Rocks, Landscapes & Water — Extension · Earth & Space Science, Grade 9
Identify Earth materials and explain how rock, water, and surface processes shape landscapes.
Account for Water in a Landscape Model
Investigate
How might a permeable surface change runoff during equal rainfall?
Plan three teaching sessions: define the model and comparison; run or analyze repeated supplied/collected records; then graph, explain, revise and submit the notebook. These independent home-study routes do not certify the school’s mandated investigations or laboratory minutes.
Materials
- Supplied water-budget table
- Calculator
- Graph paper; optional teacher-prepared model trays
Before you begin
The supplied data are sufficient. For an optional teacher-supervised tray test, use clean materials and room-temperature water, contain spills, wash hands, and keep water away from electrical equipment. Do not drink collected water.
Plan a fair test
Surface type is compared while input water, tray area, initial moisture, slope, and collection time are held constant in the model. Repeat each condition before making a general claim.
Method
- Predict which surface will yield the most runoff and explain a mechanism.
- For each trial, total runoff, infiltration, and remaining surface storage.
- Compare each total with the 100 mL input and discuss measurement losses.
- Calculate mean runoff for each surface and draw a labeled comparison graph.
- Explain where infiltrated water could move next.
- Propose a repeat with one additional surface or a different initial moisture condition.
Open the investigation data (illustrative)
Illustrative data created for this activity; these are not measurements from an actual site or an official reference table.
| Surface / trial | Input (mL) | Runoff (mL) | Infiltration (mL) | Surface storage (mL) |
|---|---|---|---|---|
| Sealed 1 | 100 | 85 | 0 | 15 |
| Sealed 2 | 100 | 83 | 0 | 17 |
| Permeable 1 | 100 | 25 | 60 | 15 |
| Permeable 2 | 100 | 29 | 57 | 14 |
Analyze and explain
- Compare mean runoff and calculate the percent reduction.
- Why is infiltration not identical to groundwater recharge?
- Which controls and uncertainties limit a real-site prediction?
- Identify the system boundary, units and conditions held comparable.
- Explain how the graph or figure supports the mechanism rather than merely repeat its trend.
- State one uncertainty or scale limitation and design a follow-up comparison that could challenge the explanation.
What a strong explanation includes
- Balances every water budget
- Calculates and compares mean runoff
- Shows percentage reduction relative to a named baseline
- Separates infiltration, storage, and deeper recharge
- Keep observations separate from model-generated or supplied illustrative records.
- Explain a revision using the evidence and a stated model limitation.
Parent / teacher guide: discuss after the investigation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.
Compare this model with the learner’s actual evidence. Different measurements can support a different conclusion; check the reasoning and limitations, not matching wording.
Extend the chapter investigation by evaluating its evidence and proposing a better test.
Problem 1
Answer and explanation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.
Problem 2
Answer and explanation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.
Problem 3
Answer and explanation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.
Problem 4
Answer and explanation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.
Problem 5
Answer and explanation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.
Problem 6
Answer and explanation
Mean runoff falls from 84 to 27 mL, a reduction of (84−27)/84 × 100 ≈ 67.9%. Water entering soil can remain stored, evaporate, be used by plants, or move deeper; infiltration alone does not measure aquifer recharge. A small tray does not reproduce field soils, large storms, or saturated conditions. A complete notebook also specifies the boundary, measurement units and matched conditions. Describe a mechanism connecting the pattern to the claim, then state a limitation and an additional comparison. Supplied illustrative outcomes are not a claim about your collected results; differences must be interpreted rather than corrected to match the example.