Download 1 National Science Teachers Association Discovering Science

National Science Teachers Association
Discovering Science Lessons Plans and Experiments for the Classroom
Topic: Plants/ Roots and Erosion
Grades: 2-3
Allocated Time: Two sessions/20-35 minutes Student Population: __students/_boy_ girls
Standards
Next Generation Science Standards: 2. Structure and Function; Interactions, Energy, and Dynamics,
LS1.A, LS2-1, LS2-2, Earth’s Systems 2-ESS2-1. 3. Weather and Climate, ESS3.B
Common Core State Standards: English Language Arts, Writing, W.2.3, W.3.3
Goal for Understanding
Students will learn that plants have two kinds of root systems and that plants help reduce erosion.
Objectives
Students will
 compare plants with tap roots and plants with fibrous roots.
 observe a demonstration to see how plants prevent erosion.
 examine two kinds of plant roots, tap roots (carrots) and fibrous roots (grass).
Materials Needed (See science activity appended for additional materials.)
 plants or photos of plants
Anticipatory Set
Display a plant, or photo of a plant, one with a fibrous root and another with a tap root. List its
parts (roots, stem, leaf, flower). On an easel pad, write: What are the differences in the two
plants? Discuss responses. See two kinds of root systems here Diagram of root systems.
Instruction (I/Teacher’s role)
Discuss key content words (plants, root systems, erosion, tap root system, fibrous root system).
 Plants are living organisms. (Trees, herbs, bushes, grasses, vines, and ferns are plants.)
 Plants give us food, wood, and also change carbon dioxide into oxygen, which helps clean the
air. Plants have many parts such as roots, stem, leaves, buds, flowers, fruits, etc.
 The roots are the first part of a plant to grow. They usually grow into the ground. Roots
perform four basic functions. 1. They soak up water and nutrients from the soil. 2. They
anchor, or hold, plants in place in the soil. 3. They hold soil in place and prevent erosion.
4. They store extra food for the plant.
 Root act like tubes. They take water and minerals from the soil. Tiny root hairs extend out
from the root. The root hairs also help to absorb water. The stem takes the water and minerals
up to the leaves.
 Roots grow in different ways. Some grow in shallow ground near the surface. Some grow
straight into the ground. Some plants live in trees (orchids), and their roots cling to branches.
Some plants and their roots grow in water.
Scientists have identified two main kinds of root systems.
 Taproot systems have one large root that grows deep into the ground. For example, carrots
have a taproot system. The roots are large and grow deep in the ground. The stems and leaves
grow above the surface (beets, turnip, parsnip, dandelions, and radishes).
 Fibrous root systems have a network of many roots of similar sizes all tangled together. The
roots cling to the soil. Grasses and most plants have fibrous root systems. See an interactive
game about plants at http://urbanext.illinois.edu/gpe/case1/c1brief.html
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Erosion is the process in which water, wind, and other forces wash away rocks and soil from
Earth’s surface. Why is that a problem? Topsoil is the most fertile soil for plants. Erosion takes
away the nutrients usually found in that top layer of soil. Erosion also may wash soil into ponds
and other bodies of water and harm those habitats. Erosion is a natural process, but people cause
erosion too. They may cut down too many trees, for example. When erosion destroys the quality
of soil needed to grow crops, farmers get smaller harvests. Less food is produced. People have to
pay more for foods. Plants can help prevent erosion. How? Plants slow down water as it flows
over land. That lets the rain soak into the soil, instead of washing it away. Root systems hold soil
in place. Plants with fibrous root systems (tangled masses of roots) are better at preventing
erosion than plants with tap roots. Fibrous roots can hold soil in place during strong rains. Plant
leaves and flowers help too. They soften the impact of raindrops; the soil does not splash around
as much. Dead plants help too. Decaying plant matter soaks up rain and prevents erosion.
Guided Practice (We/Students with Teacher’s guidance)
Ask questions after a simple demonstration of erosion. Let water run on a bar of soap for a while.
Pass around the bar of soap. Ask: What does the water represent? (rain) What does the top layer
of soap represent? (top layer of soil) Ask: Why is erosion a problem? (it washes away topsoil)
Review or summary
Review facts about plants, roots, and erosion based on the guided activity. Discuss questions.
Independent Learning (You/Student)
Ask students to complete the sentences. 1. The main parts of ___ are leaves, stems, and roots.
2. The roots are usually below the __ . 3. They take in __ and minerals from the soil. 4. Erosion
occurs when water and __ wash away soil. 5. Plants help prevent the problem of __.
(Word Box: plants, ground, water, wind, erosion)
Checking for Understanding (Assessing)
Review students’ paragraphs for accuracy. Invite students to share their work.
Cross Curriculum Extension: Literature/Writing
Read aloud, The Enormous Turnip, a folktale illustrated by Kathy Parkinson. Discuss plot and
theme (teamwork). Ask students to write a different ending or add a character to the story.
Adaptation (Gifted and Talented or English Language Learners)
Give students different kinds of seeds. Have them create a seed display, labeling each seed and
showing photos of the plants they grow into. Include plants with fibrous roots and taproot plants.
Additional Reading
 The Enormous Turnip, a folktale illustrated by Kathy Parkinson
 Just a Dream, by Chris Van Allsburg
 Someday a Tree, by Eve Bunting
 What Do Roots Do? by Kathleen V. Kudlinski
 The Sea, the Storm and the Mangrove Tangle, by Lynne Cherry
Additional Resources
 National Science Teachers Association
Science and Children, December 2006, “This Land Is Your Land,” pages 22-26,
http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/sc06_044_04_22
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
Science and Children, The Strongest Mountain, page 35-37.
http://learningcenter.nsta.org/product_detail.aspx?id=10.2505/4/sc04_042_02_35
Share illustrations of root systems at http://www.botany.uwc.ac.za/ecotree/root/roottypes.htm
NSTA
Discovering Science
Grades: 2-3
Title: Erosion
Demonstration: How Do Plants Help Prevent Erosion?
Standards: Next Generation Science Standards: Life Sciences, Structure and Function,
Ecosystems, Interactions, Energy, and Dynamics, LS2.A; Earth and Space Sciences, Roles of
Water in Earth’s Surface Processes, ESS2.C
What you need
 pan of dirt kept moist but not too wet (labeled #1)
 pan with grass grown ahead of time in dirt (labeled #2)
(Grass seed about—2 tablespoons—will grow in about a week in moist soil placed in the sun.)
 watering can or measuring cups
 ramp of blocks or books to tilt pans
 basin to collect water
Time: one week in advance to plant and grow grass/15-30 minutes to observe results
What you do
1. Ask students to observe the demonstration and assist you, if necessary.
2. Place each tray so that it is on an incline with a basin at the bottom of each one.
3. Pour water from the watering can into pan #1 tray with soil.
4. Pour water onto the pan #2 with grass or plants.
What you found
When the water was poured into pan #1, the moving water, like rain, removed layers of soil and
washed it away. When it was poured into pan #2, the grass and its roots, especially fibrous roots,
can prevent erosion. The soil may still be damaged, but much of it remains intact.
Explore More!
 carrot, turnip, beet, or parsnip with roots and leaves attached
 grass or house plant with roots attached
 hand lenses
Root systems have different parts. The main part of the root is the primary root. The secondary
roots, or lateral roots, grow out of the side of the primary root. Root hairs are tiny, fuzzy roots
growing out of the main root. Root hairs increase the surface area of the root and help absorb
water and other materials. The root cap is the bottom tip of the root. It pushes down into the soil.
1. Have students work in groups. Provide some groups with a tap root plant cut in half (carrot,
radish, or beet) with leaves intact. Provide other groups with grass or plants with roots intact.
2. Ask students to closely examine the plants and roots with hand lenses.
3. Have the students sketch the roots and write the name of the plant, the kind of root, and some
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observations (shape, color, texture, length, weight, etc.). (If time permits, ask students to
swap root samples and do another observation.) Discuss observations.
Name ____________________________________________________________________
NSTA
Be a Scientist: Ask, Answer, and
Problem
Solution
Discover!
In the boxes below, sketch the problem and the solution observed in the demonstration
1. What did you observe when water was poured into the pan #1 without grass?
_____________________________________________________________________
_____________________________________________________________________
2.
What problem did you observe?
_____________________________________________________________________
3.
What did you observe when water was poured into pan #2 with grass?
_____________________________________________________________________
_____________________________________________________________________
4.
What solution did you observe?
_____________________________________________________________________
5. Draw conclusions. What might you conclude about erosion, plants, and roots based
on the demonstration?
_____________________________________________________________________
_____________________________________________________________________
6. Solve problems. Plants can reduce or prevent erosion. What are other ways to prevent
the problem of erosion?
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_____________________________________________________________________
___________________________________________________________________________
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