REACT --Page 7
Other examples of the change of energy into other forms includes:
• When natural gas burns in a home or office furnace, chemical energy stored in the gas is
converted into heat energy
• The Sun's radiant energy is converted by plants into chemical energy (a process called
photosynthesis).
WHAT ARE THE PRACTICAL SOURCES OF ENERGY?
The practical sources of energy include the fossil fuels, natural gas, petroleum (or oil), and coal.
Fossil fuels are referred to as nonrenewable energy sources because, once used, they are gone.
Scientists are exploring the practicality of other sources called renewable energy sources. These
include sun, wind, geothermal, water, and biomass. The renewable energy resources are important
in long range energy planning because they will not be depleted.
atural Gas
Sometimes natural gas is confused with gasoline, the fuel in cars. They are not the same. Gasoline is
a mixture of liquids, and natural gas is mainly methane and is piped into homes and office buildings
where it is used as an energy source for heating, cooking washing, and drying. It is raw material to
make other chemicals, and is the cleanest bumming fossil fuel. This means it contributes little
environmental pollutants when bummed.
etroleum or Oi
This is the black, thick liquid pumped from below the earth's surface wherever you see an oil rig. To
make it useful, it is refined. Refining separates the gasoline portion which is used in transportation.
Products from the remaining portions include synthetic rubber, detergents, fertilizers, textiles,
paints, and pharmaceuticals.
Coal
Coal is the most abundant fossil fuel. It is not a widely used energy source due to the cost of mining
and its impurities, which cause pollution (acid rain). There are two ways to mine coal; underground
mining and strip mining. Disadvantage to these methods is the environmental change caused in the
process. New ways of using coal are being explored, such as liquefication, in which a product
similar to oil is produced.
Solar
The sun is 93 million miles away and yet, this ball of hot gases is the primary source of all energy
on earth. In the hi ugh temperature of the sun, small atoms of hydrogen are fused, that is, the
centers of the two atoms are combined. Fusion releases far greater energy than splitting the atom
(fission, see below). Without sunlight, fossil fuels could never have existed. The sun is the supplier
of energy which runs the water cycle. The uneven heating of the earth produces wind energy. Solar
energy can be used to cook food, heat water and generate electricity. It remains the cleanest energy
source an it is renewable. It is the hope for the energy source of the future and scientists at NREL
are actively working on ways for solar energy to supply more our energy needs!
Wind
The unequal heating of the earth's surface by the sun produces wind energy, which can be
converted into mechanical and electrical energy. For a long time, the energy of wind has been to
drive pumps. Today windmills can be connected to electric generators to turn the wind's motion
energy into electrical energy, and wind over 8 miles per hour can be used to generate electricity .It
is a renewable, but unpredictable, energy source.