Earth’s Resources

Ag Earth Science – Chapter 4.1 4.1 Vocabulary

renewable resource A resource that is virtually inexhaustible or that can be replenished over relatively short time spans

nonrenewable resource Resources that take millions of years to form

fossil fuel A general term for any hydrocarbon that may be used as a fuel, including coal, oil, and natural gas

ore A material from which a useful mineral or minerals can be mined at a profit

Renewable and Nonrenewable Resources There are two categories of resources renewable nonrenewable

Renewable and Nonrenewable Resources A renewable resource can be replenished over fairly short time spans such as months, years, or decades. examples – plants, animals, food, natural fibers, water, wind, sun, etc… By contrast, a nonrenewable resource takes millions of years to form and accumulate examples – coal, oil, gas, iron, copper, etc…

Fossil Fuels Nearly 90% of the energy used in the United States comes from fossil fuels A fossil fuel is any hydrocarbon that may be used as a source of energy Fossil fuels include coal, oil, and natural gas

Fossil Fuels Coal   Coal forms when heat and pressure transform plant material over millions of years. Power plants primarily use coal to generate electricity, however the burning of the coal creates air pollution problems.

Fossil Fuels Petroleum and Natural Gas Petroleum (oil) and natural gas form from the remains of plants and animals that were buried in ancient seas.

Fossil Fuels Tar Sands and Oil Shale Some energy experts believe that fuels derived from tar sands and oil shale could become good substitutes for dwindling petroleum supplies. Tar sands are a mixture of clay and sand combined with water and varying amounts of black, thick tar called bitumen. Oil shale is a rock that contains a waxy mixture of hydrocarbons called kerogen

Formation of Mineral Deposits Practically every manufactured product contains substances that come from minerals Ore is a useful metallic mineral that can be mined at a profit Some of the most important mineral deposits form through igneous processes and from hydrothermal solutions

Formation of Mineral Deposits Igneous processes produce important deposits of metallic minerals, such as gold, silver, copper, mercury, lead, platinum, and nickel. Hydrothermal (hot water) solutions generate some of the best-known and most important ore deposits. Placer deposits are formed when eroded heavy minerals settle quickly from moving water while less dense particles remain suspended and continue to move.

Nonmetallic Mineral Resources Nonmetallic mineral resources are extracted and processed either for the nonmetallic elements they contain or for their physical and chemical properties. Examples of nonmetallic minerals include the fluorite and limestone that are part of the steelmaking process and the fertilizers needed to grow food.

Ag Earth Science – Chapter 4.2 4.2 Vocabulary

hydroelectric power The power generated by falling water

geothermal energy Energy that can be extracted from earth’s internal heat, for example, natural steam used for power generation

Solar Energy Solar energy is by far Earth’s most abundant energy resource Solar energy has two advantages “fuel” is free non-polluting

Solar Energy Solar energy disadvantages equipment and installation is expensive   does not work well on cloudy days Research developing on improving technology, efficiency, productivity, and costs

Nuclear Energy Nuclear energy comes from radioactive materials that release energy through nuclear fission.   In nuclear fission, the nuclei of heavy atoms such as uranium-235 are bombarded with neutrons. The uranium nuclei then split into smaller nuclei and emit neutrons and heat energy.

Nuclear Energy Nuclear energy advantages Nuclear energy disadvantages “clean” energy (nothing released in the atmosphere) Nuclear energy disadvantages radioactive waste and extreme health hazards during radiation (power plant) accidents

Wind Energy Some experts estimate that in the next 50-60 years, wind power could meet between 5 to 10 percent of the country’s demand for electricity. Wind power advantages clean and renewable

Wind Energy Wind power disadvantages Not consistent (wind does not blow 100% of the time) Technology costs

Hydroelectric Power Power that falling water generates is called hydroelectric power The water held in a reservoir behind a dam is a form of stored energy that can be released through the dam to produce electric power.

Hydroelectric Power Hydroelectric power advantages clean and renewable Hydroelectric power disadvantages Dams alter environment Limited locations and limited lifespan (due to sediment build-up)

Geothermal Energy Geothermal energy is harnessed by tapping natural underground reservoirs of steam and hot water. Hot water is used directly for heating and to turn turbines to generate electric power.

Geothermal Energy Geothermal energy advantages clean Geothermal energy disadvantages Limited locations Limited lifespan (wells eventually “run out of steam”)

Tidal Power Tidal power is harnessed by constructing a dam across the mouth of a bay or an estuary in coastal areas with a large tidal range. The strong in-and-out flow that results drives turbines and electric generators. “Clean” energy, but not economical

Ag Earth Science – Chapter 4.3 4.3 Vocabulary

point source pollution Water pollution that comes from a known and specific location

nonpoint source pollution Water pollution that does not have a specific point of origin

runoff Water that flows over the land surface rather than seeping into the ground

global warming The increase in average temperatures of earth and the atmosphere due in part to increased carbon dioxide levels

The Water Planet Water covers nearly 71% of the earth’s surface. Most of the water is salt water, not fresh water. Each day, people use fresh water for drinking, cooking, bathing, and growing food

The Water Planet Pollution has contaminated many freshwater supplies Point source pollution – pollution that comes from a known and specific location Nonpoint source pollution – pollution that does not have a specific point of origin Runoff, the water that flows over the land rather than seeping into the ground, often carries nonpoint source pollution

Earth’s Blanket of Air Earth’s atmosphere is a blanket of nitrogen, oxygen, water vapor, and other gases The chemical composition of the atmosphere helps maintain life on Earth. People and animals could not live w/o oxygen The atmosphere also makes life on land possible by shielding earth from harmful solar radiation.

Earth’s Blanket of Air The ozone layer protects Earth from 95% of the sun’s harmful UV rays Certain greenhouse gases (carbon dioxide, water vapor, methane) help maintain a warm temperature near earth’s surface. The increase in human activities relating to the burning of fossil fuels has increased the amount of carbon dioxide in the atmosphere. This has caused an increase in global warming due to the increase in greenhouse gases.

Land Resources Earth’s land provides soil and forests, as well as mineral and energy resources.

Ag Earth Science – Chapter 4.4 4.4 Vocabulary

conservation The careful use of resources

compost Partly decomposed organic material that is used as fertilizer

recycling The collecting and processing of used items so they can be made into new products

Protecting Resources Each year, Americans throw out about 30 million cell phones, 18 million computers, 8 million TV sets, and enough tires to circle the earth about 3 times. With just 6% of the world’s population, Americans use about 1/3 of the world’s resources – and produce about 1/3 of the world’s garbage.

Protecting Resources The way to protect resources and lower pollution is to think conservation and pollution prevention Conservation is the careful use of resources. Pollution prevention means stopping pollution from entering the environment

Protecting Resources Keeping Water Safe Starting in the 1970’s the federal government passed several laws to prevent or decrease pollution and protect resources

Protecting Resources Protecting the Air In 1970, Congress passed the Clean Air Act, the nation’s most important air pollution law.

Protecting Resources Caring for Land Resources Protecting land resources involves preventing pollution and managing land resources wisely Compost is partly decomposed organic material that is used as fertilizer Recycling is the collecting and processing of used items so they can be made into new products