classical physics
DESCRIPTION
Classical Physics. The Foundation of pure & applied (macroscopic) physics & engineering! Newton’s Laws + Boltzmann’s Statistical Mechanics (& Thermodynamics): Describe most of the macroscopic world Classical Mechanics : The Physics of the 17 th & 18 th centuries. Still useful! - PowerPoint PPT PresentationTRANSCRIPT
Classical Physics
– The Foundation of pure & applied (macroscopic) physics & engineering!
– Newton’s Laws + Boltzmann’s Statistical Mechanics (& Thermodynamics):
Describe most of the macroscopic world
– Classical Mechanics: The Physics of the 17th & 18th centuries. Still useful!
– High speeds (v ~ c): Special Relativity: 20th century physics!
– Small size (atomic & smaller): Quantum Mechanics: 20th century physics! Physics 5301!
Mechanics • HOW objects move (behave) under given forces. • (Usually) Does not deal with the sources of forces.
Answers the question:Given the forces, how do objects move?
• Forces are classified into 4 types:
Four Fundamental Forces Of Nature!Mechanics applies to all four!
4 Fundamental Forces of NatureSources of the forces, in order of decreasing strength
• Strong Nuclear Force: – Binds nuclei together. Still being researched.
• Electromagnetic Force:– E&M phenomena. Chemical forces. Most everyday forces.
Maxwell, Coulomb, Ampere, Faraday, ...
• Weak Nuclear Force:– Nuclear decay. Fermi, Bethe, others. Still being researched.
• Gravitational Force:– Newton (classical mechanics)– Einstein (general relativity)
4 Fundamental Forces of NatureSources of the forces, in order of decreasing strength
4 Fundamental Forces
• The “Electro-Weak” Force: – Since ~ the late 1960’s, in some sense the 4
fundamental forces have been reduced to 3!
– The Electromagnetic Force & the Weak Nuclear Force were combined into one theory.
S. Weinberg & A. Salaam:
1972 Nobel Prize in Physics!
The Standard Model of Particle PhysicsThe “Periodic Table for Elementary Particles”!
Quantum Chromodynamics (QCD) and the Electroweak Theory
Protons & Neutrons consist of 3 Quarks each.
Standard Model
Standard Model
Standard Model
Atomic Physics
MolecularPhysics
Solid StateQuantum Chromodynamics
Quantum Electrodynamics
Physics
Nuclear & Particle Physics
Heisenberg) (Dirac)
Strong Nuclear Force)
High Speed
Special Relativity (Einstein)
Relativistic Quantum
(Feynman, Schwinger)
(Gluons, Quarks, Leptons
(Photons, Weak Nuclear Force)
SUMMARY: THE STRUCTURE OF PHYSICS
Large size
Low Speed
< ~ atomic size (Schrodinger, Mechanics
Quantum Field Theory
v << c v < ~ c
Small size
Classical Mechanics(Newton, Hamilton,
Quantum Mechanics
>> atomic sizeLagrange)
The Rest of Physics!• What we’ve mentioned is all of physics except:
Statistical Mechanics: (This course!)
– Mechanics of systems of huge numbers of particles
(>> ~ 1023).– Uses Probability & statistics to compute macroscopic
properties from microscopic force laws.– Applies to BOTH the Classical Mechanics
& the Quantum Mechanics world!– The major LINK between microscopic & macroscopic physics!
– Contains Thermodynamics as a sub-theory!