Ramya Entropy 11


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Student Presentation made for the Sci-Fi course July 11-September 18 (2009) at Srishti School of Art, Design and Technology, Bangalore.

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Ramya Entropy 11

  1. 1. Thermodynamics .Second Law .Entropy
  2. 2. Thermodynamics: I s the branch of physical science that studies of the conversion of energy into work and heat ( and by extension, the interconvertibility of all forms of energy), and its relation to macroscopic values such as temperature and pressure . The central concept of thermodynamics is that of energy, the ability to do work. 4 laws of thermodynamics: The starting point for most thermodynamic considerations are the laws of thermodynamics , which postulate that energy can be exchanged between physical systems as heat or work Entropy : They also postulate the existence of a quantity named entropy, which can be defined for any system Systems and Surroundings: In thermodynamics , interactions between large ensembles of objects are studied and categorized . Central to this are the concepts of system and surroundings
  3. 3. 4 Laws of Thermodynamics There are generally considered to be four principles (referred to as "laws"): 1. The Zeroth law of Thermodynamics , which underlies the definition of temperature. 2. The First law of Thermodynamics , which mandates conservation of energy, and states in particular that heat is a form of energy. 3. The Second law of Thermodynamics , which states that the Entropy of the universe always increases, or (equivalently) that perpetual motion machines are impossible. 4. The Third law of T hermodynamics , which concerns the entropy of an object at absolute zero temperature , and implies that it is impossible to cool a system all the way to exactly absolute zero
  4. 4. Zeroth Law of Thermodynamics: “ If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.” A B C
  5. 5. FIrst Law of Thermodynamics: “ Energy can neither be created nor destroyed. It can only change forms.In any process, the net total energy of the universe remains the same.” For a thermodynamic cycle the net heat supplied to the system equals the net work done by the system .
  6. 6. Second Law of Thermodynamics: “ The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.” . Any system that is not in Equilibrium ,i.e. has not achieved absolute zero temperature, will keep striving towards it
  7. 7. Third Law of Thermodynamics: “ As a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value.”
  8. 8. Systems and surroundings -A thermodynamic system is any part of the universe which is under consideration, in Thermodynamics A system is composed of particles, whose average motions define its properties , which in turn are related to one another through equations of state -A hypothetical boundary separates the system from the rest of the universe, which is referred to as the environment, surroundings, or reservoir Thermodynamic systems are classified on the basis of the nature of their boundaries Isolated - the system can neither exchange energy nor matter with its surroundings Open - the system can exchange both matter and energy with the surroundings Closed - the system can exchange energy , but not matter with its surroundings And the quantities flowing through it, such as matter, energy, work, heat and entropy
  9. 9. Entropy -The concept of thermodynamic entropy is central to the second law of thermodynamics which deals with physical processes and whether they occur spontaneously. -Entropy is defined as the quantity of heat lost due to the work done by a system that is not in equilibrium . -It is a measure of how close a system is to equilibrium or absolute zero . -Or the measure of energy dispersed within/by a system due to work done in order to attain equilibrium . -Traditionally, 20th century textbooks have introduced Entropy as order and disorder so that it provides “ a measurement of the disorder or randomness of a system”.
  10. 10. <ul><li>- These laws (esp. First and second laws of thermodynamics) are some of the most fundamental laws in physics. </li></ul><ul><li>-These Laws are applicable to any systems about which one knows the balance of energy and matter transfer </li></ul><ul><li>-They find a wide variety of applications from Biology , Engineering, Economics to Evolution and Human Behavior, and even Probability. </li></ul><ul><li>Eg: What is Life? is a non-fiction book on science for the lay reader written by physicist Erwin Schrodinger </li></ul><ul><li>Theorized the DNA structure before it was discovered, provided inspiration for research </li></ul><ul><li>The main principle involved with &quot;order-from-disorder&quot; is the </li></ul><ul><li>Second Law of Thermodynamics, according to which entropy only increases. Schrodinger explains that living matter evades the decay to thermodynamic equilibrium by feeding on negative entropy. </li></ul><ul><li>Life is based on a different principle “order form order </li></ul>
  11. 11. <ul><li>Interested in: </li></ul><ul><li>-Change in physical, ecological, energy systems </li></ul><ul><li>How these changes affect human systems </li></ul><ul><li>Basic physics of systems and studying changes that take place in their elements- Thermodynamics </li></ul>