Introduction to Classical Physics

Physics

• Physics is a natural science examining matter, its basic parts, motion, behavior through space/time, energy, and force.
• It aims to understand the universe's behavior as one of the most fundamental sciences.
• Physics is among the oldest academic fields, including astronomy.
• Physics, chemistry, biology, and some math were part of natural philosophy for two millennia.
• The 16th-century Scientific Revolution saw these areas become unique sciences.
• Physics crosses into biophysics and quantum chemistry, among other interdisciplinary studies, but its boundaries are flexible.
• Physics' new ideas can clarify other sciences' mechanisms, opening new research avenues.

Classical Physics

• Classical physics is pre-20th century, before quantum mechanics and relativity revolutionized science.
• The major branches are classical mechanics, thermodynamics, optics, and electromagnetism.
• Classical mechanics studies how forces affect motion.
• Key concepts: Newton’s laws, conservation of energy, momentum, angular momentum.
• Thermodynamics looks at heat, work, and energy in balanced macroscopic systems.
• Key principles involve thermodynamics laws, entropy, and heat transfer.
• Optics studies light's behavior/properties: reflection, refraction, diffraction, interference.
• Electromagnetism explains how electric currents and magnetic fields interact.
• Key concepts: electric charge, electric and magnetic fields, electromagnetic waves.

Modern Physics

• Modern physics started with early 20th-century quantum mechanics and relativity breakthroughs.
• Quantum mechanics studies atomic/subatomic matter and energy behavior.
• Key concepts: quantization, wave-particle duality, uncertainty principle, quantum entanglement.
• Relativity (special and general) studies spacetime and gravity.
• Special relativity introduces spacetime and the constant speed of light.
• General relativity describes gravity as spacetime curvature from mass/energy.

Mechanics

• Mechanics studies object motion and its causes.
• Kinematics describes motion via displacement, velocity, and acceleration, without regard to causes.
• Dynamics studies motion's causes, including Newton's laws.
• Statics studies resting or balanced objects.
• Key concepts: force, mass, inertia, momentum, and energy.

Thermodynamics

• Thermodynamics studies energy, heat, work, and their relation to matter.
• The first law of thermodynamics: energy is conserved.
• The second law introduces entropy, stating that an isolated system's entropy tends to rise.
• The third law states a perfect crystal’s entropy at absolute zero is zero.
• Key concepts: temperature, heat, work, internal energy, enthalpy, and entropy.

Electromagnetism

• Electromagnetism explains electric charge and magnetic field interactions.
• Electric charge is a fundamental property that can be positive or negative.
• Electric fields are created by electric charges act on other charges.
• Magnetic fields are created by moving electric charges and act on other moving charges.
• Electromagnetic waves are disturbances in electric and magnetic fields that propagate through space including light.
• Key concepts: electric potential, capacitance, inductance, and electromagnetic induction.

Optics

• Optics is the study of light and its behavior.
• Reflection is the bouncing of light off a surface.
• Refraction is light bending when moving between mediums.
• Diffraction is light spreading through an opening or around an object.
• Interference is the overlapping of light waves, creating constructive/destructive patterns.
• Key concepts include wavelength, frequency, amplitude, polarization, and coherence.

Quantum Mechanics

• Quantum mechanics studies atomic and subatomic matter/energy behavior.
• Quantization means physical values like energy/momentum exist only in discrete amounts.
• Wave-particle duality: particles act like waves, and waves act like particles.
• The uncertainty principle: position and momentum cannot be perfectly known simultaneously.
• Quantum entanglement links two or more particles, sharing the same fate regardless of distance.
• Key concepts: Schrödinger equation, wave functions, energy levels, quantum states.

Relativity

• Relativity explains spacetime and gravity.
• Special relativity is based on: physics laws are constant for uniformly moving observers, and light speed in a vacuum is constant for all observers.
• General relativity describes gravity as spacetime curvature caused by mass and energy.
• Key concepts include spacetime, time dilation, length contraction, mass-energy equivalence (E=mc^2), and gravitational fields.

Branches of Physics

• Classical Mechanics: Motion of macroscopic objects
• Electromagnetism: Interactions of electric and magnetic fields
• Thermodynamics: Heat, energy, and entropy
• Optics: Behavior of light
• Acoustics: Study of sound
• Quantum Mechanics: Behavior of matter at the atomic and subatomic levels
• Nuclear Physics: Structure and properties of atomic nuclei
• Particle Physics: Fundamental particles and forces
• Condensed Matter Physics: Properties of solids and liquids
• Astrophysics: Physics of celestial bodies and the universe
• Biophysics: Application of physics to biological systems
• Geophysics: Physics of the Earth