Do atoms really exist or are they just a useful theory that fits in really well with the available evidence? Do they exist in the same way that “keyboards” exist?
Yes, in fact you keyboard is made of’em.
I’m sure another member will be along that can explain how to calculate the number of electrons in the different orbits of the atoms
Atoms (and a whole bunch of even smaller particles) most certainly do exist. Here’s a couple of photos of atoms:
Atomic theory is so solidly grounded, so lacking in abstraction, and having so many practical applications, that there is really no room to question whether it is “true” or merely “useful.”
At work we work with micrometer tolerances 1/1000 mm. Beyond that is the nanometer: 1/1000 µm. Then we go to the picometer: 1/1000 nm.
Atoms are between 100 and 500 picometers in diameter. http://hypertextbook.com/facts/MichaelPhillip.shtml The thing is, that really isn’t even that small. You can down to about 2 µm with a good optical microscope. Hence, an atom might be, oh, just a million times smaller.
What is shown in those images (I believe) is a 3-d mapping of the changes in current with respect to a microscopic needle, an indirect visualization of atoms that is helpful to us humans, but doesn’t answer the question of how atoms fundamentally exist.
I’m thinking this is what the OP had in mind (if not i’m curious myself–excuse the modest hijack):
Do atoms and subatomic particles have any shape or form, like the happy little spheres we are so used to, or do no such things exist at the quantum level?
Will the chain of subatomic particles keep on going, ie atoms are made up of protons/neutrons/electrons, P & N are made up of quarks, quarks are made up of … ad infinitum.
What is the true distinguishing factor between matter and non-matter? Is it form vs. non-form?
Well, they are invisible, so they can have no shape in that sense. It may be that, for example, the quarks of proton are in a line so that we can think of a proton not as a sphere but elongated (I’m just making that up as a hypothetical). Certainly, we think of molecules as having a “shape” based on the formation of atoms in them. But I think it would have to be in this sense only.
Based on my limited knowledge, no. The smallest theoretical length is the Planck length, beyond which the concept of distance can have no meaning. I can only suppose a particle could not be smaller than that.
Do you mean matter and energy? I don’t think anyone really knows.
String theory attempts to explain matter as strings of energy that coil and vibrate in specific patterns. Subatomic particles in this model don’t have a physical shape really, just a certain energy pattern. This is a very new and poorly understood area of science however.
This is a question of metaphysics. It can be argued that atoms do no exist, and that in fact, the material universe does not exist. It has been a hotly debated topic between the essentialists and the existentialists for quite some time.
Libertarian: I think adding a metaphysical issue to a thread on the existence of atoms constitutes multiplying entities beyond necessity. =) The atomic theory is consistent with nuclear physics, quantum mechanics, physical chemistry and every other field it touches. It has predictive power. One might even say, paraphrasing Dobzhansky, “Nothing in physics or chemistry makes sense except in the light of atomic theory.” I think we know with great confidence, at least, that protons, neutrons and electrons do exist.
Science is inherently incapable of gathering evidence on philosophical questions such as the existence of the universe. Philosophy is inherently incapable of supporting its claim with vast networks of interconnecting physical evidence. I tend to require physical evidence to support my beliefs, so I would tend to support the existence of atoms. Regardless of the nature of subatomic particles, I do think the current model of the atom is substantially correct, simply because it makes so many things make sense.
Incidentally, the building in which I spent much of the last 4 years is named after a chemist who did not believe in atoms. Until he retired – in the 20s, I think, well after the work of Bohr and Rutherford – he believed that ‘atoms’ were energy minima, not physical entities. Doctoral candidates were actually failed because they believed in atoms – it always made me wonder how much of what I was learning (particularly things for which evidence is weak, such as reaction mechanisms) would later be shown to be wrong.
Physicist Ernst Mach, as far as I know, never accepted atoms as anything other than a useful fiction.
But, does it really make any difference? The atomic theory allows scientists to explain so much that it would be difficult to imagine that it would be completely overturned. Modified certainly but not abandoned in favor of an entirely different concept.
The OP’s 2nd question clarifies the intent, as some posters seem to have missed. Yes, atoms exist in the same way that keyboards exist. The latter is made from the former.
I can’t get my head around the OP. Is this a question of whether atomic theory is likely to be overturned, or a question of whether it is right? If it is the former, then yes, atoms exist in the same way keyboards exist. If it is the latter, then the safest answer is that we talk of atoms in roughly the same way that we talk of keyboards, and we have what we consider to be evidence of atoms in enough abundance that we no longer commonly speculate about whether it is a more or less accurate picture of underlying reality or not.
Atoms “exist”, but as another poster indicated I think the interesting question in metaphysical terms is how they exist at the borderline between the quantum world and the non-quantum world.
As one author indicated
One thing about these pictures that show atoms neatly arranged in rows, and how we manipulate them with atomic force microscopes: why doesn’t this violate the Uncertainty Principle?
Well, as a chemistry professor explained it (long ago, but the imagery has always stuck with me): An individual atom is largely nothing. Imagine an atom the size of the Astrodome (or any domed stadium). The nucleus (protons and neutrons) would be the size of a baseball in the center of the stadium, while the electrons in their various shells would be the size of grains of sand orbiting out to the size of the stadium.
I don’t know if this model is still in favor (or is even that accurate as far as proportions and what-not), but like I said, it has always stuck with me.
I hope this helps.
The uncertainly principle says, among other things, that we cannot measure simultaneously the position and the momentum of a particle to absolute accuracy. This also implies that the greater the precision we measure one component of, say position, the larger the error we encounter in measuring the other component, in this case momentum.
I don’t see how the atom manipulation violates this.
My thinking was, given the nature of the images, it would seem that we know the position with very little uncertainty, meaning there must be a huge uncertainty in the momentum. Therefore, why aren’t the atoms flying off in all directions? I’m thinking the problem is I’m a little fuzzy on what it means for there to be a “huge uncertainty in momentum” - does that mean they could be moving at anything from 0 mph to close to the speed of light? Are these pictures then just an instantaneous snapshot, after which the atoms fly off in different directions? If not, it would seem we’ve nailed down the position (“right there, row 3, column 4”) of an atom as well as its momentum (0, since they’re apparently stationary) in violation of the UP.
I disagree with your ultimate sentence. I would say that I speak of atoms in exactly the same way that I speak of keyboards. I use the same physical methods to determine the existence and physical properties of both. Doubting the existence of atoms brings up the metaphysical questions of existence and perception mentioned above. But if you think your keyboard exists I’m going to put you in the “atoms exist” camp.
Also, astro, there is no borderline between the quantum world and non-quantum world simply because the latter does not exist. I carry three polarizing filters in my wallet at all times to demonstrate this very fact to folks I can manage to trap in conversation…
This is actually a pretty hairy question when you get down to the philosophy. Suffice to say: any philosopher would probably say that atoms exist in the same way (whatever that may be) as your keyboard does.
Ian Hacking (admittedly talking specifically about electrons) staked out the position that anything usable in an experiment with a measurable effect is real: “If you can spray them, then they are real”[1]. As atoms have been used in experiments, this shows that they are real in Hacking’s sense, which is good enough for me (admittedly someone who doesn’t care much for the real world in his work).
[1]Hacking, Ian. Representing and Intervening. (Cambridge: Cambridge University Press 1988) 21-31
Existence is itself sufficiently complex philosophically that the OP’s question cannot have a factual answer. It may be said, for example, that the universe is nothing more than a probability distribution. Can such a thing exist?