Quantum Theory
Claimed by Chris Cooper
The Main Idea
Quantum theory is the accepted modern explanation of the observed behaviors of matter based upon atomic energy and particle interactions. After many notable physicists had hypothesized and disproved various theories to describe the structure of the atom, scientists arrived at the Bohr Model, which currently has the most support from other work and theories from quantum mechanics. After the Rutherford's Gold Foil Experiment, the idea came about that the atom actually exists as many particles held together or near each other by electromagnetic force, which is the attraction or repulsion of charged particles, or the strong force, which holds protons and neutrons together at the nucleus of an atom, and that between these particles there is nothing but empty space. Why these particles stay together in certain configurations and their reactions to incidence with energy or other other particles is explained by quantum physics.
History
The theory and all of its applications, much like any other scientific development of the 20th century, comes from contributions of multiple notable scientists over the course of many years. Initially, Newtonian Laws dominated physics, but the atom was represented by the plum pudding model, which developed after the discovery of the electron and the idea that atom must be made from more particles than previously suspected. None of the leading theories at the time, though, could explain electric discharges or the phenomenon of black lines appearing in the spectra from light passed through various materials. Some scientists were unsure of whether electrons existed as particles or if the electrons themselves were the energy and radiation observed from interactions with atoms. One of the earliest elements that lead to the current model was Max Planck's idea that energy could be quantified or defined by smaller units, which he called "quanta". Later, Albert Einstein applied Planck's work to radiation via what is called the photoelectric effect, where he determined that the results of electron particle interaction with incident radiation, not just energy, depended specifically upon the frequency of the radiation. Niels Bohr determined his model of atomic structure in 1913; rejecting that idea that electrons orbiting the nucleus eventually lose energy and fall into the nucleus, he proposed that electrons were held in fixed orbits by electromagnetic forces and that they could shift to other orbits, or other energy levels, by absorption or emission of energy. Werner Heisenberg also suggested that electrons simply could not possibly be defined by an exact location or momentum by physicists, not without applying some radiation incident to the electron and measuring the disturbance of the system in effect- this idea known as the uncertainty principle. All of these ideas come together to form our current understanding of quantum physics, which greatly impacts the practice of modern physics.
Mathematical Application
From the development of the quantum theory, we obtain fundamental equations.
- As Einstein determined, the incident energy that may be absorbed or emitted from electrons (or any particle for this case) depends on the frequency of the radiation:
[math]\displaystyle{ {E = hν} }[/math]
example [math]\displaystyle{ {\frac{d\vec{p}}{dt}}_{system} = \vec{F}_{net} }[/math] where p is the momentum of the system and F is the net force from the surroundings.
A Computational Model
How do we visualize or predict using this topic. Consider embedding some vpython code here Teach hands-on with GlowScript
Examples
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Connectedness
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See also
- Atomic Theory
- Bohr Model
- Electronic Energy Levels and Photons
- Rutherford Experiment and Atomic Collisions
Further reading
Chabay R., Sherwood B. Matter and Interactions. 4th ed. Hoboken, NJ: Wiley, 2015. Print.
External links
Internet resources on this topic
References
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