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*the strong force
*the strong force
The electric and magnetic forces were once considered to be separate, but they were unified so straightforwardly in the late 19<sup>th</sup> century that they are no longer treated as separate. The electromagnetic and weak forces were unified in the late 1960's, into the "electroweak force", but that connection is sufficiently esoteric that it has not supplanted the separate electromagnetic and weak forces. There are "grand unified theories" unifying the last three of these forces, and the physics community continues to search for a "theory of everything" that brings gravity into the picture. For all practical purposes, the four forces listed above are generally considered the fundamental forces.
The electric and magnetic forces were once considered to be separate, but they were unified so straightforwardly in the late 19th century that they are no longer treated as separate. The electromagnetic and weak forces were unified in the late 1960s, into the "electroweak force", but that connection is sufficiently esoteric that it has not supplanted the separate electromagnetic and weak forces. There are "grand unified theories" unifying the last three of these forces, and the physics community continues to search for a "theory of everything" that brings gravity into the picture. For all practical purposes, the four forces listed above are generally considered the fundamental forces.
The first two of these forces are well known without specialized knowledge of nuclear physics, mostly because they operate at macroscopic distances. The last two only operate at microscopic distances (about 10<sup>-15</sup> meters, or the diameter of a proton), so they are limited to subatomic particles.
The first two of these forces are well known without specialized knowledge of nuclear physics, mostly because they operate at macroscopic distances. The last two only operate at microscopic distances (about 10<sup>−15</sup> meters, or the diameter of a proton), so they are limited to subatomic particles.
*Q: Why are they called "forces"? What is doing the pushing?
*Q: Why are they called "forces"? What is doing the pushing?
==Given that something can happen, how often does it happen?==
==Given that something can happen, how often does it happen?==
The probability, per unit time, of a beta transformation happening, varies enormously, and determines the substance's half-life. This probability is determined by how "close" the particles get to each other. They must be extremely close—the weak force is weak, and only acts over a distance of about the size of a nucleon, or 10<sup>-15</sup> meter. This distance is measured in terms of the size of the [[quantum mechanics|quantum mechanical wave function]]. It can actually be quite large (compared with the size of a nucleon) in electron capture, because electrons typically have a rather dispersed wave function.
The probability, per unit time, of a beta transformation happening, varies enormously, and determines the substance's half-life. This probability is determined by how "close" the particles get to each other. They must be extremely close—the weak force is weak, and only acts over a distance of about the size of a nucleon, or 10<sup>−15</sup> meter. This distance is measured in terms of the size of the [[quantum mechanics|quantum mechanical wave function]]. It can actually be quite large (compared with the size of a nucleon) in electron capture, because electrons typically have a rather dispersed wave function.
*Q: How about neutron decay? How can the closeness of approach be theorized for a single particle?
*Q: How about neutron decay? How can the closeness of approach be theorized for a single particle?