Chem 125 Lecture 29/8/06

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Samuel Pepysas

a Science Student

Samuel Pepys (1633-1703)

Diary 1660-1669

Saw Charles Ibeheaded 1649

B.A. Cantab. 1654

WhalleyDixwellGoffeHamden

“Clerk of the Acts”Navy Board 1660

Samuel Pepys (1633-1703)

July 4, 1662

…By and by comes Mr. Cooper, mate of the Royall Charles, of whom I intend to learn mathe-matiques, and do begin with him to-day, he being a very able man... After an hour's being with him at arithmetique (my first attempt being to learn the multiplication-table); then we parted till to-morrow.

Diary 1660-1669

Samuel Pepys (1633-1703)

July 9, 1662Up by four o'clock, and at my multiplicacion-table hard, which is all the trouble I meet withal in my arithmetique. July 11, 1662Up by four o'clock, and hard at my multiplicacion-table, which I am now almost master of… December 25, 1662 [Christmas!]

…so to my office, practising arithmetique alone and making an end of last night's book with great content till eleven at night, and so home to supper and to bed

Diary 1660-1669

Samuel Pepys (1633-1703)

December 6, 1663 [Sunday]

…I below by myself looking over my arithmetique books and timber rule. So my wife rose anon, and she and I all the afternoon at arithmetique, and she is come to do Addition, Subtraction, and Multiplicacion very well, and so I purpose not to trouble her yet with Division...

Diary 1660-1669

Samuel Pepys (1633-1703)

May 8, 1664

…strange how in discourse he cries up chymistry from some talk he has had with an acquaintance of his, a chymist, when, poor man, he understands not one word of it.

Diary 1660-1669

1684-86 President of

the Royal Society for the

improving of Natural

Knowledge by experiments

Isaac Newton (1643-1727)

www.wizardtower.com

Pepy’s Problem (11/22/1692)A - has 6 dice in a Box, wth wch he is to fling a 6.

B - has in another Box 12 Dice, wth wch he is to fling 2 Sixes.

C - has in another Box 18 Dice, wth wch he is to fling 3 Sixes.

Q. whether B & C have not as easy a Taske as A, at even luck?

If the Question be thus stated, it appears by an easy computation that the expectation of A is greater then that of B or C, that is, the task of A is the easiest.

What is ye expectation or hope of A to throw every time one six at least wth six dyes? [etc.]

Newton’s Reply (11/26/1692)

Pepy’s Reply (12/6/1692)

...You give it in favour of ye Expectations of A, & this (as you say) by an easy Computation. But yet I must not pretend to soe much Conversation wth Numbers, as presently to comprehend as I ought to doe, all ye force of that wch you are pleas'd to assigne for ye Reason of it, relating to their having or not having ye Benefit of all their Chances; and therefore were it not for ye trouble it must have cost you; I could have wish'd for a sight of ye very Computation.

3103146656A 0.6651=

13467042112176782336B 0.6187=

Pepys “WHY?”

"I cannot bear the Thought of being made Master of a Jewell I

know not how to wear."

Isotope Ratio Mass Spectrometry

Read Pepys & Newton and get together to do Problems for

Monday.Try contributing

to Wiki.

Isaac Newton (1643-1727)

Force : GravityAttraction at a

Distancevs. blocked repulsion

Are There Atoms &

Molecules?What Force Holds Atoms Together?

When doesa Chain of Atoms

Snap?

Force Laws & Molecular Structure

Spring (ut tensio sic vis) Gravity / Electrical Charge

Balanced minimum Balanced minimum !

F = -k x F = k / (r)2

Pot

entia

l Ene

rgy

Single Minimum Double Minimum

x

x

sum

sum

Slope = F

Thus with springs you might make a stable polyatomic

molecule from point atoms.(not with ions or magnets)

(not with ions or magnets)

But Hooke’s Law bonds would never

break.

Morse Potential(1929)

Snaps atInflection Point

Sum

(Change from direct to inverse force)

Is therea ChemicalForce Law?

Isaac Newton (1643-1727)

Query 31 in Opticks (1717) Have not the small Particles

of Bodies certain Powers, Virtues, or Forces by which they act at a distance, not only upon the Rays of Light for reflecting, refracting and inflecting them, but also upon one another for producing a great part of the Phaenomena of Nature? For it's well know that Bodies act one upon another by the Attractions of Gravity, Magnetism and Electricity; and these Instances shew the Tenor and Course of Nature, and make it not improbable but that there may be more attractive Powers than these. For Nature is very consonant and conformable to her self.

Query 31How these Attractions may be perform'd, I do not here con-sider. What I call Attraction may be perform'd by impulse, or by some other means unknown to me. I use that Word here to signify only in general any Force by which Bodies tend towards one another, whatsoever be the Cause. For we must learn from the Phaenomena of Nature what Bodies attract one another, and what are the Laws and Properties of the attraction, before we enquire the Cause by which the Attraction is perform'd, The Attractions of Gravity, Magne-tism and Electricity, react to very sensible distances, and so have been observed by vulgar Eyes, and there may be others which reach to so small distances as hitherto escape obser-vation; and perhaps electrical Attraction may react to such small distances, even without being excited by Friction.

Query 31 The Parts of all homogeneal hard Bodies which fully touch one another, stick together very strongly. And for explaining how this may be, some have invented hooked Atoms, which is begging the Question; and others tell us that Bodies are glued together by rest, that is, by an occult Quality, or rather by nothing; and others that they stick together by conspiring Motions, that is, by relative rest amongst themselves. I had rather infer from their Cohesion, that their Particles attract one another by some Force, which in immediate Contact is exceeding strong, at small distances performs the chymical Operations above mention'd, and reaches not far from the Particles with any sensible Effect.

i.e. NOT F 1/r2

Query 31

…the Attraction [between glass plates separated by a thin film of Oil of Oranges] may be proportionally greater, and continue to increase until the thickness do not exceed that of a single Particle of the Oil.

Query 31

There are therefore Agents in Nature able to make the Particles of Bodies stick together by very strong Attractions. And it is the business of experimental Philosophy to find them out.

Is there aChemical Force

Law?

What ARE Bonds?

19th Century Experiments led to VALENCE

1861

ElectronDiscovered

1897

G.N. Lewis

(1875-1946)

& his

Cubic Octet

Lewis on running board

G. N. Lewis

Octet "Explains" Periodicity, Electron Transfer(1902)