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Happy Birthday, Atom 139

Posted by michael
from the how-old-are-you-now-how-old-are-you-now dept.
Shipud writes "200 years ago today (Oct. 21) John Dalton revolutionized chemistry by starting the process of turning it into an exact science. He presented the Table of Atomic Weights, at the Manchester literary and Philosophical Society. Dalton's work proposed atoms exist: and not just as an explanatory or philosophical tool. His theory laid the foundations for the periodic table of the elements (1869, Mendeleev), and indeed to all modern chemistry. The molecular weight of compounds is today measured in Daltons, the weight of a hydrogen atom. Read more about Mr. Dalton in today's Nature: a man of many interests, whose atomic theory preceded experimental evidence by a century. Read also about Daltonism -- and why it is named after him."
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Happy Birthday, Atom

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  • by FortKnox (169099) on Tuesday October 21, 2003 @05:59PM (#7275704) Homepage Journal
    Thanks for almost making me fail Chemistry cause my dumb-ass teacher made me memorize the first 80 elements for a test!

    This comment was just a joke. If you are replying to say anything about how it'd be harder or memorizing 80 things are easy, save your fingers
    • You must be the dumbass. The symbols make a nice pronouncable string of sylables.

      h-heli-beb-cnof-ne-na-mg-al-sips-clark-ca....

      We only had to memorize the first 40, but the teacher demonstrated that he could still do the first 80.

      It's important to memorize the periodic table if you want to do anything in chemistry, so if you can't handle it, you deserve to fail. Everyone knows chemistry is mostly memorization anyway.

      Jason
      ProfQuotes [profquotes.com]
    • Be thankful, before Dalton turned chemistry into an exact science, it was a big collection of recipes.
      Memorizing 80 recipes would be a lot harder than those 80 names and abbreviations.
      • And I quote:
        This comment was just a joke. If you are replying to say anything about how it'd be harder or memorizing 80 things are easy, save your fingers.

        Yeah, I KNEW IT WAS HARDER, but it was just a joke. I even tried to warn everyone not to take it too seriously... but I knew someone would eventually do it...
  • by rev063 (591509) on Tuesday October 21, 2003 @05:59PM (#7275717) Homepage
    Dalton proposed the existence of the atom, but it took Rutherford to verify its structure and prove it existed as Dalton suggested.
    • Ahhh, Rutherford another Manchester boy.
    • by Shipud (685171) on Tuesday October 21, 2003 @06:07PM (#7275781)
      Actually, by Rutherford's time the atomic theory was well established experimentally by Jean Perrin [nobel.se] Rutherford contributed to the nuclear theory of the atom (i.e. that it is composed of a nucleus which holds most of teh atom's mass and orbiting electrons of opposite charges).
      • by siskbc (598067) on Tuesday October 21, 2003 @07:08PM (#7276308) Homepage
        Actually, by Rutherford's time the atomic theory was well established experimentally by Jean Perrin Rutherford contributed to the nuclear theory of the atom (i.e. that it is composed of a nucleus which holds most of the atom's mass and orbiting electrons of opposite charges).

        Not really. Perrin did work complementary to that of Thomson regarding the negative nature of part of the atom (ie, cathode rays). He also *proposed* a solar-system model for the atom in 1901, but wasn't able to substantiate this. Later, he did some work on Brownian motion, and that's what he got the prize for (as mentioned in your link, actually). But he didn't get any experimental evidence for the heavy nucleus surrounded by a very undense region. Rutherford did, in 1909, with his alpha-particle backscattering experiment. Without that experiment, which was certainly not redundant, it's hard to imagine how established atomic theory could possibly have been.

        Really, atomic theory wasn't well established at least until Millikan did his oil-drop experiment, establishing the charge/mass ratio of the electron, and by deduction, the proton as well.

    • by devphil (51341) on Tuesday October 21, 2003 @06:49PM (#7276141) Homepage


      Even today many schoolrooms have recently-published science books that show a model of the atom that looks like a little solar system, electrons in orbits and all. No mention of quantum/wave dynamics, or the fact that they don't behave anything like orbiting bodies in a solar system.

      No, I don't expect 5th graders to learn quantum theory. But just because spherical trigonometry is also too hard for them, I don't expect them to be taught that the earth is flat.

      Side note: http://www.intuitor.com/physics_test/index.html is from the same people who brought you the Insultingly Stupid Movie Physics site. See whether you know more about physics than a random chimpanzee!

      • Even today many schoolrooms have recently-published science books that show a model of the atom that looks like a little solar system, electrons in orbits and all. No mention of quantum/wave dynamics, or the fact that they don't behave anything like orbiting bodies in a solar system.

        My high school physics teacher told us that electrons most likely have an eliptical orbit like planets, but that there's really no way to know.

        Granted this was a phyics concepts class, so very little math was involved, but wh
        • My high school physics teacher told us that electrons most likely have an eliptical orbit like planets, but that there's really no way to know.

          Wasn't that the Sommerfeld model? Just before Schroedinger set us up the wave equation?
          • The reason for many of the errors of modern natural science to lie in the completely incorrect standing that science had assigned to the simple sense impression. Our science transfers all sense qualities (sound, colour, warmth, etc.) into the subject and is of the opinion that "outside" the subject there is nothing corresponding to these qualities except processes of motion of matter. These processes of motion, which are supposedly all that exists within the "realm of nature," can of course no longer be per
      • Dunno about that. I was taught a model of probility clouds. They drew little probability cones (at 90% probibility I think) like you see in most university text books. They also taught us breifly some of the previous models like the Bohr model (I think that's the one you are talking about) and back to the Dalton model.

        However the coolest demonstration was in university, with magnets. Playing with multiple magnets gave you a fields that layed out iron filings in the same shape as different electron orbits.
      • While wrong, the "orbiting/spinning electron" picture gives surprisingly valid results. For instance, the magnetic moment of an electron can be easily calculated by assuming it is spinning (even though if this were the case, areas on the surface of the electron would be traveling faster than c!), and the orbital angular momentum of an electron about its nucleus (in the simple case of hydrogen) can likewise be simply calculated using an orbital picture. This was essentially the method Bohr used when he fir
        • It is not invalid to model electrons as "small spinning blobs" of EM/energy packets. This is Modern EM/Quark Physics.

          It equally valid in many contexts to model the electron as a "wave function". This is Modern Qauntum Physics.

          What's the big deal?
      • by Rasta Prefect (250915) on Tuesday October 21, 2003 @09:18PM (#7277224)
        Even today many schoolrooms have recently-published science books that show a model of the atom that looks like a little solar system, electrons in orbits and all. No mention of quantum/wave dynamics, or the fact that they don't behave anything like orbiting bodies in a solar system.

        True, but assuming that they're fifth graders, this provides a handy model for the way things actually work when the point you want to get across is that everything is made of atoms and they share electrons to form molecules. We also teach them Newtons three laws of motion, not mentioning until later "Well this gets all screwed up when you add in gravity and motion". It's an approximation, it's good enough when it's a means to an end. Not everything has to be learned at once.

        • Newtons three laws ... [snip] ... It's an approximation, it's good enough when it's a means to an end.

          It's not just good enough, it bloody well works. Newton's three basic laws underpin most of mechanical and civil engineering. Much of the infrastructure of our society is designed and built on "approximations" which don't account for quantum/wave mechanics.
        • And the old "atoms are like solar systems" model is still wrong and not really all that useful. How many fifth graders have the "experience" of a solar system to relate it too.

          It would be more useful and MUCH more correct to describe the electrons as a spherical cloud around the nucleus... or even like moths around a light.

          Newtons three laws of motion and Newtons Law of Gravitation are still valid and useful on the scale that most fifth graders have any experience with. They only get weird at velocities n
      • And what is the right way, may i ask?

        Really, there is no really good way to describe atoms. Sure you can say that QM is the way to go, but as someone else pointed out, the simplistic model of orbiting electrons works quite nice in may situations.

        QM also has its failures. For instance, in calculating certain molecular orbital energies, using just a strict ionic resonance (the desciption that you would arrive at by just basic valence considerations) is much more accurate than the energy arrived at by addi
        • As a chemistry teacher, here's the problem I have with teaching a wrong picture of atoms:

          A student learns the wrong picture in the 5th grade, has 5 years to cement it in place, and then comes to me in the 10th or 11th grade and has to be untaught his previous picture of the atom that Mr. ______ (fill in beloved 5th grade teacher's name here) taught him. Typical 10th graders do not easily change cherished notions they've held for years.
          I don't think it would be any harder to present 5th graders wit
      • sounds like a good business opportuntity to me. you can sell schools giant cotton balls with a sign on them saying "HYDROGEN ATOM - electron may or may not be in here somewhere"
    • Good point about Rutherford, but Dalton should be particularly commended for striving to teach the greatness of the Scientic Method in resolving ideas with reality.

      One could say that Rutherford had the "hindsight" of 100 years of Science to help him develop a robust theory of the Atom. I am sure Dalton would have done as well given another 100 years, good eyesight, and a healthy body.

      Ironically, Nuclear Physicist Rutherford won his Nobel Prize in Chemistry :)
  • Daltons (Score:5, Informative)

    by friendofafriend (602350) on Tuesday October 21, 2003 @06:01PM (#7275733)
    Actually, isn't a dalton 1/12th the mass of a C12 atom? While very close to the mass of H1, they are not identical.
    • Yes, that's correct.
      The average mass of Hydrogen is 1.008 amu

      I tried posting the source of this information, but slashdot's retarded lameness filter wanted me to use fewer 'junk' characters.
    • The atomic mass unit is defined as 1/12 a C12 atom (used to be 1/16 an O16 atom)...I don't know if the amu is the same thing as a Dalton.
    • In fact... (Score:1, Funny)

      by Anonymous Coward
      3 Daltons is roughly equivalent to one Lucky Luke.
    • Yes, but it's more commonly known as the atomic mass unit, amu.
  • Atom! (Score:2, Funny)

    by pheared (446683)
    Ranier Wolfcastle: Up and at them!
  • by Limburgher (523006) on Tuesday October 21, 2003 @06:06PM (#7275769) Homepage Journal
    I mean, what do you get for the guy who's everything? (rimshot)
  • by winkydink (650484) * <sv.dude@gmail.com> on Tuesday October 21, 2003 @06:06PM (#7275770) Homepage Journal
    I am soooooo screwed.
  • Dalton? (Score:4, Funny)

    by (void*) (113680) on Tuesday October 21, 2003 @06:08PM (#7275793)
    Personally, I think Sean Connery ... oh wait, nevermind.
  • You know those atomic models we played with at school.. the coloured balls that we attached together with plastic sticks.. making up molecules... Dalton must have had quite a lot of trouble with that if he was colour blind.. so even more kudos for being able to work all that stuff out.. I give him an A+
  • by Richard Mills (17522) on Tuesday October 21, 2003 @06:18PM (#7275880)
    "200 years ago today (Oct. 21) John Dalton revolutionized chemistry by starting the process of turning it into an exact science"

    Can't argue with John Dalton having helped revolutionize chemistry, but he didn't start the process of turning it into an exact science. I think that the credit for that probably belongs to British chemist Joseph Black, who founded calorimetry and was one of the first scientists to emphasize quantitative experiments. (Interestingly, at Edinburgh his chemistry chair was unsalaried!)
    • by madmancarman (100642) on Tuesday October 21, 2003 @06:35PM (#7276012)
      There should also be some credit given to Henry Mosely [k12.il.us], the British scientist who arranged the periodic table not only by chemical properties, but by atomic number (number of protons) as well.

      Unfortunately for Mosely, he was volunteered for the British army in World War I and was killed in action when he was 27.

    • Traditionally, Laviosier (sp?) is considered the "Father of Modern Chemistry," for his quantitive experiments in the 1600's. Boyle is also given a lot of credit. I was looking through my brothers HS text book, and Joseph Black isn't even mentioned. It skips from Laviosier/Boyle -> Dalton -> Thomson -> Milikan -> Rutherford -> Plank -> Einstien (not neccesarily chronological order, but rather grouped based on discovery).
  • by nucal (561664) on Tuesday October 21, 2003 @06:29PM (#7275964)
    John Dalton [nature.com] and John Lennon [newgenevacenter.org].
  • Only 200 Years? (Score:5, Insightful)

    by Cyno01 (573917) <Cyno01@hotmail.com> on Tuesday October 21, 2003 @06:35PM (#7276021) Homepage
    If dalton didn't prove anything and only theorized, didn't Leucippus and Democritus beat him by a few thousand years?
    • Dalton (1766-1844) is widely regarded as the founder of the idea that all matter is made of tiny, indivisible particles called atoms. Although atoms were proposed 2500 years ago in ancient Greece, Dalton's work made them an indispensable part of chemical theory.
      yes
    • The point is, is his timing was just right to spawn the revolutionary system of thinking in that time period, regaurdless of whether he stole the idea or thought it up.

      Either way, the difference he made has an impact on our society, and that is why we must give him props. ^^
    • As I understand it, the ancient concept of an "atom" was more philosophical, whereas Dalton's concept was made in order to explain experimental results. So he gets the credit for the theory.
  • by queen of everything (695105) on Tuesday October 21, 2003 @06:35PM (#7276022) Homepage
    He taught chemistry but had no experience of chemical research

    Resembles some teachers I had in High School
  • by juan2074 (312848) on Tuesday October 21, 2003 @06:38PM (#7276040)
    Good thing atoms were invented.
    Before that, everything was made of plum pudding!
  • Wait... (Score:3, Informative)

    by Tribius (88884) on Tuesday October 21, 2003 @06:40PM (#7276059)
    modern chemists don't measure molecular masses in daltons, they use gram/mole. Daltons aren't used until you get into larger molecules like proteins, as in "that protein is 70 kDa (kilodaltons) in size".
    • I've never heard a chemist use Daltons at all and I used to know a lot of chemists (my dad's a Uni professor).

      They all use amu these days, I think. Maybe in the backward non-metric world they still use Daltons?
  • Huh. (Score:3, Funny)

    by Unknown Kadath (685094) on Tuesday October 21, 2003 @06:46PM (#7276115)
    200? I could have sworn atoms were around 13.7 billion years old, give or take.

    -Carolyn
    • by xihr (556141)
      That would be take :-). Shortly after the Big Bang, whole atoms couldn't form since the photon destiny was way too high -- if a nucleus captured an electron (practically all H and He at that time), it would almost immediately be knocked out. And vice versa: the mean free path of a photon was tiny because it would always encounter nuclei or electrons. When things cooled down sufficiently, photons could travel free and atoms could form and expect to stay around. The transition where this occurred is call
      • 13.699 billion years, then. That's still eight orders of magnitude off from 200 years, no matter how many nits you pick. ;)

        Thanks for the astrophysics lesson, though.

        -Carolyn
      • When things cooled down sufficiently, photons could travel free and atoms could form and expect to stay around. The transition where this occurred is called decoupling...

        Technically this is called "recombination", whereas "decoupling" refers to any thermodynamic decoupling of distinct species when their interaction becomes negligible. (An example other than radiation-matter decoupling is neutrino decoupling from all other weakly-interacting massive fermions occurred at ~1 to 10 second, or ~10^10 K.)

        Also

  • Ironically (Score:4, Informative)

    by exp(pi*sqrt(163)) (613870) on Tuesday October 21, 2003 @06:46PM (#7276121) Journal
    When Dalton originally proposed his atomic theory there was much resistance. The idea of tiny, hard, indivisible units was unreasonable to many of the people around Dalton and it took a long time for people to accept his ideas. But guess what! The people who resisted were right. Today we have completely replaced the idea of an indivisible atom with a wavefunction in a Hilbert space. We might still call these things 'atoms' but they bear very little relationship with what Dalton was thinking of. In fact, at the time people used Dalton's theory as a metaphor as they couldn't take the ideas literally at all. And that's exactly what physicists do today.
    • You know, the ancient Greeks had the basic idea long before Dalton. Their arguments were obviously not based on experimentation, but they were reasonably compelling philosophical arguments why there must be elementary bits of matter. And that was a lot longer than 200 years ago.
      • Re:Ironically (Score:3, Insightful)

        I think the crucial point is that the atoms themselves aren't the interesting thing and that's why it's not really worth crediting Democritus and Co. The crucial thing that Dalton did was come up with numbers that turn into testable hypotheses.

        When any Ancient Greeks argued for the existence of atoms they were saying more about themselves than about the universe. They were revealing that many humans have a problem with the concept of a continuum and prefer everything to be made out of discrete parts. This

  • Now if we could just quantify the rest of the psudo-sciences!! e.g. Psycology, Sociology, and the like.
    • Psychology and Sociology (one small one large) can be quantified as the neural electrical feedback on sensory input and motor output between individuals and/or environment. When those sensory input and motor output and the feedback process can be quantified to a acceptable precision. Psychology and Sociology becomes a quantifiable science.
  • by Stephen Samuel (106962) <samuel@bcgre e n . com> on Tuesday October 21, 2003 @07:05PM (#7276289) Homepage Journal
    200 years ago today
    Mr Dalton taught the world to say
    that our matter's an atomic pile

    and it changed our scientific style.

    So let me introduce to you
    Common, lets give a cheer!
    particle physics and nuclear chemistry!

    (RIAA note: satire makes for fair use, so there!)

    • Technically RIAA could give a rat's rear quarters (sometimes referred to as 'Burbank') about you ripping off Beatle lyrics. Its ASCAP (or their alter-ego whose acronym temporarily escapes me) that would come after you for a musical publication.
  • by espo812 (261758) on Tuesday October 21, 2003 @07:51PM (#7276615)
    I just had a western civilization exam today. So to make up for my poor score on the test itself, I will attempt to impart something I actually did learn in the class (that was not tested). To quote my text:

    [...] the philosopher Democritus (b. ca. 460 B.C.) [...] concluded that all things consisted of tiny, indivisible particles, which could be arranged and rearranged in an infinate variety of configurations. He called these particles
    atoma, "the uncuttable" (from which the word atom is derived).
    So, this puts the atom at abount 2400 years old.
  • Happy 18th birthday to me. here's to gambling, strippers, and cigarettes
  • by gklinger (571901) on Tuesday October 21, 2003 @10:07PM (#7277548)
    Two atoms are walking down the street and one says to the other, "I think I lost an electron..."

    "You sure?"

    "I'm positive!"

  • The molecular weight of compounds is today measured in Daltons, the weight of a hydrogen atom.

    I studied Chemical Engineering for 3 1/2 years in college before switching majors and never heard the unit Dalton mentioned, ever. I highly doubt it's in common usage. It's not SI and it's not even listed in my copy of CRC Handbook of Chemistry and Physics, 72nd edition. The atomic mass unit, on the other hand, is listed on page 1-1.

    • Me too. I've never heard of the Dalton before.
    • Well, I finished my Chemical Engineering study and hadn't heard of it either until i got into biosensorics. In biochemistry and related fields it's the commonly used mass unit and it means exacly the same as the atomic mass unit wich is gramms per mol.

      For example the 'size' of an IgG-antibody is roughly 150 kDa (150000 g/Mol).

      For those who don't know what a mol is:
      one mol consists of roughly 6E23 atoms (see the Avogadro constant for exact count).

  • Since we're on the topic of chemistry history, don't forget that the 23rd of October (get it? 10-23? Ha!) is mole day [moleday.org]

  • Dalton vs. Rutheford (Score:2, Interesting)

    by Legendre (634519)
    Dalton (a chemist) proposed this atomic theory in 1803. 'Chemists' of the time were convinced, but the real scientists, physicists, weren't. In 1906 Boltzmann (a physicist) committed suicide because his theories, based on the atomic postulate, were not well-received. During a physics conference at the turn of the century, he was the only one to defend the atomic model. Other physicists of the time simply didn't buy it. in 1914 Rutheford (a physicist) finally verified experimentally the structure of the at
  • Atoms (Score:2, Insightful)

    by Anonymous Coward
    "Nothing exists but atoms and the void"

    -Democritus, c.400 BC
  • by NoMercy (105420)
    I share my birthday with the atom... and it's also the day that the battle of Trafalgar took place :)
  • You've heard of social Darwinism, now in the US we have social Daltonism: classifying people based on their weight. You do know that Americium [webelements.com] is an unstable, overweight atom...
  • before this date they had to make stuff out of other stuff, then they invented these new fangled atoms, and before you knew it everything was made out of them.
  • Are you trying to tell me that until 200 years ago Atoms did not exist??? I think you mean the birthday of the Discovery of Atoms.
    • Are you trying to tell me that until 200 years ago Atoms did not exist??? I think you mean the birthday of the Discovery of Atoms.

      Unless you subscribe to the strong anthropic principle which some people have taken to mean that the universe is consructed as we see it because of the way we see it. So, Dalton created atoms by constructing a coherent enough view point and convincing others of its validity, thus shaping a new reality.

      Great for semi-drunken debates and science fiction stories (Charles Harness,

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