Miss Nelson

SCIENCE ~ CHAPTER 12

ENERGY AND MATERIAL

RESOURCES

Renewable Sources of Energy

SECTION 1

What other sources can you name besides coal, oil, and natural gas?

ANTICIPATORY SET

S 6.6.a-Students 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.b-Students 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

STANDARDS

What forms of energy does the sun provide?

What are some renewable sources of energy?

THE BIG IDEA

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

KEY TERMS

Read Renewable Sources of Energy on page 485 of your textbook.

RENEWABLE SOURCES OF 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

HARNESSING THE SUN’S ENERGY

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 POWER PLANTS

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

SOLAR CELLS

Can be used to heat buildings

Converts sunlight into thermal energyDistributed with pumps or fans

Just like a car heating up on a hot day

PASSIVE 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

ACTIVE SOLAR HEATING

Read Harnessing the Sun’s Energy on page 486 of your textbook

HARNESSING THE SUN’S ENERGY

Other renewable sources of energy include:WaterWinBiomass fuelsGeothermal energyThe 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

HYDROELECTRIC POWER

Is also an indirect form of solar energyThe 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 landWind 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

WIND POWER

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

BIOMASS FUELS

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

TAPPING EARTH’S 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

TIDAL ENERGY

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.

CHECK FOR UNDERSTANDING

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.

GUIDED PRACTICE

Complete Energy 12-2 Independent Practice

INDEPENDENT PRACTICE