ECOLOGY
The study of the
environment in relation to
organisms/people
ECOSYSTEM
• A community of animals,
plants, & microscopic life that
interact in a particular place in
the environment.
• Penguins live with polar bears,
ducks, foxes, seals, & wolves
in a cold environment.
FOOD CHAIN
•A pathway of food &
energy through an
ecosystem. Each species in
the chain depends on the
other in some way.
Each has a role
(producer/consumer)
Producer-one who
makes food
Consumer-one who
eats food
FOOD CHAIN
EXAMPLES
Acorns--- mouse--- owl
Grass--- sheep--- people
• 90% of all energy comes from fossil
fuels
• Formed millions of years ago from
the remains of dead plants & animals.
• The remains decay & get buried in
mud, & clay. Over millions of years,
heat & pressure change the sediment
into fossil fuels.
Fossil Fuels
•3 main fossil fuels are:
coal, oil, natural gas
•Fossil fuels are useful as
an energy source because
they are rich in
hydrocarbons.
HYDROCARBONS
Substances that contain the
elements hydrogen &
carbon.
COMBUSTION
• Process in which hydrocarbons
in fossil fuels are combined
with oxygen at high temps to
release heat and light energy.
• Also called BURNING.
ADVANTAGES OF F.FUELS
Produce more heat than
wood does
Are easier to transport, store,
and use than wood.
DISADVANTAGES
•When coal is burned, it
releases pollutants
(sulfur) into the air.
•Nonrenewable
1-2 Solar Energy
• Energy from the sun
• Solar energy received by earth in
one day could meet the world’s
energy needs for 30 years.
• Most of the solar energy that hits
earth is unused.
USES OF SOLAR
ENERGY
•Heat homes (and water)
•Produce electricity
•To be useful, the sun’s
energy must be
collected, stored, &
converted.
PASSIVE SOLAR HEATING
• Windows of a building are
positioned so that sunlight
enters directly & heats the
building.
• At night, pull down shades to
keep the heat in.
PROBLEMS
1. Need for a backup
system
(At night?, rain?,)
2. It only heats part of the
house.
ACTIVE SOLAR HEATING
• Involves collecting the sun’s
energy in a device called a solar
collector.
• Solar collector – a black surface
covered with glass which absorbs
energy from the sun & converts it
to heat.
How it works?
• Pipes are filled with water in the
solar collector. The water gets heated
& is pumped down to a storage tank.
Then the heated water is pumped
throughout the house giving off heat
where needed. Water cools & returns
to the solar collector to be reheated
by sun.
Active Heating Diagram
PROBLEMS
• Depends on time of day,&
weather conditions
• Solar devises expensive
SOLAR CELLS
• Photovolatic cell- a solar cell that
converts light energy into
electricity.
• Solar calculator, solar phone.
• Produces a small amount of
electricity & are costly.
POWER TOWER
• An array of mirrors that focus
sunlight onto a boiler mounted
on a tower. The sunlight heats
the water in the boiler &
converts it to steam. The steam
turns a turbine to generate
electricity.
1-3 Wind & Water Energy
• Past Uses of wind: propel
ships, pump water from wells
• Past Uses of water: grind
corn
• Today both are used to
produce electricity
Wind
• Winds are caused by the
uneven heating of the earth
by the sun.
• An indirect form of solar
energy.
Advantages of Wind Energy
• Saves fossil fuels
• Runs clean, reduces
pollution
• Natural resource
• Light weight & easy to
install
Disadvantages
• Doesn’t work on calm days
• Windmills are easily
knocked down/broken
• Limited to geographical
areas like Great Plains,
Mountains, and Coast.
Water Energy
• Another indirect form of solar
energy. The sun powers the water
cycle.
• Sun evaporates water from lakes,
and oceans, Water vapor condenses
to form clouds, & vapor changes to
rain and falls from sky.
Hydroelectric Power
• The use of mechanical
energy of falling or running
water to generate electricity.
• Example: Hoover Dam
How it works
• A dam is built to hold back tons
of water in a reservoir. Water is
drawn into the power plant
through pipes. Water is pushed
through the pipes & turns the
blades of several turbines which
turn the electromagnets on the
generators to produce electricity.
Advantages
• Clean, no pollution, natural
• Efficient means to make
electricity
• Fairly cheap
Disadvantages
• Limited areas to construct
big dams
• Harmful to environmentcould alternate patterns of
fish migration, can cause
flooding.
1-4 Nuclear Energy
• Energy locked within the
atomic nucleus
• Atom- basic building block
of matter. All objects in the
world are made of matter &
thus of atoms.
Nucleus Makeup
1. Protons- positively charged
particles found in nucleus
2. Neutrons- neutral or no
charge, found in nucleus
3. Electrons- whirls around
nucleus, negatively charged
Nucleus Diagram
•
Einstein's Prediction
•If a nucleus of an atom
could be split, a new &
powerful energy source
would be produced.
Nuclear Fission
• The splitting of an atomic
nucleus into 2 smaller nuclei
during which nuclear energy
is released.
Most Common Type of Fission
Reaction
• Splitting of Uranium-235
nucleus
Fission Reaction Steps
1)Scientists shoot a “nuclear
bullet”(neutron) into the nucleus.
2)neutron strikes Uranium-235
nucleus & splits into 2 smaller
nuclei.
3)2 or more neutrons are released
along with energy
• Each Neutron released
during a fission reaction by
splitting another Uranium235.
Nuclear Chain Reaction
• Process in which the splitting
of one nucleus causes the
splitting of additional nuclei.
Controlled N. Chain Reaction
• If controlled, the energy can
be a valuable energy source.
Nuclear Power Plant.
• If uncontrolled, it creates a
huge explosion like the atom
bomb.
Nuclear Power Plants
• Produce electricity from
energy locked within the
nuclei of atoms.
How it works
1.Uranium 235 is mined
& put on fuel rods in
the reactor vessel.
2. Water is pumped in &
neutrons strike the fuel rods
(fission begins).
3. Heat energy converts water
into steam.
4. Steam passes through pipes
& spins the blades of a
turbine which turns the
magnets in the generator to
produce electricity.
5. Water cools & is recycled
back to reactor vessel. Some
is dumped into stream.
To Control Nuclear Fission
• Drop in the control rods.
• Control rods act like magnets &
absorb all the neutrons which
slows down fission reactions.
• To speed up fission, take out
control rods.
Problems
1) SafetyA) radiation leaking into
environment
B) what to do with radioactive
wastes
C) melt down overheating
D) security-terrorists.
• 2) money- expensive to
build
Nuclear Fusion
• Combining of 2 atomic nuclei
to produce 1 larger nucleus &
release energy.
• 2 Hydrogen’s join to form a
Helium & energy is released.
Advantage’s
• Produces far more energy than
fission.
• Produces less waste.
• Hydrogen’s can be obtained from
water-(water is abundant)
Fusion Problem
• Needs more research to
solve high temps. and high
pressure problems, needed
for fusion. Can’t happen
naturally on earth.
1-5
Alternative Energy
Sources
Geo Thermal Energy
• Geo=Earth
Thermal=Heat
•Energy is produced
from heat energy
with in the Earth.
Hot Spots
•Molten rock within the
Earth that comes close to
Earth’s surface.
Geyser
• When water comes in contact
with hot spots, water is heated &
bursts from the Earth into
fountains of hot water & steam.
How it works
• Steam from geysers is used to
generate electricity.
• Wells can be drilled into hot
rock, heat turns water into steam.
Steam is pumped to surface and
used for electricity.
Problem
• Number of Hotspots on the
Earth is limited so it is
unlikely to keep pace with
the worlds energy needs.