Unit 1: Back to the Earth
Lesson 2: What’s Your Soil?
Grade Level: Fifth Grade
Time Required: 45 minutes, follow up on the next day.
Primary AZ State Standards:
(Cross-reference “Standards Matrix” for full listing)
Science:
S05-S1C3-01: Analyze data obtained in a scientific investigation to identify
trends and form conclusions.
S05-S5C1-02: Distinguish between mixtures and compounds.
Math:
M05-S1C1-01: Determine equivalence by converting between benchmark
fractions, decimals, and percents.
Objective(s):
Students will determine the physical composition (sand, silt, clay) of soil samples in
percentages.
Students will evaluate the drainage of different soils types and relate findings to plant
needs.
Materials:
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Key Vocabulary:
Dry erase board or chart paper
3 different soil samples, about 6-8 cups of each
Tablespoon
Jars with lids (3 per group)
Water (optional: pitchers for each group)
Centimeter rulers (1 per group)
3 deep bowls
Appendix 5B – Soil testing worksheet
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Silt
Sand
Clay
Humus
Loam
Mixture
Compound
Preparation
_X_ Adaptation of Content
_X_ Links to Background
_X_ Links to Past Learning
_X_ Strategies Incorporated
Instruction Features
Scaffolding
_X_ Modeling
__ Guided Practice
_X_ Independent Practice
_X_ Comprehensible Input
Grouping Options
_X_ Whole Class
_X_ Small Groups
__ Partners
__ Independent
Integration of Process
__ Reading
_X_ Writing
_X_ Speaking
_X_ Listening
Application
_X_ Hands-on
_X_ Meaningful
_X_ Linked to Objectives
_X_ Promotes Engagement
Assessment
__ Individual
__ Group
__ Written
__ Oral
Background Information:
Soil is the literal foundation on which you build your garden. Soil is not only a
physical anchor for plants, but its composition also affects water availability and
nutrient supplies for plants. While some soils, such as those in the Midwestern
United States, are considered to be “fertile” soils, the truth is that not all plants need
rich, humus-laden soils. There is no “one-size-fits-all” soil. Successful gardening
necessitates matching plant needs with soil types.
Consequently, before planting, it’s very important to know what kind soil you
are working with. Soils can be described by both their physical and chemical
compositions. Physically, soils contain different proportions of sand, silt, clay, and
humus. Sand is made of small grains of rock that have broken up and disintegrated
over time. Silt consists of even smaller grains than sand, and is often found either
suspended in water or deposited at the bottom of a body of water. Clay has the finest
particles of the three soils components. Clay is sticky and pliable when wet, but very
hard when dry. Lastly, humus is the scientific term for broken down organic material
that is in the soil.
Different mixtures* of these components result in different soils types. In this
lesson, students will determine what type of soil mixture they have. Loam is a soil
type that has equal concentrations of sand, silt, and clay. Soil types are usually
named after what type of loam they are. For example, sandy loams have more sand
than silt and clay, silt loams have more silt, and clay loams have more clay. However,
not all soils may have all three components.
When doing the soil typing experiment, students will put soil samples in water
and then allow the particles to settle out. The larger the particle, the more quickly it
will settle; as a result, sand would settle before silt which would settle before clay.
Humus floats at the top or just below the surface of the water. Students will examine
the layers and make estimates about soil composition. They will also consider how
the different sizes of soil particles would retain or allow water to drain away from
plant roots.
*As part of state standards, students should be aware that mixtures are different then
compounds in that mixtures are physical combinations of materials that can easily be
separated back out. Compounds, on the other hand, have undergone some type of chemical
bonding or transformation. The original components of compounds cannot be physically
separated back out without great effort.
Pre-lesson Preparation:
The week of the lesson…
1. Collect three samples distinctly different samples of soil from around town or
around the school property.
2. Collect enough jars with lids so that each group of students can have 3 jars.
3. Consider putting a larger jar or pitcher of water with each group to facilitate
experiment set up.
Activity Instructions:
Discussing soil elements
Whole class
10 minutes
1. Tell students to close their eyes and prepare to take a sensory trip to some
different places.
2. Tell students, “Imagine you are walking barefoot through all these different
places. Imagine the feelings on your feet.”
a. Walking on the beach.
b. Walking through the rain across wet grass.
c. Walking through a thick pile of mud.
3. Tell students to open their eyes and describe what they felt.
4. Explain that today we are going to be talking about different kinds of soil.
5. Show students a sample of the dirt. Ask students, “Who can tell me what dirt is
made of?” Discuss.
6. Share with students the information in the Background section by having them
guess as much as possible. For example, tell them, “There are three different
ingredients that most soils are made of. One of them is sand. Can you guess
the other two?” Write this information on the board or chart paper.
7. Tell students they are going to do some experiments to figure out what their
soils are made of.
Physical composition of soils
(Adapted from “Getting in ‘touch’ with your soils” Kids Gardening activity with
permission. See Resources.)
Smaller groups of 3
15 minutes
1. Explain and model the procedure to students:
a. Take about 8 tablespoons (approximate) of soil and put in the jar. Repeat
for each of the three samples.
b. Add water to about 1” from the top of the jar.
c. Shake well for about 1 minute.
d. Allow particles to settle out for an entire day (24 hours).
e. Estimate the fraction of the whole that is made up of each type of soil
after the first 10 minutes. Write the fraction on the Appendix 5B
worksheet, and convert to a percent.
f. Tomorrow, make a second observation by first writing a fraction and
then a percentage.
g. Tomorrow, compare the percentages and name type of soil on
worksheet.
2. Divide students into groups of 3.
3. Distribute 3 jars to each group.
4. Have one student from each group come and scoop several tablespoons of each
different soil type into jars.
5. Have another student come and fill jars with water, almost to the top.
6. Have the third student shake up the jar and a label it.
7. Circulate as students work, asking them questions such as:
 Where do you think these soil samples came from? Why?
 What is your preliminary guess as to what this soil type is? Why?
 Do you think this type of soil will drain quickly or slowly?
Soil ribbons
(Adapted from “Getting in ‘touch’ with your soils” Kids Gardening activity with
permission. See Resources.)
Small groups 3
10 minutes
1. Explain to students, “If you are finished, another quick test to check for soil
type is doing a ‘ribbon test’. Good scientists often use more than one test to
check their findings.”
2. Walk around and distribute rulers (1 per group) as well as one more tablespoon
of soil in each student’s hand. Model and tell students to add a little water to
form a ball.
3. Again, by modeling, show students to use their thumbs to create a ribbon with
the dirt. The more clay that is present, the easier this will be. If there is no clay,
it will be almost impossible to do.
4. Have students record their observations by measuring the lengths of ribbons in
centimeters.
5. Ask students, “Does this confirm your preliminary predictions and
observations?”
Soil drainage
Whole class
10 minutes
1. Bring class back together as a whole, and explain that the students will check
their samples again tomorrow and make final observations and comments on
their worksheets.
2. Tell students, “However, we will do one last physical test today. Many of you
gave me predictions about which soil you thought would drain the most and
least quickly. Let’s test your theories now.”
3. Take several cups full of each soil type and pack it into a deep bowl. Make a
small well in the middle. Have a student pour a cup or two of water one of the
bowls, inside the well. Have another student time how long it takes for the
water to drain out. Another student can write this data on the board. Groups
should record this data on their experiment sheet.
4. Repeat for each soil sample.
5. Ask students which soil drains fastest and slowest.
6. Ask students, “What does this mean for us as gardeners?” Have to consider
plant needs and modify the soils if needed.
7. Follow up with students again the next day when students look at their soil
sample and confirm or adjust their soil type results. Have students compare
answers and come up with a class decision.
8. Reveal where the soils came from.
Resources:
Getting in “touch” with your soil. National Gardening Association: Kids
Gardening Website. Accessed June 30, 2010 from
http://www.kidsgardening.com/Dig/DigDetail.taf?ID=2271&Type=Art