Earth’s Changing Surface: Teacher’s Guide
Grade Level: 5-8
Curriculum Focus: Earth Science
Lesson Duration: Four+ class periods
Program Description
Underground expeditions and satellite navigation give students an exciting introduction to
geology and geography. GPS: Mapping Earth’s Surface—Explains an innovative mapmaking
technology. American Prairie Soil—Traces the origins of a fertile region of our country. Exploring
Caves—Leads students on a spelunking expedition into one of Earth’s last frontiers. The Grand
Canyon: Investigating Our Geologic Past—Reveals how exposed layers of rock give scientists a
snapshot of Earth’s history.
I. GPS: Mapping Earth’s Surface (5 min.)
II. American Prairie Soil (6 min.)
III. Exploring Caves (5 min.)
IV. The Grand Canyon: Investigating Our Geologic Past (4 min.)
Onscreen Questions
Segments I
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How has GPS technology improved the ability of cartographers to make accurate maps?
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In what new ways does GPS technology allow us to use maps?
Segments II
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What makes American prairie soil fertile?
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What is humus and how does it form?
Segments III
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How do weathering and erosion contribute to cave formation?
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What is a speleothem and how is it formed?
Segments IV
•
What kinds of forces helped form the Grand Canyon?
•
What do fossil remains tell us about the land surrounding the Grand Canyon?
Earth’s Changing Surface: Teacher’s Guide
2
Lesson Plan
Student Objectives
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Explain how caves are formed.
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Demonstrate how speleothems are formed.
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Describe the difference between stalactites and stalagmites.
Materials
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Earth’s Changing Surface video and VCR, or DVD and DVD player
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Food coloring (optional)
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Glass jars (jelly jars or chemistry beakers), 2 per student group
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Plastic-coated plate or petri dish, 1 per student group
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Plastic spoon, 1 per student group
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Thick twine, 1 length per student group
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Baking soda, about 2/3 cup per student group
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Warm water
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Magnifying glasses, 1 per student group
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Science logs, 1 per student
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Computer with Internet access (optional)
Procedures
1. Introduce the lesson by talking about caves. What are caves? How are they formed? What kinds
of rock and crystal formations are found inside caves? A good way to introduce this
information is to view the “Exploring Caves” segment of Earth’s Changing Surface.
2. After watching the program, tell students they will make their own stalactites and stalagmites
using baking soda, water, and string. Make sure students understand that although their
classroom models should form within a few days because you are using concentrated solutions
and help from the sun, natural speleothems in caves take thousands of years to form.
3. Divide students into groups of five and give each group the supplies they will need to make
their speleothems (baking soda, warm water, jars and plate or petri dish, plastic spoon, twine,
and food coloring). Have students place their jars about 6 to 12 inches apart in a warm, sunlit,
and stable area of the classroom where they can be left out untouched for a few days.
4. Direct students to fill the jars about halfway with warm water and dissolve as much baking
soda as possible to create a saturated solution. They may stir a few drops of food coloring into
the solution. Then have them pour a small amount of dry baking soda on the plate or petri dish
and place it between the two glasses. Have students saturate their lengths of twine in the water-
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Earth’s Changing Surface: Teacher’s Guide
3
baking soda solution and drape them between the glass jars. They will place both ends of twine
well into the glasses and make sure the center drips directly over the plate or petri dish.
5. Once students have set up their group experiment, have them draw a picture of it in their
science logs and record any predictions about what will happen over the course of the
experiment. Tell students they will observe their experiment once a day for several days. Each
student will record the changes in a science log because their records are an important part of
the scientific process. Discuss the experiment and ask students to tell you their predictions.
6. For the next three days, have students spend a few minutes observing their experiments,
discussing them with their group, and recording the changes in their science logs. Give the
groups a magnifying glass to closely observe the crystals; stalactites and stalagmites should
form by the fourth day.
7. End the experiment once stalactites and stalagmites have formed. Have students make one final
entry into their science logs to record how the experiment changed and if they made accurate
predictions. Discuss the formations. Did crystals form up from the dishes or down from the
twine? Talk about the classroom formations and why they formed as they did. Allow students
to walk around the classroom and observe all the experiments. Talk about the different kinds of
speleothems in caves. What are the differences between stalactites and stalagmites? How closely
do the classroom formations mirror natural speleothems? Allow students to spend time looking
at pictures of real speleothems on the following Web sites:
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http://www.lcc.ctc.edu/departments/natural_sciences/pictures/cavepics.xtm
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http://www.nps.gov/wica/Speleothems.htm
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http://www.nps.gov/jeca/tour-pictures.htm
Assessment
Use the following three-point rubric to evaluate students’ work during this lesson.
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3 points: Students actively participated in class discussions; worked cooperatively in their
groups; used science materials wisely; correctly recorded information about the experiment
in their daily science logs; could explain the differences between stalactites and stalagmites.
•
2 points: Students somewhat participated in class discussions; worked somewhat
cooperatively in their groups; used the science materials somewhat wisely; recorded two or
three days of the four-day experiment in their science logs; could explain the differences
between stalactites and stalagmites with assistance.
•
1 point: Students somewhat participated in class discussions; were unable to work
cooperatively in their groups; were unable to use the science materials without teacher
assistance; recorded one or two days of the four-day experiment in their science logs; could
not explain the differences between stalactites and stalagmite.
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Earth’s Changing Surface: Teacher’s Guide
4
Vocabulary
deposition
Definition: The act or process by which an agent of erosion (such as wind or water) leaves
behind sediment
Context: The formations inside the Caverns of Sonora, near San Antonio, Texas, are the result of
erosion and deposition working together.
erosion
Definition: The act or process of being worn away by the action of wind, water, or glacial ice
Context: Erosion helps create caves, canyons, and other marvels of nature.
speleothem
Definition: A calcite deposit created when calcium carbonate dissolves in water seeping through
limestone cave walls
Context: Like caves, speleothems form very slowly over time.
stalactite
Definition: A deposit of calcium carbonate resembling an icicle hanging from the roof or sides of
a cavern
Context: Speleothems that grow downward from the ceiling of a cave are called stalactites.
stalagmite
Definition: A deposit of calcium carbonate formed on the floor of a cave by the drip of calcareous
water
Context: The formations on the bottom of caves that grow upward from deposits of mineral-rich
water are stalagmites.
weathering
Definition: To undergo or endure the action of the elements
Context: The powerful forces of weathering, erosion, and deposition contribute to the formation
of caves.
Academic Standards
National Academy of Sciences
The National Science Education Standards provide guidelines for teaching science as well as a
coherent vision of what it means to be scientifically literate for students in grades K-12. To view the
standards, visit http://books.nap.edu.
This lesson plan addresses the following science standards:
•
Science as Inquiry
•
Earth and Space Science
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Earth’s Changing Surface: Teacher’s Guide
5
Mid-continent Research for Education and Learning (McREL)
McREL’s Content Knowledge: A Compendium of Standards and Benchmarks for K-12 Education
addresses 14 content areas. To view the standards and benchmarks, visit link:
http://www.mcrel.org/compendium/browse.asp
This lesson plan addresses the following national standards:
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Science—Earth and Space Sciences: Understands Earth's composition and structure; Nature
of Science: Understands the nature of scientific inquiry
•
Language Arts—Viewing: Uses viewing skills and strategies to understand and interpret
visual media
Support Materials
Develop custom worksheets, educational puzzles, online quizzes, and more with the free teaching tools
offered on the Discoveryschool.com Web site. Create and print support materials, or save them to a
Custom Classroom account for future use. To learn more, visit
•
http://school.discovery.com/teachingtools/teachingtools.html
DVD Content
This program is available in an interactive DVD format. The following information and activities are
specific to the DVD version.
How To Use the DVD
The DVD starting screen has the following options:
Play Video—This plays the video from start to finish. There are no programmed stops, except by
using a remote control. With a computer, depending on the particular software player, a pause
button is included with the other video controls.
Video Index—Here the video is divided into four parts (see below), indicated by video thumbnail
icons. Watching all parts in sequence is similar to watching the video from start to finish. Brief
descriptions and total running times are noted for each part. To play a particular segment, press
Enter on the remote for TV playback; on a computer, click once to highlight a thumbnail and read
the accompanying text description and click again to start the video.
Curriculum Units—These are specially edited video segments pulled from different sections of the
video (see below). These nonlinear segments align with key ideas in the unit of instruction. They
include onscreen pre- and post-viewing questions, reproduced below in this Teacher’s Guide. Total
running times for these segments are noted. To play a particular segment, press Enter on the TV
remote or click once on the Curriculum Unit title on a computer.
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Earth’s Changing Surface: Teacher’s Guide
6
Standards Link—Selecting this option displays a single screen that lists the national academic
standards the video addresses.
Teacher Resources—This screen gives the technical support number and Web site address.
Video Index
I. GPS: Mapping Earth’s Surface (5 min.)
Global positioning systems have changed how we interact with the world around us. See how this
technology is revolutionizing the way we use maps.
II. American Prairie Soil (6 min.)
Vast grasslands stretch across much of the center of the United States. Learn about the geography of
the American prairie.
III. Exploring Caves (5 min.)
Go underground to explore some deep, dark caves and see how the powerful forces of erosion,
weathering, and deposition help form caverns and speleothems.
IV. The Grand Canyon: Investigating Our Geologic Past (4 min.)
Formed billions of years ago, the Grand Canyon can tell us much about our Earth’s history. Learn
about the rocks and fossils found throughout the Grand Canyon.
Curriculum Units
1. Using GPS
Pre-viewing question
Q: How has modern technology improved our mapmaking abilities?
A: Answers will vary.
Post-viewing question
Q: What are some ways you use GPS in your daily life?
A: Answers will vary.
2. Prairies of the United States
Pre-viewing question
Q: What do you think our planet would be like without prairie lands?
A: Temperature is the rate of the speed of a substance’s molecules.
Post-viewing question
Q: What are the three zones of prairie grasslands, and where are they located?
A: The short grasslands area is closest to the Rocky Mountains; the tall grass zone is closest to the
Eastern forest; the middle zone contains a mixture of grass types.
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Earth’s Changing Surface: Teacher’s Guide
7
3. Outside Elements
Pre-viewing question
Q: Do you think humans are destroying the prairie?
A: Answers will vary.
Post-viewing question
Q: How can fires benefit the prairie?
A: Many prairie grasses have buds and seeds that lie just below the surface of the soil. After the
fires consume the plants above ground, these seeds can sprout quickly. Fire also turns dead plant
material into ash, which provides nourishment for new plants.
4. Inside Mammoth Cave
Pre-viewing question
Q: What can we learn about the Earth by studying caves?
A: Answers will vary.
Post-viewing question
Q: What is a karst landscape?
A: An area of limestone or other carbonate bedrock that has been shaped over thousands of years
by water wearing away the stone. This erosion creates underground channels for the water, as well
as sinkholes and caves.
5. Deposition and Speleothems
Pre-viewing question
Q: What is the difference between a stalactite and a stalagmite?
A: Stalactites are deposits of sediment that grow downward from the ceiling of a cave. Stalagmites
are similar deposits that grow from the ground up.
Post-viewing question
Q: What is deposition?
A: The process by which an agent of erosion, such as wind or water, leaves behind—or deposits—
sediment.
6. Learning from Layers of Rock
Pre-viewing question
Q: Why is the Grand Canyon an important place for scientists studying Earth’s history?
A: Answers will vary.
Post-viewing question
Q: What kinds of rock can be found throughout the Grand Canyon?
A: Granite and schist are found in the inner gorge at the bottom of the canyon. Above this is a layer
of sedimentary rock, namely limestone, shale, and sandstone. The bulk of the canyon’s walls consist
of sandstone, shale and red limestone. Within and around the canyon are sheets of hardened black
lava.
Published by Discovery Education. © 2005. All rights reserved.