The purpose of this resource is to introduce students to the importance of soil. In the first activity, students generate a list of why soils are important. In the second activity, students are asked to describe the five factors that form a unique soil profile and to explore these concepts. In the third activity, students are shown a demonstration of how much soil there is on Earth that is available for human use. Educational levels: Primary elementary, Intermediate elementary, Middle school, High school

The GLOBE Program, University Corporation for Atmospheric Research (UCAR)

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GLOBE® 2005 Why Do We Study Soil? Learning Activity - 1 Soil
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ppendix
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elcom
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Introduction
Protocols
Learning A
ctivities
!
?Why Do We Study Soil?
Purpose
To introduce students to the importance of soil 
and why it needs to be studied
Overview
In the first activity, students generate a list of 
why soils are important. In the second activity, 
students are asked to describe the five factors 
that form a unique soil profile and to explore 
these concepts. In the third activity, students are 
shown a demonstration of how much soil there 
is on Earth that is available for human use.
Student Outcomes
Students will understand the importance of 
soil science. 
Students will be able to provide reasons for 
studying soil. 
Students will understand how soil properties 
are determined by the five soil forming 
factors. 
Students will appreciate the relative amounts 
of usable soil that exist on Earth.
Science Concepts
Earth and Space Sciences
Earth materials are solid rocks, soil, water, 
biota, and the gases of the atmosphere.
Soils have properties of color, texture, 
structure, consistence, density, pH, 
fertility; they support the growth of 
many types of plants.
The surface of Earth changes.     
Soils are often found in layers, with 
each having a different chemical 
composition and texture.
Soils consist of minerals (less than 2 mm), 
organic material, air and water.
Water circulates through soil changing 
the properties of both the soil and the 
water.
Physical Sciences
Objects have observable properties.
Life Sciences 
Organisms can only survive in 
environments where their needs are met.
Earth has many different environments 
that support different combinations of 
organisms.
All populations living together and the 
physical factors with which they interact 
constitute an ecosystem.
Scientific Inquiry Abilities
Identify answerable questions.     
Design and conduct an investigation.     
Use appropriate tools and techniques 
including mathematics to gather, 
analyze, and interpret data.
Develop descriptions and explanations, 
predictions and models using evidence.
Communicate procedures 
  and explanations.     
Time
One or two class periods (depending on level of 
exploration for second activity)
Level
All
Materials and Tools
Apple and small knife (or diagrams or 
overhead materials of apple activity)
Soil medicine examples (e.g. diarrhea 
medicine, antibacterial gel or cream, 
facial masks)
Soil art examples (e.g. mud cloth, sand 
painting, pottery)
Soil building material examples (e.g. red 
brick, photos of adobe and Earthship 
houses)
Makeup (e.g. foundation, blush)
Soil samples (if available, especially soils 
that match the colors or textures of 
the medicine, art, building material, or 
makeup examples)
Plant
Soil story example (e.g. Maryland Flood 
Plain Soil)
Prerequisites
None
GLOBE® 2005 Why Do We Study Soil? Learning Activity - 2 Soil
Why are soils important?
Soils exist as natural ecosystems on the surface 
of Earth made up of macro and microorganisms, 
minerals, organic matter, air, and water. Soils are 
living systems that provide many of the most 
fundamental functions needed for life. Important 
functions of soil include:
• Providing the fertile medium in which we 
grow our food and fiber
• Producing and storing gases such as CO
2
• Storing heat and water
• Providing a home for billions of plants, 
animals and microorganisms 
• Filtering water and wastes
• Providing the source material for 
construction, medicine, art, makeup, etc.
• Decomposing wastes
• Providing a snapshot of geologic, 
climatic, biological, and human history
Soil forms very slowly and comprises only 
about 10 or 11% of Earth’s surface. So, it is 
important to study this essential natural resource 
and understand how it should be used and 
conserved properly.
What To Do and How To Do It
Activity One: Why are soils important?
1. Collect as many materials and tools as 
possible from list in Materials and Tools 
section of gray box.
2. Ask the class “Why are soils important?” 
and “Why do you think it is important to 
study soils?”
3. Record their answers on a blackboard or 
somewhere that all students can read the 
responses.
4. As students give answers that relate to 
the collected materials, bring out those 
materials and show them to the class. For 
example, if a student says that we use 
soil as art, have a clay pot available for 
viewing. If students run out of ideas about 
the uses of soils, ask them about soil as 
art (and bring out the African mud cloth 
[Bogolanfini] or a picture of one) or soil as 
medicine (for diarrhea, antibacterial gel, 
examples of people eating soil for digestive 
problems, etc.) Also bring out soil samples 
that resemble these materials for comparison.
5. Lead the discussion to the many possible 
reasons why it is important to study soil (see 
above).
Activity Two: Are soils all the same?
1. Show students photographs from the Soil 
Investigation Introduction section titled Soils 
Around the World. Have students check the 
World Wide Web (e.g. soils.usda.gov or soils.
gsfc.nasa.gov), library, and other sources for 
other photographs of soil profiles. Also, look 
for color drawings or photographs of soil 
properties by GLOBE students on the GLOBE 
Web site (try going to the data access page, 
then to GLOBE Sites and then to Soil Profiles).
2. Ask students why one soil profile looks 
different from another? What are some of 
the factors that would make a soil look the 
way it does? Help guide their responses 
by reading the Five Soil Forming Factors 
(parent materials, climate, topography, 
biota, and time) in the GLOBE Soil 
Investigation Introduction.
3. Have the students identify the 5 soil 
forming factors at their school and ask how 
they might differ at other locations, within 
the neighborhood, or around the world.
4. Discuss the concept that every soil tells a 
different story based on the properties that 
have formed it because of the 5 soil forming 
factors. As an example, use the following 
Maryland Flood Plain Soil photograph and 
story.
 This soil profile is from a creek bed in College 
Park, Maryland, USA in the Chesapeake Bay 
watershed. When the soil scientists were 
studying this profile, they noticed that there 
was a black layer right in the middle of the 
profile. When the scientists looked at this 
layer with a hand lens (small magnifying 
glass) they could see that the black color was 
due to many tiny bits of charcoal and ash. 
Using different kinds of tests, they learned 
that this material was deposited about 300 
- 350 years ago.
GLOBE® 2005 Why Do We Study Soil? Learning Activity - 3 Soil
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ppendix
W
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Introduction
Protocols
Learning A
ctivities
 Where would charcoal and ash have come 
from about 300-350 years ago? What was 
going on in the Chesapeake Bay region at 
about that time?
 Settlers coming to this region for the first 
time were burning the forests to make room 
for farms. The residue from those forest 
fires flowed down into the rivers and creeks 
and eventually some of it was deposited in 
this creek bed and became part of this soil 
profile. The soil above this layer was created 
after the ash and charcoal were deposited 
by flooding of the river and the addition 
of sediments eroded from the local area 
on top of the charcoal layer.  In soils, the 
youngest materials are found at the top of the 
profile. After the sediments were deposited 
by the flooding water, soil processes took 
over to form structure, color, and other soil 
properties that we can see and measure.
 The scientists also noticed that in the horizon 
below the charcoal and ash layer, there 
were clam and oyster shells (as well as some 
pebbles rounded by washing down the river 
during flood events). With careful testing, 
they learned that the objects in this horizon 
were deposited here about 400 - 450 years 
ago.
 What was going on in the Chesapeake Bay 
about 400 - 450 years ago?
 The indigenous people who lived in 
this area before the settlers came would 
come to the Bay for their holiday feasts 
and they would celebrate and eat lots 
of clams and oysters. What we see here 
was what was left behind. These shells 
eventually flowed down into this creek 
bed and became part of the soil profile.
 The last part of the story takes us to the 
beginning. The lowest two horizons 
in this profile are of an earlier soil that 
was buried under the river sediments 
of the newer soil. The buried soil shows 
structure, colors and other features that 
indicate it is many thousands of years 
old and was in a swampy area before the 
river changed its course and began to 
bury it.
 This is an example of how a soil can be a 
record of the history of the area around it 
and can tell us its story. Other stories are 
available on the Soil Science Education 
Web page (soils.gsfc.nasa.gov) under the 
“Every Soil Tells a Story” feature.
5. Ask students to try to come up with 
“stories” about how other soils may have 
formed and the properties that they 
have.
6. Introduce the concept of diversity in soil 
which states that because every soil is 
different, each one can only be used in 
a certain way. For example, which kind 
of soils would be best for growing crops 
(flat, fertile, moist, deep, etc.)? Which 
soils would be best for building a pond 
or reservoir (clay with massive structure, 
high density, low porosity, flat or depressed 
area on the landscape, etc.)? Which would 
be best for filtering wastes (high surface 
area, lots of organisms, not too cold or 
wet, etc.)? Have the students think of other 
land uses and what kinds of soil properties 
would be best for those uses too cold or 
wet, etc.)? Have the students think of other 
land uses and what kinds of soil properties 
would be best for those uses.
Figure-SO-WH-1: College Park, Maryland
GLOBE® 2005 Why Do We Study Soil? Learning Activity - 4 Soil
Activity Three: How much soil is there on 
Earth?*
1. Take an apple and a small knife, or use the 
graphics below to conduct the following 
demonstration:
2. Teacher says: “Pretend that this apple is 
the planet Earth, round, beautiful, and full 
of good things. Notice its skin, hugging 
and protecting the surface.”
3. Teacher asks and discusses:
 a. “How much of the surface of the earth 
is covered by water?”
 b. Answer: Water covers approximately 
75% of the surface. 
 Action: Cut the apple in quarters. Toss 
three quarters (75%) away. 
4. Teacher says: “The three quarters (75%) 
that was just removed represents how 
much of the earth is covered with water 
- oceans, lakes, rivers, streams. What is 
left (25%) represents the dry land. Fifty 
percent of that dry land is desert, polar, or 
mountainous regions where it is too hot, 
too cold or too high to be productive”.
 Action: Cut the “dry land” quarter in half and 
toss one piece away.
5. Teacher says: “When 50% of the dry land is 
removed, this is what is left (12.5% of the 
original). Of that 12.5%, 40% is severely 
limited by terrain, fertility or excessive 
rainfall. It is too rocky, steep, shallow, poor 
or too wet to support food production.”
 Action: Cut that 40% portion away.
6. Teacher says: “What is left is approximately 
10% of the apple. 
 Action: Peel the skin from the tiny 
remaining sliver.
7. Teacher says: “The remaining 10% 
(approximately), a very small fragment 
of the land area, represents the soil we 
depend on for the world’s food supply. 
This fragment competes with all other 
needs - housing, cities, schools, hospitals, 
shopping centers, land fills, etc., and, 
sometimes, it does not win.”
 Action: Discuss with students some ways 
in which they could be more mindful 
of the soil and the way soils are being 
used at their homes or in their town. For 
example, discuss the idea of composting 
to recycle wastes and help make the soil 
rich in organic matter, and about keeping 
soil covered with vegetation so that it will 
not erode away or become compacted.
* How Much Soil Is There? Learning Activity courtesy 
of: The Natural Resources Conservation Service, 
U.S. Department of Agriculture
(This material can be downloaded from soils.gsfc.
nasa.gov.)


Why Do We Study Soil

http://www.globe.gov/tctg/whysoil.pdf?sectionId=100

Why Do We Study Soil

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