The Student Knows That the Earth S Surface Is Constantly Changing and Consists of Useful

Objective

The student knows that the Earth’s surface is constantly changing and consists of useful resources. The student is expected to identify alternative energy resources, such as wind, solar, hydroelectric, geothermal, and biofuels.

Foundation

From the time of the earliest humans, the Earth has been considered a resource from which to draw sustenance for living. Natural resources are materials from the Earth that people use, and every feature, product, and particle has been examined by humans with an eye toward usefulness. In the thousands of years before the Industrial Revolution began in the late eighteenth century, the population of the Earth was low enough that not much concern was given to the environmental welfare of the planet because nature could renew and replenish the resources used by people faster than they could consume them.

With the coming of the Industrial Age, however, with its massive factories demanding huge quantities of fossil fuels for production which in turn resulted in an exponentially increasing contribution to pollution, humans had finally reached the dubious capability to pollute nature faster than nature could cleanse itself, and the struggle for maintaining a balance between sustaining economic prosperity and protecting our planet began. The tug of war between planet and prosperity has become more serious with each passing day due to the exploding population of the Earth and the resulting demand for more resources.

In the last three decades, we have seen a growing concern for the welfare of our planet, and environmentalists, scientists, and an expanding group of citizens are offering suggestions and taking steps to reduce our impact on the Earth. Earth’s resources can be categorized into natural resources, such as rocks, water, soil, air, etc., and manmade resources which actually are natural resources that have been modified in some way for our use like glass, paper, fabric, and lumber. The source, if you will, of each resource determines whether it is classified as a renewable or a nonrenewable resource. Renewable resources are materials which can be replenished by nature in a relatively short time. Lumber comes from trees, and, in the United States, for every tree felled to be made into building materials, a new seedling is planted to take its place. By maintaining a twenty year cycle of tree management, we have been able to stop the deforestation of our lands. Nonrenewable resources are materials of which there is a finite or fixed amount, and once they are consumed, they cannot be replaced by the Earth in any reasonable time. Fossil fuels such as oil, coal, and natural gas are irreplaceable once they are burned or manufactured into a manmade product.

With our ever-growing population and increasing demand for resources, we have learned that even renewable resources need to be properly managed and conserved. Although air, water, soil, plants, and animals are renewable resources, proper conservation and management policies need to be in place to insure we do not use these resources faster than they can be replenished. With a nonrenewable resource, it becomes clear that excessive consumption only hastens the day when that resource will no longer be available. There are only two solutions: reduce dramatically our consumption or find alternative resources. Energy resources are the most obvious example. Fifty years ago we thought we had hundreds of years of fossil fuel resources available, but now we realize that fossil fuels could become extremely scarce in a lifetime. The result has been an increased interest in alternative energy sources. The ideal energy resource would be one which would be classified renewable and, even more ideally, inexhaustible (unlimited supply), such as sunlight or wind power.

Alternative energy resources include geothermal energy, hydroelectricity, biofuels (also known as biomass), wind, and solar energy. These resources come from the Earth's natural processes and can be transformed into energy forms that we can use. Geothermal energy can be used to generate steam, which turns turbines that power electrical generators. The water that was heated to create steam can be condensed and sent back into the Earth's crust for re-heating. The power of moving water can be harnessed to generate electricity also, and biofuels can be used to generate fuel. However, with biofuels, the easiest way to transform the organic material into energy is through burning, which releases carbon dioxide into the atmosphere. Students should understand that although more beneficial than fossil fuels, alternative energy can have disadvantages also. Wind and solar energy, once classified as inexhaustible, are additional resources available in plenteous supply and that can be used without polluting.

Whether the resource is renewable or nonrenewable, we have learned to reduce our consumption of our Earth’s riches through recycling. Though water, soil, and plants are renewable, we can reduce our impact by reusing and recycling. Oil is a nonrenewable resource, but many of the products which come from oil, such as plastics and fabrics, can be recycled many times to insure that we are reducing the quantity of oil we are removing from the Earth. Many metals such as aluminum and copper are used in thousands of products and can be recycled to reduce our need for additional mining of these nonrenewable resources.