Have you ever been so tired that you felt like you didn't have enough energy to get out of bed in the morning? You are too tired to get dressed, work, or play. To you the word energy has a special meaning. Most likely that meaning is not too much different from the simple definitions scientists use to define energy. Simply stated, energy is the ability to do work. Any object can do work if it has energy. For example you eat food to give you energy to live, run, play, and study. When you do work on an object, you give that object some of your energy. By kicking a ball, you do work on the ball. Now, the ball has energy to move. In doing work, you transfer energy from yourself to the ball.
Energy can be stored in fuels, or can be available from moving water and wind. In the video, stored energy released from coal or atoms heated water, changing it to steam. The steam turned turbines that then rotated generators. The video showed how moving water also turns turbines and rotates generators. The result was electric energy to send out to homes, businesses and factories. Regardless of its form, energy can change to other forms for our use. For example, turning on a light switch makes electrical energy available to light up your room. The generating plant converted energy from a fuel source to electricity. A light bulb converts electric energy to light and heat energy.
You know that appliances in your home help make work easier for you and your family. Energy released in gasoline engines also makes work and transportation easier. Simply, energy is the ability to do work.
In What Ways Do We Use More Energy Today?
Think about all the things you and your family do during a usual day. Many of these activities need electricity. Years ago, people did most of these jobs by hand and took more time to do them. Life today is very different from life only fifty years ago! Not only do we dress differently, we also use many machines that save us time. Most machines use energy, such as electricity, to do work. We also use energy to make these machines and to get rid of them when they wear out.
Think of how much energy goes into making a car. First, people who make cars must eat food. Growing and transporting their food uses energy. Second, many of the workers drive to and from the factory. Their cars use the energy from gasoline. In the factory electricity lights up the rooms and moves the assembly lines. In addition, furnaces burn coal or oil to heat the factory. The factory workers use electric tools to put the cars together. Finally, the finished cars are transported to many parts of the world by trucks, trains, and ships that use fuels.
The diagram compares how much energy people in Iowa use for different activities. These activities are grouped together as transportation, agriculture, residential, and industrial uses. Other activities consume the remainder of the energy used in Iowa. What were the largest uses of energy in Iowa in 1990? How do we use energy in the transportation, agricultural, residential and industrial parts of our society?
Each year we use more and more energy. More and more people travel by cars, trains, and airplanes. Farmers use machines to grow food. Factories manufacture more products that use energy. Since the year 1900, the amount of energy people in the United States use has doubled about every twenty years. To avoid running out of energy, we must plan our uses of energy wisely. We must learn how to use energy more efficiently. We can also search for sources of energy that will last a long time.
Think It Over:
1. In what ways do we use energy today?
2. What are the energy use classifications of our society?
3. How are we using more energy every year?
4. Challenge How has using energy improved our lives?
What Are Fossil Fuels?
Coal, petroleum, and natural gas are called fossil fuels because the energy in these fuels comes from the remains of dead organisms.
Millions of years ago, large swamps covered many parts of the earth. The plants that lived in the swamps captured the sun's energy and stored it in their leaves, stems, and roots. When the plants died, the stored energy became trapped in their remains. The plants formed thick layers of dead matter on the swamp floor. After millions of years, the layers of dead plant matter became the coal we use today.
The diagrams on this page show how this change happened. The dead plants started decaying as decomposers broke them down into simpler materials. When more dead plants fell on top of the decaying plants, the decomposers' oxygen supply was cut off. As a result, the plants decayed only partly. The layers of dead matter eventually formed a wet, spongy mass called peat. Later, seas flooded some of the peat. The floods covered the peat with thick layers of mud and rock. The peat was packed into a hard material as more layers pressed down on it over many years. Eventually the pressure produced heat in the lower layers. The heat and pressure chemically changed the peat into coal. Study the diagram and the explanations.
Click here to see the Coal
Formation Diagram
Did you know there is a coal mining industry in Iowa? Electric generation in Iowa burned approximately 380,000 tons of Iowa coal in 1990. Iowa utilities imported the remaining 97% of the coal used to generate electricity in Iowa at a cost of $420 million. Look at the state map of Iowa on this page. Which are the two Iowa coal mines closest to your hometown?
Now study the diagrams on the next page. They show several methods of coal mining. Make sure you know the differences between surface mining and underground mining.
Click here to see the Map of Iowa
Coal Mines
Click here to see Surface
Coal Mining
Click here to see Underground
Coal Mining
Petroleum is a liquid fuel formed from the remains of tiny ocean organisms that lived millions of years ago. Layers of sand and rock covered the partly decayed organisms on the ocean floor. Pressure and heat from the rock layers squeezed the dead matter into a thick liquid. After some time, this petroleum moved upward and became trapped between layers of rocks. Oil rigs drill wells into the rocks and pump out the petroleum. Oil companies clean the petroleum and separate it into gasoline, kerosene, oils, and waxes. About 0.23% of fuels used by Iowa's electric utilities is petroleum.
Some petroleum traps also have natural gas. The decaying organisms on the ocean floor released gases that became trapped in the rock layers that covered the organisms. The diagram below shows how oil and natural gas form.
Natural gas is an odorless, poisonous gas that burns easily. Utility companies add a strong odor to natural gas. This allows us to detect dangerous leaks in our gas supply. Large pipes carry natural gas from petroleum deposits to cities and towns. Gas appliances and furnaces burn natural gas for cooking food and heating homes. About 0.79% of fuels used by Iowa's electric utilities is natural gas.
Click here to see the Gasoline
Graphic
How Long Will Fossil Fuels Last?
Today, nearly 90 percent of all the energy used in Iowa comes from fossil fuels. People are using fossil fuels millions of times faster than the fuels are forming. Fossil fuels are nonrenewable energy sources because we cannot replace them as fast as we use them.
Another problem with using fossil fuels is the pollution they produce. Burning fossil fuels releases harmful gases and particles, such as sulfur dioxide and soot, into the air. These harmful products can cause health problems, kill wildlife, and damage buildings. Iowa depends upon coal for over 85% of its electric generation, yet coal is the "dirtiest" of the many fuels burned for energy. Burning coal releases gases such as carbon dioxide, methane, carbon monoxide and nitrous oxides, thought to cause global climate change. Coal burning releases toxic gases into the atmosphere and the residues, or ash, left after combustion are often hazardous, requiring special handling in landfills.
Fossil fuels probably will not meet Iowa's or our nation's growing energy needs. We should use fossil fuels wisely and efficiently so our supplies last longer. In the meantime we need to develop other types of energy sources.
The diagram shows current uses of fossil fuels. Study the diagram. How many ways do you use fossil fuels?
Think It Over:
1. Name three fossil fuels and explain how they form.
2. Why are fossil fuels nonrenewable energy sources?
3. Challenge How can fossil fuels be helpful and harmful?
How Do We Get Energy From Falling Water?
For hundreds of years, people used the energy of moving water to do work. Fast-flowing rivers or waterfalls were used to power water wheels. The moving water pushed against the blades of the water wheel, causing it to turn. The turning water wheel was connected to grindstones to grind grain. Other water wheels supplied the energy to operate large saws in lumber mills.
The energy of moving water can also produce electricity. In the video, you learned that some power plants use moving water to turn generators that produce electricity. Electricity produced by water power is called hydroelectric power
.Hydroelectric power plants are often built next to dams, where water flows from a high place to a low place. Look at the diagram below. Dams hold the water in a storage area until the water is needed to produce electricity. When needed to generate electricity, the dam gates open to release the stored water. The water rushes through pipes. The rapidly flowing water is piped into the power plant where it turns the fan-like blades of machines called turbines. The moving blades of the turbines turn a generator that produces electricity. Large cables carry the electricity to nearby towns and cities.
Is Moving Water a Good Energy Source to Use?
We do not have to worry about running out of water, as we do with fossil fuels. Falling water is a renewable energy source because rainfall and melting snow replace the water we use in a short time. Water also is a good energy source because it does not pollute the air as fossil fuels do.
Energy from moving water can only be used in areas with rivers with dams or waterfalls. In countries with many rivers, such as New Zealand, power plants use moving water to produce most of the electricity used. In the United States, hydroelectric power plants produce about one-seventh of the electricity we use. Areas that are dry or have few rivers cannot rely on moving water as an energy source.
At one time more than 30 different hydroelectric power plants were operating in Iowa. Because of low fossil fuel prices and mechanical failures, owners shut down or abandoned many of the plants. Currently there are eight hydroelectric plants generating electricity. These eight plants produce 2.3% of the state's electricity. This represents 1% of the total energy consumed in Iowa in 1990.
Think It Over:
1. How can water wheels do work?
2. How is hydroelectric power generated?
3. How do dams and power plants work together to produce electricity?
4. Challenge How is a water wheel similar to a turbine in a hydroelectric power plant?
How Do We Get Energy From Atoms?
We can get energy from an atom by shooting particles at the central part, or nucleus, of the atom. The nucleus splits and releases large amounts of energy. Power plants can use this energy to produce electricity.
The diagram shows the process used to release energy from the nucleus of an atom, or nuclear energy. A moving neutron particle hits an atomic nucleus, causing the nucleus to split into two smaller nuclei. The splitting nucleus releases neutrons and huge amounts of energy. Some of these neutrons hit other nuclei that also split. This releases more neutrons and energy. The collisions between the neutrons and nuclei continue on and on in a chain reaction. Each collision releases huge amounts of energy.
The splitting of atomic nuclei, or nuclear fission, can be harmful or helpful. In an uncontrolled reaction, so many collisions occur that the energy is released in an explosion. An atom bomb explosion results from an uncontrolled chain reaction. But scientists can decrease the collisions in a chain reaction by removing some of the neutron particles released by the splitting atoms. Nuclear power plants control the nuclear energy released and use it to produce electricity.
Nuclear power plants usually split uranium atoms to produce nuclear energy. This nuclear fission takes place in a container, such as the one in the picture. The container controls the nuclear fission so that it does not produce an explosion. The nuclear energy produced in a nuclear power plant heats large amounts of water to a high temperature. The hot water heats pipes carrying cooler water that boils into steam. The steam turns a turbine that turns an electrical generator. The electricity produced provides energy for homes, businesses, and factories.
A single gram of uranium can produce as much heat as 3 million grams of coal. The nuclear fission of uranium atoms provides enough energy to last a long time. Submarines and spacecraft can travel for months using small amounts of nuclear fuel. Today, many communities in the United States get their electricity from nuclear power plants. Some people prefer using nuclear energy to produce electricity because it does not pollute the air as fossil fuels do.
Can Nuclear Energy Be Dangerous?
Nuclear energy has received attention as a "clean" fuel source. Nuclear generating plants emit almost no gases that might pollute the environment. However many people have concerns about possible problems caused by nuclear waste disposal and by the possibility of harmful accidents.
Nuclear fission produces radioactive wastes that give off harmful particles and rays. In large amounts these particles and rays can make people ill. Hundreds or thousands of years must pass before some radioactive wastes change into harmless substances. As a result, nuclear power plants have to store the radioactive wastes they produce. They store some wastes in large containers. The containers have thick walls that help stop the radioactive wastes from leaking through.
Some people think radioactive wastes eventually will leak through the storage containers. Other people are afraid that accidents might happen in the nuclear power plant, which would release large amounts of radioactive wastes into the environment.
Think it over:
1. How do we use nuclear fission to produce electricity?
2. Why are radioactive wastes potentially harmful to people for hundreds of years?
3. Challenge How can nuclear energy be both helpful and harmful?
In What Ways Do We Use More Energy Today?
1. Answers will vary.
2. Transportation, commercial and industrial, residential, agricultural, other.
3. We use more transportation; we have more appliances in our homes; business, industry, and agriculture use more technology to produce and sell their products; we use more energy for recreational and entertainment activities, etc.
4. We are able to do things in faster and more convenient ways. (Students may give more specific examples.)
What Are Fossil Fuels?
1. Coal is formed when decaying plants form peat and pressure and heat change the peat into coal. Petroleum is liquid fuel formed from the remains of tiny ocean organisms that were partly decayed on the ocean floor. Natural gas is released from decaying organisms on the ocean floor and gets trapped in layers of rock.
2. Because we cannot replace them as fast as we use them.
3. Fossil fuels are helpful because they provide us with the energy we need for everyday living, and they are harmful because burning them releases harmful gases and pollutants that can cause health problems and environmental problems.
Is Moving Water a Good Energy Source To Use?
1. Water wheels have been used to operate grindstones for grinding grain and large saws to cut lumber.
2. Hydroelectric power is generated from falling water.
3. The dam holds the water in a storage area. The gates open to release stored water, which flows many meters downward. It is piped into the power plant to turn the blades of turbines, which turn generators that produce electricity.
4. Both have blades which can be turned by moving water.
Can Nuclear Energy Be Dangerous?
1. Nuclear fission produces heat, which can be used to turn water into steam. The steam turns a turbine that turns a generator.
2. It takes that long for them to change into harmless substances. They give off harmful particles and rays for many years.
3. Nuclear energy can help reduce air pollution because it emits almost no gases into the environment. Use of nuclear energy can help conserve fossil fuels. The radioactive wastes given off by nuclear fission can be harmful if they are not disposed of safely or if there are accidents at nuclear power plants.
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