Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
UNIT: Soil
LESSON # 2
TITLE: What Makes Soil
Summary: This lesson deals with the question,
NASA Source:
Grade level:
Time:
Children
Learning
Outcomes:
“What makes soil?” ” It starts with the
facilitator reading about soil profiles in
the Elementary Globe book, “The Scoop
on Soils”. Children then do several
activities to show how parent rock
breaks down to form soil.
Partially adapted from NASA, Elementary
GLOBE Unit: The Scoop on Soils © 2006
University Corporation for Atmospheric
Research
<http://training.globe.gov/k-4/soil>
K -2
Total time: 70 minutes
Snack & introduction:
10 minutes
Reading “The Scoop on Soils”: 25 minutes
Breaking rocks:
20 minutes
Physical erosion demo:
10 minutes
Journaling and cleanup:
5 minutes
Children will begin learning that:
 Soil from different locations is different.
 Soil is made by breaking down parent
material (rocks) through weathering.
Children will engage in and thereby
strengthen a number of scientific
practices such as:
 Communicating when listening to the
story in “The Scoop on Soils”.
 Inferring by imaging that soil can be
made from rocks just like the rocks that
they broke up.
Children will be able to (cultural goals):
 Relate overall science learning goals to
the context of their schools, families,
and community.
 Communicate ideas, collaborate with
other children, and learn in a personally
meaningful way.
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Materials:
for The Scoop on Soils
The group facilitator will need
one color copy of the book, “The
Scoop on Soils”. This can be
downloaded at
http://training.globe.gov/k4/soil
for breaking rocks
Item
Quantity per
trio
Plastic
container
with a wide
mouth and a
1
screw-on
top (do not
use glass)
Pieces of
rock of
various
sorts (e.g.
granite,
basalt, soft
sandstone,
chalk,
limestone)
4–5 rocks
or building
material
(e.g.
concrete,
brick,
cement
block,
mortar)
Magnifying
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
Big Questions:  What is soil composed of?
 How is humus made (and what is it)?
Lesson format: Reading a book, discussion, hands-on
activity and a demonstration.
National This activity relates to the following
Standards standards from the Next Generation
Addressed: Science Standards:
4-ESS2-1. Make observations and/or
measurements to provide evidence of
the effects of weathering or the rate of
erosion by water, ice, wind, or
vegetation.
5-PS1-3. Make observations and
measurements to identify materials
based on their properties.
glass
White copy
1
paper
for physical erosion
demonstration
Item
Quantity per
group of 6–15
Aluminum
roasting
2
pans, 3
inches deep
to cover 1/3 of
Loose soil
one pan 2
inches deep
Lawn sod or
turf (or
to cover 1/3 of
groundcover
one pan
plants)
Wooden
blocks to
elevate one
end of
2
aluminum
pan about 2
inches
*Paper cups
2
Water
2 cups or more
* Poke 4 or 5 holes in the bottom
of one paper cup with a sharp
pencil.
Prepare aluminum pans ahead of
time with soil and sod in place.
Word Wall:
Include following words in
discussion (in both English and
Spanish), orally defined in
understandable terms, and
visibly displayed. If possible,
project a large image of the
words (and associated pictures)
on the wall of the teaching area.
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
 Soil profile
• Perfil del
suelo
 Soil color
• Suelo color
 Soil texture • Textura del
suelo
 Soil structure • Estructura
del suelo
 Erosion
• Erosión
 Weathering •Envejecimiento
 Organic
• Material
material
orgánico
DIRECTIONS:
Overview: This session involves four parts and one take-home activity:
1)
2)
3)
4)
5)
Introduce the lesson.
Read and discuss “The Scoop on Soils”.
Children do breaking rocks activity.
Children observe physical erosion demonstration.
Instruction for Take-home Kit/activity.
Steps:
LESSON INTRODUCTION (10 minutes)
Tell children that today, we will learn more about soil and where soil comes from.
Remind the children that by learning about soil they will gain a better overall
understanding of climate change, because soil is one of the important elements of our
environment.
LESSON LEARNING TASKS (60 minutes)
The Scoop on Soils (25 minutes)
Before reading, ask the children, “What do you think the soil would look like if you dig a
deep hole?” Take a few answers and then introduce the idea of a soil profile. Tell them
that as you dig down you get layers that look different from each other and are made up
of different materials. These layers that you see are called a soil profile. Tell them that
today, you are going to read them a story about some kids and their dog named Scoop,
who likes to dig holes, and what those kids find out about soil from looking at the holes.
Read them the story. Be sure to point out the illustrations of the soil profiles from
different locations. The big idea that we want the children to get is that the soil is
different in different locations.
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
After reading the story ask your group, “What did Anita, Dennis and Simon learn about
soils?” If the children do not mention it explicitly, talk about how the soil was different
in the different places that Scoop dug.
Breaking Rocks (20 minutes)
Tell the children that the rest of what they do today will deal with the question, “Where
does soil come from and how is it made? Remind them of what they saw in the shake
bottle; that soil is actually made of very small particles of various sizes that we call sand,
silt and clay. Tell them that these little particles actually come from rocks. How can that
be? This activity will help them see how.
1. Give each group of 3 children a wide-mouth, plastic container and cap and the
piece of paper.
2. Give each group its supply of rocks. Have children lay the rocks out on the piece
of paper and look at them closely.
3. Tell them to put the rocks in the plastic bottle and screw the top on tightly.
Check the bottles to make sure the top is on tight.
4. Tell each group that they are going to shake the bottle of rocks hard and see
what happens. Tell them you will time them so that each child will get to shake it
for about 30 seconds. Demonstrate how to shake the bottle before the children
start.
5. Have each child in the in group of 3 shake their bottle for about 30 seconds.
6. Have each group open their bottle and pour out the contents onto the white
paper. Ask them to look closely at what came out and tell the group what they
notice. They can use the magnifying glass to help observe.
You would expect them to see that some of the rocks have broken up and that
there are some small pieces of rocks that look a lot like sand or smaller particles.
7. Tell the children that, like the rocks they were working with, rocks in nature can
also break into smaller pieces. Nature does not put the rocks in a bottle and
shake them but it has its own way of breaking down rocks. Some of the ways
nature breaks down rocks include water getting in cracks and freezing and plant
roots growing into rocks. The general term for this natural rock breakdown is
called weathering.
Physical Erosion Demonstration (10 minutes)
1. Set up the two aluminum pans, one with loose oil and the other with sod or plants in
soil where the children can all see them. Elevate the ends with the dirt and sod.
2. Tell the children that rain and water flow can also cause erosion. Tell them that you
are going to do something on the table that shows what happens when rain falls on
plain soil versus soil with plants growing in it.
3. Ask the children what they think will happen when water falls on the loose soil. Ask
a child to hold the cup with the holes in the bottom over the high end of the loose
soil and pour a cup of water into it. You should expect to see much of the soil washed
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
to the bottom of the pan. Tell the children that washing away soil like that is called
erosion.
4. Now ask the children what they think will happen when water falls on the sod. Then
ask a different child to hold the cup with the holes in the bottom over the high end of
the sod and pour a cup of water into it. You should expect to see very little soil wash to
the bottom of the pan. Tell the children that plants can help prevent erosion.
LESSON SUMMARY (5 minutes)
Review word wall words while discussing observations children had about their activities.
Ask children to write and draw about what they did today in their journals. Clean up and
put materials away.
From this lesson, children should have learned:
 Soil can be very different from one place to another.
 Soil is made from rocks by weathering and erosion.
ASSESSMENT:
 Ongoing, through the discussion and activities: monitor children’s usage and
understanding of words and ideas related to today’s lesson. Ask supporting questions
to encourage children to make connections. Clarify misconceptions.
 Demonstrations of understanding: do any drawings, writing, theater, etc., display
sophisticated, accurate understanding of today’s lesson? Were children able to make
personal connections to the ideas? Were children able to make connections to prior
lessons?
 Take-Home work (assessed following week): did children follow through and discuss
the lesson with their families, bring a related show and tell object, and/or make a
drawing/other art project related to today’s lesson? Did discussion around these things
show continuing understanding of the ideas, including making connections to prior
lessons and to community?
Do children’s understandings, as displayed by their demonstrations of understanding,
questions, and discussion show connections between today’s topic, and the big picture
of the unit topic?
 Photograph objects and save drawings brought in for sharing in individual child’s
portfolio. Do the artifacts in the portfolio demonstrate an increasing trajectory of
understanding about the elements of the Earth System over time? Do children show
understanding of climate change? Do children show personal connections, including
self, school, family, and community, to their understandings of climate change?
RELATED NASA ACTIVITIES AND RESOURCES:
Soil Science Education
http://soils.gsfc.nasa.gov/
The portal to a large array of NASA education resources on soil.
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
Soil Science Education: Introduction to Soil Forming Factors
http://soils.gsfc.nasa.gov/index.php?section=78
Introduction to soil formation including parent materials and how they breakdown into
soil.
Soil Science Education: Every Soil Has A Story
http://soils.gsfc.nasa.gov/soilstory/
An introduction to soil profiles.
BACKGROUND INFORMATION:
This chart is from http://soil.gsfc.nasa.gov/index.php?section=73 , part of NASA’s GLOBE Soil
Science Education program
The top layer of the solid surface of the Earth is called the pedosphere. This layer is
primarily made up of soil but also contains air, water and living things. The pedosphere is
critical to the Earth system as it is the prime interface between all parts of the system. It
interacts with air, water and important parts of the biosphere (living things) and is the
place where incoming sunlight is absorbed and transformed to heat energy.
The pedosphere serves a number of functions. It is home to plants and animals. It is a
medium for plant growth and critical for crop production. It adds particular gases to and
takes particular gases from the atmosphere including carbon dioxide and nitrogen. It
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
contains waste decomposing organisms. It filters water and removes wastes. It provides
materials for building, pottery (e.g. clay), art (e.g. pigments), make-up and medicine.
The pedosphere is made of a combination of organic matter, minerals, water and air. There
are many living things in the soil from microbes, to plants and burrowing animals. The
minerals in the soil are produced from the breakdown of larger rocks. Clay, in addition to
being broken down rock, undergoes a reassembling into new structures. The mineral parts
of the soil are defined by particle size. According to the USDA, the soil parts are defined as:



Sand
Silt
Clay
2.00mm–0.05mm
0.05mm–0.002mm
less than 0.002mm
The very fine organic material in the soil is called humus. Humus is plant and animal matter
in the soil that is broken down and reassembled into large stable molecules. Humus is
critical to the fertility of the soil.
The mineral part of the soil comes from breaking down “parent” material into very fine
particles. The parent material for soil in a particular place may come from rock, broken
down in place or deposits carried to that place by water, wind, glaciers, volcanoes or
rockslides.
The breakdown of parent material is done by weathering. Wind, rain, snow, heat, living
organisms (including bacteria, plants and people) can all break down rocks. Topography
plays a big role in this process. For instance, water running down steep mountainsides can
lead to rapid erosion and deposition. Weathering can also take place by chemical means.
For instance, natural processes can produce acidic rain. The acidic water then breaks down
rocks like limestone. Most of these processes are slow. The average time that it takes to
build up one inch of soil is 50 to 100 years. Clay undergoes additional processes in its
formation. Through physical and chemical weathering nature can produce a microscopic
mixture of flat, plate-like particles. These form the basis of clay. They have a very large
surface area that can serve to bind nutrients and hold water in the soil. Clay is therefore, a
very important ingredient for fertile soil.
The composition and characteristics of soil change from one location to another and over
time. Soil composition and characteristics depend on five things. They are:
1. Parent material
Parent material is the stuff from which soil is made. This includes bedrock of the
place, organic materials and eroded materials that are deposited in the location.
2. Climate
Heat, wind, rain, snow and ice can all break down parent material and move the
broken down material around. So breakdown and transport depend on climate.
3. Living things
Plants, animals, microorganisms and people all live in or on the soil. Dead plants and
animals are broken down to form the organic part of the soil. Worms and burrowing
animals all contribute to the process of breaking down bits of organics to smaller
bits.
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
4. Topography
Steep slopes can enhance the effects of running water, glaciers and rockslides.
5. Time
All of the above factors take time. Over longer periods, we see increased breakdown
of parent material, increased erosion and repeated cycles of living organisms.
These five factors and their interactions vary from one place to another making the soil in
each location unique. This unique character shows up in soil profiles. A soil profile is what
you see when you take a deep cut into the soil. As you look at the cut from top to bottom
you see distinct “horizons” where the character of the soil changes. This profile changes as
you move horizontally from place to place. The horizons change vertically as you dig
deeper. Horizons near the surface contain more organics since the organics were formed
and deposited at the surface. As you move to lower layers, there is less accumulation of
organics and some of the organics have likely decomposed and been leached away. Factors
of erosion, deposition and human activity also play large roles in the character of the soil
profiles at each location.
The fine organic part of the soil, humus, is formed by breaking down of dead plants and
animals into simple organic components that reassemble into larger, more stable
molecules. The bulk of the final breakdown and reassembly is done by bacteria, fungi and
protists. These microorganisms use dead plants and animals for food that gives them
energy and building parts for their bodies. When the microbes die or are eaten by other soil
organisms, the nutrients in their bodies can be used by growing plants. Humus is made by
these organisms in a different process. In this process, soil organic matter is transformed
via extracellular “digestion” into more complex, stable humus particles.
Earthworms are very helpful in this process. Initially, most organic waste is composed of
pieces that are too large for microbes to effectively break down. Worms “chew” fresh
organic waste into small particles that are more easily broken down by microbes.
The decomposition of dead plants and animals is a natural process that is all around us.
Composing mimics this process. We gather dead plant material. We add microbes (from the
soil) that do all the real work of breaking down everything into stable organic materials
and nutrients that plants can use. When these materials are completely broken down and
reformed, we have humus.
Like clay, humus provides critical nutrients and water holding properties to the soil.
CULTURAL BACKGROUND INFORMATION:
Communities around the world have adapted their agricultural needs to its soils and
geography.
During pre-Hispanic times one of the methods of agriculture of ancient peoples of
Mesoamerica was by the system of "chinampas.” The Toltecs developed this system. A
“chinampa” is something like a floating garden that was planted on the banks of lakes. The
soil of a chinampa was obtained from the bottom of the lake, and thanks to its nourishing
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Developed by CLACE- PI Marina La Grave, Dr. Barry Kluger-Bell and Kristine Johnson
properties, crops prospered and were able to produce up to 6 harvests per year. An
important fact of this practice is that a sustainable chinampas did not need watering, as
plants simply absorbed the water off the lake or from rain. “Ahuejotes”, (willow tress) were
planted on the banks of the chinampas in order to provide greater stability.
Many countries continue to use this sustainable ancient practice!
LESSON CONNECTIONS
The soil unit has two strands. The soil strand deals with what makes up soil and what soil
contributes to life. The transformation strand deals with change over time including how
soil is made and things growing in soil.
This lesson is tied to ideas in other lessons:
In Lesson 1 (What makes up soil ), children learn about the components of soil (sand, silt,
clay and humus). They begin to make humus by constructing a composter.
In Lesson 3 (What makes soil good for growing), children explore what makes soil that is
good to grow things in and how plant roots interact with the soil.
In Lesson 4 (What lives in the soil), children learn about things that live in the soil from
microscopic bacteria to worms and bugs to burrowing mammals like rabbits.
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