Transcript Simple Machines

Electricity & Magnetism
at Work
Generating Electric Energy
Chapter 3
Section 2
Electromagnetic Induction
• An electric current will
be produced in a
conductor when the
conductor moves
across the lines of a
magnetic field
AC/DC
• The flow of the induced current may be
constant (direct), or it may change
directions (alternating).
Alternating Current
• From power plant
• A current consisting of
charges that move
back and forth
Direct Current
• Battery
• Electrons move away
from one end of the
battery and into the
other end
Generators
• Uses motion to
produce an electric
current
• A motor… run
backwards
Turbines
• Flowing water from a
dam, wind, steam
from the burning of
fuels, and even the
ocean’s tides can be
used to turn turbines
Generating Electricity
• Coal
– 56.5%
• Nuclear
– 21.9%
• Hydroelectric
– 10.7%
• Natural Gas
– 8.5%
• Petroleum
– 2.2%
• Other
– 0.2%
Renewable Resources
• Can be replaced in
nature at a rate close
to the rate at which it
is used.
Nonrenewable Resources
• Exists in a
fixed/limited amount
• Fossil Fuels
Coal
• Moderate Cost
• Large Supply
• Damage from mining
• Air Pollution (Sulfur)
Oil
• Moderate cost
• Adequate supply
• Oil Spills
Natural Gas
• Moderate cost
• Adequate supply
Nuclear Power
• No air pollution
• Expensive set-up
• Radioactive waste
• Terrorist target
Hydroelectricity
• Low costs
• No waste
• Dam able rivers are rare
• Disturbs wildlife
Wind
• Moderate cost
• No wastes
• Inexhaustible supply
• Winds are variable
• Wind farms require
large areas of land
Sun
• No waste
• Inexhaustible supply
• Expensive set up
• Requires large area
of land
• Sunlight varies with
weather and time of
day
Geothermal Power
• Low operating costs
• Moderate set-up
costs
• Potential sites are
uncommon
Tidal Plant
• No waste
• Expensive set-up
• Power varies with the
tides