Wonders of Water
20
12
-20
13
Student Guide
ELEMENTARY
What is Energy?
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.
Energy is Light
We 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 Heat
We 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.
Light
Factories burn fuel to make the products they sell. Power plants
burn coal and natural gas to make electricity.
Energy Makes Things Grow
All 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.
Heat
Animals cannot change light energy into sugars. Neither can
people. We eat plants and use the energy stored in them to grow.
Tree
2
Wonders of Water
Energy Makes Things Move
It 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.
Motorcycle
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 Machines
It takes energy to run our TVs, video games, 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? Very different.
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 and the wind.
Also, we can make electricity with the energy of
moving water.
Computer
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
3
Energy is Change
gAS STATION
When 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.
The total amount of energy in the universe
stays the same; it just changes from one form
to another.
Energy is the Ability to
Do Work
sOCCER
The 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 applying 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 (apply a force)
the ball (an object).
Energy allows you to play soccer and move the ball down the field.
The soccer ball (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.
4
Wonders of Water
Energy Comes From
Many Sources
Formation and Production of Oil and Natural Gas
We use many different energy sources to
do work for us. They are classified into two
groups—renewable and nonrenewable.
In the United States, most of our energy
comes from nonrenewable energy
sources. Coal, petroleum, natural gas,
propane, and uranium are nonrenewable
energy sources. They are used to make
electricity, heat our homes, move our cars,
and manufacture all kinds of products.
These energy sources are called
nonrenewable because their supplies are
limited. Oil and natural gas, for example,
were formed over millions of years from
the remains of ancient plants and animals.
We cannot make more in a short time.
Biomass, geothermal energy, hydropower,
solar energy, and wind are renewable
energy sources. They are called renewable
because they can be replenished (made
again) in a short time. Day after day, the sun
shines, the wind blows, and the rivers flow.
We use renewable energy sources mainly
to make electricity.
Small marine organisms died in the oceans and over millions of
years they were buried under many layers of dirt, which turned
into rock. Heat and pressure turned the dead organisms into oil
and natural gas. We can drill and retrieve the oil and natural gas
to use its energy.
How
HowWind
WindisisFormed
Formed
U.S.
bySource,
Source,2010
2010
U.S. Energy
Energy Consumption
Consumption by
WA
RENEWABLE
4.4%
NATURAL GAS 25.2%
HYDROPOWER
2.6%
COAL
WIND
0.9%
35.1%
Uses: transportation,
manufacturing
Uses: heating,
manufacturing, electricity
Uses: electricity,
manufacturing
21.3%
Uses: heating, electricity,
transportation
Uses: electricity
Uses: electricity
URANIUM
8.6%
GEOTHERMAL
0.2%
PROPANE
1.6%
SOLAR
0.1%
Uses: electricity
Uses: heating,
manufacturing
IR
BIOMASS
PETROLEUM
RM A
NONRENEWABLE
Uses: heating, electricity
Uses: heating, electricity
CO O L A I
R
1. The sun shines on land and water.
2. Land heats up faster than water.
3. Warm air over the land rises.
4. Cool air over the water moves in.
Data: Energy Information Administration
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
5
Electricity
Electricity is Mysterious
LIGHTNING
Electricity 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 Particles
Lightning is a form of electrical energy.
Atom
Atom
PROTON
NUCLEUS
NEUTRON
ELECTRON
An 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.
When an atom is in balance, it has the same
number of protons and electrons. It can have
a different number of neutrons.
6
Wonders of Water
Protons and Electrons Attract
Each Other
Electrons 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.
Carbon Atom
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.
OUTER
Magnets are Special
In most objects, all the atoms are in balance. Half of the
electrons spin in one direction, half spin in the other
direction. They are randomly spaced in the object.
Magnets are different. In magnets, the atoms are arranged
so that the electrons are not in balance.
The electrons do not move from one end to the other
to find a balance. This creates a force of energy called a
magnetic field around a magnet.
We call one end of the magnet the north (N) pole and the
other end the south (S) pole. 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.
EL
R ENERGY LEVE
INNE
L
NUCLEUS
PROTONS (+)
NEUTRONS
ELECTRONS (–)
Electricity is Moving Electrons
The 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.
ENERGY LEV
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.
Bar Magnets
Bar Magnet
Like Poles
Like
poles
Like
Polesof magnets (N-N or S-S) repel each
Like poles of magnets (N-N or S-S) repel each other.
other.
Opposite Poles
Opposite
poles of magnets (N-S) attract
Opposite Poles
each
other.
Opposite poles of magnets (N-S) attract 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.
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
7
Magnets Can Make
Electricity
Magnetism and electricity are always linked
together; you cannot have one without the
other. This is called electromagnetism.
Power Plants Use
Magnets
Turbine Generator
TURBINE
TURBINE SPINS SHAFT
Spinning Coil of Wire
MAGNET
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.
Turbine Generator
MAGNET
We can use magnets to make electricity. A
magnetic field can pull and push electrons to
make them move. Some metals, like copper,
have electrons that are loosely held. They are
easily pushed from their shells.
North
Pole
South
Pole
DIRECTION OF ELECTRIC CURRENT
TO TRANSMISSION LINES
Power plants use huge magnets to make, or
generate, electricity. In a generator, a big
coil of copper wire spins inside the magnets.
As it spins, the magnetic fields push and pull
electrons in the wire.
We Generate Electricity With Many Fuels
In the U.S., coal is the top energy source for making electricity. It generates almost half 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.
8
Wonders of Water
We Get Our Electricity Through Wires
A 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.
Transporting
Electricity
Transporting
Electricity
Power Plant
Transmission Line
Distribution Line
Transformers
Home
There are Other Ways to Produce Electricity
Electricity 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 frees more electrons in one metal than in the other.
One end of the battery is attached to one of the metals; the other end is attached to the other
metal. The end that frees more electrons develops a positive charge and 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.
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
9
Electricity Flows in
Circuits
Electricity travels in closed loops called
circuits. It 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 electrical
current flows from the electric 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. It flows straight
through the switch.
If we want to use an incandescent light bulb,
we turn on a light switch. When the switch
is on it closes a circuit. Then electricity flows
through a tiny tungsten wire in the bulb. The
wire gets very hot and glows. When the bulb
burns out, the tiny wire has broken. The path
through the bulb is gone. The circuit is open.
Electrical
ElectricalCircuits
Circuits
FLOW OF ELECTRONS
–
WIRES
+
LOAD
ENERGY SOURCE
CLOSED SWITCH
closedcircuit
circuitisisa acomplete
complete
path
allowing
electricity
AAclosed
path
allowing
electricity
toflow
flowfrom
from
energy
source
the load.
to
thethe
energy
source
to thetoload.
FLOW OF ELECTRONS
–
WIRES
+
LOAD
ENERGY SOURCE
OPEN SWITCH
We Use Electricity
Every Day
Electricity 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.
Anopen
opencircuit
circuit
a break
theThere
path.isThere
An
hashas
a break
in theinpath.
no flowisofno
flow of because
electricity
becausecannot
the electrons
cannot
electricity
the electrons
complete the
circuit.
complete the circuit.
Machines That Use Electricity
Microwave
Projector
Television
Video Game System
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.
10
Wonders of Water
Wonders of Water
Liquid: Water
Solid: Ice
Gas: Water Vapor
Water is Found in Three States of Matter
Water covers 75 percent of the Earth’s surface. It is found in three states of matter: liquid, solid,
and gas. The liquid state is water. The solid state is ice. The gas state is 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.
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
11
The Water Cycle
The Water Cycle
SOLAR ENERGY
CONDENSATION
(Gas to Liquid)
PRECIPITATION
EVAPORATION
(Liquid or Solid)
(Liquid to Gas)
EVAPORATION
(Liquid to Gas)
OCEANS, LAKES, RIVERS
(Liquid)
Water Changes State in a Cycle
In our Earth system, 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, where 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, pulled by the force of gravity.
The rivers, lakes, and oceans are replenished, and the cycle starts again. This is the water cycle.
12
Wonders of Water
Water has Been Used as
a Source of Energy for
Many Years
Water has been used as a source of energy for
centuries. The Greeks used waterwheels to
grind wheat into flour more than 2,000 years
ago. In the early 1800s, American and European
factories used waterwheels 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 generate electricity. The rest were built
to control flooding, irrigate crops, or provide a
reliable water supply.
Waterwheel
Niagara Falls
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
13
A Dam That Generates Electricity
is a Hydropower Plant
Hydropower (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 converts the
energy of the moving water into electricity.
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
the generators. The generators produce electricity, which 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.
About 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 2010, six percent
of U.S. electricity was made
using hydropower. That’s
enough power for 22 million
households.
Using
hydropower
to
produce
electricity
has
many advantages, but it has
disadvantages too because of
its impact on the environment.
Hydropower
PlantPlant
Hydropower
view from above
GENERATOR
MAGNETS
COPPER COILS
RESERVOIR
Intake
1
ROTATING
SHAFT
DET
AIL
Electricity from
Hydropower
DAM
PEN
GENERATOR
STO
CK
2
SWITCHYARD
4
5
3
TURBINE
6
RIVER
1. Water in a reservoir behind a hydropower dam flows through an intake screen,
which filters out large debris, but allows smaller fish 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 fish to pass
through unharmed.
4. Inside the generator, the shaft spins coils of copper wire inside a ring of
magnets. This creates an electric field, 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 flows out of the penstock into the downstream river.
14
Wonders of Water
Building Hoover Dam
Hoover Dam is located in Black Canyon
on the Colorado River, about 30 miles
southeast of Las Vegas, Nevada. It was built
in the early 1930s at the height of 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 itself could
begin, the Colorado River had to be diverted around the construction site. Four tunnels were
drilled through the canyon walls, two on each side of the canyon. Then temporary earthen
cofferdams were built above and below the site to channel the river water through the tunnels
and protect the construction site.
There are 4,360,000 cubic yards of concrete in the dam, power plant, and other structures needed
to operate the dam. 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, but 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, which 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.
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
15
Advantages of Hydropower
ƒƒHydropower is a clean energy source. It is fueled by moving
water, so it doesn’t produce emissions. Hydropower does not
increase the level of greenhouse gases in the atmosphere.
ƒƒHydropower 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.
ƒƒHydropower is available when it is needed. The flow of
water through a dam can be controlled to produce electricity
when it is needed.
ƒƒHydropower is an economical way to produce electricity.
The electricity generated by hydropower facilities is the
cheapest electricity in the country.
Glen Canyon Dam
ƒƒDams create reservoirs that offer a wide variety of benefits.
People use the reservoir for fishing, swimming, and boating.
ƒƒHydropower facilities can help manage the water supply.
They provide flood control and a reliable supply of drinking
water.
ƒƒHydropower dams are very safe and durable. They are built
to last for hundreds of years.
Disadvantages of Hydropower
ƒƒHydropower plants depend on the water supply. When
there is a drought, for example, hydropower plants cannot
produce as much electricity as when there is plenty of rain.
ƒƒHydropower dams on rivers permanently change the
natural 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.
ƒƒHydropower 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.
Image courtesy of Grant County Public Utility District
Fish Bypass
ƒƒDams can block fish from migrating. Some fish populations,
such as salmon, migrate upstream to spawn and migrate
downstream to return to the ocean. Fish ladders may be built
to help fish swim upstream. Fish may be sent through specially
designed spillways or bypasses as they head downstream.
16
Wonders of Water
The Future of Hydropower
We 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:
ƒƒways to generate more electricity from existing hydropower dams;
ƒƒways to add turbine generators to existing dams that do not produce electricity now; and
ƒƒways to use the energy of moving water in the ocean.
Generating More Electricity from Existing
Hydropower Plants
Some 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 Dams
There are 84,000 dams in the United States, but only 2,200
of them 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.
Generators
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
17
IDAL BUL
AR T
GE
NE
EARTH
of th
ation e Earth
Rot
Near 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.
Tidal
TidalBulge
Bulge
TIDAL BULGE
FAR
Energy from Tides
Gravitational Attraction
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.
Image courtesy of OpenHydro
A marine turbine such as this one can be used to harness tidal energy.
Tidal Barrage
One kind of power plant that captures
the energy in the tides is called a
tidal barrage. A tidal barrage is built
across an estuary, 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,
spinning the turbines and collecting
in the estuary. When the tide drops,
the water in the estuary 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 estuary.
18
Tidal Barrage
Tidal Barrage
TIDAL FLOW
DIRECTION
DAM
TURBINE
Tidal water is captured at high tide behind a dam.
When
theistide
turns,atthe
water
is released
the sea,
Tidal
water
captured
high
tide behind
a dam.toWhen
the tide turns,
passing
turbines.
the
water through
is releasedatoset
theofsea,
passing through a set of turbines.
Wonders of Water
Tidal Stream Power
Tidal 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, has developed the world’s largest
system to capture the energy in ocean currents,
known as SeaGen S. A SeaGen S is operating in
Strangford Lough, a shallow bay on 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. The
twin rotors are mounted on wing-like extensions
on either side of a steel tower that is set into a
hole drilled in the sea floor.
Wave Energy
Image courtesy of Marine Current Turbines Ltd
SeaGen S System
Ocean 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.
Roosevelt Island Tidal Energy Project, NY
The city and state of New York are working with
Verdant Power to harness the energy in the ebb and
flow of the tides in Manhattan’s East River.
From 2006-2008 six turbines were connected to
the electric power grid to test the technology and
effects of tidal turbines. Along with studying how the
electricity generated from tidal power connected
to the grid, scientists monitored the environmental
impacts of the turbines.
Verdant Power recently received permission to
install 30 turbines that will generate electricity for
local customers.
Image courtesy of Verdant Power
Free Flow System turbine being installed in East
River, NY.
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
19
Capturing Wave Energy
The 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.
Oscillating Water Column
Oscillator Water Column
VENT
CHAMBER
CLIFF FACE
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.
TURBINE
WAVE
VENT
TURBINE
Air pushed
through by
incoming wave
CHAMBER
WAVE
VENT
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.
TURBINE
Air pulled back
as wave
retreats
Scientists are designing new ways to capture
the ocean’s energy all the time. In the future, a
lot of the energy we use might come from the
ocean.
CHAMBER
WAVE
Wave Energy Converter
Wave Energy Converter
FLOATING TUBES
POWER CABLE
JOINTS
Passing waves cause each tube to rise and fall like a giant sea snake. The motion tugs at the joints linking the tubes. The joints
act as a pumping system, pushing high pressure oil through a series of motors that drive the generators to produce electricity.
The wave energy devices will be connected to the seafloor by moorings and then connected to the electric grid with underwater
power cables.
20
Wonders of Water
Energy KWL Chart
What I Think I Know About Energy
What I Want to Know About Energy
What I Have Learned About Energy
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
21
Forms of Energy
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.
Energy is Light
Energy is Heat
Energy is Motion
Energy is Growth
Energy is Electricity
22
Wonders of Water
The Energy We Use
Make 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.
U.S. Energy Consumption by Source, 2010
NONRENEWABLE
RENEWABLE
BIOMASS
4.4%
NATURAL GAS 25.2%
HYDROPOWER
2.6%
COAL
WIND
0.9%
PETROLEUM
35.1%
Uses: transportation,
manufacturing
Uses: heating,
manufacturing, electricity
Uses: electricity,
manufacturing
21.3%
Uses: heating, electricity,
transportation
Uses: electricity
Uses: electricity
URANIUM
8.6%
GEOTHERMAL
0.2%
PROPANE
1.6%
SOLAR
0.1%
Uses: electricity
Uses: heating,
manufacturing
Uses: heating, electricity
Uses: heating, electricity
Data: Energy Information Administration
PERCENTAGE THE SOURCE PROVIDES
50%
40%
30%
20%
10%
0%
ENERGY SOURCES
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
23
The Electricity We Use
Make 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
Natural Gas
Uranium
Hydropower
Wind
Biomass
Petroleum
Other
45%
24%
20%
6%
2%
1%
1%
1%
PERCENTAGE THE SOURCE PROVIDES
50%
40%
30%
20%
10%
0%
ENERGY SOURCES
24
Wonders of Water
Science of Electricity
After observing the science of electricity demonstration, draw and label a diagram of the device.
Explain how electricity was generated with the device.
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©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
25
Water and Energy KWL Chart
What I Think I Know About Water and Energy
What I Want to Know About Water and Energy
What I Have Learned About Water and Energy
26
Wonders of Water
The Water Cycle
Draw 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 and/
or in your written explanation.
Word Bank
condensation
liquid
evaporation
ocean
lake
cloud
river
air
solar energy
atmosphere
gas
precipitation
water vapor
water
gravity
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©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
27
Land and Water 1
? Question

How does water change land?
 Materials
ƒƒ Wallpaper
ƒƒ Pen
ƒƒ Sand
ƒƒ Beaker with 300 mL of water
ƒƒ Ruler
ƒƒ Sink or Bucket
 Hypothesis
Read the procedure. Complete this hypothesis sentence:
If I pour water onto the land, the land will ________________________________________________
because ___________________________________________________________________________.
 Procedure
1. 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.
28
Wonders of Water
© 2009 THE NEED PROJECT • PO BOX 10101 • MANASSAS, VA 20108 • 1-800-875-5029
Wonders of Water Student
PAGE 27
Land and Water 1 Observations
Draw 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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__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
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©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
29
Land and Water 2
Assignment
Plan an investigation of your own with your pan and sand, using one of the following ideas:
ƒƒ Mold the sand with your hands to create mountains and valleys.
ƒƒ Pour the water at different heights.
ƒƒ Pour the water at different speeds.
ƒƒ Raise the end of the pan to different heights.
ƒƒ Place an object in the path of the water.
? Question

__________________________________________________________________________________________
__________________________________________________________________________________________
 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 Plan
Record your observations on the next page.
30
Wonders of Water
Land and Water 2 Observations
Draw 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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__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
31
Hydropower Plant
Label 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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__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
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32
Wonders of Water
Moving Water Can do Work
? Question

How can water do work?
 Materials
ƒƒ 1 Round-barrel pencil
ƒƒ 2 Polystyrene cups
ƒƒ 30 cm Thread
ƒƒ 1 Polystyrene craft ball
ƒƒ 4 Blades
ƒƒ Scissors
ƒƒ Glue
ƒƒ Tape
ƒƒ Water
ƒƒ Paper clips
ƒƒ Ruler
 Procedure, Part 1
1. 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 and place rings of glue on either side to secure the ball to the pencil.
2. 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.
3. Cut two small V-shaped grooves on opposite sides of the top of the cup as shown in Diagram 3.
4. Insert four blades into the foam ball, equal distances from each other as shown in Diagram 2.
5. Place the pencil into the grooves on the cup so the foam ball is in the center of the cup. Adjust the blades so
that they do not hit the edge of the cup. Glue the blades into place and let dry.
6. When the blades are dry, place the waterwheel system at the edge of a table so the 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. What
happens? Record your observations.
 Observations
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
CONTINUED ON THE NEXT PAGE
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
33
? Question

How many paper clips can your waterwheel 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 line 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.
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 waterwheel, 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 line.
34
Wonders of Water
Effect of Penstock Height
on the Force of Water
? Question

What effect does penstock height have on the force of water?
 Hypothesis
If _________________________________________________________________________________________
then_______________________________________________________________________________________
because ______________________________________.
 Materials
ƒƒ 1 2-Liter soda bottle
ƒƒ Ruler
ƒƒ Water supply
ƒƒ 1 Push pin
ƒƒ 1 Wallpaper pan
ƒƒ Towel
ƒƒ Permanent marker
ƒƒ Duct tape Preparation
ƒƒ 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.
20 cm
 Procedure
1. 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.
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.
15 cm
10 cm
5 cm
CONTINUED ON THE NEXT PAGE
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
35
 Data and Observations
Record your data in the table below.
PENSTOCK HEIGHT
TRIAL 1
TRIAL 2
TRIAL 3
AVERAGE
 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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__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
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36
Wonders of Water
Future of Hydropower
Describe ways to increase electricity from hydropower:
at existing hydropower plants.
at existing water control dams.
using energy from tides and ocean currents.
using wave energy.
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
37
Hydropower Glossary
atom
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
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
energy
the ability to do work or make a change
energy level
location within an atom where electrons are held
estuary
the area of water at the mouth of a river
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 waterwheel or turbine
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
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
penstock
a closed conduit or pipe for conducting water to a waterwheel, turbine, or powerhouse
power line
a wire that carries electricity
power plant
the equipment attached to a dam that generates electricity, including the turbines and generators
38
Wonders of Water
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
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
transmission line
a wire that moves electricity in large amounts from a power plant to a town
water vapor
the gaseous form of water
work
applying a force to move an object across a distance
©2012 The NEED Project P.O. Box 10101, Manassas, VA 20108 1.800.875.5029 www.NEED.org
39
NEED National Sponsors and Partners
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