
Happy Birthday, Atom 139
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."
Gee Thanks Pal (Score:3, Funny)
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
Re:Gee Thanks Pal (Score:2, Funny)
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]
Re:Gee Thanks Pal (Score:2)
Re:Gee Thanks Pal (Score:1)
Memorizing 80 recipes would be a lot harder than those 80 names and abbreviations.
Re:Gee Thanks Pal (Score:2)
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...
Why don't you wait... (Score:1, Troll)
You don't like it, block science stories. It's easy, and then you won't have to tax your widdle bwain.
Re:Gee Thanks Pal - WHAT A WASTE (Score:2)
No, nothing to care about at all.
Re:Gee Thanks Pal - WHAT A WASTE (Score:2)
I etch my Slashdot commets on the walls of my cave in Lascaux using bison blood and charcoal, you insensitive clod!
He proposed, but did not prove (Score:5, Informative)
Re:He proposed, but did not prove (Score:1)
Re:He proposed, but did not prove (Score:1)
Re:He proposed, but did not prove (Score:1)
Re:He proposed, but did not prove (Score:5, Informative)
Perrin didn't get experimental evidence (Score:5, Informative)
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.
And we're still teaching it wrongly (Score:5, Insightful)
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 (Score:1)
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
Re:And we're still teaching it wrongly (Score:2)
Wasn't that the Sommerfeld model? Just before Schroedinger set us up the wave equation?
Sense Impressions and Atoms (Score:2)
Re:Sense Impressions and Atoms (Score:1)
Ummmm (Score:2)
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.
Re:And we're still teaching it wrongly (Score:1)
Re:And we're still teaching it wrongly (Score:1)
It equally valid in many contexts to model the electron as a "wave function". This is Modern Qauntum Physics.
What's the big deal?
Re:And we're still teaching it wrongly (Score:4, Insightful)
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.
Re:And we're still teaching it wrongly (Score:2)
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.
Re:And we're still teaching it wrongly (Score:1)
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
Re:And we're still teaching it wrongly (Score:3, Informative)
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
Re:And we're still teaching it wrongly (Score:1)
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
Re:And we're still teaching it wrongly (Score:2)
Re:He proposed, but did not prove (Score:2, Insightful)
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)
Re:Daltons (Score:1)
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.
Re:Daltons (Score:2)
In fact... (Score:1, Funny)
Re:Daltons (Score:2)
Re:He's a terrorist! (Score:1)
Atom! (Score:2, Funny)
What should it's present be? (Score:3, Funny)
DUH! (Score:3, Funny)
(rimshot)
Re:What should it's present be? (Score:1)
You let your kitten go feral and expect to be taken seriously?
Really - of all the cheek!
T&K.
Re:What should it's present be? (Score:2)
Of course, it's probably still in level 12, waiting for me. . .
Re:What should it's present be? (Score:1)
Ah well, just pelt 'em with tripe, and all will be well...
T&K.
Re:What should it's present be? (Score:2)
The lyrics are:
You're older than you've ever been,
And now you're even older.
And now you're even older.
And now you're even older.
(*lather, rinse, repeat*)
Time! (dhh dhh)
Marches on! (dhh dhh)
And time! (dhh)
Is still marching on! (dhh dhh)
And so on...
Re:What should it's present be? (Score:1)
Now you've got me scouring my collection to listen to this.....
Re:What should it's present be? (Score:2)
Re:What should it's present be? (Score:2)
prizes that aren't and have him look for them.
Re:How about a rimjob? (Score:1)
Oh shit! I forgot to buy a present! (Score:3, Funny)
Re:Oh shit! I forgot to buy a present! (Score:3, Funny)
Re:Oh shit! I forgot to buy a present! (Score:2)
You think you're screwed now... (Score:2)
Dalton? (Score:4, Funny)
Dalton's problems with those atomic models (Score:2, Insightful)
For those who don't get it... (Score:1)
Creative and funny
Re:Dalton's problems with those atomic models (Score:1)
I give him an A+
I wish you would give me one of those damn things so I can pass this class and get it over with
Re:Dalton's problems with those atomic models (Score:1)
Give Joseph Black his due credit! (Score:4, Informative)
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! (Score:5, Informative)
Unfortunately for Mosely, he was volunteered for the British army in World War I and was killed in action when he was 27.
Re:Give Joseph Black his due credit! (Score:2)
Separated at Birth (Score:3, Funny)
Only 200 Years? (Score:5, Insightful)
Re:Only 200 Years? (Score:3, Informative)
yes
Re:Only 200 Years? (Score:1)
Either way, the difference he made has an impact on our society, and that is why we must give him props. ^^
Re:Only 200 Years? (Score:2)
This sounds familiar... (Score:3, Funny)
Resembles some teachers I had in High School
plum pudding no more (Score:3, Funny)
Before that, everything was made of plum pudding!
Re:plum pudding no more (Score:2)
Quantum Mechanics... the dreams stuff is made of...
(With apologies to whoever owns the
Wait... (Score:3, Informative)
Re:Wait... (Score:2)
They all use amu these days, I think. Maybe in the backward non-metric world they still use Daltons?
Huh. (Score:3, Funny)
-Carolyn
Re:Huh. (Score:2)
Re:Huh. (Score:2)
Thanks for the astrophysics lesson, though.
-Carolyn
Re:Huh. (Score:1)
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
Re:Huh. (Score:1)
Ironically (Score:4, Informative)
Re:Ironically (Score:2)
Re:Ironically (Score:3, Insightful)
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
Re:Ironically (Score:1)
Re:Ironically (Score:2)
Off topic - don't read (Score:1)
The expression is very close to an integer, because of a rather strange collection of facts. The imaginary quadratic field of discriminant -163 (elements are sums of rational numbers with rationals times sqrt(-163)) has class number 1 and Weber showed in the first half of the last century that the modular j function takes algebraic integers in class number 1 fields to rational integers. The function j(z) has fourier expansion 1/q + 744 + 196884q + O(q^2), with q=exp(2*pi*i*z), so feeding in (-1 + sqrt(-163
Now for the rest of them (Score:1)
Re:Now for the rest of them (Score:1)
To Seargant Pepper (Score:4, Funny)
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!)
Re:To Seargant Pepper (Score:1)
200 years old? Try 2400. (Score:5, Informative)
So, this puts the atom at abount 2400 years old.
Today's my birthday also! (Score:1)
Re:Today's my birthday also! (Score:1)
Re:Today's my birthday also! (Score:1)
An on-topic joke (Score:5, Funny)
"You sure?"
"I'm positive!"
Daltons as a unit? (Score:1)
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.
Re:Daltons as a unit? (Score:1)
Re:Daltons as a unit? (Score:1)
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).
Mole day is thursday! (Score:2)
Dalton vs. Rutheford (Score:2, Interesting)
Atoms (Score:2, Insightful)
-Democritus, c.400 BC
Wooo (Score:1)
Social Daltonism (Score:2)
Happy Birthday Atom (Score:1)
Ummmm.... (Score:1)
Re:Ummmm.... (Score:2)
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,
Re:That reminds me of ..... (Score:2)
I had a Profy in our freshmen year by the name Dalton. He would always refer to "Quantum Numbers" as "Condom Numbers"
You may have misheard him say Condon, as in the Condon-Shortley phase convention [wolfram.com] for spherical harmonics [wolfram.com].