Re: How is an electon knocked out of its orbit in the first place?

The conduction of electric currents in solid substances is made possible 
by the presence of free electrons (electrons that are free to move about). 
Most of the electrons in a bar of copper, for example, are tightly bound 
to individual copper atoms. However, some are free to move from atom to 
atom, enabling current to flow. Ordinarily the motion of the free 
electrons is random; that is, as many of them are moving in one direction 
as in another. However, if a voltage is applied to the two ends of a 
copper bar the “potential difference” provides the energy required to move 
these electrons in a coherent direction. That is the function of a battery 
or other source of electric current: to maintain potential difference. A 
battery or other potential difference sources do this by supplying 
electrons to the negative end of the bar to replace those that drift to 
the positive end and also by absorbing electrons at the positive end. The 
higher the potential difference, the more electrons move 
creating “friction” and thereby increasing the heat. Heat can also be 
generated by lower potential sources that have low “characteristic” 
impedance. In other words, sources with ample supply and sink of free 
electrons.
Insulators cannot conduct electric currents because all their electrons 
are tightly bound to their atoms. A perfect insulator would allow no 
charge to be forced through it, but no such substance is known at room 
temperature. The best insulators offer high but not infinite resistance at 
room temperature. Some substances that ordinarily have no free electrons, 
such as silicon and germanium, can conduct electric currents when small 
amounts of certain impurities are added to them. Such substances are 
called semiconductors. Semiconductors generally have a higher resistance 
to the flow of current than does a conductor, such as copper, but a lower 
resistance than an insulator, such as glass.

Particle physics is the study of tightly held electrons that can get 
knocked in-out orbits as the result of energy exchange. Although this 
realm of physics dabbles with things unseen and many times unobservable, 
it points-out that the universe as we see it likely has many, many 
more “dimensions” to which we have no access. Point your Internet browser 
to: http://wwwpdg.cern.ch/pdg/cpep/adventure_home.html

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