Welcome to Modern Physics!!
Modern
Physics
PHGN 300 Fall 2012
PHGN Prof.
300Lawrence
Fall 2009
Wiencke
TA Xiaoning Zang
Prof. Lawrence Wiencke
Syllabus
Organizational, Grading
Short Survey
Science and Engineering before Modern Physics
http://inside.mines.edu/~lwiencke/PH300/F12
Or google mines ph300 2012
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PHGN 300 Topics
•
Review of Waves
•
Special Relativity
•
Light Quanta
•
Atomic Models
•
Intro to Quantum Mechanics
•
Quantum Structure – Atoms, Solids

•
Solid State Devices
Nuclei and Nuclear Physics
Particle and Astrophysics
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•
1895
–
First Electric Light Systems
–
Moving Picture Projector
–
First Automobile Race in US
–
1st female PhD in science earned
(Caroline Willard Baldwin) – Cornell
Most of the Physics Research –
Great Britain, Germany, France
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Classical physics by the end of the 19th
century
• Mechanics:
– Galileo 1564-1642 ; Newton 1642-1727…
• Electromagnetism:
– Coulomb 1736-1806 ; Ampere 1775-1836
– Faraday 1791-1867 ; Maxwell 1831-1879…
• Thermodynamics:
– Carnot 1796-1832 ; Kelvin 1824-1907…
Kinetic Theory of Gases
• Thermodynamics and “atomic” theory of matter
– Gay-Lussac 1778-1850: ideal gas: PV=nRT
– Avogadro 1776-1856: the Avogadro number
– 1895’s: Maxwell-Boltzmann velocity distribution
• It works… but, in 1895, nobody knows what an
atom really is !
1895
The atom considered fundamental unit of matter
•
Inaccurate description
•
Nucleus not yet discovered

8/24/11
no nuclear physics/engineering
1895
No fundamental particles had been discovered
•
No electron, muon, ..
•
Also no proton or neutron
Higgs Boson (2012)
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1895 (II)
No Quantum Mechanics
•
–
Deterministic philosophy
–
Statistics and probability - motivated by???
–
particle wave duality not understood
No Special Relativity
–
But the speed of light had
been measured
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Astronomy – yes
•
1895 (II)
–
Spectroscopy of sun and stars
–
Astrophysics – Newtonian
–
Sun’s energy from gravity?
–
Milky Way was the Universe
–
−
no galaxies)
•
Great debate about Nebula still 25 years away
No Cosmology, No astro-particle physics
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Chemistry: First Periodic Table of elements ~1870
Dmitry Meldeleev
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Mechanical Engineering
Steam power, industrial revolution
Strong material widely available – Steel
1890 – First US patent for ARC welding
but no X-ray inspections
Engineering Hall 1894
Electrical separation process for Aluminum invented in late 1880’s
Control systems existed
limited to mechanical, hydraulic
No plastics, no lasers, no electronics
No computer aided nothing
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Materials Science
Many metals known and studied
•
–
Particulate and chemical/extraction
metallurgical-and-materials processing
•
No atomic physics
•
No electron microscope
–
(no electrons!)
Band-Gaps? Photovoltaics
•
–
Nano-Structures?
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Yeah, right.
Electrical Engineering
•
V and I really big
•
Few buildings had electricity

AC (Westinghouse) vs DC (Edison)
•
How is charge carried?
•
Vacuum tubes just starting
•
No transistors, circuit boards
•
Maxwell’s equations known
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Electrical Engineering 1895
Phys. Rev. (Series I) 3, 49 (1895)
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Math/Computer Science
Mathematics – well ahead of the physics
•
–
Calculus (Newton)
–
Number theory, Group theory, Set theory,
–
Euclidean and non-Euclidian geometry
–
Complex variables
–
And even many of the equations known for
hundreds of years
•
–
– Legendre polynomials, Taylor series
World wide Application?
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Celestial Mechanics (navigation)
Math/Computer Science
•
Calculations done by hand
•
–
with look-up tables.
No computers
•
–
Hollerith Tubulator machine
–
Idea described (Babbage)
–
Idea of mechanical computations not pursued
–
No transistors, no atomic physics
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1895 Hints and Hot Topics
Discovery of Helium
–
Structure in spectra of heated gasses (and stars)
–
Propagation of Radio Waves
•
Relation between Temperature and Color
–
•
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What exactly is waving?
Can’t be reproduced by classical theories
–
Nature of light
–
Kinetic Theory of Gasses
1895
Start of Revolution of concepts
VERY FAST:
•
–
•
Special relativity replaces Newton mechanics
VERY SMALL:
– Quantum physics replaces Newton mechanics
•
VERY LARGE:
– General relativity replaces Newton gravitation
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