Pollution Lesson Plan: Terrarium Ecosystem Lab Grade 4

Grade Band: Upper Elementary (4–5)
Subject Area: Science

This free classroom investigation helps students understand pollution by observing real environmental change in a controlled setting. Students create a small ecosystem, introduce different pollutants, and track how living things respond over time.

Overview

Students build a simple terrarium that represents an ecosystem. They care for it, observe plant growth, then introduce pollutants to compare healthy and damaged environments. Throughout the investigation students record data, discuss cause and effect, and connect their findings to real environmental issues.

Learning Goals

• Define ecosystem and pollution
• Identify common types of pollution
• Use observation and measurement to collect scientific data
• Compare results between a control and experimental condition
• Explain how human actions affect the environment

Materials

• Clear plastic bottles (2-liter recommended)
• Potting soil
• Grass seed or fast-growing seeds
• Rubber bands
• Nylon stocking or mesh fabric
• Water
• Measuring cups
• Salt, vinegar, and liquid dish soap (pollutants)
• Rulers
• Science notebooks
• Labels or masking tape

Preparation

• Cut bottles about 5 inches from the base
• Prepare student work groups (3–4 students)
• Set aside a sunny location for plant growth
• Prepare a sample data chart students can copy into notebooks

Teaching Procedure

Session 1 – Introducing Pollution

1. Teacher leads a class discussion asking students what pollution means and where they have seen it in real life. Students share examples and the teacher records ideas on the board.
2. Teacher introduces the idea of an ecosystem and explains that scientists study environmental changes by running experiments. Students sketch a simple ecosystem diagram in their notebooks.
3. Teacher demonstrates how the experiment will work. Students write a prediction about what might happen to plants exposed to pollutants.

Session 2 – Building the Ecosystem

1. Teacher models how to assemble the terrarium using a bottle, water reservoir, filter layer, soil, and seeds. Students build their own terrarium in groups.
2. Students label their terrarium and gently water the soil. Teacher checks for correct setup and placement in a lighted area.
3. Students create a data table in their notebooks and record Day 1 observations.

Session 3 – Observation and Measurement

1. Teacher shows students how to measure plant height using a ruler. Students measure and record growth.
2. Students observe color, moisture, and soil condition and write short descriptions in their notebooks.
3. Teacher introduces the idea of a “control.” Students identify which terrarium will remain unchanged.

Session 4 – Adding Pollution

1. Teacher explains safe handling of materials and assigns one pollutant to each group. Students add a small amount to one terrarium and a larger amount to another.
2. Students leave the third terrarium unchanged as the control and record exactly what was added.
3. Students update predictions and discuss what they expect to happen over the next several days.

Session 5 – Tracking Environmental Change

1. Students measure plant height and record changes in color, growth, or plant health.
2. Teacher leads a brief group conversation comparing healthy plants to affected plants. Students write a short explanation of cause and effect.
3. Students create a simple graph in their notebook showing plant growth across several days.

Session 6 – Conclusions and Communication

1. Students review their data and write a conclusion answering the question: How does pollution affect an ecosystem?
2. Teacher organizes small group presentations. Students explain their results and show their data charts.
3. Students propose one realistic action people can take to reduce pollution.

Assessment

• Completed data table with measurements
• Accurate observations
• Clear written conclusion
• Participation in group presentation

Differentiation

• Provide sentence starters for written conclusions
• Allow verbal explanations instead of written reports when needed
• Offer pre-drawn data charts for students who need organizational support
• Assign roles within groups such as measurer, recorder, or materials manager

Extension Ideas

• Research real-world examples of air or water pollution
• Compare acid rain to the vinegar treatment
• Design posters encouraging environmental protection
• Test how clean water can help plants recover