4.2.C.

= Analyze factors that influence the availability of natural resources. = =        =     __   Natural Resources Produced by the United States    __ >>  = Analyze how man-made systems have impacted the management and distribution of natural resources. =
 * The United States produces several natural resources to help free itself from dependency on other countries.
 * The United States is rich in most of the metals and minerals needed to supply it's basic industries.
 * Iron and Steel
 * "The nation produces more than 75 million tons of iron a year for it's steel mills" (United States 1991).
 * "Steel is vital to the manufacture of some 200,000 other products. Three-quarters of the iron ore comes from the Lake Superior region of the Great Lakes" (United States 1991).
 * Coal
 * "Coal is the second major natural resource found in large quantities in the United States. There are sufficient reserves to last hundreds of years" (United States 1991).
 * "Most of the coal is used by steam plants to produce electricity, with about half of the nation's electric power coming from such plants" (United States 1991).
 * Oil and Natural Gas
 * "Oil wells in the United States produce more than 2,700 million barrels of petroleum a year" (United States).
 *   "The production, processing and marketing of such petroleum products as gasoline and oil make up one of America's largest industries" (United States 1991).
 *   "Natural gas and manufactured gas furnish more than one-third of the nation's power. Natural gas is carried by huge pipelines thousands of kilometers from oil and gas fields to heat homes and buildings and to operate industrial plants" (United States 1991).
 *   Others
 * Other basic metals and minerals mined on a large scale in the United States include zinc, copper, silver and phosphate rock, which is used for fertilizers.
 * The United States is also influenced by other countries and organizations, such as the Oragnization of Petroleum Exporting Countries, or OPEC, which controls much of the world's oil. (United States 1991).

Each natural resource must go through an individual process to get the most usable material out of the raw substance. Logging for example has a unique process that involves processes like bucking and skidding. First in the process of logging is called bucking, which is when the trees are cut down through varying processes, in modernized areas power saws are used to cut down the trees, however in less modern areas trees are sometimes cut down with saws or axes. The power saws used in modern areas can be used by individuals carrying power saws or through equipment with multiple blades operated by a single person. Once the trees are cut down the wood is considered timber, the timber then goes through a process called skidding. Skidding is when the timber is transported to the sawmill through different methods. In modern areas trucks are used to transport the timber but in some less modern areas when it is cold the trees are cut and then transported it frozen rivers on sleds pulled by oxen, mules or other animals and when the river thawed the timber would float downstream to a sawmill. (Britannica encyclopedia - logging) Other main man-made systems that have impacted the management and distribution of natural resources are; dams, solar panel, windmills, oil rigs, and nuclear power plants. All of these systems have made collecting materials and collecting energy from our natural resources more efficient, faster, and less dangerous towards humans. media type="file" key="Upload Science Wiki Project Movies - Logging.mov" width="504" height="504"

(United Learning, 1996)