Top 50 Physics Ideas

The following list is based on an excellent science book known as the 50 Physics Ideas You Really Need to Know.  It is about the top ideas that change this natural science forever and help us have a better understanding of nature and how the universe behaves.  It covers the discoveries of the last two millennia from the mathematic laws of nature developed by the ancient Greeks way up to the infinite possibilities of Quantum Physics, passing be key elements of Scientific Revolution.  The list as well as the book is dived into various sections including Matter In Motion, Beneath The Waves, Conundrums, Splitting Atoms and finally Space and Time.   Hopefully, it will give you a good overview of Physics, one of academic oldest disciplines.

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Top 50 Physics Ideas: the principles that changed the world


Matter in Motion

The following is some of the most important physics ideas about matter and motion, including:

  1. Mach’s principle: Mass matters for motion
  2. Newton’s laws of motion: Motion captured
  3. Kepler’s laws: Law of the worlds
  4. Newton’s laws of gravitation: Mass attraction
  5. Conservation of energy: Indestructible energy
  6. Simple harmonic motion: The science of swing
  7. Hooke’s law: Elastic fantastic
  8. Ideal gas law: Pressure cooker physics
  9. Second law of thermodynamics: Law of disorder
  10. Absolute zero: The big chill
  11. Brownian motion: An invisible microscopic dance
  12. Chaos theory: Order in chaos
  13. Bernoulli equation: Arteries and aerodynamics

Mach’s principle

Mach’s principle: where mass matters for motion

The Mach’s principle is the name given by Einstein to an imprecise hypothesis often credited to the physicist and philosopher Ernst Mach. The idea is that the local motion of a rotating reference frame is determined by the large scale distribution of matter.

Newton’s laws of motion

Newton’s laws of motion: how motion is captured

The Newton’s laws of motion combine three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces.

Kepler’s laws

Kepler’s laws: the astronomical principles of the worlds

In astronomy, Kepler’s laws give a description of the motion of planets around the Sun.

Newton’s laws of gravitation

Newton’s laws of gravitation: attraction of mass

The Newton’s law of universal gravitation states that every point mass in the universe attracts every other point mass with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Conservation of energy

Conservation of energy: Indestructible energy over time

The nineteenth century law of conservation of energy is a law of physics which states that the total amount of energy in an isolated system remains constant over time. The total energy is said to be conserved over time

Simple harmonic motion

Simple harmonic motion: the science of swing

The simple harmonic motion, in mechanics and physics, is a type of periodic motion where the restoring force is directly proportional to the displacement. It can serve as a mathematical model of a variety of motions, such as the oscillation of a spring or the motion of a simple pendulum.

Hooke’s law

Hooke’s law: elastic power

The Hooke’s law of elasticity, in mechanics and physics, is an approximation that states that the extension of a spring is in direct proportion with the load applied to it. Many materials obey this law as long as the load does not exceed the material’s elastic limit.

Ideal gas law

Ideal gas law: pressure cooker physics

The ideal gas law is the equation of state of a hypothetical ideal gas.  Although it has several limitations, it is a good approximation to the behaviour of many gases under many conditions.

Second law of thermodynamics

Second law of thermodynamics: principle of disorder

The second law of thermodynamics is an expression of the tendency that over time, differences in temperature, pressure, and chemical potential equilibrate in an isolated physical system.

Absolute zero

Absolute zero: the big chill

The Absolute zero is the theoretical temperature at which entropy reaches its minimum value. The laws of thermodynamics state that absolute zero cannot be reached using only thermodynamic means.

Brownian motion

Brownian motion: an invisible microscopic dance

The Brownian motion named after the botanist Robert Brown is the presumably random drifting of particles suspended in a fluid (a liquid or a gas) or the mathematical model used to describe such random movements, which is often called a particle theory.

Chaos theory

Chaos theory: order in chaos

The Chaos theory is a field in mathematics theory, which studies the behaviour of dynamical systems that are highly sensitive to initial conditions, an effect which is popularly referred to as the butterfly effect.

Bernoulli equation

Bernoulli equation: arteries and aerodynamics

The Bernoulli equation, in fluid dynamics, states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid’s potential energy. The principle is named after the Dutch-Swiss mathematician Daniel Bernoulli who published his principle in his book Hydrodynamica in 1738.

Beneath the Waves

The following is some of the most important physics ideas about light, waves and colours, including:

  1. Newton’s theory of colour: Beyond the rainbow
  2. Huygen’s principle: Wave progression
  3. Snell’s law: Light finds the shortest path
  4. Bragg’s law: Spotting structure
  5. Fraunhofer diffraction: Interfering light waves
  6. Doppler effect: Perfect pitch
  7. Ohm’s law: Circuit theory
  8. Fleming’s right hand rule: Induction rules
  9. Maxwell’s equations: and so there was light

Newton’s theory of colour

Newton’s theory of colour: Beyond the rainbow

Newton’s theory of colourstates that colour is the result of objects interacting with already-coloured light rather than objects generating the colour themselves.

Huygen’s principle

Huygen’s principle: Wave progression

The Huygens–Fresnel principle is a method of analysis applied to problems of wave propagation both in the far-field limit and in near-field diffraction.  It is named after Dutch physicist Christiaan Huygens and French physicist Augustin-Jean Fresnel.

Snell’s law

Snell’s law: Light finds the shortest path

The Snell’s law, also known as the Snell–Descartes law or the law of refraction, is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water and glass.

Bragg’s law

Bragg’s law: Spotting structure

The Bragg’s law in physics gives the angles for coherent and incoherent scattering from a crystal lattice. When X-rays are incident on an atom, they make the electronic cloud move as does any electromagnetic wave.

Fraunhofer diffraction

Fraunhofer diffraction: Interfering light waves

The Fraunhofer diffraction equation in optics,  is used to model the diffraction of waves when the diffraction pattern is viewed at a long distance from the diffracting object, and also when it is viewed at the focal plane of an imaging lens.

Doppler Effect

Doppler Effect: Perfect pitch

The Doppler effect (or Doppler shift), named after Austrian Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave.

Ohm’s law

Ohm’s law: Circuit theory

The Ohm’s law states that the current through a conductor between two points is directly proportional to the potential difference across the two points. Introducing the constant of proportionality, the resistance, one arrives at the usual mathematical equation that describes this relationship: I = V/R.

Fleming’s right hand rule

Fleming’s right hand rule: Induction rules

The Fleming’s right-hand rule for generators and left-hand rule for motors are a pair of visual mnemonics. They were originated by John Ambrose Fleming, in the late 19th century, as a simple way of working out the direction of motion in an electric motor, or the direction of electric current in an electric generator.

Maxwell’s equations

Maxwell’s equations: and so there was light

Maxwell’s equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of classical electrodynamics, classical optics, and electric circuits.

Quantum Conundrums

The following is some of the most important physics ideas about the Quantum Conundrums, including:

  1. Planck’s law: Energy budget
  2. Photoelectric effect: Photon bullets
  3. Schrodinger’s wave equation: Here, there, but not everywhere
  4. Heisenberg’s uncertainty principle: Know your limits
  5. Copenhagen interpretation: You choose
  6. Schrodinger’s cat: Dead or alive?
  7. The EPR Paradox: Instant messaging
  8. Pauli’s exclusion principle: Is this seat taken?
  9. Superconductivity: Resistance is futile

Planck’s law

Planck’s law: Energy budget

The Planck’s law in physics, describes the amount of electromagnetic energy with a certain wavelength radiated by a black body in thermal equilibrium.

Photoelectric effect

Photoelectric effect: Photon bullets

The photoelectric effect demonstrates that electrons are emitted from matter (metals and non-metallic solids, liquids or gases) as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet radiation.

Schrodinger’s wave equation

Schrodinger’s wave equation: Here, there, but not everywhere

The Schrödinger wave equation in quantum mechanics describes how the quantum state of a physical system changes with time. It was formulated in late 1925, and published in 1926, by the Austrian physicist Erwin Schrödinger.

Heisenberg’s uncertainty principle

Heisenberg’s uncertainty principle: Know your limits

The Heisenberg uncertainty principle in quantum mechanics, states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle can be simultaneously known.   In other words the more precisely one property is measured, the less precisely the other can be controlled, determined, or known.

Copenhagen interpretation

Copenhagen interpretation: You choose

The Copenhagen interpretation is one of the earliest and most commonly taught interpretations of quantum mechanics.  It holds that quantum mechanics does not yield a description of an objective reality but deals only with probabilities of observing, or measuring, various aspects of energy quanta, entities which fit neither the classical idea of particles nor the classical idea of waves.

Schrodinger’s cat

Schrodinger’s cat: Dead or alive?

Schrödinger’s cat is a thought experiment, sometimes described as a paradox, devised by Austrian physicist Erwin Schrödinger in 1935. It illustrates what he saw as the problem of the Copenhagen interpretation of quantum mechanics applied to everyday objects. The scenario presents a cat that might be alive or dead, depending on an earlier random event.

The EPR Paradox

The EPR Paradox: Instant messaging

The EPR paradox is an early and influential critique levelled against quantum mechanics. Albert Einstein and his colleagues Boris Podolsky and Nathan Rosen (known collectively as EPR) designed a thought experiment intended to reveal what they believed to be inadequacies of quantum mechanics. To that end they pointed to a consequence of quantum mechanics that its supporters had not noticed.

Pauli’s exclusion principle

Pauli’s exclusion principle: Is this seat taken?

The Pauli Exclusion Principle is the quantum mechanical principle that no two identical fermions (particles with half-integer spin) may occupy the same quantum state simultaneously. A more rigorous statement is that the total wave function for two identical fermions is anti-symmetric with respect to exchange of the particles. The principle was formulated by Austrian physicist Wolfgang Pauli in 1925.


Superconductivity: Resistance is futile

Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in certain materials when cooled below a characteristic critical temperature. It was discovered by Heike Kamerlingh Onnes in Leiden in 1911.

Splitting Atoms

The following is some of the most important physics ideas about Splitting Atoms, including:

  1. Rutherford’s atom: The hard core
  2. Antimatter: Mirror image matter
  3. Nuclear fission: Splitting the atom
  4. Nuclear fusion: Star power
  5. Standard model: All in the family
  6. Feynman diagrams: Three-pronged approach
  7. The God particle: Swimming against the tide
  8. String theory: Universal harmonies

Rutherford’s atom

Rutherford’s atom: The hard core

The Rutherford model or planetary model is a model of the atom devised by Ernest Rutherford which directed the famous Geiger-Marsden experiment in 1909.  It suggested that the so-called "plum pudding model" of J. J. Thomson of the atom was incorrect.


Antimatter: Mirror image matter

Antimatter in particle physics, is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles

Nuclear fission

Antimatter: Mirror image matter

Nuclear fission, in nuclear physics and nuclear chemistry, refers to either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts (lighter nuclei), often producing free neutrons and photons (in the form of gamma rays), and releasing a very large amount of energy, even by the energetic standards of radioactive decay.

Nuclear fusion

Nuclear fission: Splitting the atom

Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release of large quantities of energy. Fusion is the process that powers active stars, the hydrogen bomb and some experimental devices examining fusion power for electrical generation.

Standard model

Standard model: All in the family

The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles. Developed throughout the mid to late 20th century, the current formulation was finalized in the mid 1970s upon experimental confirmation of the existence of quarks. Since then, discoveries of the bottom quark (1977), the top quark (1995) and the tau neutrino (2000) have given further credence to the Standard Model.

Feynman diagrams

Feynman diagrams: Three-pronged approach

The Feynman diagrams are pictorial representations of the mathematical expressions governing the behaviour of subatomic particles. The scheme is named for its inventor, Nobel Prize-winning American physicist Richard Feynman, and was first introduced in 1948.

The God particle

The God particle: Swimming against the tide

The God Particle idea in physics is based on the 1993 popular science book by Nobel Prize-winning physicist Leon M. Lederman and science writer Dick Teresi, known as The God particle: If the Universe Is the Answer, What is the Question?  The book provides a brief history of particle physics, starting with the Pre-Socratic Greek philosopher Democritus, and continuing through Isaac Newton, Roger J. Boscovich, Michael Faraday, and Ernest Rutherford and quantum physics in the 20th century.

String theory

String theory: Universal harmonies

String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything (TOE), a self-contained mathematical model that describes all fundamental forces and forms of matter.

Space and Time

The following is some of the most important physics ideas about Space and Time, including:

  1. Special relativity: Motion is relative
  2. General relativity: Warped space-time
  3. Black holes: Light traps
  4. Olber’s paradox: Our finite universe
  5. Hubble’s law: The expanding universe
  6. The Big Bang: The ultimate explosion
  7. Cosmic inflation: Cosmic growth spurt
  8. Dark matter: Dark side of the universe
  9. Cosmological constant -The fifth force
  10. Fermi paradox:  Is there anybody out there?
  11. Anthropic principle: The just so universe

Special relativity

Special relativity: Motion is relative

Special relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein, after the considerable and independent contributions of Hendrik Lorentz, Henri Poincaré and others in the paper "On the Electrodynamics of Moving Bodies".

General relativity

General relativity: Warped space-time

General relativity, or the general theory of relativity, is the geometric theory of gravitation published by Albert Einstein in 1916 and the current description of gravitation in modern physics.

Black holes

Black holes: Light traps

A black hole is a region of space-time from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform space-time to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return. It is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics

Olber’s paradox

Olber’s paradox: Our finite universe

The Olbers’ paradox, in astrophysics and physical cosmology, named after the German astronomer Heinrich Wilhelm Olbers and also called the "dark night sky paradox", is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. The darkness of the night sky is one of the pieces of evidence for a non-static universe such as the Big Bang model. If the universe is static and populated by an infinite number of stars, any sight line from Earth must end at the (very bright) surface of a star, so the night sky should be completely bright. This contradicts the observed darkness of the night.

Hubble’s law

Hubble’s law: The expanding universe

The Hubble’s law is the name for the astronomical observation in physical cosmology that all objects observed in deep space (interstellar space) are found to have a Doppler shift observable relative velocity to Earth, and to each other; as well as this Doppler-shift-measured velocity, of various galaxies receding from the Earth, is proportional to their distance from the Earth and all other interstellar bodies.

The Big Bang

The Big Bang: The ultimate explosion

The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe.  According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the Universe to cool and resulted in its present continuously expanding state. According to the most recent measurements and observations, the Big Bang occurred approximately 13.75 billion years ago, which is thus considered the age of the Universe.

Cosmic inflation

Cosmic inflation: Cosmic growth spurt

The Cosmic inflation or cosmological inflation, in physical cosmology is the theorized extremely rapid exponential expansion of the early universe by a factor of at least 1078 in volume, driven by a negative-pressure vacuum energy density. 

Dark matter

Dark matter: Dark side of the universe

Dark matter, in astronomy and cosmology, is a currently unknown type of matter hypothesized to account for a large part of the total mass in the universe. Dark matter neither emits nor absorbs light or other electromagnetic radiation, and so cannot be seen directly with telescopes.  Dark matter is estimated to constitute 83% of the matter in the universe and 23% of the mass-energy.

Cosmological constant

Cosmological constant: The fifth force

The cosmological constant, in physical cosmology, was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a stationary universe. Einstein abandoned the concept after the observation of the Hubble redshift indicated that the universe might not be stationary, as he had based his theory on the idea that the universe is unchanging.  However, the discovery of cosmic acceleration in 1998 has renewed interest in a cosmological constant.


Fermi paradox

Fermi paradox:  Is there anybody out there?

The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations.

Anthropic principle

Anthropic principle: The just so universe

The Anthropic principle in astrophysics and cosmology is the philosophical consideration that observations of the physical Universe must be compatible with the conscious life that observes it. Some proponents of the anthropic principle reason that it explains why the Universe has the age and the fundamental physical constants necessary to accommodate conscious life. As a result, they believe that the fact is unremarkable that the universe’s fundamental constants happen to fall within the narrow range thought to be compatible with life.

All lists

The following is the complete list of the world’s most important physics ideas:

  1. Mach’s principle
  2. Newton’s laws of motion
  3. Kepler’s laws
  4. Newton’s laws of gravitation
  5. Conservation of energy
  6. Simple harmonic motion
  7. Hooke’s law
  8. Ideal gas law
  9. Second law of thermodynamics
  10. Absolute zero
  11. Brownian motion
  12. Chaos theory
  13. Bernoulli equation
  14. Newton’s theory of colour
  15. Huygen’s principle
  16. Snell’s law
  17. Bragg’s law
  18. Fraunhofer diffraction
  19. Doppler effect
  20. Ohm’s law
  21. Fleming’s right hand rule
  22. Maxwell’s equations
  23. Planck’s law
  24. Photoelectric effect
  25. Schrodinger’s wave equation
  26. Heisenberg’s uncertainty principle
  27. Copenhagen interpretation
  28. Schrodinger’s cat
  29. The EPR Paradox
  30. Pauli’s exclusion principle
  31. Superconductivity
  32. Rutherford’s atom
  33. Antimatter
  34. Nuclear fission
  35. Nuclear fusion
  36. Standard model
  37. Feynman diagrams
  38. The God particle
  39. String theory
  40. Special relativity
  41. General relativity
  42. Black holes
  43. Olber’s paradox
  44. Hubble’s law
  45. The Big Bang
  46. Cosmic inflation
  47. Dark matter
  48. Cosmological constant
  49. Fermi paradox
  50. Anthropic principle