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Electricity makes downtown Los Angeles sparkle at dusk. Prepared by Pat Davis, Science Teacher, Durham Middle School, Lewisville ISD.

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Presentation on theme: "Electricity makes downtown Los Angeles sparkle at dusk. Prepared by Pat Davis, Science Teacher, Durham Middle School, Lewisville ISD."— Presentation transcript:

1 Electricity makes downtown Los Angeles sparkle at dusk. Prepared by Pat Davis, Science Teacher, Durham Middle School, Lewisville ISD

2 Energy and Fossil Fuels Energy exists in several different forms:Energy exists in several different forms: –Mechanical –Thermal –Chemical –Electrical –Electromagnetic –Nuclear.

3 Energy Transformation Energy can be changed from one form to anotherEnergy can be changed from one form to another –A change from one form of energy to another is called an energy transformation Sometimes called energy conversionSometimes called energy conversion

4 Energy Transformations in the Home Water HeatersWater Heaters –heating element that transforms electrical energy into thermal energy –water to become hotter Cooling SystemsCooling Systems –transfer thermal energy from a cool area to a warm area –transfer thermal energy from a cool area to a warm area This diagram shows the basic parts of a refrigerator.

5 Fuels and Energy A fuel is a substance that provides a form of energyA fuel is a substance that provides a form of energy –Examples HeatHeat LightLight ElectricityElectricity MotionMotion Electric power plants generate electricity by converting energy from one form to another. In the furnace, fuel is burned, releasing thermal energy. This energy is used to boil water and make steam. The mechanical energy of the moving steam turns the blades of a turbine. The turbine turns the shaft of the generator, producing an electric current.

6 Fuels and Energy The process of burning a fuel is called combustion.The process of burning a fuel is called combustion. Fossil fuels are the energy-rich substances formed from the remains of once-living organisms.Fossil fuels are the energy-rich substances formed from the remains of once-living organisms. –made of hydrocarbons = energy-rich chemical compounds that contain carbon and hydrogen atoms –Coal –Oil –Natural Gas

7 Fossil Fuels Because fossil fuels take hundreds of millions of years to form, they are considered nonrenewable resources.Because fossil fuels take hundreds of millions of years to form, they are considered nonrenewable resources. –natural resources that are not replaced as they are used One fourth of all the oil earth has already been used

8 Oil A thick, black, liquid fossil fuel.A thick, black, liquid fossil fuel. –Sometimes called Petroleum More than one third of the energy produced in the worldMore than one third of the energy produced in the world Fuel for: cars, airplanes, trains, ships any many homesFuel for: cars, airplanes, trains, ships any many homes The United States consumes about one third of all the oil produced in the world. But only three percent of the world’s supply is located in this country. The difference must be purchased from countries with large oil supplies. relatively cheap and plentiful energy sourcerelatively cheap and plentiful energy source producing and using petroleum does affect the environmentproducing and using petroleum does affect the environment burning it contributes to air pollution.burning it contributes to air pollution.

9 Oil Finding oil is difficultFinding oil is difficult –Use sound waves to test an area for oil –Measure echoes –Measure time sound waves travel through solid rock or liquid oils. –about one out of every six wells drilled produces a usable amount of oil.

10 Refining Oil A factory where crude oil is separated into fuels and other products by heating is called a refinery.A factory where crude oil is separated into fuels and other products by heating is called a refinery. –Products produced from oil. Gasoline, heating oilGasoline, heating oil PetrochemicalsPetrochemicals –Plastics –Paints –Medicines –Cosmetics. Oil refineries can affect the environment. Chemicals produced in the refining process may escape into the air or water, causing pollution.

11 Natural Gas Fossil fuelFossil fuel Mixture of methane and other gases.Mixture of methane and other gases. Less dense than oilLess dense than oil AdvantagesAdvantages –produces large amounts of energy –lower levels of air pollutants –easy to transport DisadvantageDisadvantage –gas leak can cause a violent explosion and fire. Natural gas actually has no odor. Gas companies add a chemical with a distinct smell to the gas before it is piped to homes and businesses so that any leaks will be noticed.

12 Coal Solid fossil fuelSolid fossil fuel Formed from plant remainsFormed from plant remains Provides 23 percent of the energy used in the United StatesProvides 23 percent of the energy used in the United States Major use is to fuel electric power plantsMajor use is to fuel electric power plants minedmined Difficult to obtainDifficult to obtain Deposits of coal know as reservesDeposits of coal know as reserves Most plentiful fossil fuel in the United StatesMost plentiful fossil fuel in the United States Easy to transportEasy to transport Produces a lot of air pollutionProduces a lot of air pollution Coal mining can be a dangerous job. New safety procedures and better equipment, including robots and drills that produce less coal dust, have made coal mining safer.

13 Renewable Sources of Energy Renewable resources are naturally replaced in a short period of time.Renewable resources are naturally replaced in a short period of time. –Sunlight –Wind –Trees These resources help meet people’s energy needs.

14 Energy From the Sun Solar Energy The sun constantly gives off energy in the form of light and heat.The sun constantly gives off energy in the form of light and heat. Solar energy is the source, directly or indirectly, of most renewable energy resources.Solar energy is the source, directly or indirectly, of most renewable energy resources. Can be thought of as a inexhaustible resourceCan be thought of as a inexhaustible resource Solar TechnologiesSolar Technologies –Solar Plants - rows of mirrors focus the sun’s rays to heat a tank of water –Solar Cells - a “sandwich” of very thin layers of the element silicon & other materials. The upper and lower parts of the sandwich have a negative and a positive terminal, like a battery. When light hits the cell, electrons move across the layers, producing an electric current. powers calculators, lights, telephones, and other small devicespowers calculators, lights, telephones, and other small devices

15 Solar Heating Systems Solar Heating Systems Passive solar systemPassive solar system –converts sunlight into thermal energy without using pumps or fans. Active solar systemActive solar system –captures the sun’s energy, then uses fans and pumps to distribute the heat

16 Solar House This solar house uses passive and active heating systems and solar cells to convert solar energy into heat and electricity

17 Sources of Renewable Energy –Water Hydroelectric power is electricity produced by flowing waterHydroelectric power is electricity produced by flowing water –Biomass materials WoodWood Crop wastesCrop wastes Food wastesFood wastes Manure.Manure.

18 Hydroelectric power is generated by changing energy from one form to another. Hydroelectric Power Plant

19 –Geothermal Energy In Iceland and New ZealandIn Iceland and New Zealand Magma heats underground water to the boiling point. The hot water and steam are valuable sources of geothermal energy.Magma heats underground water to the boiling point. The hot water and steam are valuable sources of geothermal energy. In Reykjavik, Iceland, 90 percent of homes are heated by water warmed underground in this way. Geothermal energy can also be used to generate electricity. Sources of Renewable Energy A geothermal power plant uses heat from Earth’s interior as an energy source. Cold water is piped deep into the ground, where it is heated by magma. The resulting steam can be used for heat or to generate electricity.

20 –Wind “wind farms” consist of many windmills“wind farms” consist of many windmills 1 percent of the world’s electricity1 percent of the world’s electricity Portions of Texas have a high potential for utilizing wind energy.Portions of Texas have a high potential for utilizing wind energy. Sources of Renewable Energy The Panhandle contains the state's greatest expanse with high quality winds. Well- exposed locations atop the caprock and hilltops experience particularly attractive wind speeds.

21 –Hydrogen Power burns cleanlyburns cleanly water is the byproductwater is the byproduct creates no smoke, smog, or acid raincreates no smoke, smog, or acid rain transported through pipelinestransported through pipelines hydrogen can be obtained by passing an electric current through waterhydrogen can be obtained by passing an electric current through water –takes more energy to obtain the hydrogen than is produced by burning it again Sources of Renewable Energy The object fascinating these three astronauts is a bubble of water—the harmless byproduct of the hydrogen fuel cells used on the space shuttle.

22 Nuclear Energy Fission Reactions and EnergyFission Reactions and Energy –Albert Einstein developed a formula that described the relationship between energy and matter. –E = energy –m = mass –C = speed of light The central core of an atom that contains the protons and neutrons is called the nucleus. The reactions that involve nuclei, called nuclear reactions, involve tremendous amounts of energy. Two types of nuclear reactions are: fission fusion. The central core of an atom that contains the protons and neutrons is called the nucleus. The reactions that involve nuclei, called nuclear reactions, involve tremendous amounts of energy. Two types of nuclear reactions are: fission fusion. This equation states that when matter is changed into energy, an enormous amount of energy is released.

23 Nuclear fission Nuclear fission is the splitting of an atom’s nucleus into two smaller nuclei.Nuclear fission is the splitting of an atom’s nucleus into two smaller nuclei. –When the neutron hits the U-235 nucleus, the nucleus splits apart into two smaller nuclei and two or more neutrons. In a nuclear fission reaction, a neutron “bullet” strikes a U-235 nucleus. As a result, the nucleus splits into two smaller nuclei. More neutrons are released, along with a great deal of energy.

24 Nuclear Power Plants Controlled nuclear fission reactions take place inside nuclear power plants.Controlled nuclear fission reactions take place inside nuclear power plants.  reactor vessel is the section of a nuclear reactor where nuclear fission occurs  reactor contains rods of U-235, called fuel rods  The reactions are controlled by placing control rods made of the metal cadmium between the fuel rods  Heat is removed from the reactor  fluid passes through a heat exchanger  fluid boils water to produce steam  which runs the electrical generator In a nuclear power plant, the heat released from the reactions is used to change water into steam. As in other types of power plants, the steam then turns the blades of a turbine to generate electricity

25 The Risks of Nuclear Fission Nuclear power plants generate about 17 percent of the world’s electricityNuclear power plants generate about 17 percent of the world’s electricity The fuel rods generated so much heat that they started to melt, a condition called a meltdown.The fuel rods generated so much heat that they started to melt, a condition called a meltdown. In 1986, in Chernobyl, Ukraine, the reactor vessel in a nuclear power plant overheated. A series of explosions blew parts of the roof off and injured or killed dozens of plant workers and firefighters. Radioactive materials escaped into the environment. Today, the soil in an area the size of Florida remains contaminated with radioactive waste.

26 The Quest to Control Fusion Second type of nuclear reaction is fusionSecond type of nuclear reaction is fusion –Combining of two atomic nuclei to produce a single larger nucleus In a nuclear fusion reaction, two nuclei combine to form a single larger nucleus. Two kinds of hydrogen nuclei are forced together in a fusion reaction.

27 Energy Conservation Although fossil fuels may never be completely used up, they will eventually become scarcer and more expensive.Although fossil fuels may never be completely used up, they will eventually become scarcer and more expensive. Nonrenewable fossil fuels generate over two thirds of the nation’s electricity. What can be done?What can be done? –find new sources of energy –make the fuels that are available now last as long as possible

28 Conservation and Efficiency Reducing energy use is called energy conservation.Reducing energy use is called energy conservation. Efficiency is the percentage of energy that is actually used to perform work.Efficiency is the percentage of energy that is actually used to perform work. LightingLighting –10 percent of the electricity in your home –Most of lights is lost on heat –Improve efficiency by changing to fluorescent bulbs Heating and CoolingHeating and Cooling –Loss of energy through roof and walls –Increase efficiency by adding insulation TransportationTransportation –Development of Hybrid cars. –Improve tires –Change the fuel to ethanol

29 What You Can Do You can reduce your personal energy use by changing your behavior in some simple ways.You can reduce your personal energy use by changing your behavior in some simple ways. –Keep your home cooler in winter and warmer in summer. Instead of turning up the heat, put on a sweater. Use fans instead of air conditioners. –Use natural light instead of electric lights when possible. –Turn off the lights or television when you leave a room. –Walk or ride a bike for short trips. Ride buses and trains. –Recycle, especially metal products. Recycling an aluminum can uses only 5 percent of the energy making a new can uses! The items in this list are small things, but multiplied by millions of people they add up to a lot of energy saved for the future.

30 Key Ideas A fuel is a substance that provides a form of energy as a result of a chemical change.A fuel is a substance that provides a form of energy as a result of a chemical change. Energy can be converted from one form to another.Energy can be converted from one form to another. The three major fossil fuels are coal, oil, and natural gas. These fuels release more energy when they are burned than most other substances do.The three major fossil fuels are coal, oil, and natural gas. These fuels release more energy when they are burned than most other substances do. Because fossil fuels take hundreds of millions of years to form, they are considered nonrenewable resources.Because fossil fuels take hundreds of millions of years to form, they are considered nonrenewable resources.

31 Key Ideas The sun constantly gives off energy in the form of heat and light. Solar energy can serve directly or indirectly as a renewable energy source.The sun constantly gives off energy in the form of heat and light. Solar energy can serve directly or indirectly as a renewable energy source. Because the sun causes winds and drives the water cycle, wind power and water power are considered indirect forms of solar energy.Because the sun causes winds and drives the water cycle, wind power and water power are considered indirect forms of solar energy. Biomass fuels, geothermal energy, and hydrogen power are other renewable energy sources that are currently in limited use.Biomass fuels, geothermal energy, and hydrogen power are other renewable energy sources that are currently in limited use.

32 Key Ideas Nuclear reactions include fission reactions and fusion reactions.Nuclear reactions include fission reactions and fusion reactions. In a fission reaction, the impact of a neutron splits an atom’s nucleus into two smaller nuclei and two or more neutrons. In a fusion reaction, two kinds of hydrogen nuclei are forced together. A large amount of energy is released in both processes.In a fission reaction, the impact of a neutron splits an atom’s nucleus into two smaller nuclei and two or more neutrons. In a fusion reaction, two kinds of hydrogen nuclei are forced together. A large amount of energy is released in both processes. In a nuclear power plant, the thermal energy released from controlled fission reactions is used to generate electricity.In a nuclear power plant, the thermal energy released from controlled fission reactions is used to generate electricity. Disadvantages of nuclear power include the risk of a meltdown and radioactive waste.Disadvantages of nuclear power include the risk of a meltdown and radioactive waste.

33 Key Ideas To avoid an energy shortage in the future, people must find new sources of energy and conserve the fuels that are available now.To avoid an energy shortage in the future, people must find new sources of energy and conserve the fuels that are available now. Insulation keeps a building from losing heat to, or gaining heat from, the outside.Insulation keeps a building from losing heat to, or gaining heat from, the outside. Ways to conserve energy use in transportation include making more efficient vehicles, carpooling, and using public transit.Ways to conserve energy use in transportation include making more efficient vehicles, carpooling, and using public transit.


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