chapter 1 - 1.1 Introduction Energy and Society When...

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1.1 Introduction Energy and Society When thinking about energy the following questions may come to your mind: > What is energy? > How do we measure it? > Where is it coming from? > Do we have enough? > What is the impact of energy use ? Energy is the life blood of any modern society. Energy is used in every walk of life. Without it, modern life would almost come to a standstill. From the moment of waking up in the morning by an alarm clock, we use energy for almost everything we do. What is Energy? Energy is a property of matter that can be converted to work, heat or radiation. 1.2 Forms of Energy Six Basic Forms Energy exists in a number of different forms, all of which measure the ability of an object or system to do work on another object or system. There are six different basic forms in which we use energy in our day to day life: 1a: Mechanical Energy (Kinetic) Energy that a body possesses by virtue of its motion. Examples: A baseball player pitching a ball, a plow being pulled by a tractor, a hammer that is being used to pound nails. In the United States we use about a third of our total energy for transportation or movement of people and goods. 1b. Mechanical Energy (Potential) Energy that a body possesses by virtue of its position relative to a reference point. Examples: A pendulum, bow (archery), spring, hammer that is raised in preparation to pound nails. 2. Chemical Energy Energy locked in the bonds of molecules in the form of microscopic potential energy, which exists because of the electric and magnetic forces of attraction exerted between the different parts of each molecule: ›It is the same attractive force involved in thermal vibrations
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›The molecular parts get rearranged in the chemical reactions, releasing or adding to this potential energy •Examples: Battery, burning wood, glucose in the body •Approximately 85% of the energy used in the U.S. comes from fossil fuels such as coal, oil and natural gas ›All of these fuels store energy in the form of chemical energy ›When they are burnt, these fuels release energy in the form of heat or thermal energy 3. Thermal or Heat Energy: •Energy that combines microscopic, kinetic and potential energy of the molecules. •Example: A hot beverage or boiling water. •Temperature is really a measure of how much thermal energy something has: The higher the temperature, the faster the molecules are moving around and/or vibrating, i.e. the more kinetic and potential energy the molecules have. •Fuels (chemical energy) are oftentimes burnt and converted to thermal or heat energy, which is then converted to motion in an automobile or electricity. 4. Electrical Energy: •Energy created through the movement of electrons among the atoms of matter. •Examples: Although electricity is seldom used directly, it is one of the most useful and
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This note was uploaded on 09/02/2008 for the course EGEE 102 taught by Professor Pisupati,sarmave during the Fall '07 term at Pennsylvania State University, University Park.

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chapter 1 - 1.1 Introduction Energy and Society When...

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