Of course chemists had little doubt in the existence of atoms. But they could not determine their masses. All "atomic masses" were relative to that of hydrogen. (And they still are, at least approximately, given that 1/12 of carbon-12 is almost the same.)Thecla said:
To condense that a bit, the idea is roughly that the relative variance goes as ##\sqrt{\frac{1}{n}}## rather than as ##\frac{1}{n}## where n is the number of atoms per smoke particle?Ibix said:
By whom>Thecla said:
Who?Thecla said:
I believe that Max Planck was skeptical of atomic theory until the 1890's. There's a piece here, for example:Vanadium 50 said:
Thecla said:
Vanadium 50 said:
This is a very interesting addition to the "story." Especially when combined withPeroK said:
Vanadium 50 said:
As discussed in David Lindley's book Boltzmann's Atom, The Great Debate That Launched A Revolution In Physics, and above, Einstein explained Brownian Motion using Boltzmann's atomic theory in 1905. The book has the history of the development of these ideas.Thecla said:
Many physicists of the time were not convinced of the existence of atoms. This persisted well into the 1900's. Einstein presented an argument for the existence of atoms, but these things are never proofs. They are simply pieces of evidence that support the existence of atoms. It's not like one day there's suddenly proof and everyone instantaneously becomes convinced.Thecla said:
I suspect even those who did accept the existence of the atom eventually died as well!Mister T said:
Historically the "atomic hypothesis" in the 19th century was much more accepted by chemists, because the then well-established stoichometrics found a very natural explanation from it, i.e., why chemical reactions go in integer proportions involving "elements", which could be (at least roughly) ordered in systems like Mendeleev's "periodic table". Of course, the details are not always that clear. Even today there is some discussion about the correct ordering in some parts (lanthanides and actinides etc.). Nevertheless the idea of "discrete building blocks" was much more natural for chemists than physicists. The latter had more continuum/field theories of matter, including phenomenological thermodynamics, in mind than atomistic ones. That's why the early "atomists", using statistical methods (kinetic theory of gases a la the Bernoullis, Gibbs, Maxwell, Boltzmann et al), had a hard time to convince their more conservative colleagues.Mister T said:
Yes, but the point is that those who remained shared their acceptance of the atom.PeroK said:
That was understood but @PeroK 's joke was clever and very funny.Mister T said:Yes, but the point is that those who remained shared their acceptance of the atom.
gmax137 said:
No no, Democritus was right. It's not his fault that our atoms are misnamed. Using his terminology, neutrinos and quarks and electrons and so forth are atoms.Delta2 said:
For now.Hornbein said:
He certainly managed to tidy things up a lot but IMO Lavoisier more or less introduced the idea of atoms before he had his head removed by those nasty French Revolutionaries in 1794. The experimental evidence didn't all arrive at once and it's a matter of opinion what constituted an actual proof. The existence of isotopes didn't exactly help things.Thecla said:
Dalton generally gets the credit for atomic theory in chemistry, followed closely by Avogadro. Lavoisier is more known for his formulation of the law of mass conservation.sophiecentaur said:
Did Democritus said that one kind of atom can turn into another? In other words, that atoms can be created and destroyed?Hornbein said:
To Democritus an atom was the smallest amount of something possible. Neutrinos, quarks, and electrons don't fit this definition. For example the smallest amount of gold is one atom of gold. That part he got right. He thought of these atoms as indivisible. He got that part wrong.Hornbein said:
What a loser. ?Mister T said:
Ibix said:
I think modern particles are so far from anything he imagined, e.g. in typical states their properties and even their number are undefined, that one can't really say he was right.Hornbein said:
I suspect that even if Democritus had come up with the basics of QFT, you'd give him no credit!Son Goku said:
Hardly, he's my favourite 5th Century Thracian.PeroK said:
Yes, QM has changed our view of the world a lot. In hindsight, we only have experience with 'clumps' of quantum stuff and can only probe the quantum world by interacting with those clumps. That this led to a theory predicting the probabilities of those interactions (aka observations) is only expected. We are lucky, though, in that mathematical analysis shows it is just an example of a broader class of probabilistic theories than ordinary probability theory and led to the creation of a new area of mathematical investigation called Generalised Probability Theories:Son Goku said:
There are several lines of evidence that support the existence of atoms. One of the most compelling is the observation of Brownian motion, which is the random movement of tiny particles suspended in a fluid. This can only be explained by the collisions of individual atoms. Additionally, experiments such as the Millikan oil drop experiment and the Thomson's cathode ray tube experiment provide evidence for the existence of subatomic particles, which make up atoms.
The concept of atoms as the building blocks of matter can be traced back to ancient Greek philosophers, but the modern understanding of atoms was developed through scientific experiments and observations. The law of conservation of mass, which states that matter cannot be created or destroyed, supports the idea that matter is made up of indivisible particles. Additionally, the periodic table of elements, which organizes all known elements based on their atomic structure, further supports the idea of atoms as the fundamental units of matter.
No, atoms cannot be seen with a traditional light microscope. This is because atoms are much smaller than the wavelength of visible light, making them impossible to observe with this type of microscope. However, with the development of advanced technologies such as scanning tunneling microscopes and atomic force microscopes, it is now possible to directly image atoms.
The existence of atoms has been confirmed through numerous experiments and observations over the years. These include the discovery of subatomic particles, the behavior of gases, and the results of nuclear reactions. In addition, the atomic model has been continuously refined and improved upon as new evidence and technologies become available, further solidifying the reality of atoms.
While the existence of atoms is widely accepted in the scientific community, there have been alternative theories proposed throughout history. One such theory is the concept of continuous matter, which suggests that matter is infinitely divisible and does not consist of individual particles. However, this theory has been largely disproven by modern scientific evidence and the atomic model remains the most widely accepted explanation for the nature of matter.