Earth: A First Look
1 videocassette............................................. 17 minutes
Copyright MM Rainbow Educational Media
4540 Preslyn Drive
Raleigh, NC 27616-3177
INTRODUCTION
This program is designed to help young students understand and appreciate the planet that is their home. It focuses
first on characteristics that can be seen from the earth's
surface, particularly water, air, and land. It then explores
the earth's interior and describes the core, mantle, and
crust.
The video emphasizes that the earth is characterized by
continuous change. Students learn that over millions of
years continents move, mountains form, and rivers carve
deep canyons. Students also see that earthquakes and
volcanoes can change the earth's crust in minutes or even
seconds.
The program includes an interview with a geologist to
show why scientists are interested in studying the earth.
Graphics and animation clarify important points. In addition, students are shown demonstrating experiments and
activities that make key concepts easier to understand. In
this way, students learn not only about the earth but also
about the importance of observation and experimentation
in the scientific process.
Grade level: This program is designed for students in
Grades 1-3
OBJECTIVES
After seeing the video, students will be able to:
- describe the major features of the earth's surface;
particularly water, air, and land.
- explain how water, air, and land provide valuable
resources.
- describe the structure of the earth, including the crust,
mantle, and core.
- explain how the earth's crust is constantly changing
as a result of weathering, erosion, continental drift,
and the effects of volcanoes and earthquakes.
SUMMARY
The video begins by asking students to describe the earth as
seen by astronauts orbiting high above its surface. It focuses on the earth's most apparent features: water, land,
and air.
The narrator describes how most of the earth's surface is
covered by oceans, but there also is freshwater in lakes,
rivers, streams and ponds. The narrator states that water is
an important resource. We need freshwater water to drink
and we get food from the oceans.
The program explains that, in addition to water, life on the
earth depends on air. It describes how the earth is surrounded by a thin layer of air called the atmosphere. The
video shows scenes of deserts, mountains, plains, and
canyons to illustrate the diversity of land forms.
The narrator then compares the layers of the earth to the
layers of an egg. Graphics show the interior of the earth and
its different parts, focusing on the core, mantle and crust. It
describes the composition of each of these layers.
The video describes how sometimes hot liquid rock in the
earth's mantle pushes its way out through a weak spot in the
earth's crust. As the lava cools and becomes solid rock, it
changes the surface of the earth.
The program introduces David Kring, a geologist, who
describes how he became interested in geology by observing the rocks around his house as a child. Kring describes
how the desert landscape near where he lives was once
covered by a lake and then was the site of a large volcano.
He also explains how weathering breaks up rock into
smaller pieces and how erosion moves weathered material
from one place to another.
Students demonstrate the effects of erosion by pouring
water into baking pan filled with sand. The teacher has an
opportunity here to pause the video to allow viewers to
discuss what will happen. When the program resumes, the
video shows how the water moves sand from the top of the
pan to the bottom and creates little gullies. The video then
shows images of a desert canyon carved over millions of
years by erosion and weathering.
The program next describes how continents drift over the
earth's surface. It compares the shapes of the continents to
pieces of a jigsaw puzzle and suggests that these shapes hint
that the earth's continents once were bunched together. The
video shows how moving continents cause other changes in
the earth's crust. Mountains form when continents collide.
A student demonstrate this process by pushing two towels
together, showing how they bunch up.
In the next segment the video describes how earthquakes
occur when continents slide past each other...causing rock
to bend and break.
A brief summary concludes the program.
REVIEW QUESTIONS
1. What are major features of the earth you can observe
from its surface?
Answers will vary. Earth has water, air, and land.
Students may cite many other things as well, including
plants and animals.
2. Why is the earth sometimes called the blue planet?
Most of the earth's surface is covered by oceans.
3. Besides the salt water found in oceans, what other kind
of water can you find on the earth's surface? Where can
you find it?
Freshwater is the other kind of water on the earth's
surface. You can find freshwater in lakes, rivers,
streams, and ponds.
4. What is the atmosphere?
The thin layer of air surrounding the earth.
5. What are the main layers of the earth?
The inner and outer cores, the mantle, and the crust.
6. How do the temperatures of the different layers within
the earth vary ?
The temperatures are hotter the deeper you go. The
inner and outer cores are hotter than the mantle,
which is hotter than the crust.
7. What are some different forms the earth's crust can
take?
Answers will vary. Examples in the program include
mountains, plains, and canyons.
8. What is a geologist?
A geologist is a scientist who studies rocks, and the
history and structure of the earth.
9. What is lava?
Hot liquid rock that erupts from a volcano.
10. What are some different ways the earth changes?
Answers will vary. The program describes how conti
nents drift, how weathering weakens rock and breaks
it into smaller pieces, and how erosion carries mate
rial from one place to another. It also describes how
mountains form when continents collide and shows
the effects of volcanoes and earthquakes.
11. What is an earthquake?
An earthquake is the shaking of the earth's crust.
ACTIVITIES
1. To illustrate the effects of erosion, the program shows
two students pouring water over sand in a tilted baking
pan. Your students can do interesting variations on this
experiment. In addition to sand, students can use pebbles
of different sizes. Ask students to predict how the
pebbles will move in comparison to the sand. (They will
not move as far because they are heavier.)
Ask the students what will happen if they raise the end
of the pan to form a steeper slope. (The water will move
faster and move more sand.)
2. Natural history museums have many different exhibits
focusing on different aspects of the earth. If your school
is near a museum, arrange for a class trip. The appendix
lists many of the major museums in the United States
and Canada.
3. Invite a local geologist to talk about the geological
history of the area in which students live. The geologist
could talk about local features such as mountains and
lakes and how they were formed.
4. Students can make models of volcanoes out of papier
mache, clay, or other material. They should make sure
that they leave a vent in the center of their volcano.
Have them pour about one-quarter cup of baking soda
into the vent. Then pour a similar amount of vinegar. The
baking soda reacts with the vinegar, producing a foam
that erupts out of the vent in a way similar to how lava
erupts during a volcanic eruption.
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There are several different kinds of volcanoes. In many
places, volcanoes occur at the boundaries of large blocks
of rock called plates that slowly move over the earth's
mantle. In Hawaii, volcanoes occur over "hot spots" in
the middle of a plate.
Volcanoes also form different kinds of cones. Cinder
cones form from explosive eruptions and have steep
slopes. Shield cones form from nonexplosive eruptions
and have gentler slopes. Ask more advanced students to
research and report on different types of volcanoes.
Their reports can include drawings.
The program describes how the earth's continents slowly
drift. Ask students to imagine and draw what the continents might look like in the future; for example 50
million years, 100 million years, and 200 million years
from now.
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GLOSSARY
astronaut: person trained for space flight.
atmosphere: thin layer of air surrounding the earth.
continent: large land mass. crust: outermost layer
of the earth. Earth: third planet from the sun.
earthquake: shaking of the earth's crust.
erosion: process of moving weathered rock and soil by
water, wind, or ice.
geologist: scientist who studies the history and structure of
the earth.
inner core: innermost part of the earth.
lava: molten rock that reaches the earth's surface.
mantle: layer of the earth underneath the crust.
outer core: layer of the earth between the mantle and inner
core.
planet: large body orbiting the sun.
resource: something that is useful to us.
soil: thin layer of loose material on top of the crust.
volcano: opening in the earth's crust through which an
eruption can take place.
weathering: process by which rocks are broken up by
water, ice, plants and other factors.
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BIBLIOGRAPHY
Books
Cattermole, Peter. Earth and Other Planets. NY: Oxford
University Press, 1995.
Cole, Joanna. The Magic School Bus: Inside Earth. NY:
Scholastic, 1987.
Llewellyn, Claire. Our Planet Earth. NY: Scholastic, 1997.
Markle, Sandra. Earth Alive! NY: Lothrop, Lee & Shepard
Books, 1991.
Morrison, David. Exploring Planetary Worlds. NY: Scientific American Library, 1993.
Parsons, Alexandra. Make It Work! Earth. NY: Thomson
Learning, 1992.
Pellant, Chris, editor. Earth. London: Dorling Kindersley,
1992.
VanCleave, Janice. Earthquakes: Spectacular Science
Projects. NY: John Wiley & Sons, 1993.
___ . Volcanoes: Spectacular Science Projects. NY: John
Wiley & Sons, 1994.
Web Sites
There are many web sites devoted to the earth. Below are
few sites to start with. These have links to many others.
Learning Web
http://info.er.usgs.gov/education
This is a part of the United States Geological Survey web
dedicated to K-12 education.
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The Exploratorium
http://www.exploratorium.edu
This site, run by San Francisco's science museum, offers
activities and an extensive data base of resources.
The Observatorium
http://ivv.nasa.gov
The observatorium is NASA's public access site for earth
and space data. It includes a listing of resources for teachers.
Douglas Henderson's Earth History Elustrations
http://gallery.in-tch.com/~earthhistory/
This site includes a timeline and a collection of illustrations
of the earth's history.
Volcanoes Online
http://library.advanced.org/17457/
This site has games, quizzes, databases, and lesson plans
focused on volcanoes.
14
RELATED VIDEOS FROM RAINBOW
For Grades 1-3
Air: A First Look
The Fabulous Five: Our Senses
Magical Mother Nature: The Four Seasons
Magnets: A First Look
Plants: A First Look
The Sky Above: A First Look
Water: A First Look
Weather: A First Look
For Grades 4-8
Continents Adrift: An Introduction to Continental Drift
and Plate Tectonics
Coral Reef Biomes: Essential and Endangered Desert
Biomes: Essential and Endangered Earthquakes: Our
Restless Planet Fossils: Windows into the Past
Grassland Biomes: Essential and Endangered Oceans:
Earth's Last Frontier Our Changing Earth Rocks and
Minerals: The Hard Facts Source of Life: Water and the
Environment Struggling to Survive: Tropical Rain
Forests Temperate Deciduous Forests Treasures of the
Deep: Our Ocean Resources Volcanoes: Mountains of
Fire Wetland Biomes: Essential and Endangered What's
Inside the Earth?: An Introduction to the Earth's
Interior, Crust and Mineral Resources Why Are the
Mountains So High ?: An Introduction to
Mountains and Mountain Building
15
APPENDIX: MUSEUMS OF NATURAL HISTORY
United States
American Museum of Natural History
New York, NY
Carnegie Museum of Natural History
Pittsburgh, PA
Cleveland Museum of Natural History
Cleveland, Ohio
Dallas Museum of Natural History
Dallas, TX
Field Museum of Natural History
Chicago, JL
Florida Museum of Natural History
Gainesville, FL
Fort Worth Museum of Science and History
Fort Worth, TX
Harvard Museum: Museum of Cultural and Natural History Cambridge, MA
Houston Museum of Natural History
Houston, TX
Los Angeles County Natural History Museum
Los Angeles, CA
Madison Geology Museum, University of Wisconsin
Madison, WI
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Museum of Geology, South Dakota School of Mines
Rapid City, SD
National Museum of Natural History, Smithsonian Institution Washington, DC
North Carolina Museum of Natural Sciences
Raleigh, NC
Peabody Museum, Yale University
New Haven, CT
University of Kansas Natural History Museum
Lawrence, KS
Virginia Museum of Natural History
Martinsville, VA
Canada
Canadian Museum of Nature
Ottawa, Ontario
Provincial Museum of Alberta
Edmonton, Alberta
Royal British Columbia Museum
Victoria, British Columbia
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SCRIPT
Title: Earth: A First Look
Narrator:
Imagine being an astronaut in the space shuttle high above
the earth. As you look out a window, you can see the earth
from far away. How would you describe our planet?
Students:
The earth is round.
It has clouds floating in the air.
It has land.
It's blue. It has lots of water.
Narrator:
Land...air... water. These are three important features of the
planet that we call our home.
Of these three, water may be the most obvious. Stand on a
beach and look out across the ocean. The water stretches as
far as the eyes can see. In fact, the earth is often called the
blue planet because most of the earth's surface is covered
by oceans.
For us humans, the oceans provide important resources. A
resource is something that is useful to us. We get food from
the oceans, such as fish, oysters, and lobsters. Ships use the
oceans to get from one place to another, and we swim and
have fun in the oceans.
The water in the oceans is salt water, but the earth also has
lots of fresh water—water that doesn't have much salt in it.
18
Students:
There are streams and rivers...
lakes and ponds.
Narrator:
Fresh water also is an important resource. We need fresh
water to drink. Without water we and other living things
would soon die.
But we need something else to be alive...air. The earth is
surrounded by a layer of air called the atmosphere. Compared to the rest of the earth, this layer is very thin.
We can't see the air in the atmosphere; but when we blow
air out of our lungs, it will fill a bag, and you can feel the air.
The earth's atmosphere makes possible the many different
kinds of plants and animals we see around us. Without air,
there wouldn't be flowers in a garden, or birds, or any other
kinds of animals. Without air and water, there wouldn't be
you.
Land is a third thing we notice about the earth. Think of the
ways land is important to us.
Students:
We walk on land.
We build houses on it
We grow food on it.
Narrator:
Plants that we eat and other kinds of plants grow in the soil.
Soil is the very top layer of land.
19
Soil is made up of loose material that can be very different
depending on where you live. Look at the soil in a forest. It
is made up of rotting leaves and other plants along with
small stones and rocks.
But if you live in the desert, the soil will look very different.
There are fewer plants in the desert, so instead of the
remains of rotting plants the soil is largely made up of rocks
and stones.
The earth's land looks very different in different places. In
some places, there are tall mountains. In other places, there
are flat plains covered with grass, or deep canyons, or rocky
deserts.
But looking at the earth's surface tells us only part of the
story about the earth. It doesn't tell us much about what's
beneath the surface.
Looking at the earth's surface is a little like looking at only
the outside of an egg.
Student:
It's white and hard
Narrator:
Now look at a hardboiled egg cut in half. You get a different
view.
Student:
It has a yellow yolk and around the yolk is white.
Narrator:
Like an egg, the earth has different layers. Deep within the
earth, at the center, there is the inner core. The inner core is
20
made up of iron and some nickel. The inner core is very hot.
The deeper you go in the earth, the hotter it is.
Surrounding this inner core of the earth is an outer core
made mostly of melted iron.
Above that comes a layer called the mantle, which is largely
made up of solid rock, although some of this rock is partly
melted. The mantle is less hot than the inner and outer
cores, but it is still very hot.
The top layer is the crust. Like the shell of an egg, the crust
is very thin compared to the other layers. The crust is made
up of rock and soil. It is the only layer that we can see.
Mountains, valleys, and plains are all different forms of the
crust.
Sometimes magma, hot liquid rock in the earth's mantle,
pushes its way out through a weak spot in the earth's crust.
In a way, it's like shaking a can filled with soda. Shaking
the can builds up pressure or force inside, and the soda
explodes out of the can.
In a similar way, when magma inside the earth floats up
near the surface, gases in the magma build up pressure, and
the magma erupts explosively. When magma spills out
onto the earth's surface, it is called lava.
An erupting volcano is one of the earth's most awesome
displays. Lava soars into the air and forms red-hot rivers
that scorch everything they touch.
As lava flows across the earth's surface, it cools and
becomes solid rock again. In this way it changes the way the
earth's crust looks. In places where volcanoes have been
active, much of the rock covering the surface was once lava
21
or is made up of other material that erupted from the
volcanoes.
Scientists who study rocks are called geologists. A geologist is someone who studies the history and structure of the
earth. This is a geologist named David Kring.
David Kring:
I got interested in geology as a child. I wanted to know
about the rocks in my driveway and in my backyard. Also
when I was young, astronauts landed on the moon and
started collecting rocks there, and suddenly I realized that
not only could I learn about the rocks around my house but
I could learn about the geology of whole planets.
Narrator:
David Kring lives near the Tucson Mountains in the desert
of southern Arizona. These mountains look like they have
always been around; but in fact, the land here once looked
very different. One of the things David Kring studies is how
the land near his home has changed.
David Kring:
Today we are in a broad desert environment. But many
millions of years ago there was actually a large lake here.
By studying the rocks in these mountains we can tell that
there were fish in this lake. There were clams in this lake,
and along the beaches dinosaurs roamed.
After that lake grew, it was replaced by volcanic activity
which again changed the surface of the earth. A huge
volcanic crater existed here and erupted a whole series of
rocks that you see spanning the landscape behind me.
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Narrator:
After the mountains were formed by volcanic activity, the
rocky landscape changed in still other ways through weathering and erosion.
David Kring:
Weathering is a process that takes rock and makes it
weaker. For example, rain water can chemically alter rock.
Ice can get in cracks and break it apart. All of these things
can produce small fragments of more massive rocks. Once
weathering has weakened a rock, erosion takes over. It will
take these small rock fragments and carry them away.
Narrator:
Erosion is the moving of rocks and soil from one place to
another. Wind, for example, blows sand in these dunes and
this process changes the shape of the dunes.
Water is another important cause of erosion. Flowing water
can carry soil, sand or small rocks downstream.
You can do an experiment to see how erosion works. Fill a
baking pan with sand and tilt the pan by propping it on a
piece of wood or some stones. What do you think will
happen if you slowly pour water over the sand at the top of
the pan?
Your teacher can pause the video here for you to answer this
question. Otherwise, the program will resume in ten seconds.
pause
What happens when you pour water over the sand? The
water moves some of the sand from the top of the pan to the
bottom, and it creates little gullies.
23
Something similar happens on the earth's surface. Sand
and rocks are carried by rivers and streams. The water, sand
and rocks grind and rub against the surrounding rock and
wear away the earth's surface.
This is the Salt River in Arizona. It has cut a deep canyon
through part of the desert. This has taken millions of years.
The earth has undergone changes that are even more
dramatic. If you look at a map of the earth, you see the
continents, major land masses such as North and South
America, and Africa. But have the continents always been
where they are today? One clue to this question lies in the
shapes of the continents.
Think of the continents as pieces of a jigsaw puzzle. When
you work on a jigsaw puzzle, you look for pieces whose
shapes allow them to fit together.
In the same way, some of the continents have shapes that
seem to fit together. South America, for example, fits very
nicely with Africa. This suggests that once these two
continents were joined.
Based on clues like the shapes of the continents, geologists
think that long ago in the earth's history all the continents
were bunched together like this. Then, over many millions
of years, the continents separated, slowly moving to where
they are today.
Moving continents cause other changes in the earth's crust.
Imagine these two towels are two continents. Move them
slowly together and see what happens.
24
Student:
They bunch up.
Narrator:
The same thing happened in the past when continents
collided. Where the continents came together, the land
bunched up, forming mountains. This happened very slowly
over many millions of years.
But other changes in Earth's crust occur in a matter of
minutes and even seconds. Earthquakes are sudden movements of the earth's crust, when it shakes or slides.
Earthquakes can be very powerful and destructive. They
not only change the way the surface of the earth looks, they
damage or even destroy buildings, roads and bridges.
Earthquakes occur when sections of the earth's crust move
past each other, building up pressure or force.
It's a little like bending a stick. You can bend it only so
much before the stick snaps.
The same thing happens when pressure builds as a result of
different parts of the earth's crust moving. Suddenly the
rock will snap.
In this program we saw many things about the planet Earth.
The earth's surface is covered mostly by water, particularly
the salt water of oceans but also by the fresh water of rivers,
streams, lakes, and ponds.
Earth is also covered by land,
and it is surrounded by a thin layer of air called the
atmosphere.
25
If we could cut open the earth, we could see other things
about the earth. Inside is a solid inner core of iron and nickel
that is surrounded by an outer core of melted iron and then
a rocky mantle. On top of this is the thin crust.
We saw how the earth's crust is constantly changing. Some
changes occur very slowly over many millions of years... as
when continents move and rivers carve deep canyons.
Other changes occur quickly as volcanoes erupt pouring
lava out over the surface,
and earthquakes shake and crack the landscape.
Finally, we saw that geologists study the earth and how it
changes.
We, too, can study and learn many things about the planet
that is our home.
The End
26
CREDITS
Author and Producer:
Principal Videography:
Peter Cochran
Dan Duncan
Peter Scheer
Narrator:
Curriculum Consultant:
Randye Kaye
Michael Worosz
Our appreciation to Dr. David Kring of the
University of Arizona
Produced for Rainbow Educational Media by
Cochran Communications
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