1. Physics (Level 2)
   1. Physicist
   2. Physics education
2. Outline of physics
3. Physical property
4. Physical quantity
5. Energy (Level 2)
   1. Conservation of energy (Level 4)
   2. Energy density
6. Homogeneity (physics)
7. Matter (Level 2)
   1. Exotic matter
   2. Physical object
8. Vacuum (Level 3)
9. Fundamental interaction (Level 4)
   1. Gravity (Level 3)
   2. Electromagnetism (Level 3)
   3. Strong interaction (Level 3)
   4. Weak interaction (Level 3)
   5. Fifth force
10. Conservation of energy (Level 4)
11. Spacetime (Level 4)
    1. Curved spacetime
    2. Space (Level 3)
       1. Action at a distance
       2. Principle of locality
    3. Time (Level 2)
       1. Arrow of time
       2. Time in physics
12. Mass–energy equivalence (Level 4)
13. Conservation law
14. Hysteresis
15. Transport phenomena
16. Radiation (Level 4)
    1. Ionizing radiation (Level 4)
    2. Background radiation
17. Scalar (physics)
18. Field (physics) (Level 4)
    1. Classical field theory
       1. Mean-field theory
       2. Renormalization
    2. Flux (Level 4)
19. Symmetry (physics) (Level 4)
20. Instability
    1. Metastability
21. Classical physics
22. Modern physics
23. Naïve physics
24. Theoretical physics (Level 4)
25. Experimental physics
26. Computational physics
27. Atmospheric physics
28. Biophysics
29. Chemical physics
30. Polymer physics
31. Mathematical physics
32. List of unsolved problems in physics
33. Scale invariance
34. Classical limit
35. Macroscopic scale

1. Physical constant
2. Bohr magneton
3. Bohr radius
4. Boltzmann constant
5. Electron magnetic moment
6. Nucleon magnetic moment
7. Elementary charge
8. Fine-structure constant
9. Gravitational constant
10. Impedance of free space
11. Magnetic flux quantum
12. Planck constant
13. Speed of light (Level 3)
    1. Foucault's measurements of the speed of light
14. Vacuum permeability
15. Vacuum permittivity

This section contains 39 articles.

1. Atom (Level 3)
2. Atomic physics (Level 4)
3. Atomic orbital (Level 4)
4. Binding energy (Level 4)
5. Plum pudding model
6. Rutherford model
7. Bohr model (Level 4)
   1. Franck–Hertz experiment
8. Electron configuration (Level 4)
9. Electron shell (Level 4)
10. Exotic atom
    1. Onium
       1. Positronium
11. Ion (Level 4)
    1. Oxonium ion
12. Rutherford scattering experiments (Level 4)
13. Principal quantum number
14. Azimuthal quantum number
15. Magnetic quantum number
16. Spin quantum number
17. Spherical harmonics
18. Density functional theory

This section contains 17 articles.

1. Energy level (Level 4)
2. Spectral line
3. Fine structure
4. Hyperfine structure
5. Spin–orbit interaction
6. Degenerate energy levels
7. Stark effect
8. Zeeman effect
9. Stimulated emission
10. Spontaneous emission
11. Hydrogen spectral series
    1. Rydberg constant
    2. Rydberg formula
    3. Hydrogen-alpha
12. Hydrogen line
13. Einstein coefficients
14. Optical pumping

This section contains 9 articles.

1. Molecular physics
2. Molecular orbital (Level 4)
   1. Molecular orbital theory (Level 4)
3. Rigid rotor
4. Molecular dynamics
5. Cross section (physics)
6. Emission spectrum
7. Rotational–vibrational spectroscopy
   1. Rotational spectroscopy

This section contains 30 articles.

1. Color (Level 3)
2. Blacklight
3. CIE 1931 color space
4. CIELAB color space
5. CIELUV
6. CMYK color model (Level 4)
7. Color theory (Level 4)
   1. Primary color (Level 4)
   2. Secondary color
8. Color model
9. Color space
10. Gamut
11. Gloss (optics) (Level 4)
12. HCL color space
13. HSL and HSV
14. HWB color model
15. ISCC–NBS system
16. Munsell color system
17. RGB color model (Level 4)
    1. RGB color spaces
       1. Adobe RGB color space
       2. sRGB
18. RGBA color model
19. RYB color model
20. Impossible color
21. Chromaticity
    1. Line of purples
22. Hue
23. Tint, shade and tone
24. Web colors

This section contains 46 articles.

1. Amber (color)
2. Azure (color)
3. Beige
4. Black (Level 4)
5. Blue (Level 4)
   1. Egyptian blue
   2. Navy blue
   3. Sky blue
   4. Ultramarine
6. Brown (Level 4)
7. Burgundy (color)
8. Cerulean
9. Chartreuse (color)
10. Bronze (color)
11. Cyan
12. Fuchsia (color)
13. Gold (color)
14. Green (Level 4)
    1. Lime (color)
15. Grey (Level 4)
16. Indigo
17. Lavender (color)
18. Magenta
19. Mauve
20. Olive (color)
21. Orange (colour) (Level 4)
22. Pink (Level 4)
23. Purple (Level 4)
    1. Tyrian purple
24. Red (Level 4)
    1. Crimson
    2. Maroon
    3. Scarlet (color)
25. Rose (color)
26. Ruby (color)
27. Saffron (color)
28. Silver (color)
29. Spring green
30. Tan (color)
31. Teal
32. Turquoise (color)
33. Vermilion
34. Violet (color)
35. Viridian
36. White (Level 4)
37. Yellow (Level 4)

This section contains 8 articles.

1. Condensed matter physics (Level 4)
2. Solid-state physics (Level 4)
3. Mesoscopic physics
4. Einstein solid
5. Nanoparticle
6. Soft matter
7. Bonding in solids
8. Bloch's theorem

This section contains 10 articles.

1. Electronic band structure
   1. Band gap
   2. Fermi level
   3. Valence and conduction bands
2. Free electron model
3. Hubbard model
   1. Mott insulator
4. Rock magnetism
5. Plasmon
6. Polaron

This section contains 32 articles.

1. Crystallography (Level 4)
2. Crystal (Level 4)
3. Crystallization (Level 4)
   1. Crystal growth
   2. Grain growth
4. Crystal structure
5. Crystal system
   1. Triclinic crystal system
   2. Monoclinic crystal system
   3. Orthorhombic crystal system
   4. Tetragonal crystal system
   5. Hexagonal crystal family
   6. Cubic crystal system
6. Perovskite (structure)
7. Unit cell
   1. Bravais lattice
8. Reciprocal lattice
   1. Brillouin zone
   2. Fermi surface
9. Crystal optics
10. Crystallographic defect
    1. Grain boundary
    2. Dislocation
    3. Misorientation
    4. Vacancy defect
11. Crystal twinning
12. Miller index
13. Atomic packing factor
14. Coordination number
15. Crystal polymorphism
16. X-ray crystallography
17. Crystal engineering

This section contains 19 articles.

1. State of matter (Level 3)
2. Solid (Level 3)
   1. Amorphous solid (Level 4)
3. Liquid (Level 3)
4. Gas (Level 3)
   1. Vapor (Level 4)
5. Plasma (physics) (Level 3)
   1. Vlasov equation
6. Degenerate matter (Level 4)
   1. Bose gas
   2. Fermi gas
7. Bose–Einstein condensate (Level 4)
8. Superfluidity
9. Supercritical fluid
10. Supersolid
11. Liquid crystal
12. Quasiparticle
    1. Electron hole
    2. Phonon

This section contains 24 articles.

1. Phase transition (Level 4)
2. Phase (matter) (Level 4)
3. Phase diagram (Level 4)
4. Boiling (Level 4)
   1. Boiling point
   2. Superheating
5. Melting (Level 4)
   1. Melting point
6. Freezing (Level 4)
7. Evaporation (Level 4)
8. Condensation (Level 4)
   1. Superheated steam
9. Vaporization
10. Ionization (Level 4)
11. Plasma recombination
12. Sublimation (phase transition)
13. Deposition (phase transition)
14. Critical point (thermodynamics) (Level 4)
    1. Self-organized criticality
15. Triple point (Level 4)
16. Metallization pressure
    1. Metallic hydrogen
17. Curie temperature
18. Phase rule

This section contains 13 articles.

1. Classical electromagnetism
2. Electricity (Level 2)
3. Magnetism (Level 3)
   1. Magnet (Level 4)
      1. Electromagnet (Level 4)
4. Dipole (Level 4)
5. Metamaterial (Level 4)
   1. Negative-index metamaterial
   2. Photonic metamaterial
   3. Tunable metamaterial
   4. Nonlinear metamaterial
6. Oil drop experiment (Level 4)
7. Photoelectric effect (Level 4)

This section contains 19 articles.

1. Electrostatics (Level 4)
   1. Static electricity
2. Coulomb's law (Level 4)
3. Electric charge (Level 4)
   1. Charge density
4. Electric field (Level 4)
   1. Electric displacement field
   2. Electric-field screening
      1. Debye length
5. Electric potential (Level 4)
   1. Voltage (Level 4)
6. Electric potential energy
7. Electric flux
8. Electric dipole moment
9. Polarization density
10. Dielectric (Level 4)
11. Electric susceptibility
12. Electrostatic induction
13. Permittivity

This section contains 20 articles.

1. Magnetostatics (Level 4)
2. Magnetic field (Level 4)
3. Magnetic flux
4. Biot–Savart law
5. Magnetic dipole
6. Magnetic moment
7. Magnetization
   1. Antiferromagnetism
   2. Diamagnetism
   3. Ferrimagnetism
   4. Ferromagnetism (Level 4)
      1. Ising model
      2. Potts model
   5. Paramagnetism
   6. Spontaneous magnetization
8. Magnetic susceptibility
9. Permeability (electromagnetism)
10. Magnetic monopole
11. Magnetohydrodynamics
12. Ampère's force law

This section contains 26 articles.

1. Maxwell's equations (Level 4)
   1. Gauss's law
   2. Gauss's law for magnetism
   3. Ampère's circuital law
   4. Faraday's law of induction
2. Lorentz force (Level 4)
3. Electromagnetic field (Level 4)
4. Electromagnetic four-potential
   1. Lorenz gauge condition
5. Electric current (Level 4)
   1. Alternating current (Level 4)
   2. Direct current (Level 4)
   3. Current density
6. Displacement current
7. Electric power
   1. AC power
8. Electromagnetic induction (Level 4)
9. Electromotive force (Level 4)
10. Eddy current (Level 4)
11. Hall effect
    1. Quantum Hall effect
12. Electrical resistivity and conductivity
13. Retarded time
14. Lenz's law
15. Poynting's theorem
16. Right-hand rule

This section contains 37 articles.

1. Electromagnetic radiation (Level 3)
   1. Electromagnetic wave equation
2. Electromagnetic spectrum (Level 4)
   1. Radio wave (Level 4)
   2. Microwave (Level 4)
   3. Terahertz radiation
   4. Infrared (Level 4)
   5. Light (Level 3)
      1. Visible spectrum (Level 4)
   6. Ultraviolet (Level 4)
   7. X-ray (Level 4)
   8. Gamma ray (Level 4)
3. Poynting vector
4. Evanescent field
5. Transverse mode
6. Waveguide (radio frequency)
7. Larmor formula
8. Bremsstrahlung (Level 4)
9. Cyclotron radiation
10. Synchrotron radiation
11. Compton scattering
12. Radiative transfer
13. Faraday effect
14. Absorption (electromagnetic radiation)
    1. Absorption band
15. Near and far field
16. Radiant flux
17. Irradiance
18. Point source
19. Radiance
20. Radiometry
21. Spectral density
22. Luminescence
    1. Fluorescence (Level 4)
    2. Phosphorescence
    3. Scintillation (physics)
       1. Scintillator

This section contains 24 articles.

1. Electrical network (Level 4)
2. Electrical impedance (Level 4)
3. Electrical reactance
4. Electrical resistance and conductance (Level 4)
   1. Joule heating
   2. Ohm's law (Level 4)
5. Electrical conductor
   1. Electrode
6. Insulator (electricity)
7. Semiconductor (Level 3)
   1. Depletion region
   2. Metal–semiconductor junction
   3. Ohmic contact
8. Superconductivity (Level 4)
   1. Cooper pair
   2. High-temperature superconductivity
   3. Josephson effect
   4. Type-I superconductor
   5. Type-II superconductor
9. Capacitance (Level 4)
10. Gain (electronics) (Level 4)
11. Ground (electricity)
12. Inductance (Level 4)
13. Kirchhoff's circuit laws (Level 4)

This section contains 24 articles.

1. Mechanics (Level 4)
   1. Ballistics (Level 4)
   2. Continuum mechanics (Level 4)
   3. Flight (Level 4)
   4. Kinematics (Level 4)
      1. Chasles' theorem (kinematics)
      2. Screw axis
   5. Mechanical advantage
   6. Statics (Level 4)
2. Collision
   1. Elastic collision
   2. Inelastic collision
3. Degrees of freedom (mechanics)
4. Displacement (geometry)
5. Free particle
6. Mechanical equilibrium
7. Oscillation (Level 4)
   1. Harmonic oscillator (Level 4)
      1. Simple harmonic motion (Level 4)
   2. Normal mode
8. Point particle
9. Shock (mechanics)
10. Test particle
11. Virial theorem

This section contains 99 articles.

1. Quantum mechanics (Level 3)
   1. Introduction to quantum mechanics
   2. Quantum
2. AdS/CFT correspondence
3. Born rule
4. Bra–ket notation
5. Correspondence principle
   1. Ehrenfest theorem
6. Dirac equation
   1. Pauli equation
   2. Pauli matrices
7. Expectation value (quantum mechanics)
8. Gauge theory (Level 4)
   1. Introduction to gauge theory
9. Gyromagnetic ratio
   1. g-factor (physics)
10. Interpretations of quantum mechanics
    1. Copenhagen interpretation
    2. De Broglie–Bohm theory
       1. Quantum potential
    3. Many-worlds interpretation
    4. Schwinger's quantum action principle
11. Hidden-variable theory
12. Mathematical formulation of quantum mechanics
13. Matrix mechanics
    1. BKS theory
14. Measurement in quantum mechanics
    1. Measurement problem
15. Observable
    1. Invariant (physics)
    2. Quantum contextuality
    3. Schrödinger's cat
16. Operator (physics)
    1. Angular momentum operator
    2. Hamiltonian (quantum mechanics)
       1. Unitary transformation (quantum mechanics)
    3. Momentum operator
    4. Position operator
    5. Rotation operator (quantum mechanics)
17. Parity (physics)
    1. Wu experiment
18. Particle in a box
    1. Finite potential well
       1. Delta potential
19. Path integral formulation
20. Pauli exclusion principle (Level 4)
21. Perturbation theory
    1. Fermi's golden rule
22. Planck postulate
23. Position and momentum spaces
24. Probability amplitude
25. Problem of time
26. Quantization (physics)
27. Quantum chromodynamics (Level 4)
28. Quantum electrodynamics (Level 4)
    1. Wheeler–Feynman absorber theory
29. Quantum entanglement (Level 4)
    1. Bell's theorem
       1. Bell test
    2. Einstein–Podolsky–Rosen paradox
    3. Quantum nonlocality
30. Quantum field theory (Level 4)
    1. Casimir effect
    2. Conformal field theory
    3. Propagator
    4. Quantum vacuum state
       1. QCD vacuum
       2. QED vacuum
31. Quantum fluctuation
    1. Quantum foam
32. Quantum harmonic oscillator
33. Quantum indeterminacy
34. Quantum information
35. Quantum number
36. Quantum state
    1. Bound state
    2. Excited state
    3. Ground state
       1. Topological order
    4. Stationary state
    5. Virtual state
37. Quantum superposition
38. Quantum tunnelling (Level 4)
39. Relativistic quantum mechanics
40. Schrödinger equation (Level 4)
41. Stern–Gerlach experiment
42. Symmetry in quantum mechanics
43. Uncertainty principle (Level 4)
44. Variational method (quantum mechanics)
45. Wave function (Level 4)
    1. Wave function collapse
46. Wave–particle duality (Level 4)
    1. Compton wavelength
    2. Davisson–Germer experiment
    3. Electron diffraction
       1. Double-slit experiment
    4. Matter wave
47. WKB approximation
48. Zero-point energy

This section contains 45 articles.

This section contains 97 articles.

1. Classical mechanics (Level 3)
   1. Analytical mechanics
   2. Hamiltonian mechanics (Level 4)
      1. Poisson bracket
   3. Lagrangian mechanics (Level 4)
      1. D'Alembert's principle
      2. Euler–Lagrange equation
      3. Generalized coordinates
      4. Virtual work
2. Action (physics)
3. Angular acceleration
   1. Angular momentum (Level 4)
   2. Centripetal force (Level 4)
4. Angular displacement
5. Angular frequency
6. Angular velocity
7. Canonical coordinates
8. Damping
9. Force (Level 3)
   1. Central force
   2. Conservative force
   3. Fictitious force
      1. Centrifugal force
      2. Coriolis force (Level 4)
   4. Normal force
   5. Resultant force
   6. Restoring force
10. Frame of reference (Level 4)
    1. Inertial frame of reference
    2. Non-inertial reference frame
11. Free body diagram
    1. Net force
12. Force field (physics)
13. Friction (Level 4)
    1. Rolling resistance
14. Galilean transformation
    1. Absolute space and time
    2. Galilean invariance
    3. Relative velocity
15. Gravitational field
16. Gravitational potential
17. Impact (mechanics)
    1. Mechanical resonance
18. Impulse (physics) (Level 4)
19. Inertia (Level 4)
20. Kinetic energy (Level 4)
21. Mass (Level 3)
    1. Density (Level 4)
    2. Center of mass
    3. Conservation of mass (Level 4)
    4. Reduced mass
22. Moment (physics)
23. Moment of inertia (Level 4)
24. Momentum (Level 3)
25. Motion (Level 3)
    1. Acceleration (Level 4)
    2. Bouncing ball
    3. Circular motion
    4. Equations for a falling body
    5. Equations of motion (Level 4)
       1. Constant of motion
    6. Free fall
    7. Jerk (physics)
    8. Linear motion
    9. Locomotion in space
    10. Newton's laws of motion (Level 3)
        1. Newtonian dynamics
    11. Position (geometry)
    12. Projectile motion
    13. Speed (Level 4)
    14. Steady state
    15. Trajectory
    16. Velocity (Level 4)
26. n-body problem
    1. Two-body problem
       1. Kepler problem
27. Newton's law of universal gravitation (Level 4)
    1. Cavendish experiment
28. Perpetual motion
29. Potential energy (Level 4)
    1. Potential well
30. Power (physics) (Level 4)
31. Precession
32. Projectile
33. Radiation pressure
34. Reaction (physics)
35. Rolling
36. Rotation (Level 4)
37. Scalar potential
    1. Equipotential
38. Tidal force
39. Torque (Level 4)
40. Vector potential
41. Vibration
42. Weight (Level 4)
    1. Weighing scale (Level 4)
43. Work (physics) (Level 4)

This section contains 53 articles.

1. Fluid mechanics (Level 4)
2. Bernoulli's principle (Level 4)
3. Boundary layer
4. Buoyancy (Level 4)
   1. Archimedes' principle
   2. Metacentric height
5. Circulation (physics)
   1. Kelvin's circulation theorem
6. Compressibility
   1. Compressible flow
   2. Incompressible flow
7. Computational fluid dynamics
8. Convection (Level 4)
9. Deformation (physics)
10. Diffusion (Level 4)
    1. Diffusion equation
11. Drag (physics) (Level 4)
12. Euler equations (fluid dynamics)
13. Flow measurement
    1. Mass flow rate
    2. Volumetric flow rate
14. Fluid
    1. Newtonian fluid
    2. Non-Newtonian fluid
15. Fluid dynamics (Level 4)
    1. Aerodynamics (Level 4)
    2. Flow visualization
16. Flow velocity
17. Hydrostatics
    1. Communicating vessels
    2. Hydrostatic equilibrium
    3. Pascal's law
    4. Vertical pressure variation
18. Laminar flow
    1. Hagen–Poiseuille equation
19. Lift (force) (Level 4)
20. Mass flow (life sciences)
21. Navier–Stokes equations (Level 4)
    1. Berman flow
    2. Jeffery–Hamel flow
    3. Rayleigh problem
    4. Stokes problem
    5. Taylor–Culick flow
22. Osmosis (Level 4)
23. Pipe flow
24. Reynolds number (Level 4)
25. Rheology
26. Slosh dynamics
    1. Free surface effect
27. Surface tension (Level 4)
28. Turbulence (Level 4)
29. Viscosity (Level 4)
30. Vorticity

This section contains 30 articles.

1. Solid mechanics (Level 4)
2. Bulk modulus
3. Contact mechanics
4. Crystallite
5. Deformation (engineering) (Level 4)
   1. Poisson's ratio
6. Elastic modulus (Level 4)
7. Elasticity (physics) (Level 4)
8. Fatigue (material) (Level 4)
9. Finite strain theory
10. Fracture toughness
11. Hooke's law (Level 4)
12. Plasticity (physics) (Level 4)
    1. Brittleness
    2. Ductility
13. Piezoelectricity
14. Rigid body
    1. Rigid body dynamics
15. Shearing (physics)
16. Shear modulus
17. Stiffness (Level 4)
18. Strength of materials (Level 4)
19. Stress (mechanics) (Level 4)
    1. Cauchy stress tensor
    2. Compression (physics)
    3. Tension (physics)
    4. Torsion (mechanics)
    5. Shear stress
20. Toughness
21. Young's modulus

This section contains 3 articles.

1. Soil mechanics
2. Angle of repose
3. Granular convection

This section contains 26 articles.

1. Statistical mechanics (Level 4)
2. Boltzmann distribution
3. Density of states
4. Detailed balance
5. Distribution function (physics)
   1. Maxwell–Boltzmann distribution
6. Ensemble (mathematical physics)
   1. Canonical ensemble
      1. Grand canonical ensemble
      2. Microcanonical ensemble
7. Entropy (statistical thermodynamics)
   1. Entropy as an arrow of time
   2. Entropy (energy dispersal)
   3. Entropy (order and disorder)
8. Fluctuation–dissipation theorem
9. Indistinguishable particles
10. Maxwell's demon
11. Microstate (statistical mechanics)
12. Molecular diffusion
13. Particle statistics
    1. Bose–Einstein statistics
    2. Fermi–Dirac statistics
       1. Fermi energy
    3. Maxwell–Boltzmann statistics
14. Partition function (statistical mechanics)
15. Work (thermodynamics)

1. Nuclear physics (Level 4)
2. Atomic nucleus (Level 4)
3. Nucleon
4. Nuclide (Level 4)
   1. Isotope (Level 4)
5. Nuclear binding energy
6. Nuclear fission (Level 4)
   1. Critical mass
7. Nuclear fusion (Level 4)
   1. Cold fusion
8. Nuclear reaction
9. Nuclear isomer
10. High-energy nuclear physics
11. Nuclear force
12. Nuclear structure
13. Nucleosynthesis (Level 4)
14. Semi-empirical mass formula
15. Nuclear magnetic resonance
    1. Electron paramagnetic resonance
    2. Magnetic resonance
    3. Nuclear magnetic resonance spectroscopy
16. Island of stability
17. Hypernucleus
18. Isotope separation

This section contains 10 articles.

1. Radioactive decay (Level 3)
2. Alpha decay
   1. Alpha particle (Level 4)
3. Beta decay
   1. Beta particle (Level 4)
4. Neutron radiation
5. Decay product
6. Half-life
7. Decay energy
8. Radioactive source

This section contains 31 articles.

1. Particle physics (Level 3)
2. Standard Model (Level 3)
   1. Yang–Mills theory
      1. Yang–Mills existence and mass gap
   2. Higgs mechanism
   3. Mathematical formulation of the Standard Model
3. Particle (Level 4)
4. Scattering (Level 4)
   1. Elastic scattering
   2. Inelastic scattering
   3. Thomson scattering
5. Annihilation
6. CP violation
7. CPT symmetry
8. Electroweak interaction
9. Hierarchy problem
10. Feynman diagram
11. Generation (particle physics)
12. Pair production
13. Particle decay
    1. Free neutron decay
14. Discovery of the neutron
15. Charge conservation
16. QCD matter
17. Quark model
18. Scalar field theory
19. Symmetry breaking
    1. Spontaneous symmetry breaking
20. Noether's theorem
21. Baryon asymmetry
22. Vacuum energy

This section contains 12 articles.

1. Spin (physics) (Level 4)
   1. Spin-1/2
2. Baryon number
3. Lepton number
4. Color charge
5. Flavour (particle physics)
6. Strangeness
7. Isospin
8. Weak isospin
9. Hypercharge
10. Weak hypercharge
11. Chirality (physics)

This section contains 12 articles.

This section contains 7 articles.

1. Particle accelerator (Level 4)
2. Collider
3. Linear particle accelerator
4. Large Hadron Collider (Level 4)
5. Tevatron (Level 4)
6. Relativistic Heavy Ion Collider
7. Synchrotron

This section contains 5 articles.

1. Particle detector (Level 4)
2. Semiconductor detector
3. Cloud chamber (Level 4)
4. Calorimeter (particle physics)
5. Bubble chamber

This section contains 45 articles.

This section contains 8 articles.

1. Subatomic particle (Level 3)
2. Elementary particle
3. List of particles
4. Massless particle
5. Virtual particle
6. Tachyon
7. Fermion (Level 4)
8. Boson (Level 4)

This section contains 16 articles.

This section contains 9 articles.

1. Lepton (Level 4)
2. Electron (Level 3)
3. Muon (Level 4)
4. Tau (particle) (Level 4)
5. Neutrino (Level 4)
   1. Cowan–Reines neutrino experiment
   2. Electron neutrino
   3. Muon neutrino
   4. Tau neutrino

This section contains 7 articles.

1. Quark (Level 4)
2. Up quark
3. Down quark
4. Strange quark
5. Charm quark
6. Bottom quark
7. Top quark

This section contains 13 articles.

1. Hadron (Level 4)
   1. Eightfold way (physics)
   2. Parton (particle physics)
2. Baryon (Level 4)
   1. Neutron (Level 3)
   2. Proton (Level 3)
   3. Hyperon
3. Pentaquark
4. Meson (Level 4)
   1. Pion
   2. Kaon
   3. J/psi meson
5. Tetraquark

This section contains 8 articles.

1. Force carrier
2. Gauge boson (Level 4)
   1. Photon (Level 3)
      1. Biophoton
   2. Gluon (Level 4)
   3. W and Z bosons (Level 4)
   4. Graviton
3. Higgs boson (Level 4)

This section contains 7 articles.

1. Antimatter (Level 4)
   1. Antihydrogen
2. Antiparticle (Level 4)
   1. Positron (Level 4)
      1. Electron–positron annihilation
   2. Antiproton
   3. Antineutron

This section contains 20 articles.

1. Physics beyond the Standard Model (Level 4)
2. Axion
3. Grand Unified Theory
4. Neutrino oscillation
   1. Neutral particle oscillation
5. Proton decay
6. Quantum gravity (Level 4)
   1. Loop quantum gravity
7. String theory (Level 4)
   1. D-brane
   2. Brane
   3. M-theory
   4. String (physics)
   5. Superstring theory
8. Supergravity
9. Supersymmetry (Level 4)
   1. Minimal Supersymmetric Standard Model
10. Theory of everything
11. Unified field theory
    1. Classical unified field theories

1. Thermodynamics (Level 3)
2. Heat (Level 4)
3. Temperature (Level 3)
   1. Thermodynamic temperature
   2. Cold
   3. Absolute zero (Level 4)
4. Pressure (Level 4)
   1. Internal pressure
   2. Partial pressure
   3. Pressure gradient
   4. Pressure–volume diagram
5. Particle number
6. Laws of thermodynamics (Level 4)
   1. Zeroth law of thermodynamics
   2. First law of thermodynamics
   3. Second law of thermodynamics
   4. Third law of thermodynamics
7. Fundamental thermodynamic relation
8. Heat capacity (Level 4)
   1. Heat capacity ratio
   2. Specific heat capacity
9. Latent heat
10. Heat transfer (Level 4)
    1. Heat equation
    2. Thermal conduction
    3. Convection (heat transfer)
    4. Newton's law of cooling
11. Entropy (Level 4)
    1. Introduction to entropy
    2. Entropy (classical thermodynamics)
    3. Boltzmann's entropy formula
12. Internal energy (Level 4)
13. Thermodynamic cycle (Level 4)
    1. Brayton cycle
    2. Carnot cycle
    3. Diesel cycle
    4. Ericsson cycle
    5. Heat pump and refrigeration cycle
    6. Otto cycle
    7. Rankine cycle
    8. Stirling cycle
14. Thermodynamic free energy (Level 4)
15. Ideal gas
    1. Ideal gas law (Level 4)
16. Heat engine
    1. Carnot heat engine
    2. Stirling engine
17. Energy conversion efficiency
18. Kinetic theory of gases
    1. Effusion
    2. Mean free path
19. Thermodynamic state
    1. Equation of state
       1. Van der Waals equation
       2. Redlich–Kwong equation of state
       3. Virial expansion
20. Thermal conductivity and resistivity
21. Thermodynamic equilibrium
    1. Equilibrium thermodynamics
22. Thermodynamic potential
    1. Enthalpy (Level 4)
       1. Enthalpy of vaporization
    2. Helmholtz free energy
    3. Gibbs free energy
23. Thermal radiation
    1. Black-body radiation (Level 4)
    2. Black body
    3. Planck's law
    4. Planckian locus
    5. Stefan–Boltzmann law
    6. Ultraviolet catastrophe
    7. Wien approximation
    8. Wien's displacement law
24. Equipartition theorem
25. Thermodynamic process
    1. Adiabatic process
    2. Isenthalpic process
       1. Joule–Thomson effect
    3. Isothermal process
    4. Endothermic process
    5. Exothermic process
    6. Quasistatic process
    7. Reversible process (thermodynamics)
    8. Irreversible process
26. Chemical potential
27. Intensive and extensive properties
28. Thermodynamic system
    1. Closed system
29. Brownian motion
30. Photon gas
31. Entropy of mixing
32. Fluctuation theorem
33. Thermal energy
34. Thermal equilibrium
35. Thermodynamic equations
36. Boltzmann equation
    1. H-theorem
    2. Loschmidt's paradox
37. Maxwell relations
38. Thermal expansion
39. Thermal fluctuations
40. Thermodynamic limit

1. Wave (Level 3)
   1. Transverse wave
   2. Longitudinal wave
2. Mechanical wave
3. Amplitude (Level 4)
4. Phase (waves)
5. Frequency (Level 4)
6. Wavelength (Level 4)
7. Wavenumber
8. Wave vector
9. Diffraction (Level 4)
   1. Diffraction-limited system
   2. Fraunhofer diffraction
   3. Huygens–Fresnel principle
      1. Fermat's principle
   4. Bragg's law
10. Doppler effect (Level 4)
    1. Relativistic Doppler effect
11. Wave interference (Level 4)
12. Noise (Level 4)
13. Resonance (Level 4)
14. Superposition principle (Level 4)
15. Wave equation (Level 4)
16. Node (physics)
17. Radio frequency
18. Wavefront
19. Harmonic
20. Pulse (physics)
21. Group velocity
22. Phase velocity
23. Shock wave
24. Waveform
25. Coherence (physics)
26. Standing wave
27. Wave packet
28. Dispersion (water waves)
29. Plane wave

This section contains 10 articles.

1. Acoustics (Level 4)
2. Sound (Level 3)
3. Speed of sound (Level 4)
4. Sonic boom
5. Sound pressure
6. Loudness
7. Ultrasound (Level 4)
8. Beat (acoustics)
9. Echo
10. Acoustic resonance

This section contains 54 articles.

1. Optics (Level 3)
2. Darkness
3. Geometrical optics
   1. Caustic (optics)
   2. Optical path
      1. Optical path length
   3. Ray (optics)
4. Physical optics
5. Focus (optics) (Level 4)
6. Focal length (Level 4)
7. Optical aberration
   1. Chromatic aberration
   2. Spherical aberration
8. Photonics
9. Polarization (waves) (Level 4)
   1. Circular polarization
   2. Linear polarization
   3. Stokes parameters
10. Reflection (physics) (Level 4)
    1. Curved mirror
    2. Reflection coefficient
    3. Transmission coefficient
    4. Total internal reflection
11. Refraction (Level 4)
    1. Photonic crystal
    2. Refractive index (Level 4)
    3. Snell's law
12. Transparency and translucency (Level 4)
13. Opacity
14. Optical depth
15. Optical power
16. Fresnel equations
17. Nonlinear optics
18. Birefringence
    1. Dichroism
19. Intensity (physics)
20. Newton's rings
21. Rayleigh scattering
22. Aperture
23. Angle of incidence (optics)
24. Virtual image
25. Dispersion (optics)
26. Shadow
27. Beer–Lambert law
28. Fourier optics
29. Invisibility
30. Iridescence
31. Magnification
32. Moiré pattern
33. Photometry (optics)
    1. Illuminance
    2. Luminance
    3. Luminous flux
    4. Luminous intensity