Introduction: Energy Unit

Energy Unit TEKS Objectives: TEK: Describe and compare renewable and non-renewable energy sources. Big Idea: Learn about and compare energy sources like oil, coal, wind, natural gas, solar, geothermal, hydroelectric and wind.

Energy Unit TEKS Objectives: TEK: Investigate and explain the effects of energy conversions within an ecosystem in terms of the laws of thermodynamics. Big Idea: Energy cannot be created or destroyed. Investigate how energy is transferred between nuclear, gravitational, kinetic, light, chemical and electrical energy. For example, how does the sun’s nuclear energy turn into the light and thermal energy of a toaster?

Energy Unit TEKS Objectives: TEK: Explain the flow of energy in an ecosystem including loss of energy through heat. Big Idea: Explain how energy flows from producers to consumers (Food chains) and the loss of most of the energy through heat by conduction, convection and radiation.

Energy Energy creates the power to drive tools and machines, to process materials into manufactured products and to create structures. Power is generated from nonrenewable energy sources such as coal, oil, and gas, or can be generated from natural resources such as geothermal, solar, and gravitational energies.

Classifications of Energy Sources Limited Oil Coal Natural gas Uranium Unlimited Unlimited Solar Wind Hydroelectric Tidal Geothermal Fusion Renewable Wood Biofuels (Ethanol) Animal Power Human Muscle Power

NONRENEWABLE RESOURCES COAL Although coal is found in many places throughout the world, nearly half of it is located in the United States. Of the 700 million tons of coal mined each year in the United States, two- thirds is burned to fuel electric generating plants. The remainder is used to provide heat for buildings and to make steel and other industrial products.

NONRENEWABLE RESOURCES NATURAL GAS It is estimated that there is only enough natural gas in the world to last for 20 more years. Most of the recoverable supplies are found In the Russia, the Middle East, and the United States. Natural gas provides about 32% of the total energy used in the United States. Some natural gas is used for home heating and cooking, but most is used in industry.

NONRENEWABLE RESOURCES NUCLEAR POWER Nuclear power requires uranium as the fuel source. When uranium atoms are split (fission), heat is released. Water is circulated through the reactor to keep it cool. As the water turns to steam, it is forced through a turbine to generate electricity. There are 52 nuclear generating plants, which provide about 20% of our total energy in the United States.

NONRENEWABLE RESOURCES OIL Oil is a fossil fuel that is recovered by drilling wells either on land or from offshore rigs. The world produces about 20 million barrels of all each year - one-third of which is used by the United States. Only about 35% of the oil in a well can be recovered. Some oil is used to heat buildings and to generate electricity. The remainder is distilled (cooked) to produce gasoline and other by- products.

RENEWABLE RESOURCES BIOFUELS Biofuels are organic (once-living) matter such as trees, sugarcane, corn, manure, and seaweed. Some of these organic materials can be burned directly to produce heat. Others are converted into flammable liquids or gases. Corn can be distilled to produce ethanol, which is then mixed with gasoline to produce gasohol. Biofuels provide about 2% of our energy in the United States.

RENEWABLE RESOURCES GEOTHERMAL POWER Geothermal energy comes from the tremendous heat trapped deep within the earth. Natural steam geysers are used to generate electricity. Hot water can also be pumped out of the ground to heat buildings. Geothermal sources account for less than 1 % of the total energy produced In the United States. Most of the sources are in the western third of the nation.

RENEWABLE RESOURCES WATER POWER Moving water holds a tremendous amount of potential energy. Dams are built to direct failing water through turbine blades to generate electricity. About 3% of our total energy in the United States comes from waterpower. Small generators are being developed to generate electricity from small streams and rivers.

RENEWABLE RESOURCES OCEAN POWER Experiments are currently under way to capture power from the tides. Other efforts are being directed toward using temperature changes and wave action to produce electricity. There may be enough energy in the oceans to power all the Industrial machines in the world. But we still need to discover some practical ways to harness this power.

RENEWABLE RESOURCES SOLAR POWER The sun's energy can be used to directly heat buildings or to provide hot water. It can also be converted to electricity. Photovoltaic devices (often called "solar cells") are expensive and can as yet produce only small amounts of electricity. Although solar power presently provides less than 1% of our energy, future developments may make it a convenient and inexpensive source of energy.

RENEWABLE RESOURCES WIND POWER Windmills have been used for many years to pump water or to grind flour. Modern wind devices are being developed to generate electricity. Small wind turbines can light a home or run small appliances. A little more than 1 % of our energy is now being produced by wind power, but larger, more efficient generators are being installed, especially in Texas.

Energy sources in the United States (2006)