You're puzzling about some of the very things that physicists are puzzling about. Understanding the exact mechanisms by which gravity, electromagnetism and other physical phenomena manifest themselves is exactly what physicists try to do. As humans we start from a high level concept or observation (for instance, seeing an apple fall) and slowly work our way to more fundamental understanding by studying the physical phenomena we're interested in (in this case, gravity). Newton took more than a few steps in that direction when he described the physical law of gravitational force. However, for centuries, people like you and me wondered "why? Why this law of gravitation? Where does this come from?". Einstein took a couple of more steps with his enlightening discovery of general relativity. The "why" of Newton's gravity was answered with this new understanding that mass curves spacetime, objects travel on geodesics and the speed of light is the same in to any observer (among other things). But now there are plenty of "why's" associated with Einstein's theory!
As Mike said, "how" and "why" ("describe" vs. "explain") are used interchangeably by physicists. In fact, I would challenge you to find a difference between the two when talking about physical phenomena! Asking "how" a physical phenomenon manifests itself will inevitably lead to a more fundamental understanding of it.
The most rigorous, specific, and efficient way to explain the "how" is through mathematics (pure symbolic logic). The alternative, describing things with words, fails sooner or later. While in many cases describing physical concepts with words can be extremely helpful (since for most people it provides for a better intuitive
understanding about the topic at hand), it will always be subject to the ambiguity of the language and many times will produce only partially accurate analogies. In short, there is no perfect
way to describe things with words. Mathematics, on the other hand, allows us to be precise
In fact, you can think of mathematics as being analogous to a language like English. The reason we usually prefer things to be explained with words is because our language is, to us, the most familiar
way to communicate ideas. While Mathematics might seem like an unfamiliar foreign language at times, it is by definition the most precise
way to communicate ideas.
You asked a few specific questions about magnetism and what exactly force means. Let's start with magnetism:
"What is magnetism actually pushing and pulling?" A magnetic field exerts a force on moving electric charges. If you think of a loop of wire with a current running through it, the magnetic field exerts a force on the moving charges in the loop in a direction perpendicular to the path of the current. You also brought up a "hose" analogy for the magnetic field. Your understandable question can really be translated to this: "what exactly is
a magnetic field made of
?" The answer to that question was given a few years ago on this site. You can see the explanation here: What are magnetic fields made of?
And last but not least, you asked the question "what is force?"
Force is a more general term which describes something that changes an object's momentum. The physical quantity is measured by that change in momentum divided by the time it took to occur. So, kind of like how speed measures the change in distance over time, force measures the change in momentum over time.
I hope that satisfies at least some of your curiosities. Feel free to prod us with more questions!
I'll take a crack at this too, in parallel with John's answer, since these philosophy issues aren't cut-and-dried. We seem to accept certain types of interactions (strings pulling, hands pushing,...) without much trouble. These are interactions where the visible objects involved touch, i.e. they are too close for us to see any gap. This feeling is captured in your language: "tiny invisible strings....running into things..." Probably we have some evolved sense of expecting interactions of that sort.
When you think enough about it, though, such interactions are no more or less mysterious or explained than other interactions, such as between the earth and moon or between two magnets. On a small enough scale, all of our descriptions turn into patterns of mathematical fields filling space- even those strings, and hands, etc. So our role here is in one way like what you're looking for- to eliminate the dualism between the familiar contact forces and the more abstract field-based forces. Unfortunately it's by converting the former into the latter, not vice-versa.
(published on 04/21/11)