2 WondersofWater
Energy is many things. Energy is light. Energy is heat. Energy makes things grow. Energy makes things move. Energy is electricity to run machines. Energy is the power to change things. Energy is the ability to do work.
What is Energy?
Energy is LightWe use light energy to see. Our light during the day comes from the sun. At night, we turn on light bulbs powered by electricity. We also burn candles. Flashlights use batteries to make light.
Energy is HeatWe use energy to make heat. We burn fuel to cook our food. The food we eat helps our bodies stay warm. When it is cold outside, we use energy to heat our homes. A campfire makes heat, too.
Factories burn fuel to make the products they sell. Some power plants burn coal and natural gas to make electricity.
Energy Makes Things GrowAll living things need energy to grow. Plants use light from the sun to grow. Plants change the sun’s energy into sugar. The sugar is stored in their roots and leaves and provides nourishment for the plant. This process is called photosynthesis.
Animals cannot change light energy into sugars. Neither can people. We eat plants and use the energy stored in them to grow.
Light
Heat
Tree
e
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Energy Makes Things MoveIt takes energy to make things move. Cars use the energy in gasoline to speed down the highway. Many toys run on the energy stored in batteries. Sailboats glide across the bay, pushed by the energy in the wind.
Water flows down creeks and rivers from mountain tops to the ocean, pulled by the force of gravity. Leaves that fall from the trees on the river bank are carried down by the water, too.
After a long game of soccer, you may feel too tired to move. You’ve run out of energy. You need to eat some food to refuel.
Energy Runs MachinesIt takes energy to run our TVs, video games, computers, and microwaves. This energy is in the form of electricity.
We use electricity every day. It gives us light and heat. It runs our games and appliances. What would your life be like without electricity?
We can make electricity by burning coal, oil, gas, and even trash. We can make electricity from the energy that holds atoms together. We can make electricity with energy from the sun, the wind, and moving water.
Computer
4 WondersofWater
Energy is ChangeWhen we use energy, it does not disappear. We change it into other forms of energy. When we burn wood, we change its energy into heat and light. When we drive a car, we change the energy in gasoline into heat and motion. When we eat food, we change its energy into motion and heat.
Energy is the Ability to Do WorkThe word work means many things. Your parents may leave the house every morning to go to work. Exercise is often called working out. Your teacher gives you homework to do. You might think that work is the opposite of play.
In science, work has a different meaning. Work is using a force to move an object across a distance. To do work, there must be energy. Energy is the ability to do work.
Think about playing soccer. A soccer ball cannot move by itself. You must kick it. The food you eat gives your body energy. Your muscles use this energy to kick (a force) the ball.
The soccer ball (the object) rolls (moves) across the field (distance) to score a goal. You have just done work! Would you have done work if you had missed the goal? Yes, the ball still moved across a distance.
GAS STATION
SOCCER
Energy allows you to play soccer and move the ball down the field.
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Energy SourcesIn the United States we use ten energy sources to do work. We put these sources into two categories: nonrenewable and renewable.
The nonrenewable energy sources we use are petroleum, coal, natural gas, propane, and uranium. These sources are found in the Earth. It takes a very long time for the Earth to produce these sources. Once we use them, we can’t use them again or get them back quickly. We use nonrenewable energy sources to move our cars, heat our homes, and make electricity.
Renewable energy sources can be used over and over again. It does not take very long to replenish the supply of these resources, so we will never run out. Renewable energy sources are biomass, hydropower, solar energy, wind energy, and geothermal energy. Day after day, the sun shines, the wind blows, and the rivers flow. We use renewable energy sources mainly to make electricity.
Nonrenewable sources are relatively inexpensive and we can use them 24 hours a day. Some renewable sources like solar and wind are free to use, because no one owns the sun or the wind. The machines and parts needed to turn these sources into energy we can use can be expensive, however. Every source of energy has advantages and disadvantages to using it.
Data: Energy Information Administration
BIOMASS 5%Uses: heating, electricity,transportation
HYDROPOWER 3%Uses: electricity
NATURAL GAS 26%Uses: heating,manufacturing, electricity
PETROLEUM 35%Uses: transportation,manufacturing
PROPANE 2%Uses: heating,manufacturing
URANIUM 8%Uses: electricity
WIND 1%Uses: electricity
SOLAR <1%Uses: heating, electricity
Nonrenewable Sources
Nonrenewable Energy Sources and Percentage of Total Energy Consumption
Renewable Sources
Renewable Energy Sources and Percentage of Total Energy Consumption
91%9%
10% 20% 30% 40% 50% 60% 70% 80% 90% 100%0%PERCENTAGE OF UNITED STATES ENERGY USE
U.S. Consumption of Energy by Source, 2011
COAL 20%Uses: electricity,manufacturing
GEOTHERMAL <1%Uses: heating, electricity
6 WondersofWater
Electricity is MysteriousElectricity is a mysterious form of energy. We cannot see it like we see the sun. We cannot hold it like we hold coal. We know when it is working, but it is hard to understand exactly what it is.
Before we can understand electricity, we need to know about atoms.
What are Atoms?Everything is made of atoms—every star, every tree, every animal. Even you and I are made of atoms. The air and water are too. Atoms are the building blocks of the universe. They are very, very tiny particles. Millions of atoms would fit on the head of a pin.
Atoms are Made of Even Smaller ParticlesAn atom looks like the sun with the planets spinning around it. The center is called the nucleus. It is made of protons and neutrons. Electrons move around the nucleus in clouds, or energy levels, far from the nucleus.
Electricity
PROTON
NEUTRONNUCLEUS
ELECTRON
Atom
LIGHTNING
Lightning is a form of electrical energy.
Atom
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Protons and Electrons Attract Each OtherElectrons stay in their levels because a special force holds them there—protons and electrons are attracted to each other. Protons have a positive charge (+) and the electrons have a negative charge (–). Opposite charges attract each other.
Electricity is Moving ElectronsThe electrons near the nucleus are held tight to the atom. Sometimes, the ones farthest away are not. We can push some of these electrons out of their energy levels. We can move them. Moving electrons are called electricity.
Magnets are Special We call one end of a magnet the north (N) pole and the other end the south (S) pole. A magnet is a special type of material that has a force of energy around it called a magnetic field. The force of the magnetic field flows from the north pole to the south pole.
Have you ever held two magnets close to each other? They do not act like most objects. If you try to push the two north poles together, they repel each other. If you try to push the two south poles together, they repel each other.
Turn one magnet around and the north and the south poles attract. The magnets stick to each other with a strong force. Just like protons and electrons, opposites attract.
Bar Magnet
Like PolesLike poles of magnets (N-N or S-S) repel each other.
Opposite PolesOpposite poles of magnets (N-S) attract each other.
OUTER ENERGY LEVEL
Carbon AtomA carbon atom has six protons and six neutrons in the nucleus, two electrons in the inner energy level, and four electrons in the outer energy level.
INNER ENERGY LEVEL
PROTONS (+)
ELECTRONS (–)
NEUTRONS
NUCLEUS
Like Poles
Opposite Poles
Bar Magnets
Carbon Atom
A carbon atom has six protons and six neutrons in the nucleus, two electrons in the inner energy level, and four electrons in the outer energy level.
Like poles of magnets (N-N or S-S) repel each other.
Opposite poles of magnets (N-S) attract each other.
8 WondersofWater
Magnets Can Make ElectricityWe can use magnets to make electricity. A magnetic field can push and pull electrons to make them move. Some metals, like copper, have electrons that are easily pushed from their energy levels.
Magnetism and electricity are related. Magnets can create electricity and electricity can create magnetic fields. Every time a magnetic field changes, an electric field is created. Every time an electric field changes, a magnetic field is created.
Magnetism and electricity are always linked together; you cannot have one without the other. This is called electromagnetism.
Power Plants Use MagnetsPower plants use huge magnets to make, or generate, electricity. In a generator, big coils of copper wire spin inside the magnets. As they spin, the magnetic fields push and pull electrons in the wire. But how do we make the generator spin to generate electricity?
We need energy to run the generator to make electricity. A device called a turbine is connected to the generator to make it spin. A turbine is made of several blades, like a fan. These blades spin and are connected to a rod or shaft that turns the coils or magnets in the generator. We can make a turbine spin using moving air, water, or steam.
We Generate Electricity With Many Fuels In the U.S., coal is the top energy source for making electricity. It generates about 42% of the electricity we use. Power plants burn the coal to heat water. When the water gets very hot, it expands and turns into steam. The steam is under high pressure and rushes through pipes to spin turbines. The turbines are connected to generators. As the turbines spin, the generators spin to make electricity.
Moving water—hydropower—is the leading renewable energy source that generates electricity. In a hydropower plant, the flowing water is used to spin turbines to generate electricity.
GENERATOR
MAGNETS
COPPER COILS
ROTATING SHAFT
The copper coils spin inside a ring of magnets. This creates an electric �eld, producing electricity.
Generator
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We Get Our Electricity Through WiresA power plant makes electricity. The electricity flows through power lines called transmission lines held up by power towers. The transmission lines carry large amounts of electricity to electric poles in cities and towns.
Distribution lines carry small amounts of electricity from the electric poles to houses and businesses. The electricity flows through the wires in our homes, providing the energy to operate our lights, machines, and appliances.
There are Other Ways to Produce ElectricityElectricity can also be produced in other ways. A solar cell turns radiant energy from the sun into electricity. A battery turns chemical energy into electricity.
A battery produces electricity using two different metals in a chemical solution. A chemical reaction between the metals and the chemicals pushes electrons free from their energy levels.
One end of the battery is attached to one of the metals; the other end is attached to the other metal. One end has more electrons pushed away and develops a positive charge. The other end develops a negative charge. If a wire is attached from one end of the battery to the other, electrons flow through the wire to balance the electrical charge.
A load is a device that does work or performs a job. If a load—such as a light bulb—is placed along the wire, the electricity can do work as it flows through the wire.
In the picture of the battery and the light, electrons flow from one end of the battery through the wire to the light bulb. The electricity flows through the wire inside the light bulb and back to the other end of the battery.
Transporting Electricity
Power Plant
Transformers
Transmission Lines Power Tower
Home
Distribution Lines
Electric Poles
10 WondersofWater
Electricity Flows in CircuitsElectricity travels in closed loops called circuits. Electricity must have a complete path before the electrons can move. If a circuit is open, the electrons cannot flow. When we flip on a light switch, we close a circuit. The electric current flows from the wire through the light and back into the wire. When we flip the switch off, we open the circuit. No electricity flows to the light.
When a light bulb burns out, the circuit is also opened. The path through the bulb is gone. The bulb will no longer light.
We Use Electricity Every DayElectricity does a lot of work for us. We use it many times each day. It lights our homes, warms and cools them, and helps us keep them clean. It runs our TVs, VCRs, DVD players, video games, computers, and fax machines. It cooks our food and washes our dishes. It can power our lawn mowers. It can even run our cars.
Electricity is different from the other energy sources because it is a secondary source of energy. We must use another energy source to produce it.
A closed circuit is a complete path allowing electricity to ow from the energy source to the load.
ENERGY SOURCE
WIRESFLOW OF ELEC TRONS
LOAD
CLOSED SWITCH
An open circuit has a break in the path. There is no ow of electricity because the electrons cannot complete the circuit.
ENERGY SOURCE
WIRES
LOAD
OPEN SWITCH
+–
+–
Electrical Circuits
FLOW OF ELEC TRONS
Microwave Projector
Television Video Game System
Machines That Use Electricity
Electric Circuits
A closed circuit is a complete path allowing electricity to flow from the energy source to the load.
An open circuit has a break in the path. There is no flow of electricity because the electrons cannot complete the circuit.
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Water is Found in Three States of MatterWater covers 75 percent of the Earth’s surface. It is found in three states of matter: solid, liquid, and gas. The solid state is ice. The liquid state is water. The gas state is often invisible and is called water vapor.
Water can change between these states in six ways:
• Freezing changes liquid water into ice.
• Melting changes ice into liquid water.
• Evaporation changes liquid water into water vapor.
• Condensation changes water vapor into liquid water. For example, morning dew on the grass comes from water vapor.
• Sublimation changes ice or snow into water vapor without passing through the liquid state. The ice or snow seems to disappear without melting first.
• Deposition changes water vapor into ice without the vapor becoming a liquid first. Water vapor falls to the ground as snow.
Wonders of Water
Liquid: WaterSolid: Ice Gas: Water Vapor
Machines That Use Electricity
12 WondersofWater
Water Changes State in a CycleOn Earth, water is continually changing from a liquid state to a vapor state and back again. Energy from the sun evaporates liquid water from oceans, lakes, and rivers, changing it into water vapor.
As warm air over the Earth rises, it carries the water vapor into the atmosphere where the temperatures are colder. The water vapor cools and condenses into a liquid state in the atmosphere. It forms clouds. Inside of clouds, drops of water join together to form bigger and bigger drops. As the drops become heavy, they start to fall. The clouds release the liquid water as rain or snow that falls back to Earth. It is pulled to the ground by the force of gravity.
The rivers, lakes, and oceans are replenished, and the cycle starts again. This is the water cycle.
SOLAR ENERGY
CONDENSATION(Gas to Liquid)
PRECIPITATION(Liquid or Solid)EVAPORATION
(Liquid to Gas)EVAPORATION(Liquid to Gas)
OCEANS, LAKES, RIVERS(Liquid)
The Water CycleThe Water Cycle
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Water has Been Used as a Source of Energy for Many YearsWater has been used as a source of energy for centuries. The Greeks used water wheels to grind wheat into flour more than 2,000 years ago. In the early 1800s, American and European factories used water wheels to power machines.
The oldest dams were built over 5,000 years ago to irrigate crops in Mesopotamia. In 2900 BC, Egyptians in the city of Memphis built a dam around the city. The dam protected the city from flooding by the Nile River and created a reservoir for drinking water.
In 1881, the street lamps in Niagara Falls, NY were lit using hydropower. Today, there are about 84,000 dams in the United States, but only 2,200 were built to generate electricity. The rest were built to control flooding, irrigate crops, or provide a reliable water supply.
Water wheel
Niagara Falls
14 WondersofWater
A Dam That Generates Electricity is a Hydropower PlantHydropower (hydro means water) is energy that comes from the force of moving water. Usually a dam is built across a river, forming a lake called a reservoir behind the dam.
There are three main parts of a hydropower plant. The reservoir stores the water. The dam holds back the water. There are openings in the dam to control its flow. The power plant captures the energy of the moving water using a turbine.
The process begins with water flowing from the reservoir into penstocks, which are very large pipes. The distance the water drops is called the head; the farther the water drops, the greater the head. The amount of moving water is called the flow; more flow equals more force.
The water flows down the penstocks to turbines at the bottom, spinning the turbines to power generators. The generators use the motion energy from the turbine to produce electricity. The electricity is sent to power lines that carry it to consumers.
The water that entered the penstocks returns to the river below the dam and continues its downstream journey.
Electricity from HydropowerAbout 17 percent of the world’s electricity is from hydropower. In the United States, 5–10 percent of our electricity comes from hydropower, depending on rainfall. In 2011, eight percent of U.S. electricity was made using hydropower. That’s enough power for 28 million households.
Using hydropower to produce electricity has many advantages, but it has disadvantages too because of its impact on the environment.
RIVER
SWITCHYARD
view from aboveMAGNETS
COPPER COILS
ROTATING SHAFT
1. Water in a reservoir behind a hydropower dam �ows through an intake screen, which �lters out large debris, but allows smaller �sh to pass through.
2. The water travels through a large pipe, called a penstock.
3. The force of the water spins a turbine at a low speed, allowing �sh to pass through unharmed.
4. Inside the generator, the shaft spins coils of copper wire inside a ring of magnets. This creates an electric �eld, producing electricity.
5. Electricity is sent to a switchyard, where a transformer increases the voltage, allowing it to travel through the electric grid.
6. Water �ows out of the penstock into the downstream river.
GENERATOR
GENERATOR
TURBINE
RESERVOIR
IntakeDAM
PENSTOCK
DETAIL
1
2
3
45
6
Hydropower PlantHydropower Plant
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Building Hoover DamThe Hoover Dam is located on the Colorado River, about 30 miles southeast of Las Vegas, Nevada. It was built in the early 1930s during the Great Depression, providing jobs for thousands of workers.
Hoover Dam is 726.4 feet tall from the foundation to the roadway on the top of the dam. It provides electricity, flood control, and irrigation to areas of the Southwest.
Before construction of the dam could begin, the Colorado River had to be moved around the construction site. Four tunnels were drilled through the canyon walls, two on each side of the canyon. Next, temporary earthen cofferdams were built above and below the site to force the river water through the tunnels and protect the construction site.
There are 4,360,000 cubic yards of concrete in the dam and power plant. This much concrete would pave a highway from San Francisco to New York City—a distance of more than 2,500 miles.
It took five years to build the dam and power plant. About 21,000 men worked on the dam—an average of 3,500 men daily. A total of 96 men died due to construction of the dam. No one is buried in the concrete, although tales about buried bodies have been told for years.
Before construction of the dam could begin, the following projects had to be completed:
• the construction of a new town, Boulder City, to house the workers;
• the construction of seven miles of highway from Boulder City to the dam site;
• the construction of over 32 miles of railroad from Las Vegas to Boulder City to the dam site; and
• the construction of a 222-mile-long power transmission line from California to the dam site to supply electricity for construction.
Once the dam was completed, a reservoir formed behind the dam called Lake Mead. The lake is an attraction to boaters, swimmers, and fishermen. The Lake Mead National Recreation Area is home to thousands of desert plants and animals that can survive in an extreme place where rain is scarce and temperatures can soar over 100 degrees.
Summarized from the U.S. Department of the Interior, U.S. Bureau of Reclamation web site: www.usbr.gov/lc/hooverdam/faqs/damfaqs.html.
16 WondersofWater
Advantages of Hydropower �Hydropower is a clean energy source. It is fueled by moving water, so it doesn’t produce pollution or emissions. Hydropower does not add greenhouse gases to the atmosphere.
�Hydropower is a renewable energy source. It relies on the water cycle, which is driven by the sun. The total amount of water in a hydropower system does not change.
�Hydropower is available when it is needed. The flow of water through a dam can be controlled to produce electricity when it is needed.
�Hydropower is an inexpensive way to produce electricity. The electricity generated by hydropower facilities is the cheapest electricity in the country.
�Dams create reservoirs that offer a wide variety of benefits. People use the reservoir for fishing, swimming, and boating.
�Hydropower facilities can help manage the water supply. They provide flood control and a reliable supply of drinking water.
�Hydropower dams are very safe and durable. They are built to last for hundreds of years.
Disadvantages of Hydropower �Hydropower plants depend on the water supply. When there is a drought, hydropower plants cannot produce as much electricity as when there is plenty of rain.
�Hydropower dams on rivers permanently change the ecology of large areas of land, upstream and downstream. When a dam is built, the reservoir floods large areas of land upstream from the dam. The natural ecology of the river downstream is changed, too.
�Hydropower dams can affect water quality. Reservoirs can change the amount of oxygen in the water, which can be harmful to fish and other creatures downstream.
�Dams can block fish from migrating. Some fish populations, such as salmon, migrate upstream to lay eggs and migrate downstream to return to the ocean or usual habitat. Fish ladders may be built to help fish swim upstream. Fish may be sent through specially designed spillways or bypasses as they head downstream.
Glen Canyon Dam
Fish BypassImage courtesy of Grant County Public Utility District
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The Future of HydropowerWe probably will not build any more large hydropower dams in the United States. We already have dams in most of the best places. That does not mean we will not use more hydropower in the future, though. The U.S. plans to get much more electricity from hydropower.
The U.S. Department of Energy conducts research on hydropower, such as:
�ways to generate more electricity from existing hydropower dams;
�ways to add turbine generators to existing dams that do not produce electricity now; and
�ways to use the energy of moving water in the ocean.
Generating More Electricity from Existing Hydropower PlantsSome reservoirs have more water than the power plants can use. They release the extra water through spillways. At some of these power plants, they are installing more penstocks and turbines. The extra water flows through the penstocks and spins the turbines to make more electricity.
The turbines in some hydropower plants are very old. Scientists are designing new turbines that are more efficient. Power plants are replacing the old turbines with new ones so that they can make more electricity with the same amount of water.
Adding Turbine Generators to Existing DamsThere are 84,000 dams in the United States, but only a small amount of these were built to generate electricity. Many of the others are used to control the water supply. They are designed to release the amount of water that is needed by the people downstream every day. They hold extra water to help prevent flooding when there is too much rain. They release extra water to help prevent drought when there is too little rain.
We could add power plants to many of these dams. The water would produce electricity as it is released through the power plant, then would flow down the river to the people who need it. We could generate much more electricity by adding power plants to existing dams.
GeneratorsAt the Safe Harbor Hydroelectric Plant in Pennsylvania
18 WondersofWater
Energy from TidesNear shore, the oceans and seas rise and fall with the tides. Tides have an enormous amount of energy. Some power stations harness the energy in the changing tides to make electricity. Tides are caused by the force of gravity between the Earth and the moon.
The moon pulls on the water that is closest to it. This creates a bulge in the surface of the water, called a tidal bulge.
Because the Earth is rotating, the water on the opposite side of the Earth also forms a tidal bulge. These bulges produce high tides. Between the tidal bulges is lower water that produces low tides.
Tidal BarrageOne kind of power plant that captures the energy in the tides is called a tidal barrage. A tidal barrage is built across the area where a river runs into the ocean. The water here rises and falls with the tides.
A tidal barrage is like an underwater dam with turbines. As the tide rises, the water flows through the barrage, and spins the turbines. When the tide drops, the water flows back to the ocean. The water again turns the turbines. The turbines spin to generate electricity when the water is flowing into and out of the river.
EARTHMOON
Gravitational Attraction
Rotation of the Earth
NEAR TIDAL BULGEFAR T
IDAL
BULG
E
Tidal Bulge
TIDAL FLOWDIRECTION
DAM
TURBINE
Tidal water is captured at high tide behind a dam. When the tide turns, the water is released to the sea, passing through a set of turbines.
Tidal Barrage
A marine turbine like this one can be used to generate tidal energy.
Tidal Bulge
Tidal Barrage
Tidal water is captured at high tide behind a dam. When the tide turns, the water is released to the sea, passing through a set of turbines.
Image courtesy of OpenHydro
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Tidal Stream PowerTidal stream power captures the energy in ocean currents. Underwater turbines can be installed in the ocean in places with strong ocean currents.
Marine Current Turbines Ltd, a company in Bristol, England, created the world’s largest system to capture the energy in ocean currents. It is called the SeaGen S. A SeaGen S is operating off of the east coast of Northern Ireland.
The SeaGen S consists of two large rotors, each powering a generator. A rotor is the spinning part of a power system—much like a turbine. These rotors are attached like wings on either side of a steel tower that is set into a hole drilled in the sea floor.
The city and state of New York are working with Verdant Power to harness the energy of the tides in the East River.
In 2012, the state of Maine started using our country’s first tidal power system like this to generate power. This system could power approximately 2,000 homes.
From 2006-2009 six turbines were connected to the electric power grid to test the technology and effects of tidal turbines. They studied how electricity is generated from tidal power and monitored the environmental impacts of the turbines.
Verdant Power recently received permission to install 30 turbines that will generate electricity for local customers in the future.
Wave EnergyOcean waves are caused mainly by wind. The size of waves depends on how fast the wind blows, how long it blows, and how far it blows over the water. Usually, the farther the wind travels over water, or the harder it blows, the higher the waves. A strong breeze can cause waves 10 feet high.
SeaGen S System
A turbine being installed in East River, NY.Image courtesy of Verdant Power
Image courtesy of Marine Current Turbines Ltd
20 WondersofWater
Capturing Wave EnergyThe energy in waves can be used to generate electricity. The waves off the northwest coasts of the U.S. would be good for making electricity.
One way to capture wave energy is with a device called an oscillating water column. It is basically a big pipe called a chamber with a turbine inside. One end of the chamber is always in the water.
As the waves flow into the chamber, the air inside the chamber is pushed through a turbine, making it spin. A generator connected to the turbine produces electricity. As the waves flow out of the chamber, air from outside is pulled in, spinning the turbines again.
There are also floating devices that can capture the energy in the waves. They make electricity as they move up and down with the waves.
In 2012, a wave power farm was approved to be placed off the Oregon coast. This farm will use computerized buoys over 100 feet long. It is the first wave power station permitted in the U.S.
CHAMBER
VENT TURBINE
WAVE
Air pushedthrough by
incoming wave
VENT TURBINE
CHAMBER
WAVE
CLIFF FACE
VENT TURBINE
WAVE
CHAMBERAir pulled back
as waveretreats
Oscillator Water Column
FLOATING TUBES
JOINTSPOWER CABLE
Wave Energy Converter
Waves cause each buoy to rise and fall like a giant sea snake. The motion tugs at the joints linking the tubes. The joints act as a pump, pushing oil through motors that drive the generators to produce electricity. The wave energy buoys will be connected to the seafloor, and to customers with underwater power cables.
Wave Power Buoys
Oscillating Water Column
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Energy KWL ChartOscillating Water Column
What I Think I Know What I Want to Know What I Learned
e
22 WondersofWater
Forms of Energy
Energy is Light
Energy is Motion
Energy is Electricity
Energy is Heat
Energy is Growth
Energy is the ability to do work or make a change. There are many forms of energy—light, heat, growth, motion, and electricity. Write all the ways you see energy at work in your classroom and around your school.
e
©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 23
The Energy We UseMake a graph showing how much energy each source provides the United States. Write the names of the energy sources in the boxes at the bottom of the graph and fill in the columns to show the percentage each source provides.
Data: Energy Information Administration
BIOMASS 5%Uses: heating, electricity,transportation
COAL 20%Uses: electricity,manufacturing
GEOTHERMAL <1%Uses: heating, electricity
HYDROPOWER 3%Uses: electricity
PETROLEUM 35%Uses: transportation,manufacturing
PROPANE 2%Uses: heating,manufacturing
URANIUM 8%Uses: electricity
WIND 1%Uses: electricity
SOLAR <1%Uses: heating, electricity
RENEWABLENONRENEWABLE
U.S. Energy Consumption by Source, 2011
NATURAL GAS 26%Uses: heating,manufacturing, electricity
E N E R G Y S O U R C E S
P E R C E N T A G E T H E S O U R C E P R O V I D E S50%
40%
30%
20%
10%
0%
e
©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 25
The Electricity We UseMake a graph showing how much electricity each source provides the United States. Write the names of the energy sources in the boxes at the bottom of the graph and fill in the columns to show the percentage of electricity each source provides.
Coal 42%Natural Gas 25%Uranium 19%Hydropower 8%Wind 3%Biomass 1%Petroleum 1%Other 1%
E N E R G Y S O U R C E S
P E R C E N T A G E T H E S O U R C E P R O V I D E S50%
40%
30%
20%
10%
0%
26 WondersofWater
Science of ElectricityAfter observing the science of electricity model, draw and label a diagram of the device.
Explain how electricity was created or generated with the device.
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©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 27
Water and Energy KWL ChartWhat I Think I Know What I Want to Know What I Learned
28 WondersofWater
Word Bank
condensationliquidevaporationoceanlakecloudriverairsolar energyatmospheregasprecipitationwater vaporwatergravity
The Water CycleDraw a picture of the water cycle. Include arrows and labels to identify each step of the cycle. On the lines below, write a paragraph describing how the water cycle works. You may use the words in the word bank as labels on your picture and in your written explanation.
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©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 29
Land and Water 1? QuestionHow does water change land?
Materials
HypothesisRead the procedure. Complete this hypothesis sentence:If I pour water onto the land, the land will ________________________________________________
because ___________________________________________________________________________.
Procedure1. Put sand in the closed end of the pan to a depth of 5 centimeters (cm) as shown in the picture below.
2. Smooth the top of the sand.3. Place the end of the pan with the drain hole over a sink or bucket.4. Raise the end of the pan with the sand 5 centimeters.
5. Hold the beaker of water 10 centimeters above the sand and pour it onto the end in a slow, steady stream as shown in the picture below.
6. Record your observations on the next page.
© 2009 THE NEED PROJECT • PO BOX 10101 • MANASSAS, VA 20108 • 1-800-875-5029 Wonders of Water Student PAGE 27
© 2009 THE NEED PROJECT • PO BOX 10101 • MANASSAS, VA 20108 • 1-800-875-5029 Wonders of Water Student PAGE 27
� Wallpaper pan � Sand � Beaker with 300 mL of water
� Ruler � Sink or bucket
30 WondersofWater
Land and Water 1 ObservationsDraw top-view pictures of the pan with the sand before and after you poured the water.
Pan Before Water Pan After Water
Explain what happened in your investigation.
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©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 31
Land and Water 2AssignmentPlan an investigation of your own with your pan and sand, using one of the following ideas:
� Mold the sand with your hands to create mountains and valleys. � Pour the water from different heights. � Pour the water at different speeds. � Raise the end of the pan to different heights. � Place an object in the path of the water.
? Question
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Hypothesis
If ________________________________________________________________________________________
then ______________________________________________________________________________________
because __________________________________________________________________________________.
X Controlled Variables (What stays the same?):
_____________________________________________ ___________________________________________
_____________________________________________ ___________________________________________
Y Manipulated Variable (What one variable are you changing?):
Z Responding Variable (What are you measuring?):
Procedure
1. ________________________________________________________________________________________
2. ________________________________________________________________________________________
3. ________________________________________________________________________________________
4. ________________________________________________________________________________________
5. ________________________________________________________________________________________
6. ________________________________________________________________________________________
7. ________________________________________________________________________________________
Observations Teacher’s Approval of PlanRecord your observations on the next page.
32 WondersofWater
Land and Water 2 ObservationsDraw top-view pictures of the pan with the sand before and after you poured the water.
Pan Before Water Pan After Water
Explain what happened in your investigation.
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©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 33
Hydropower PlantLabel the parts of a hydropower plant in the boxes.
Explain how a hydropower plant works and the flow of energy through the plant.
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34 WondersofWater
Moving Water Can Do Work? QuestionHow can water do work?
Materials � 1 Round-barrel pencil � 2 Foam cups � 30 cm Thread � 1 Foam craft ball � 4 Blades � Scissors
� Glue � Tape � Water � Paper clips � Ruler
Procedure, Part 11. Make a hole through the middle of the foam ball with the pencil as shown in Diagram 1. Slide the foam ball
to the middle of the pencil. Place rings of glue on either side to secure the ball to the pencil.2. Insert four blades into the foam ball at equal distances from each other, as shown in Diagram 2. Glue the
blades into place and let dry. 3. Cut two small V-shaped grooves on opposite sides of the top of the cup as shown in Diagram 3.4. Tie one end of a piece of thread to a paper clip. Tape the other end of the thread to the pencil as shown in
Diagram 4.5. Place the pencil into the grooves on the cup so the foam ball is in the center of the cup. Adjust and re-glue
the blades so that they do not hit the edge of the cup.6. When the blades are dry, place the water wheel system at the edge of a table so the one paper clip hangs off
the table.7. Get a second cup and fill it nearly full with water. Pour the water slowly and evenly onto the blades, as shown
in Diagram 5 on the next page. What happens? Record your observations.
Observations
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CONTINUED ON THE NEXT PAGE
©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 35
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? QuestionHow many paper clips can your water wheel lift?
Hypothesis
Read the procedure. Write a hypothesis to answer the question.
If ________________________________________________________________________________________
then ______________________________________________________________________________________
because __________________________________________________________________________________.
Procedure, Part 2
1. Place four additional paper clips on the end of the string so there are a total of five paper clips.
2. Fill the second cup nearly full with water. Pour the water slowly and evenly onto the blades, as shown in Diagram 5.
3. Measure the distance the paper clips were lifted. Record the data in the table.
4. Pour the water you caught back into the pouring cup. Repeat the test two more times. Record the results and calculate the average distance.
5. Add five more paper clips to the end of the thread and repeat steps 2-4.
6. Continue testing your water wheel, adding five paper clips at a time until you cannot lift any more paper clips.
Data and Observations
PAPER CLIPS DISTANCE 1 DISTANCE 2 DISTANCE 3 AVERAGE DISTANCE
5
10
15
20
25
Conclusion
Explain what happened as more paper clips were added to the string.
Diagram 5
36 WondersofWater
Effect of Penstock Height on the Force of Water
? QuestionWhat effect does penstock height have on the force of water?
Hypothesis
If ________________________________________________________________________________________
then ______________________________________________________________________________________
because ______________________________________.
Materials � 1 2-Liter bottle � Ruler � Water � 1 Push pin
2Preparation � Use the ruler to measure from the bottom of the bottle to five centimeters (cm). Mark this spot with a dot. Make three more marks at 10, 15, and 20 cm. Draw a horizontal line at 20 cm as well.
Procedure1. Using the push pin, make holes at the 5 cm, 10 cm, 15
cm, and 20 cm marks. Cover each hole with a piece of duct tape.
2. Fill the bottle with water to the 20 cm line.3. Place the bottle at one end of the wallpaper pan with
the holes pointing into the pan. Place your ruler in the bottom of the pan so that zero is at the edge of the bottom of the bottle.
4. Remove the duct tape from the 5 cm hole and immediately measure the distance the water projects from the hole. Record the results on your data table.
5. Cover the hole with your finger, refill the bottle with water and place the bottle back in the pan. Uncover the hole and measure the distance the water projects again. Record your results. Repeat once more for a total of three trials.
6. Empty the bottle and dry the outside. Tape the first hole again.
7. Follow steps 2-6 again for the 10, 15, and 20 cm holes.
5 cm
10 cm
15 cm
20 cm
CONTINUED ON THE NEXT PAGE
� 1 Wallpaper pan � Towel or paper towels � Permanent marker � Duct tape
©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 37
Data and ObservationsRecord your data in the table below.
PENSTOCK HEIGHT TRIAL 1 TRIAL 2 TRIAL 3 AVERAGE
5cm
10cm
15cm
20cm
Conclusion
Was your hypothesis correct? Why or why not? What is the effect of the penstock height on the water’s force? Use data to support your answer.
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38 WondersofWater
Future of Hydropower
at existing hydropower plants.
using energy from tides and ocean currents.
using wave energy.
at existing water control dams.
Describe ways to increase electricity from hydropower:
©2013TheNEEDProjectP.O.Box10101,Manassas,VA201081.800.875.5029www.NEED.org 39
Hydropower Glossaryatom the smallest component of an element having the chemical properties of the element
attract pull toward
chamber a large pipe in an oscillating water column through which air is moved by ocean waves
circuit a path for electricity to flow
condensation the process of turning a gas into a liquid
current the flow of electricity through a circuit
dam a barrier constructed across a waterway to control the flow or raise the level of water
deposition the process of turning a gas into a solid without passing through a liquid state
distance the length or amount of space between two points
distribution line a wire that moves electricity from a transmission line to consumers
earthen cofferdam a temporary dam made of earth or dirt that encloses all or part of a construction area so that construction can be performed
ecology the relationship between a living thing and the environment
electricity the movement of electrons
electromagnetism the relationship between electrical energy and magnetism
electron the particle in an atom that carries a negative electrical charge
emissions the vapors released by vehicles, machinery, and factories, can often contain pollution
energy the ability to do work or make a change
energy level location within an atom where electrons are held
evaporation the process of turning a liquid into a gas
flow volume of water, expressed as cubic feet or cubic meters per second, passing a point in a given amount of time; the amount and speed of water entering a water wheel or turbine
force a push or pull
freezing the process of changing a liquid into a solid
generate to produce, such as to produce electricity
generator a device that converts motion energy into electrical energy
greenhouse gas gases that trap in heat; carbon dioxide, methane, and water vapor are major examples
head vertical change in elevation, expressed in either feet or meters, between the headwater level and the tailwater level
hydropower the use of moving water to generate electricity
load the part of an electrical circuit that uses electricity to do work (a light bulb, for example)
magnetic field the area of force around a magnet
melting the process of changing a solid into a liquid
neutron a particle in the nucleus of an atom that carries no charge
nonrenewable energy source
an energy source with a long term replenish rate and reserves that are limited, including petroleum, coal, natural gas, uranium, and propane
nucleus the center of an atom that contains protons and neutrons
oscillating water column
a device that captures the energy of ocean waves
a cb
40 WondersofWater
penstock a closed conduit or pipe for conducting water to a water wheel, turbine, or powerhouse
photosynthesis the process used by plants to create sugar or food from sunlight
power line a wire that carries electricity
power plant the equipment attached to a dam that generates electricity, including the turbines and generators
proton a particle in the nucleus of the atom that carries a positive charge
renewable energy source
an energy source with a short term replenish rate, including biomass, geothermal, hydropower, solar, and wind
repel push apart
reservoir a natural or artificial pond or lake for storing and regulating water
rotor the spinning part of a power system, like a turbine
secondary source of energy
an energy source that is produced by another source of energy; electricity, for example, is produced by many sources of energy, such as coal, wind, solar energy, and hydropower
spillway a channel or passageway around or over a dam through which excess water is released
sublimation the process of changing a solid into a gas without passing through a liquid state
sugar a food created by plants for nutrition
tidal barrage an underwater dam with turbines that capture the energy in rising and falling tides
tidal bulge a bulge in the surface of the ocean caused by the gravitational pull of the moon
tidal stream power a device that captures the energy in ocean currents
tides movement of water due to the moon
transmission line a wire that moves electricity in large amounts from a power plant to a town
turbine a device with blades that is turned by wind, water, or steam
water vapor the gaseous form of water
work applying a force to move an object across a distance
42 WondersofWater
NEED’s Online Resources
ENERGY EXCHANGE ANDCAREER CURRENTS NEWSLETTERSNEED publishes two newsletters. Energy Exchange is published to keep teachers and partners informed about new curriculum materials, current energy issues, and opportunities available for teachers and students. Career Currents is published to provide students with information about a variety of careers in the energy industry. The newsletters are distributed to all NEED teachers, partners, and sponsors. The latest edition of each newsletter and archived editions are available on the NEED web site at www.NEED.org.
NEED’S SMUGMUG GALLERYhttp://need-media.smugmug.com/
You can fi nd pictures of other NEED students learning and teaching about energy. You can also fi nd pictures from NEED workshops, and photos of energy from around the country that were submitted for the Great American Energy Scavenger Hunt. Would you like to submit images or videos to NEED’s gallery?
E-mail [email protected] for more information.
Use SmugMug for the following resources:
VideosNeed a refresher on The Science of Energy? Watch the Science of Energy videos. Also check out our Energy Chants videos!
Find videos produced by NEED students teaching their peers and community members about energy.
Online Graphics LibraryWould you like to use NEED’s graphics in your own classroom presentations? Download graphics for easy use in your classroom.
NEED Energy BooklistLooking for extra background reading on energy? NEED’s booklist provides an extensive list of fi ction and nonfi ction titles for all grade levels to support energy units in the science, social studies, or language arts setting. Check it out at www.NEED.org.
U.S. Energy GeographyMaps are a great way to visualize the energy picture in the United States. This set of maps will support your energy discussion and energy activities.
Go to www.NEED.org/maps to see energy production, consumption, and reserves all over the country!
E-PUBLICATIONS
The NEED Project now offers e-publication versions of various guides for in-classroom and at-home use. Go to www.NEED.org/. Don’t see what you’re looking for? Check back often, as new e-pubs will be added throughout the year.
SOCIAL MEDIAStay up-to-date with NEED, “like” us on Facebook! Search for The NEED Project.
Follow us on Twitter. We share the latest energy news from around the country, @NEED_Project.
Read the latest from the NEED family in our blog! Visit it at www.NEED.org.
NEED ANNUAL REPORTNEED’s Annual Report gives summaries of the best state and national Youth Awards projects for 2012–2013, as well as information about The NEED Project and our state programs.
Annual Report Upon Request
Online at www.NEED.org
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Petroleum Equipment Suppliers AssociationPhillips 66PNMRead & Stevens, Inc. Rhode Island O�ce of Energy ResourcesRiverWorks DiscoveryRobert ArmstrongRoswell Geological SocietySandia National LaboratorySaudi AramcoSchneider ElectricScience Museum of VirginiaC.T. Seaver TrustShellShell ChemicalsSnohomish County Public Utility District–WASociety of Petroleum EngineersDavid SorensonSouthern CompanySouthern LNGSouthwest GasSpace Sciences University–Laboratory of the University of California BerkeleyTennessee Department of Economic and Community Development–Energy DivisionTioga EnergyToyotaTri-State Generation and TransmissionTXU EnergyUnited Parcel ServiceUnited States Energy AssociationUnited Way of Greater Philadelphia and Southern New JerseyUniversity of Nevada–Las Vegas, NVUniversity of TennesseeUniversity of Texas - AustinUniversity of Texas - TylerU.S. Department of EnergyU.S. Department of Energy–Hydrogen ProgramU.S. Department of Energy–O�ce of Energy E�ciency and Renewable EnergyU.S. Department of Energy–O�ce of Fossil EnergyU.S. Department of Energy–Wind for SchoolsU.S. Department of Energy–Wind Powering AmericaU.S. Department of the Interior–Bureau of Land ManagementU.S. Energy Information AdministrationVan Ness FeldmanVestasVirgin Islands Energy O�ceWest Bay ExplorationW. Plack Carr CompanyYates Petroleum Corporation
©2013 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org