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Energy/Electrical 2013-204

term / definition or information / examples
energy / ability to make things move or change / sound, light, heat, mechanical energy, and electricity

electrical energy / energy of moving electric charges /
conductor / electrical energy can flow through easily / metals: copper and silver


insulator / electrical energy does not move through easily / nonmetals, wood, plastic, glass

electric current /
  • flow of charged particles
  • present when charges flow through a conductor
  • current must have a pathway (electric circuit) through which it can move
/
electric circuit /
  • closed path through which current, or electricity, can flow
  • consists of an energy source, one or more electrical devices (loads), a way to turn the circuit off and on, and a conductor connecting it all (such as copper wire)
/
series circuits / allows electrons to follow only one path
  • the loads must share the available voltage
  • each load will use up some portion of the voltage, leaving less for the next load in the circuit
  • this means that the light, heat, or sound given off by the device will be reduced
/

parallel circuits / can follow more than one path to return to the source
  • splits up among all available paths
  • voltage is the same across all paths in a parallel circuit
  • each device will produce at full output
/

voltage / electrical energy available for moving a charge
  • batteries—used in wireless devices; changes chemical energy into electrical energy
  • solar cells—some use solar energy; transform sunlight into electrical energy
/
Electrical Power Grids
Example of a path of electricity from a power plantto an appliance in a home—
power plant
generator
step up transformer
transmission lines (pylons)
step down transformer @ substation
distribution lines (down streets)
step down transformer (bucket on pole or underground box)
circuit breaker
junction box
outlet
TV
power grids
  • system of wires, transformers, and other devices that carry electric current from power plants to individual users
  • A grid changes the voltage of the current it carries.
  • use alternating current (AC) in transmission and distribution systems---the voltage can be changed in an alternating current system to transfer energy more efficiently
  • When a business or home uses a wind turbine or solar panels, the extra energy that is created and not being used by the home or business will go out to the rest of the grid to be used by other people.

power generation plants / produce electrical energy from fossil fuels, hydroelectric power, geothermal power, or nuclear power /
generators / machine that changes mechanical energy (moving) into electrical energy (water heated to produce steam; steam turns turbine that spins the generator) /
step-up transformer / increases voltage
makes it easier to transport the electricity over long distances /
step-down transformer / decreases voltage
/
substation /
  • located near to the end-users
  • changes voltage to lower levels for use by end-users (industrial, commercial, and residential customers)
/
transmission lines / carry electric energy from one point to another in the power system /
distribution lines /
  • smaller lines that carry electricity from substations to and throughout neighborhoods
  • underground or on overhead poles
/
circuit breaker / designed to protect anelectrical circuitfrom damage caused byoverloadorshort circuit /
junction box /
  • box (either plastic or metal) used by electricians to join wires together
  • in walls/ceilings
/
outlets /
  • U.S. outlets transmit a charge of 120 volts (AC)
  • AC direction reverses cyclically
  • more efficientto prevent the loss of excess energy
  • electricity passes through hot socket, into hot side of appliance's plug, into appliance, out through appliance’s plug, back into neutral socket
/
meter / measures the amount ofelectric energyconsumed by aresidence,business, or an electrically powered device /
Mississippi Companies
power plants /
  • Grand Gulf Nuclear Power Plant (Port Gibson)
  • Mississippi Power electric plant (Gulfport)--coal
/
businesses /
  • Kuhlman Electric Corporation (CrystalSprings)— major supplier of the transformers for the Mississippi power grid
  • Howard Industries (Laurel and Ellisville)—supplies electrical equipment for the grid
/
Energy Sources
fossil fuels /
  • remains of ancient organisms
  • coal, oil, natural gas
  • nonrenewable
/
nuclear /
  • energy stored in the nucleus of an atom
  • energy released when nuclei join together or split apart
  • ¼ of Mississippi’s electricity---nonrenewable
/
hydroelectric / energy of moving water /
geothermal / heat energy obtained from below the Earth’s surface /
wind / harnessing the wind to produce electricity through windmills /
solar /
  • radiation energy produced by the sun
  • more reaches the equatorial regions rather than the polar regions because those regions receive sun rays closest to vertical
/