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Alchemy becomes Chemistry
New Tools:
Fahrenheit thermometer
Joseph Black(1728 – 1799)
* Assisted by James Watt
* As ice melts, the temperature remains the same
Fixed Air
Combinedacid and limestone
CO2
Carbon dioxide
“Soda water”
Why do Things Burn?
Terra Pinguis -- Johann Becher
Phlogiston-- Georg Stahl
Joseph Priestley(1733 – 1804)
Unitarian minister
Invented the eraser
Lived next to brewery
Priestley’s mouse
Antoine-Laurent Lavoisier(1743 – 1794)
Conservation of mass
“Oxygène”(water maker)
Death of Phlogiston
Mercury oxide + heat -> mercury metal + ??
Henry Cavendish(1731 – 1810)
Factitious Air:flammableH2
Air -> NxOy
Thus air is composed Of nitrogen & oxygen
John Dalton(1766 – 1844)
Quaker schoolmaster
Reintroduced the Atom
Dalton’s LawpT = Σpi
Dalton’s Contributions
Elements composed of atoms
Many types of atoms
Different combinations =different compounds
Atomic weight scale
Compounds
Water Hydrogen peroxideH2O H2O2
Compounds
Nitrous oxide Nitrogen Dioxide N2O NO2
Humphrey Davy(1778 – 1829)
Used electricalcurrents to act uponchemicals
DiscoveredNa, Ba, K, Ca,Mg, F
Similar Elements
Johann Dobereiner
“Triads”
Coinage Metals
Cu, Ag, Au
Mendeleev & Meyer
1868/1869Both publishedVersions of aPeriodic table
Mendeleev’s version
Left blank spaces for undiscovered elements
E.g. Germanium 1886
Modern Periodic Table
Humphrey Davy(1778 – 1829)
Used electricalcurrents to act uponchemicals
DiscoveredNa, Ba, K, Ca,Mg, F
Elektron
InvisibleFluid???
Electricity
Pieter van Musschenbroek
Leyden Jar
Benjamin Franklin
Charles Couloumb(1736 – 1806)
Inverse square law 1
Charge ≈ (distance)2
Luigi Galvani(1737 – 1798)
“Animal Electricity”
Metal + frog leg
Electricity & Life
Electricity & Life
Alessandro Volta(1745 – 1827)
Voltaic Pile First Battery
Thermodynamics
Heat <-> Mechanical Force <-> Electricity
ENERGY
Count Rumford
“Caloric”
Rumford Inventions
James Joule
Interconversionof Energy forms
Gravity Heat
Rudolf Clausius
Heat dissipates
Entropy
Herman van Helmholtz
Conservation of EnergyNo energy lost in muscle movement
Helmholtz Coils
Electromagnetic Fields
Ørsted
Electrical currentaffects compass
Ampère
Solenoid
Ammeter
Michael Faraday
Magnetism <-> Electricity
Transformerelectrical current generatesmagnetic field
Electromagnetic Radiation
James Clerk Maxwell
Waves move at the speed of light
Electromagnetic Radiation
New Worlds of Astronomy
Wilhelm Herschel
Discovered “comet” 1781
First “Modern” Planet
Observed by Galileo?
Also discovered Uranianmoons
Planet Fever
Titius-Bode Law ( n + 4)
AU = 10
planet n Titius-Bode
Actual
Mercury 0 0.4 0.39
Venus 3 0.7 0.72
Earth 6 1.0 1.0
Mars 12 1.6 1.52
24 2.8 2.8
Jupiter 48 5.2 5.2
Saturn 96 10.0 9.54
Uranus fits the pattern!
planet n Titius-Bode Actual
Mercury 0 0.4 0.39
Venus 3 0.7 0.72
Earth 6 1.0 1.0
Mars 12 1.6 1.52
24 2.8 2.8
Jupiter 48 5.2 5.2
Saturn 96 10.0 9.54
Uranus 192 19.6 19.2
Piazzi (1801)
Palermo Catalogueof Stars
Comet?
New planet: Ceres
Asteroids
1802: Pallas
1804: Juno
1807: Vesta
Asteroid Belt
Uranus’ orbit
Neptune
Leverrier/Adams
Viewed by Gallewithin 1° of prediction
Vulcan?
Leverrier 1860
Parallax
Bessel
Messier catalog
To distinguishknown nebulae
& galaxies
Messier 64
Gustav Kirchoff
Identified thecomposition of
the Sun
Discovered Helium, Neon, Argon
The Beginnings of Modern Medicine
Life expectancy 35 – 39 years
Anesthesia
Before 1800
opiumalcoholmandrake root wine
Modern Anesthesia
Humphrey Davynitrous oxideN2O aka laughing gas
Ether Frolics
Crawford Long1842diethyl ether
Horace Wells
First dentist touse general anesthesia(N2O)
addict
James Young Simpson
Chloroform
Queen Victoriachose to use itfor 1853 childbirth
Pain Killers
Opiates
Laudanum (Paracelsus)
Sydenham
Cocaine
Albert Nieman(1859) isolatedcompound fromcoca leaves
1885 Merck
Original formulation ofCoca - Cola
Synthetic painkillers
Alfred Einhorn(1899)Novocaine
Other compounds:BenzocaineLidocaine
Synthetic Painkillers
Morphine (1804)Friedrich Wilhelm Adam Sertürner
First alkaloid isolated
High addiction rate
Heroin
Diacetyl morphine(1874)
Bayer (1895):Commercial preparation
Antisepsis
Puerperal (Childbed) fever
Ignaz Semmelweis1847: wash hands!
Crimean War
Florence Nightingale1854
Mortality rate40% -> 2%
Antiseptics
Joseph Lister
Carbolic Acid(Phenol)made from coal tar
What Causes Disease?
Miasma
Girolamo Fracastrodisease “seeds”
Variolation
Deliberate administration ofsmallpox particles
Milkmaids & Cowpox
Vaccination
Edward Jenner
Germ Theory of Disease
Louis Pasteur
Disproved “spontaneousgeneration”
Pasteurization
Quick heatingkills majorityof bacteria
Robert Koch
Isolated Anthrax, Tuberculosis
bacteria
Koch’s Postulates (1879)
Biological Scientific Revolution
Paralleled the Copernican controversy
Religion and Science
Questioning long heldbeliefs
Darwin’s Background
Linnaeus
Lamarck
Malthus
“Survival of the Fittest”
Population growthwill overwhelmfood resources
Neanderthals
1856:New species
Or
Deformed human
Erasmus Darwin
Lunar Society member
Physician
Zoonomia: “all warm-blooded animals have arisen from one living filament”
HMS Beagle
1831 – 1836
Survey/mapping
Galapagos Islands
His Discoveries
Giant Armadillo
Coastal vs. Islandspecies
Finches
Similar nests, eggscalls
Different beak sizes
Dog & Pigeon Breeding
Best equipped -> breed more
Alfred Russell Wallace
1858:"Contributions to the Theory of Natural Selection”
“a deficiency in one set of organs always being compensated by an increased development of some others--powerful wings accompanying weak feet”
Based on visits to Malaysiaand South America
Origin of Species (1859)
Concerns:
• Extinction• Extraordinary
traits• Similar
embryos
Pangenesis (1868)
Blended inheritance
All cells contribute
Descent of Man (1871)
Criticism:
Religious
Blending
Time scale
Gregor Mendel(1822 – 1884)
Plant hybrids
Laws ofparticulate inheritance
Genes and alleles
Mendelian Genetics
Pea plants
Varied in seed size,shape, colorplant size,flowers
Results
Dominantvs.recessive
Reproducible3:1 ratio
No yellow-green peas
Matthias Schleiden(1804 – 1881) botanist
John Goodsir(1814 – 1867)
“A nutritive centre, anatomically considered, is merely a cell, the nucleus of which is the permanent source of successive broods of young cells, which from time to time fill the cavity of their parent, and carrying with them the cell wall of the parent, pass off in certain directions, and under various forms, according to the texture or organ of which their parent forms a part. “
Chromosomes
Walther Fleming
Factors of inheritance
August Weissman(1834 – 1914)
Germ plasm
Heredity =½ of each parent
Nettie Stevens(1861 – 1912)
Two types ofchromosomes:
X and Y
Hertwig & Fol
First observed sperm/egg
Nuclear fusionin sea urchins
Thomas Hunt Morgan(1866 – 1945)
Used fruit flies(Drosophila)to show gene crossover
1933 Nobel prize
Gene Crossover
Non reciprocaltransfer of genetic information
Miescher’s Bandages
Isolated from white blood cells
Not protein
“Nuclein”
DNA: Same within Species
Erwin Chargraff
But variations betweendifferent species
Deoxyribonucleic acid
Double Helix
Elimination of the Ether
Newton:“universal medium of propagation
Michelson-Morley Experiment Interferometer:
Experimentintended to measure ether
The Speed of Light
Michelson: 299,796 ± 4 km/s
The New Atom
JJ Thompson (*1897)
Cathode rays = electrons
The Plum Pudding model
Random assortmentof positively charged protons and negativelycharged electrons
But. . . Don’t opposite charges attract?
Rutherford’s experiment
Ernest Rutherford
Planetary Model of the Atom
Protons in the nucleus
Electrons orbiting
X-rays
Wilhelm Röntgen
Radioactivity
Henri Becquerel
Radioactive Elements
Marie Skłodowskaand Pierre Curie
Radioactive Products
Radioactive Decay
Isotope Half LifeU - 238 4.5 x 109
yearsPu - 239 24,360 yearsC - 14 5730 years
Co - 60 5.3 yearsI - 131 8 days
Po - 214 1.63 x 10-4 sec
Relativity
Albert Einstein
€
γ = 1
1 - β 2 where β =
v
c
Relativistic Effects
Length Contraction
Time Dilation
The Atomic Age
E = mc2
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