Happy Birthday, Atom

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."

Comments

Gee Thanks Pal

[FortKnox]

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

He proposed, but did not prove

[rev063]

Dalton proposed the existence of the atom, but it took Rutherford to verify its structure and prove it existed as Dalton suggested.

Re:He proposed, but did not prove

[Shipud]

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 teh atom's mass and orbiting electrons of opposite charges).

Daltons

[friendofafriend]

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.

What should it's present be?

[Limburgher]

I mean, what do you get for the guy who's everything? (rimshot)

Oh shit! I forgot to buy a present!

[winkydink]

I am soooooo screwed.

Dalton?

[(void*)]

Personally, I think Sean Connery ... oh wait, nevermind.

DUH!

[Hal The Computer]

A universe to put it in.
(rimshot)

Re:Oh shit! I forgot to buy a present!

[Kufat]

200th anniversary? I think that's the Cesium year.

Give Joseph Black his due credit!

[Richard Mills]

"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!)

Re:Give Joseph Black his due credit!

[madmancarman]

There should also be some credit given to Henry Mosely, 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.

Only 200 Years?

[Cyno01]

If dalton didn't prove anything and only theorized, didn't Leucippus and Democritus beat him by a few thousand years?

Re:Only 200 Years?

[queen of everything]

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

This sounds familiar...

[queen of everything]

He taught chemistry but had no experience of chemical research

Resembles some teachers I had in High School

plum pudding no more

[juan2074]

Good thing atoms were invented.
Before that, everything was made of plum pudding!

Wait...

[__aaqgaf7843]

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".

Ironically

[exp(pi*sqrt(163))]

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.

And we're still teaching it wrongly

[devphil]

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!

Re:And we're still teaching it wrongly

[Rasta Prefect]

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.

To Seargant Pepper

[Stephen Samuel]

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!)

Perrin didn't get experimental evidence

[siskbc]

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.

200 years old? Try 2400.

[espo812]

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.

An on-topic joke

[gklinger]

Two atoms are walking down the street and one says to the other, "I think I lost an electron..."

"You sure?"

"I'm positive!"