*
Wind has energy to move
these wind turbines
energy
is the ability to do work (move a mass in the
direction of force) or to cause a change.
*
Moving is
kinetic
Potential energy is
greater the more the
.
mass and the height.
kinetic energy
is the energy an object has due to its motion. To increase
kinetic energy, either increase mass or speed
potential energy
is the energy stored in an object because of its position; increase
of height or mass can increase the amount of potential energy.
*
Fossil fuels put
carbon dioxide into
the atmosphere
fossil fuels
A fuel source created by the decay of biomass (plant & animal
remains) that was buried and put under tremendous heat and
pressure to form oil, natural gas or coal. Fossil fuels take millions of
years to form and when they run out, they are not replenished.
False
About
12%
Fossil fuels can
be cheaper in
the short term.
*
renewable energy
An energy source that is replaced continually. These are
hydroelectricity, solar, geothermal, wind and biomass
*
biomass
is the matter contained in all living or recently living
organisms such as compost (decaying leaves and grass
clippings), some garbage, and plant products. Fuels made
from plants like corn are called biofuels and burn cleaner
than fossil fuels. Ethanol and Biodiesel are two examples.
Limitations –
• Even though biomass is carbon neutral (releases what
it took in) when biomass like wood burns it releases
CO2 that was stored during its life and adds to the local
air pollution.
• It takes large tracks of land to grow plants for fuel that
could be used for food.
carbon
*
solar energy
Energy created by capturing the light energy of the sun. Solar
energy can be captured using photovoltaic cells to produce
electrical energy or mirrors in solar thermal plants to produce
heat. Two of the biggest solar thermal plants are in California
.
and Nevada
Limitations: large tracks of land are needed for solar arrays
that will produce enough energy for cities.
Solar energy is only efficient where there are many hours of
sunlight. Solar does not work at night. Solar can be expensive.
photovoltaic cells
a device that transforms radiant (sun)
energy directly into electrical energy by
releasing electrons from silicon atoms and
causing electricity to flow.
http://micro.magnet.fsu.edu/primer/java/solarcell/
*
hydroelectricity
Electricity created by flowing water
going through a dam, which in turn
causes turbines to spin which
generates electricity.
Limitations: Can only be located where
rivers flow and lose elevation. Building
dams are expensive and disrupts the
habitat of plants, animals and people in
the area.
http://techalive.mtu.edu/meec/module17/humaninfluence.htm
*
wind energy
Energy using wind that is
converted into electricity
through the spinning of blades
on a wind generator. Wind
farms are large groups of wind
turbines which require large
tracks of land.
Limitations: Need continuously
windy areas. Can kill birds.
http://techalive.mtu.edu/meec/module17/humaninfluence.htm
*
geothermal energy
heat energy created by the Earth
captured below the surface and used
to change hot water to steam which
then spins turbines to produce
electricity.
limitations: Can only be located in
areas that have hot spots where
magma heats rock underground. This
means that these areas are also subject
to earth quakes.
http://techalive.mtu.edu/meec/module17/humaninfluence.htm
22
a
*
Nuclear Energy is non-renewable but
very efficient and does not pollute the air.
Nuclear energy is a source of energy that is
produced through the fission (breaking
apart) of uranium 235 atoms. Heat energy is
released in a reactor. Heat is used to
produce steam to turn a turbine.
Limitations: safety issues and radioactive
waste products.
Know what is happening currently in Japan
from movie we saw.
Steam not
smoke
Skeptical –
doubtful, in need
of evidence.
Skeptical –
doubtful, in need
of evidence.
*
Risk and Reward.
Risk Reward
analysis
All technology has rewards and risks
for its use.
For example a cell phone allows you to
communicate easier, but can cause you
to be distracted and puts out radiation
that could be damaging over long
term.
To make good decisions about using
technology, we must do a risk/reward
analysis.
1
2
4
3
5
1
2
4
3
5
1
c
2
a
3
b
4
a
5
c