SCIENCE ~ CHAPTER 12
ENERGY AND MATERIAL
RESOURCES
Miss Nelson
SECTION 1
Renewable Sources of Energy
ANTICIPATORY SET
What other sources can you name besides
coal, oil, and natural gas?
STANDARDS
S 6.6.aStudents know the utility of energy sources is
determined by factors that are involved in converting
these sources to useful forms and the consequences
of the conversion process
S 6.6.bStudents know the different natural energy and
material resources, including air, soil, rocks, minerals,
petroleum, fresh water, wildlife, and forests; and know
how to classify them as renewable or nonrenewable
THE BIG IDEA
What forms of energy
does the sun provide?
What are some renewable
sources of energy?
KEY TERMS
 Solar energy – energy from the sun
 Hydroelectric power – electricity
produced using the energy of flowing
water
 Biomass fuel – fuel made from living
things
KEY TERMS
 Gasohol – a mixture of gasoline and
alcohol
 Geothermal energy – heat from
Earth’s interior
 Tide – the regular rise and fall of
Earth’s waters along its shores
RENEWABLE SOURCES OF ENERGY
Read Renewable Sources of Energy on page 485 of
your textbook.
HARNESSING THE SUN’S ENERGY
The sun constantly gives off energy
in the forms of light and heat
HARNESSING THE SUN’S ENERGY
 Solar energy is the source (either directly or
indirectly) of most other renewable energy resources
 Solar energy does not cause pollution, and will not
run out for billions of years
 Disadvantages
 It is only available when the sun is shining
 Sunlight is very spread out – to obtain a large amount of
power, it is necessary to collect solar energy from a large area
SOLAR POWER PLANTS
One way to capture the sun’s energy
involves using giant mirrors
In a solar power plant, rows of mirrors
use the sun’s rays to heat a tank of
water
The water boils, creating steam, which
can be used to generate electricity
SOLAR CELLS
 Solar energy can be converted directly into electricity
in a solar cell
 Has a negative and positive terminal (like a battery)
 When light hits the cell, and electric current is
produced
 Solar cells power some calculators, lights, and other
small devices
PASSIVE SOLAR HEATING
Can be used to heat buildings
Converts sunlight into thermal energy
Distributed with pumps or fans
Just like a car heating up on a hot day
ACTIVE SOLAR HEATING
 Captures the sun’s energy and then uses pumps and fans
to distribute the heat
 Light strikes the dark metal surface of a solar collector
 Converted to thermal energy
 Water is pumped through pipes in the solar collector to
absorb the thermal energy
 The heated water flows to a storage tank and fans
distribute the heat throughout the building
HARNESSING THE SUN’S ENERGY
Read Harnessing the Sun’s Energy on page 486
of your textbook
HYDROELECTRIC POWER
Other renewable sources of energy
include:
Water
Win
Biomass fuels
Geothermal energy
The tides
HYDROELECTRIC POWER
 Solar energy is the indirect source of water power
(heat from the sun drives the water cycle)
 Hydroelectric power is electricity produced by flowing
water
 A dam across a river controls the flow, which turns
turbines creating power
 Hydroelectric power is the most widely used source
of renewable energy
HYDROELECTRIC POWER
Read Hydroelectric Power on page 488 of your
textbook
WIND POWER
Is also an indirect form of solar energy
 The sun heats the Earth’s surface unevenly. As a
result, different areas of the atmosphere have
different temperatures and air pressures, which
causes wind as air moves from one area to another
Wind can be used to turn a turbine and
generate electricity
WIND POWER
The fastest growing energy resource
Drawbacks:
Many areas do not have sufficiently strong
winds to support wind farms
Wind farms require a lot of land
Wind often blows strongest in scenic areas,
where people object to seeing wind turbines
WIND POWER
Read Wind Power on pages 488-489 of your
textbook
BIOMASS FUELS
 Wood was probably the first fuel ever used for heat and light
 Wood belongs to a group of fuels called biomass fuels
 Are made from material that was once part of a living thing
 Other biomass fuels include leaves, food wastes, and manure
 Biomass fuels can also be converted into other fuels
 Some crops can be used to make alcohol; adding this to gasoline
forms gasohol, and can be used in fuel for cars
 Methane gas can be used to heat buildings
BIOMASS FUELS
Are renewable resources
…but it takes time for new trees to replace
those that have been cut down
Are not widely used in the United States
BIOMASS FUELS
Read Biomass Fuels on page 489 of your
textbook
TAPPING EARTH’S ENERGY
 Below Earth’s surface are pockets of very hot liquid
rock called magma
 In some places it is very close to the surface
 The intense heat from Earth’s interior that warms the
magma is called geothermal energy
 In certain places (Iceland and New Zealand) magma
heats underground water to a boiling point
 Hot water and steam can be valuable sources of energy
TAPPING EARTH’S ENERGY
Geothermal energy is an unlimited source of
cheap energy
Disadvantages:
 Only a few places where magma comes close to
Earth’s surface
 Other places, very deep wells would be needed to tap
this energy
TAPPING EARTH’S ENERGY
Read Tapping Earth’s Energy on page 490 of
your textbook
TIDAL ENERGY
 The tides are the regular rise and fall of Earth’s
waters along its shores
 Caused by the gravitational pull of the moon and sun
 Tidal power plants have been built to take advantage
of this regular motion
 Although it is a clean, renewable source of energy, it
has several limitations
 There are only a few places in the world where the tides are
high and low enough to build plants
 A dam across a bay would block boats and fish from passing
through
TIDAL ENERGY
Read Tidal Energy on page 491 of your textbook
CHECK FOR UNDERSTANDING
What two forms of energy does the sun
supply?
What are two reasons that solar energy
has not replaced energy from fossil fuels?
CHECK FOR UNDERSTANDING
What two forms of energy does the sun supply?
The two forms of energy the sun produces are
heat and light energy.
What are two reasons that solar energy has not
replaced energy from fossil fuels?
Two reasons that solar energy has not replaced
energy from fossil fuels are that solar energy is
only available when the sun is shining, and that
it must be collected from a very large area.
GUIDED PRACTICE
List five renewable energy sources
other than solar energy.
Which of these forms are actually
indirect forms of solar energy?
Explain.
GUIDED PRACTICE
List five renewable energy sources other than solar
energy.
Fiver non-solar renewable energy sources are wind,
water, biomass, geothermal, and tidal energy.
Which of these forms are actually indirect forms of
solar energy? Explain.
Wind and water energy are actually indirect forms of
solar energy because water power depends on the
water cycle, which is driven by the sun, and wind
energy depends on uneven heating of the Earth by
the sun.
INDEPENDENT PRACTICE
Complete Energy 12-2 Independent
Practice