The Case for ScienceFor the scientist (or aspiring scientist), the question of why to study science doesn't need to be answered. If you're one of the people who get science, then no explanation is required. Chances are that you already have at least some of the scientific skills necessary to pursue such a career, and the whole point of study is to gain the skills which you don't yet have.
However, for those who are not pursuing a career in the sciences, or in technology, it can frequently feel as if science courses of any stripe are a waste of your time. Courses in the physical sciences, especially, tend to be avoided at all cost, with courses in biology taking their place to fill necessary science requirements.
The argument in favor of "scientific literacy" is amply made in James Trefil's 2007 book Why Science?, focusing on arguments from civics, aesthetics, and culture to explain why a very basic understanding of scientific concepts is necessary for the non-scientist.
The benefits of a scientific education can be clearly seen in this description of science by famed quantum physicist Richard Feynman:
Science is a way to teach how something gets to be known, what is not known, to what extent things are known (for nothing is known absolutely), how to handle doubt and uncertainty, what the rules of evidence are, how to think about things so that judgments can be made, how to distinguish truth from fraud, and from show.
The question then becomes (assuming you agree with the merits of the above way of thinking) how this form of scientific thinking can be imparted upon the population. Specifically, Trefil presents a set of grand ideas that could be used to form the basis of this scientific literacy ... many of which are firmly rooted concepts of physics.
The Case for PhysicsTrefil refers to the "physics first" approach presented by 1988 Nobel Laureate Leon Lederman in his Chicago-based educational reforms. Trefil's analysis is that this method is especially useful for older (i.e. high school age) students, while he believes the more traditional biology first curriculum is appropriate for younger (elementary & middle school) students.
In short, this approach emphasizes the idea that physics is the most fundamental of sciences. Chemistry is applied physics, after all, and biology (in it's modern form, at least) is basically applied chemistry. You can of course extend beyond that into more specific fields ... zoology, ecology, & genetics are all further applications of biology, for example.
But the point is that all of science can, in principle, be reduced down to fundamental physics concepts such as thermodynamics and nuclear physics. In fact, this is how physics developed historically: basic principles of physics were determined by Galileo while biology still consisted of various theories of spontaneous generation, after all.
Therefore, grounding a scientific education in physics makes perfect sense, because it is the foundation of science. From physics, you can expand naturally into the more specialized applications, going from thermodynamics & nuclear physics into chemistry, for example, and from mechanics & material physics principles into engineering.
The path cannot be followed smoothly in reverse, going from a knowledge of ecology into a knowledge of biology into a knowledge of chemistry and so on. The smaller the sub-category of knowledge you have, the less it can be generalized. The more general the knowledge, the more it can be applied to specific situations. As such, the fundamental knowledge of physics would be the most useful scientific knowledge, if someone had to pick which areas to study.
And all of this makes sense, because physics is the study of matter, energy, space and time, without which there would be nothing in existence to react or thrive or live or die. The entire universe is built upon of the principles revealed by a study of physics.
Why Scientists Need Non-Science EducationWhile on the subject of well rounded education, I suppose I should also point out that the opposite argument holds just as strongly: someone who is studying science needs to be able to function in society, and this involves understanding the entire culture (not just the techno-culture) involved. The beauty of Euclidean geometry is not inherently more beautiful than the words of Shakespeare ... it's just beautiful in a different way.
In my experience, scientists (and physicists especially) tend to be fairly well rounded in their interests. The classic example is the violin-playing virtuoso of physics, Albert Einstein. One of the few exceptions is perhaps medical students, who lack diversity more due to time constraints than lack of interest.
A firm grasp of science, without any grounding in the rest of the world, provides little understanding of the world, let alone appreciation for it. Political or cultural issues do not take case in some sort of scientific vacuum, where historical & cultural issues need not be taken into account.
While I've known many scientists who feel that they can objectively evaluate the world in a rational, scientific manner, the fact is that important issues in society never involve purely scientific questions. The Manhattan Project, for example, was not purely a scientific enterprise, but also clearly triggered questions that extend far outside of the realm of physics.