Students will discover how plants and soils interact by observing root growth, considering the function of a plant’s roots, modeling the movement of water into the roots, and investigating the movement of water and nutrients throughout the plant.
Three 45-minute class periods plus observation time
Activity 1: How Does a Plant Grow?
Clear plastic cup, 1 per student
Paper towels, 1 per student
Pea seeds, 2-3 per student
Activity 2: From Soil to Roots
Seedling from Activity 1
Hand lens, 1 per group
Paper or styrofoam cup
Bottle of food coloring
Activity 3: From Roots to the Plant
Sharp knife (for the teacher)
Paper or styrofoam cup, 1 per group
Celery stalk pieces (approximately 2 inches), 1 per group
Ask the students the following questions to introduce the lesson:
How do plants take in water and nutrients from the soil?
How does water and nutrients get from the roots to the rest of the plant?
Can a plant circulate water and nutrients through the roots, stem, and leaves just like a human's circulatory system circulates blood and nutrients?
Activity 1: How Does a Plant Grow?
Inform the students that they will be looking at the growth of pea seeds over the next few days. Model for the students how to set up the pea seeds in a cup with a paper towel and water. Note: This set up will need to be done several days before students begin with Activity 2.
Write your name near the top of the cup using a permanent marker.
Fold the paper towel and place it into the clear plastic cup so that it lies against the walls of the cup and does not extend above the rim of the cup.
Use a spray bottle to moisten the paper towel.
Insert 2-3 pea seeds between the paper towel and the wall of the cup. The seeds should be placed evenly around the cup and about 1/3 of the way from the bottom of the cup.
Add water to the cup. The seeds should not be submerged in water—the paper towel will wick water to keep the seeds moist.
Add water periodically so that the paper towel and seeds do not dry out.
For the next few days, allow a few minutes for students to observe their pea seeds.
After students begin to observe changes or growth in their seeds, ask students to share their observations. Record the observations on the board or chart paper. Continue to add to this list for a few days. Observations may include:
The seed swells or gets larger
The root grows downward
Branching of the root system
A green stem growing upward
Small leaves on the stem
Activity 2: From Soil to Roots
Ask the students, “Why do plants need water from the soil?” Follow this with the question, “Is there anything else in the water that the plant needs?”
Introduce the word “nutrients” to the students. Nutrients are substances that plants and animals need to be healthy. Nutrients cannot be seen, but are important for health. The nutrients plants need are released from soil particles into soil water.
Continue the discussion by asking students how plants get their nutrients, "What parts of the plant are important for getting nutrients from the soil?" (roots)
Explain to the students that they will be examining the roots of a plant. Divide the students into groups of four. Pass out a young seedling (taken from the paper towel germination in Activity 1) and a hand lens to each group. Tell the students that they should look at the roots of the seedling first using just their eyes and then using the hand lens. Ask the students to draw a picture of the roots of their seedling. Note: When students look at the roots with just their eyes, they may see just a basic root structure. When they use the hand lens, they are likely to notice small, fine projections coming off the roots. These are the root hairs. The root hairs are white and very fine. It may be easier to see the root hairs if students put a dark background behind the roots.
After the students have drawn pictures to represent their observations, ask for volunteers to describe what they saw. Students can also compare their observations with the seedlings from Activity 1.
Ask students, “Why do you think plants have so many root branches and root hairs?” (More root hairs allow for more area with which to contact water and nutrients in the soil.)
Ask students, “How do nutrients in the soil water get into the root hairs?”
Explain to the students that you are going to demonstrate the process by which water enters the roots. As you lead the demonstration, explain that the cup represents the root, the water inside the cup represents the water inside the root, the water in the larger container represents the water in the soil, and the food coloring represents the nutrients dissolved in the water.
Step 1: Fill the cup about half full of water.
Step 2: Place the cup of water into the center of the larger container.
Step 3: Fill the larger container with water until its level is the same as that in the cup.
Step 4: Add several drops of food coloring to the water in the larger container and gently mix the water until the color is evenly distributed through the water. Do not add food coloring to the water in the cup!
Step 5: Using a sharp pencil, poke two small holes in the cup opposite each other.
Step 6: Watch the water in the cup for up to five minutes.
Ask the students to share their observations from the demonstration.
Ask the students, "How is the demonstration similar to what happens in the roots of plants?" (The demonstration is a model of how water and nutrients move from outside the root to inside the root.)
Activity 3: From Roots to the Plant
Ask the students, “Besides the roots, do other plant parts need water and nutrients?” followed by “How do water and nutrients get from the roots to the rest of the plant?”
Explain to the students that they are going to investigate how water moves from the roots to the rest of the plant. Ask the students to work in their groups of four from Activity 2.
Pass out a copy of Master 3.1 to each student. Read through the instructions with the students to ensure that they understand their task.
Ask the students to write their predictions about what will happen with the food coloring, water, and celery.
As the students work on their investigation, circulate among the groups to answer questions and help them with timing the investigation.
Reconvene the class and ask for volunteers to report their predictions and results about the movement of the food coloring in the celery. Ask them if their predictions were correct or incorrect. Ask them what conclusions they can make about the movement of water and nutrients in plants. (The food coloring was transported up the celery stalk and was visible as a series of colored dots along the top of the stalk.)
Concept Elaboration and Evaluation
After conducting these activities, review and summarize the following key concepts:
Water and nutrients are located in the soil.
Plants absorb water and nutrients from the soil to their roots. This process removes nutrients from the soil.
Water and nutrients are circulated through the plant's vascular system.
We welcome your feedback! Please take a minute to tell us how to make this lesson better or to give us a few gold stars!
Use carnations to show how water is transported throughout a plant. Cut the carnation stem diagonally so that the stem is about 6" (15.24 cm) long. Add six drops of food coloring into 2" (5.08 cm) of water, and place the stem of a carnation into the colored water. Within two hours, small colored areas will appear at the edges of the petals.
Through the study of organisms, inferences can be made about environments both past and present. Plants and animals have both internal and external structures that serve various functions for growth, survival, behavior, and reproduction. Animals use different sense receptors specialized for particular kinds of information to understand and respond to their environment. Some kinds of plants and animals that once lived on Earth can no longer be found. However, fossils from these organisms provide evidence about the types of organisms that lived long ago and the nature of their environments. Additionally, the presence and location of certain fossil types indicate changes that have occurred in environments over time.
Standard 4.1.1 - Construct an explanation from evidence that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction. Emphasize how structures support an organism’s survival in its environment and how internal and external structures of plants and animals vary within the same and across multiple Utah environments. Examples of structures could include thorns on a stem to prevent predation or gills on a fish to allow it to breathe underwater. (LS1.A)
Grade 5: SEEd Strand 5.3
Matter cycles within ecosystems and can be traced from organism to organism. Plants use energy from the Sun to change air and water into matter needed for growth. Animals and decomposers consume matter for their life functions, continuing the cycling of matter. Human behavior can affect the cycling of matter. Scientists and engineers design solutions to conserve Earth’s environments and resources.
Standard 5.3.1 - Construct an explanation that plants use air, water, and energy from sunlight to produce plant matter needed for growth. Emphasize photosynthesis at a conceptual level and that plant matter comes mostly from air and water, not from the soil. Photosynthesis at the cellular level will be taught in Grades 6 through 8. (LS1.C)
Grade 4: Science Standard 3
Students will understand the basic properties of rocks, the processes involved in the formation of soils, and the needs of plants provided by soil.
Objective 3 - Observe the basic components of soil and relate the components to plant growth. Meeting one or more of the following indicators: a) Observe and list the components of soil (i.e., minerals, rocks, air, water, living and dead organisms) and distinguish between the living, nonliving, and once living components of soil. b) Diagram or model a soil profile showing topsoil, subsoil, and bedrock, and how the layers differ in composition. c) Relate the components of soils to the growth of plants in soil (e.g., mineral nutrients, water). d) Explain how plants may help control the erosion of soil. e) Research and investigate ways to provide mineral nutrients for plants to grow without soil (e.g., grow plants in wet towels, grow plants in wet gravel, grow plants in water).
Agricultural Literacy Outcomes
Agriculture and the Environment
Explain how the interaction of the sun, soil, water, and weather in plant and animal growth impacts agricultural production (T1.3-5.b)
Plants and Animals for Food, Fiber & Energy
Explain how the availability of soil nutrients affects plant growth and development (T2.3-5.c)
Education Content Standards
4-LS1:From Molecules to Organisms: Structures and Processes
4-LS1-1 Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.
5-LS1:From Molecules to Organisms: Structures and Processes
5-LS1-1 Support an argument that plants get the materials they need for growth chiefly from air and water.
Common Core Connections
Anchor Standards: Language
CCSS.ELA-LITERACY.CCRA.L.1Demonstrate command of the conventions of standard English grammar and usage when writing or speaking.
Anchor Standards: Speaking and Listening
CCSS.ELA-LITERACY.CCRA.SL.1Prepare for and participate effectively in a range of conversations and collaborations with diverse partners, building on others’ ideas and expressing their own clearly and persuasively.
CCSS.ELA-LITERACY.CCRA.SL.2Integrate and evaluate information presented in diverse media and formats, including visually, quantitatively, and orally.