What is a simple definition of the laws of thermodynamics ..., Slides of Thermodynamics

Download What is a simple definition of the laws of thermodynamics ... and more Slides Thermodynamics in PDF only on Docsity! Question: What is a simple definition of the laws of thermodynamics? Thermodynamics is the study of the inter-relation between heat, work and internal energy of a system. The British scientist and author C.P. Snow had an excellent way of remembering the three laws: 1 You cannot win (that is, you cannot get something for nothing, because matter and energy are conserved). 2 You cannot break even (you cannot return to the same energy state, because there is always an increase in disorder; entropy always increases). 3 You cannot get out of the game (because absolute zero is unattainable). Answered by: Dan Summons, Physics Undergrad Student, UOS, SouhamptonIn simplest terms, the Laws of Thermodynamics dictate the specifics for the movement of heat and work. Basically, the First Law of Thermodynamics is a statement of the conservation of energy - the Second Law is a statement about the direction of that conservation - and the Third Law is a statement about reaching Absolute Zero (0� K). However, since their conception, these laws have become some of the most important laws of all science - and are often associated with concepts far beyond what is directly stated in the wording. To give you a better understanding on how these laws came about and their modern scope of coverage, you have to understand when and why these laws were generated. Our story begins back in the mid-seventeenth century. Society prior to the eighteenth century favored developments in the life sciences (largely for medical research) and astronomy (for navigation and a record of the passage of time - also a source for early mythology and folklore). Science was viewed as purely a philosophic endeavor, where little research was conducted beyond the most useful fields. Indeed, philosophy and science were inseparable in several emerging disciplines (this is always true of new fields where no firm basis of study has yet been conducted). However, European society was about to experience unforeseeable rapid changes. Prior to the mid-eighteenth century, the general European populace randomly dotted the land in small agricultural communities, industry was run out of country cottages, and scientific developments were nearly at a standstill. Suddenly, without much of a transition, new pockets of industry arose, focusing towards large-scaled machines rather than small hand tools; large industrial corporations often crushed small agriculturally centered commerce; and in many areas, city life rendered country farm cottages obsolete. Coinciding with an era of vast social and political changes, this historic event would later come to be called the Industrial Revolution. If necessity were the mother of all innovation, then the Industrial Revolution would be the mother of all necessities. Horrible living conditions in the overcrowded industrial cities bred a plethora of diseases and viruses. This along with other results of spontaneous urbanization demanded science again to address the problems of an ever- changing human civilization. Science of the Industrial Age responded to such needs by centering on medical advances in the early stages of the revolution. Such was the era of crucial medical breakthroughs, and age of greatest physiologists - such as Marie Curie (radium), Wilhelm Roentgen (x- rays), Louis Pasteur (pasteurization), Edward Jenner (smallpox vaccination), Joseph Lister (bacteria antiseptic), and Charles Darwin (evolution). Once the medical crisis was rectified, science could concentrate on the heart of an industrial society - large-scaled machinery. True of nineteenth century mass industry, the company with the greatest machines produced more products, made more money, and was consequently more successful. It is natural, therefore, that fierce competition arose to find the most industrious machinery possible, and how far the limits of these machines could be pushed as to achieve maximum productivity (without consuming much energy). Again, society would fuel scientific advancement. Nineteenth century scientists were encouraged to study the machine, and its efficiency. To do this, physicists analyzed the flow of heat in these machines, and the chemical changes that transpire when they perform work. Thus was the establishment of modern thermodynamics. First on the agenda of this new discipline was to find a means convert heat (as produced by machines) into work with full efficiency. If such a flawless conversion could be accomplished, a machine could run off its own heat, producing a never-ending cycle of heat to work, rendering heat, converting to work, and so forth ad infinitum� The idea of such a machine that could run continuously off its own exhaust, or 'perpetual-motion' machine as it was dubbed, excited the industrial corporations, who contributed much funding for its development. However, as the research was completed, the results were all but pleasing to the sponsors. As it turned out, the very same research oriented to create a perpetual-motion machine proved that the very concept is not possible. The proof lies in two theories (now three) that are currently considered the most important laws in the whole body of science - the First and Second Laws of Thermodynamics. The First Law of Thermodynamics is really a prelude to the second. It states that the total energy output (as that produced by a machine) is equal to the amount of heat supplied. Generally, energy can neither be created nor destroyed, so the sum of mass and energy is always conserved. A mathematical approach to this law produced the equation U = Q - W (the change in the internal energy of a closed system equals the heat added to the system minus the work done by the system). By its nature, this finding did