======Soil Erosion Model======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Rainfall and Soil Cover Experiment
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====Summary====                   
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====Procedure====  
  - Cut off one side of three identical plastic bottles.  
  - Fill each bottle with soil. In one bottle, plant grass seed or place sod and allow it to establish before the experiment.  
  - Add a mulch or dead-leaf cover to the second bottle, leaving the third bottle bare.  
  - Suspend the bottles at a 25–40° angle with the spouts facing downward over three clear collection cups. Use blocks, cups, or wire hangers to support them.  
  - Simulate rainfall by evenly applying water with a watering can or spray bottle across all three bottles.  
  - Collect the runoff water in the cups and compare clarity, turbidity, and sediment content.  
  - Observe and record how the soil surfaces change during and after the simulated rain.



====Links==== 
Erosion and Soil - funsciencedemos: 
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Soil erosion demonstration - Milne’s Science Tech: 
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📄 Build an Erosion Model - Soil Science Society of America: [[https://www.soils4teachers.org/files/lessons-and-activities/activities/lessonplan-erosion-model.pdf]]\\

====Variations====
  * Use different types of soil (sand, clay, loam) to compare erosion rates.  
  * Try steeper or shallower slopes to see how slope angle affects erosion.  
  * Compare effects of different ground covers, such as straw, leaves, or bark mulch.  
  * Run repeated rain simulations to test cumulative erosion effects. 



====Safety Precautions====
  * Use scissors or a utility knife carefully; adult supervision may be required.  
  * Handle soil and mulch with clean hands; wash thoroughly after the activity.  
  * Dispose of soil and water responsibly, avoiding clogged drains.




====Questions to Consider====
  * Which soil cover produced the clearest runoff water? (Grass cover usually results in the least turbidity.)  
  * Why does mulch or vegetation reduce erosion? (It protects the soil surface from rain impact and slows water flow.)  
  * Why is soil conservation important for farming? (Topsoil contains most nutrients; losing it reduces productivity.)  
  * How does soil erosion affect rivers and lakes? (Sediment reduces water quality, harming fish, plants, and insects.)  
  * What actions can gardeners or farmers take to reduce erosion? (No-till farming, planting cover crops, mulching, maintaining grass or plant cover.)