EMPTY DRY FILTER—
DRY FILTER + SEDIMENT—
Begin with the rainfall apparatus.
Keep the soil in place.
Apply the same rainfall. Collect the runoff. Compare the sediment.
Lab options
Your next action
YOUR MISSION
Which ground cover carries away the least soil?
A school wants to protect a sloped patch of soil. Compare bare soil, straw mulch, and planted cover under the same modeled rainfall.
Use three fresh trays per treatment. Measure transported sediment by filtering the runoff, drying the filter, and subtracting the filter’s original mass.
100 mL rainfall over 2 minutes500 g soil per tray10° slope · same tray area
Numerical sediment yields are a stated teaching model, not real field data. Rainfall, drainage, and drying use short time-lapses. Real outcomes depend on soil, cover, rainfall, and slope.
Why filter, dry, and subtract?
Cloudy water suggests suspended material, but color is not a mass measurement. The dry filter traps the transported soil particles in this model.
A wet filter includes water mass. Drying removes that water; subtracting the empty dry filter’s mass leaves an estimate of collected sediment mass.
We keep soil type, starting mass, initial moisture, tray area, slope, rainfall volume, rainfall duration, source height, and handling the same. Ground cover is the changed treatment. Planted cover includes both shoots and roots; this test does not isolate their individual effects.
Your measured evidence
| Trial | Ground cover | Dry filter (g) | Filter + sediment (g) | Sediment (g) |
|---|
Every trial uses fresh prepared soil, a clean cup, and a new dry filter. Sediment mass is calculated from the displayed balance readings.
3 / RECOMMEND A COVER
What do your repeated measurements support?
Compare collected sediment, then recommend a treatment for the modeled slope. Explain one reason a real site might differ.
| Ground cover | Trials | Mean sediment | Observed range | Reduction vs. bare |
|---|
Bars show observed minimum–maximum values, not confidence intervals. This experiment measures captured runoff sediment, not every possible form of soil loss.
Help me explain my results
Measurements from your investigation
These are your recorded model results. Choose the evidence that supports your own conclusion.
- Make a claim.
- Use evidence.
- Explain the science.
- Set a limit.
Before downloading: Does your explanation answer the question, use a number with units, explain why, and state a limit? Revise it above if needed.
This guide does not write or grade your explanation. A teacher reviews your scientific reasoning.
Optional calculation: sediment reduction
Reduction (%) = (bare-soil mean − planted-soil mean) ÷ bare-soil mean × 100.
The evidence choice and drying explanation are checked automatically. A teacher reviews the scientific quality of your written recommendation.