Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

10 Major Mistakes in Physics !


Published on

The very basic and the most interesting mistakes we are prone to commit when it comes to Physics. From Quantum Mechanics to Gravity, we can be in slippery soil. I have been there, and I want to share a few ideas.

I have tried to keep them very logical and simpler and I hope I get my point across. If any mistakes you spot, direct them back at me. Good riddance.

Published in: Science
  • Be the first to comment

10 Major Mistakes in Physics !

  1. 1. “Which phrases not to say in Physics”
  2. 2.  Example 1; “Particles that have zero rest mass”  Example 2; “Photons are particles having zero rest mass”  Example 3; “Electrons don’t have zero rest mass but photons do”  Reason; such wording are inconsistent with Reality, Physics Theory !  No entity in the Universe has a “zero rest mass” Not electrons, not photons.  Fact 1; Particles can only have “non-zero” rest mass, these are particles that will never have zero mass in any frame. Eg electrons.  Fact 2; Particles that have “zero” mass will have so in all frames of references, but rest does not make sense for them, there are no rest frames for them and no rest mass, Eg photons. Zero-rest-mass means [m = 0 and v = 0] such a situation can never arise.
  3. 3.  Example 1; “There are 2 types elctric charges, positive and negative” [yes there are]  Example 2; “An object is neutral; because equal & oposite electric charges cancel each other” [its true]  Reason; But such wordings can be misleading and incomplete towards reality !  Fact 1; There are 3 types of electric charges, positive, negative and neutral. [and not just two]  Fact 2; Neutral charges are not only produced if equal and opposite charges are present,  but also physically there are neutral charges, they are electrically neutral, independent of other type of charges. Neutrino, and photons are examples of neutral charges, independent of other two types.
  4. 4.  Example 1; “Atomic bombs are based on equivalence of energy E and mass m” [Yes they are]  Example 2; “When energy vanishes an equal amount of mass must be prduced” or “when mass disappears equal amount of energy must be replaced” [tricky] Or “Energy is equivalent to mass so photons have effective mass” [X]  Reason; such wordings can be tricky, misleading and incomplete, inconsistent or incorrect, with reality ! They sound innocent until misused in actual calculations.  Fact 1; Energy is equivalent to mass, only if; there is mass to begin with. is not valid for photons. Such energy does not have an associated mass, only momenta;  Fact 2; For other types, the matter particles; part of the energy is equivalent to mass and part of it is equivalent to momenta, and momenta can be independent of mass, eg for waves; In general energy is equivalent to both mass and momenta at the same time, in special case of photons; energy is equivalent to momenta only, but in other special cases, energy released can be equivalent to mass only, differences between initial and final configurations masses can release equivalent energy. 2 mcE  2242 cpcmE  pcE 
  5. 5.  Example 1; “The rules of Quantum Mechanics are valid at the small scale only” [X]  Example 2; “Quantum Mechanics would not be valid at the scale of our day to day world” [X] or “error of Quantum Mechnaics are always small at the scale of large objects” [X]  Reason; such reasoning are ill founded, misleading and incomplete, inconsistent or incorrect, with reality !  Fact 1; Most of the processes are actually semi-classical in nature. That means they are semi quantum mechanical as well.  Fact 2; Biological and Chemical scales are almost always quantum mechanical, for their precise understanding, DNA, molecules, enzymes you name it, whether or not we understand them, are not classical structures, if they were we would already understand them. No purely classical system, either purely quantum system or semi-classical semi-quantum system. Explains thermodynamics, photography, cosmological processes, effects scale up due to correspondence principle. Also semi classical pictures/models work for that reason. Eg Hydrogen atom.
  6. 6.  Example 1; “Nothing moves faster than light” [tricky]  Example 2; “Nothing surpasses the speed of light, there is a limit on the speed at which objects or information can be passed” [true but tricky]  Reason; such reasoning can be misleading and/or fairly complicated, inconsistent or incorrect, with reality !  Fact 1; Its not light its photons and only a single photon in vacuum which has this privilege. We better use “Physically nothing moves faster than speed-of- light” Light itself is complicated.  Fact 2; Light always means a classical Maxwellian wave of electric and magnetic fields that move at the speed-of- light in vacuum, an empirical constant.  Fact 3; Only a single photon in vacuum, moves at the speed of light of Maxwell waves. More photons, the property of zero invariant mass is changed, and if they are not in vacuum further obstacles can reduce it.  Fact 4; Group velocity and phase velocity are different and bring further complicacy. Only in very restricted sense Light moves at a speed that nothing can surpass.
  7. 7.  Example 1; “Gravity is not responsible for people falling in love. [unless as a dramatic license in a movie]  Example 2; “Gravity is responsible for things falling” [incorrect]  Reason; such (Ex. 2) reasoning can be misleading and physically inappropriate with reality !  Fact 1; Its not gravity which makes things fall. It just makes them fall faster.  Fact 2; Things fall at the same rate irrespective of their masses. But gravity makes different masses fall as faster as each other.  Fact 3; In Physics fast means speed, but faster means acceleration and gravity is the same amount of acceleration for all masses under same condition. Objects always fall faster, and not just fall, due to gravity, they do not fall due to gravity though.
  8. 8.  Example 1; “Satellites are in freefall around gravitational objects whose orbit they are traversing” [misleading and a misnomer]  Example 2; “Objects in freefall are weightless”  Reason; such (Ex. 1 and 2) phrases can be misleading and confusing !  Fact 1; Satellites are not in freefall around gravitational objects, they are under gravitational freefall  Fact 2; Free Particles in Physics means free from forces. Potential Energy is zero. Forces are absent.  Fact 3; Freefall on the other hand means free from forces except the gravitational forces. Freefall actually means “gravitational freefall”. The objects are falling under the influence of gravity and not on their own accord, Pot. energy is not zero.
  9. 9.  Example 1; “Gravity attracts light as light has effective mass” [X]  Example 2; “Gravity attracts light as energy is equivalent to mass and light has energy and thus effective mass” [ again incorrect, see slide 3]  Reason; such reasoning of a phenomenon also known as Gravitational Lensing, are poor understanding of basic Physics, can be highly misleading and physically inappropriate !  Fact 1; Such fallacious reasoning develops from mixing the old classical theory of gravity which is based on masses of objects and the new classical theory of Einstein known as General Relatvity as applied to gravity.  Fact 2; The deflection of light is twice that of the ratio of Schwarzschilds radius of gravitational objects and distance of radiation from such objects.  Fact 3; It is simply due to –ve potential energy requirement, light loses some of its energy and can’t travel straight. Gravity being an attraction between masses leads to falsity light has mass. See Gravity as a negative potential energy of “Light with energy” & any Mass
  10. 10.  Example 1; “Quantum Mechanics means wave particle duality so no more waves and no more particles” [bad understanding]  Example 2; “Quantum Mechanics means wave particle duality so wave and particle properties are to be shown by objects at the same time, they are kind of new entities now” [X]  Reason; such reasoning of a phenomenon also known as Wave Particle duality, are poor understanding of the philosophies of Physics, can be highly misleading and physically inappropriate !  Fact 1; Wave Particle duality simply says now the same object will show wave properties in some situations and particle properties in others, never together. This is known as complimentarity principle, wave and particle proeprties are merely exclusively complimentary.  Fact 2; In some situations wave property are dominant, in some situations only particle properties are dominant. Almost ideal waves and almost ideal particles are possible. Basically rest mass of particles being very small bring wave property to such particles with mass. More than deBroglie wavelength or momentum, rest mass of matter particles carry sign of their wave propeties. Very massive means less wave behavior
  11. 11.  What would be the last inconsistency in this list?  I could not find one for now. But given the flow of arguments there would be tons of others.  Why not find one more? Its so interesting.  If you find one contact me  I also write at  Other slideshares here are interesting. Some are highly technical, some are not, if you find any idea not so comprehensible, send an email or drop a comment. Take it as a fun thing to do; and discuss and find one for yourself !