What is physics
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Abstract
When my daughter Elena was quite young, I remember her inquir i g as to what my profession was. I told her that I was a physicist. Her next q uestion, which, of course, was quite obvious, was, “What does a physicist do?” W ithout hesitation I responded,“Physics.” Her next question was not so easy to answ er. She wanted to know what physics was. Although I do not recollect how I answered h r last question, I suspect I mumbled something about the basic structure of the uni verse, or the laws which govern its behavior, and then quickly changed the subject. T he word physics is derived from the Greek wordφυσις whose translation is nature. Hence, physics is the science of nature. Being a science, physics is, therefore, the metho dology for studying nature. In this context, physics can be considered a tool for solving problems dealing with natural phenomena. I would, however, restrict this interpretation of physics to apply only to problems whose solution, at least in principle, can b e expressed numerically. The use of the word nature in the definition of physics may be co nstrued by some as flagrant since everything that occurs is a natural phenomeno n (otherwise, it would not occur) rendering this definition of physics impractical, si nce it includes all phenomena. In spite of its generality there are problems which appear no t to fall within the scope of the physics methodology, e.g. determining the meaning of li fe.1 Although not applying to all problems, the physics methodology can be applied to so lving a broad spectrum of problems which traditionally have not been considered as phy ics problems. Indeed, physicists study problems in chemistry, biology, economic s and finance, and Complexity, an area of study relevant to a variety of topics ranging f rom the construction of ant hills to the workings of the brain. Throughout my career as a physicist, the types of physics pro blems/research which have piqued my interest have spanned the gamut, ranging from p blems in traditional areas of physics like quantum theory or relativity to non-tr aditional areas like economics, finance, or food science. I would now like to discuss i n ome detail a problem which recently gained my interest. This problem is notewort hy in that it demonstrates how the physics methodology can facilitate solving a proble m whose relationship to physics appears to be weak, at best. My wife decided that she w ould like a lighted walkway, leading from the front porch of our house to the driv eway. Furthermore, she wanted the walkway to be constructed of brick pavers. This pr oject was not the typical project to be undertaken by a homeowner lacking experience w ith projects of this type for a number reasons, including the fact that there were seri ous drainage and erosion problems that needed to be addressed and that the walkway wou ld be nearly 150 feet long. The procedure for constructing such a walkway involves prep aration of the site where the walkway will be located, involving excavation and leveling of the site and attending to any potential drainage problems. Then, a layer of fabric (geotextile) is laid over area where the walkway will be located. Limestone a ggregate, consisting of gravel ranging in size from dust to 3