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NS1300 – Emergence of Modern Science Energy and Thermodynamics. Where does our energy come from, and will there be enough in the future?. Chapter 3 – Energy. Mechanical Energy Thermal Energy Chemical Energy Electromagnetic Energy Entropy. Law of Conservation of Energy.
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NS1300 – Emergence of Modern ScienceEnergy and Thermodynamics
Where does our energy come from, and will there be enough in the future?
Chapter 3 – Energy • Mechanical Energy • Thermal Energy • Chemical Energy • Electromagnetic Energy • Entropy
Law of Conservation of Energy • Energy is Neither Created nor Destroyed • Enthalpy: H = U + pV • H is the enthalpy • U is the internal energy • p is the pressure of the system • V is the volume • Entropy: S = k log W • W is the number of microstates corresponding to a given macrostate • K is Boltzmann’s Constant • Open Systems and Closed Systems • The Universe is the Only Closed System in Nature
Energy Conversion • Any form of energy can be transformed into any other form • Energy is the Ability to Do Work
Work • Work = Force X Distance (W = Fd) • Simple Machines
Mechanical Energy • Potential Energy • PE = -G(m1m2/R) • Kinetic Energy • E = 1/2mv2
Thermal Energy • Thermal Energy • Heat • Temperature • Calories
Thermodynamics • Thermal Energy • The internal energy of a system associated with kinetic energies of the molecules: • molecular translation, • rotation, and • vibration • electron translation and spin • nuclear spin • and the phase of the system.
Heat and Temperature • Specific Heat • Latent Heat • Molecular Kinetic Energy • Temperature Scales • Fahrenheit • Celsius • Kelvin • Absolute Zero
Flow of Heat • Radiation • Conduction • Convection
Heat Budgets Heat Budget of the Atmosphere and Ocean: QT = QSW + QLW + QS + QL + QV Thermoregulation
The 1st law of Thermodynamics • The increase in the internal energy of a thermodynamic system is equal to the amount of heat energy added to the system minus the work done by the system on the surroundings. • Heat is a process by which energy is added to a system or lost to a sink. • Energy is lost to a system by doing mechanical work. • Energy is always conserved between a system and its surroundings.
Efficiency • Engines • Systems • Organisms
The 2nd Law of Thermodynamics • In an isolated system, a process can occur only if it increases the total entropy of the system. • Heat cannot spontaneously flow from a material at lower temperature to a material at higher temperature. • It is impossible to convert heat completely into work.
Applications of Entropy • Engineering • Mechanical • Chemical • Electrical • Biology • The Environment
Misconceptions About Entropy • Perpetual Motion • Free Point Energy • Complexity
Chemical Energy • Oxidation – Reduction • Photosynthesis • Respiration • Burning • Rusting
Trophic Levels • Producers • Photosynthesis • Chemosynthesis • Consumers • Grazers • Predators • Parasites • Decomposers • Saprophytes
Electromagnetic Energy • E = mc2
The Photon • Particle – Wave Duality • Photoelectric Effect • Induction
Power • Power = Work / Time (P = W/t)
Power Sources • Solar • Fossil Fuels • Electricity • Batteries
Future Energy Sources • Wind • Geothermal • Nuclear • Biofuels • Hydrogen
Zero Point Energy – An Alternative Energy Resource? • Zero Point Energy • Tachyons? • Zero Point Energy Generators? • Pseudoscience?
Quiz • 1. T or F, energy is the ability to do work. • 2. T or F, any form of energy can be converted to any other form of energy. • 3. Simple machines make work easier, but less efficient. Name a simple machine. • 4. T or F, photons can cause electrons to flow through a circuit. • 5. T or F, zero-point energy is a viable alternative source of energy for the future.