Changes

'''Quantum mechanics''' consists of the breakthrough in [[physics]] in the 1920s in understanding how particles behave inside [[atom]]s.   

'''Quantum mechanics''' consists of the breakthrough in [[physics]] in the 1920s in understanding how particles behave inside [[atom]]s.  Quantum mechanics posits that an [[electron]] (or any other [[sub-atomic particle]]) behaves as both a [[wave]] and a [[particle]]. 

 

 

{{quotebox|the essence of quantum theory is [[energy quantization]]<ref> [http://physicsworld.com/cws/article/print/373 Max Planck: the reluctant revolutionary - physicsworld.com]</ref>}}

{{quotebox|the essence of quantum theory is [[energy quantization]]<ref> [http://physicsworld.com/cws/article/print/373 Max Planck: the reluctant revolutionary - physicsworld.com]</ref>}}

Classical mechanics would predict that an [[electron]] orbits a [[proton]] just as planets orbit the sun.  Classical [[electromagnetism]] would predict that the orbiting electron would emit a time-varying electrical field just as a radio station does.  But the electron would lose energy as it emits this [[radiation]], and would orbit closer and closer to the proton, until it collapses into the proton!  Such a model cannot be correct.

Classical mechanics would predict that an [[electron]] orbits a [[proton]] just as planets orbit the sun.  Classical [[electromagnetism]] would predict that the orbiting electron would emit a time-varying electrical field just as a radio station does.  But the electron would lose energy as it emits this [[radiation]], and would orbit closer and closer to the proton, until it collapses into the proton!  Such a model cannot be correct.

Quantum mechanics posits that an electron (or any other sub-atomic particle) behaves as both a wave and a particle.  As a result of the wave nature of the electron, the position of the electron can never be precisely known.  Whenever it is attempted to be measured, knowledge of the electron's velocity is lost.  Hence, there is an inherent uncertainty that prevents precisely measuring both the position and the momentum simultaneously.  This is known as the [[Heisenberg Uncertainty Principle]].

As a result of the wave nature of the electron, the position of the electron can never be precisely known.  Whenever it is attempted to be measured, knowledge of the electron's velocity is lost.  Hence, there is an inherent uncertainty that prevents precisely measuring both the position and the momentum simultaneously.  This is known as the [[Heisenberg Uncertainty Principle]].

Quantum mechanics forms the basis for our understanding of chemical reactions, as well as all computers and electronic devices today.

Quantum mechanics forms the basis for our understanding of chemical reactions, as well as all computers and electronic devices today.