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The Nature of Energy

The Nature of Energy. Benchmarks. Standard III: Physical Sciences E. Demonstrate that energy can be considered to be either kinetic (motion) or potential (stored). F. Explain how energy may change form of be redistributed but the total quantity of energy is conserved.

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The Nature of Energy

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  1. The Nature of Energy

  2. Benchmarks Standard III: Physical Sciences E. Demonstrate that energy can be considered to be either kinetic (motion) or potential (stored). F. Explain how energy may change form of be redistributed but the total quantity of energy is conserved. G. Demonstrate that waves have energy and waves can transfer energy when they interact with matter. H. Trace the historical development of scientific theories and ideas, and describe emerging issues in the study of physical sciences.

  3. What is Energy? • Energy - ability to do work • Work - force moves an object a distance W = Fd units are Joules ( J ) for energy units for force are Newtons ( N ) units for distance are meters ( m ) *** A Joule can also be considered a “Nm” -Complete Calculating Work Practice sheet

  4. States of Energy • Potential Energy - stored energy, based on position of chemical composition Gravitational Potential Energy GPE = mass x gravity x height GPE = mgh --> units Joules m=mass (g) g=gravity (9.8 m/s2) h=height (m) • A 50kg rock is on the edge of a 20m cliff, what is its GPE? GPE = m x g x h = 50kg x 9.8m/s2 x 20m = 9800J

  5. States of Energy the Sequel • Kinetic Energy - energy of motion, based on mass and velocity of object Kinetic Energy KE = 1/2 mv2 --> units Joules m=mass (g) v=velocity (m/s) • A 1000kg car is traveling 40m/s, what is its KE? KE = 1/2mv2 = 1/2 x 100kg x (40m/s)2 = 1/2 x 100kg x 1600m2/s2 = 80,000J -Complete Calculating Power and Potential/Kinetic Energy worksheets

  6. Forms of Energy Six Forms of Energy • Mechanical - moving objects perform work Ex: wheels turning, hammer hitting a nail, sound • Chemical - energy stored in the molecules of substances Ex: coal, oil, nature gas, food • Nuclear Energy - stored in nucleus of atom Ex: Uranium used for fission

  7. Forms of Energy Six Forms of Energy 4. Heat - energy caused by molecular motion Ex: Rubbing hands together, lighting a match 5. Electrical - flow of electrons through a conductor Ex: computers, televisions, generators 6. Light - radiant energy that moves in waves Ex: sun, light bulbs, electromagnetic energy

  8. Conservation of Energy and Matter The Law of Conservation of Energy energy can be neither created nor destroyed, only transformed The Law of Conservation of Matter matter can be neither created nor destroyed, only rearranged *The total amount of matter and energy in the always remains constant in the universe

  9. Types of Energy • RENEWABLE • Solar – energy harnessed from the sun • Hydroelectric– energy harnessed from the Potential energy of water • Biomass– energy harnessed agricultural and animal waste products • Wind– energy harnessed from the wind • Geothermal– energy harnessed from heat under earth’s crust • http://library.thinkquest.org/20331/types/

  10. NONRENEWABLE • Fossil fuels: energy from natural gas, petroleum and coal • Nuclear: energy from fission and fusion • What are the advantages and disadvantages of each? • Energy brochure: what type of energy do you think Ohio should consider to help our energy demands and decrease our dependence on coal. http://www.puco.ohio.gov/puco/index.cfm/consumer-information/consumer-topics/where-does-ohioe28099s-electricity-come-from/

  11. Energy Transformations • Energy can transform from one form to another • Ex: A black car absorbs light energy from the sun and transforms it to heat energy to warm up the car • ***During many energy transformations heat is produced as an unwanted product • Ex: Motors loose a great deal of energy to unwanted heat energy -%efficiency worksheet

  12. Nuclear Energy • The three categories of forces are: • Gravitational Forces • Electromagnetic Forces • Nuclear Forces 1. Strong Force 2. Weak Force *Nuclear forces are the strongest types

  13. Fission • Fission is the process of splitting the nucleus of an atom into two lighter weight nuclei producing large amounts of energy • Bombarding Ur-235 or Pu with a neutron causes it to split into Kr and Ba, and continues as a chain reaction • Used in nuclear power plants and weapons • Produces nuclear waste

  14. Fusion • Fusion is the process of combining two or more lighter weight nuclei to form a heavier nucleus releasing large amounts of energy • Hydrogen isotopes are converted to Helium under extreme temperatures • Does not produce waste products, has abundant resources (Hydrogen), and is safer than fission

  15. Nuclear Reactor • Nuclear reactors control the fission process by using the heat produced to produce steam that turns a turbine to produce electricity • The moderator and control rods slow the speed of the fission reaction by absorbing neutrons • There is lead shielding around the core to protect against radiation

  16. Nuclear Incidents • Meltdowns: • Chernobyl in Russia • Recent Tsunami in Japan Partial Meltdowns: -3 mile Island (1979, Harrisburg, Pa) -experimental partial meltdowns: Fermi 1 (1966), Borax-1 (1954)

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