Investigating Water Properties & Earth Processes

Estimated Time: 60-90 minutes Materials: Internet-connected device, Water Properties & Earth Processes Simulation, Student Data Table (below).

Teacher Notes

Alignment to NGSS Performance Expectation: HS-ESS2-5 Plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes.

Dimensions:

• Science and Engineering Practice (SEP): Planning and Carrying Out Investigations. Students plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence.
• Disciplinary Core Idea (DCI): ESS2.C: The Roles of Water in Earth’s Surface Processes. Students investigate how water’s properties (expanding upon freezing, dissolving materials, and transporting materials) affect Earth materials.
• Crosscutting Concept (CCC): Structure and Function. Students infer how the physical structure and properties of water lead to specific mechanical and chemical functions on Earth’s surface.

Evidence Statements Addressed:

1. Identifying the phenomenon: Students describe the phenomenon connecting water’s properties to its effects on Earth materials.
2. Identifying the evidence: Students develop a plan to collect data on mechanical effects (frost wedging, stream transportation) and chemical effects (chemical weathering/solubility) of water.
3. Planning for the Investigation: Students include a means to measure the predicted effect of water on Earth’s materials (e.g., strain from freezing, mass loss from dissolution, sediment transport distance).
4. Collecting the data: Students collect and record measurements of the predicted effects.

Part 1: Engage (Anchoring Phenomenon)

Phenomenon: How do freezing water and flowing rivers shape the rock formations around us over time? How can something as seemingly gentle as water break apart solid rock and reshape entire landscapes?

Discussion Questions:

1. What properties of water do you think allow it to break rock apart during winter?
2. How might the speed of flowing water change what it can carry?
3. Record your initial thoughts and questions about how water interacts with rock: _____

Part 2: Explore (Simulation Investigation)

Access the Water Properties & Earth Processes Simulation. You will investigate three distinct ways water interacts with Earth materials.

Lab A: Frost Wedging (Mechanical Weathering)

1. Navigate to the ❄️ Frost Wedging tab.
2. Set the Water in Crevice slider to 20%.
3. Slowly lower the Temperature slider from 10 °C to -10 °C. Observe the Internal Rock Strain bar and the crack width.
4. Reset the lab. Now set the Water in Crevice to 90% and lower the temperature again.
5. Record your observations in the Data Table.

Lab B: Chemical Weathering (Solubility)

1. Navigate to the 🧪 Chemical Weathering tab.
2. Select Limestone (High Calcite) from the Rock Type dropdown.
3. Set the Water Acidity (pH) to 7.0 (Neutral). Observe the remaining rock mass over a few simulated years.
4. Lower the Water Acidity (pH) to 5.0 (Acidic). Observe how the reaction rate changes.
5. Test the same conditions with Granite (Silicate).
6. Record your observations in the Data Table.

Lab C: Stream Transport (Mechanical Transport)

1. Navigate to the 🌊 Stream Transport tab.
2. Slowly increase the Stream Velocity slider from 0.0 m/s to 50 m/s.
3. Note which type of particle (Sand, Gravel, or Boulder) moves first.
4. Continue increasing the velocity up to 200 m/s. Observe the relationship between velocity and the mass of the particles being transported.
5. Record your observations in the Data Table.

Part 3: Explain (Sensemaking)

Data Collection Table

| Lab | Independent Variable Tested | Observations / Data Collected | | :— | :— | :— | | A: Frost Wedging | Amount of Water & Temperature | ___ | | B: Chemical Weathering | pH level & Rock Type | _____ | | C: Stream Transport | Stream Velocity | _______ |

Analysis Questions:

1. Frost Wedging: Why did the rock strain increase when the temperature dropped below 0 °C? How does the volume of water affect the likelihood of the rock fracturing? _____
2. Chemical Weathering: How did the pH of the water influence the rate at which limestone dissolved? Why did granite behave differently than limestone? _____
3. Stream Transport: Describe the relationship between stream velocity and the mass of the sediment particles it can transport. Why do boulders require higher velocity to move than sand? _____

Part 4: Elaborate / Evaluate (Argumentation & Modeling)

Student Deliverable: Construct a scientific argument answering the following prompt: “How do the unique physical and chemical properties of water shape Earth’s surface over time?”

Your argument must include:

• A clear Claim addressing the prompt.
• Evidence from all three simulation labs (data on strain, mass loss, and particle transport).
• Reasoning that connects your evidence to the specific properties of water (expansion upon freezing, capacity to act as a solvent, and mechanical force of flowing water).

Extension Options

• Real-World Application: Research the formation of karst topography (like caves and sinkholes) in regions with high limestone concentrations. Explain how the chemical properties investigated in Lab B lead to these formations.
• Climate Change Connection: Investigate how increased atmospheric CO₂ is leading to ocean acidification. Relate this to the findings from Lab B regarding pH and calcite dissolution.