) [Next page](https://boards.straightdope.com/t/do-atoms-really-exist/236714.md?page=4)