demonstrations:sediment_sorting
Sediment Sorting
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Rocks, Soil and Erosion
Alternative titles: Layering of Sediments
Summary
Students mix different sediments in a water-filled jar and observe how they settle into layers over time. This models how sediment sorting occurs in natural environments and helps explain the formation of sedimentary rocks.
Procedure
- Provide each group with a lidded plastic jar, stopwatch, arrow stickers, and samples of clay, sand, silt, gravel, and plant material.
- Have students pour all sediments into the jar until it is about half full.
- Add water until the jar is about three-quarters full, leaving some air for mixing.
- Secure the lid tightly.
- Students take turns shaking the jar for at least 2 minutes.
- Use arrow stickers to mark visible sediment layers on the jar.
- Note observations about sediment size and order of settling.
Links
Make your own Sediment Jar! - Rock Talk:
Vertical Sorting / Graded Bedding Demonstration - GazdonianProductions:
📄 Sediment Sorting - National Park Service: https://www.nps.gov/teachers/classrooms/sediment-sorting.htm
Variations
- Use only two or three sediment types to simplify the experiment.
- Compare results between fast shaking and gentle swirling.
- Try different water temperatures to see if settling rate changes.
- Use a long tube instead of a jar.
Safety Precautions
- Ensure jar lids are tightly secured to prevent spills.
- Use plastic jars instead of glass to avoid breakage.
- Supervise closely to prevent students from shaking too aggressively.
Questions to Consider
- Which sediments settled first, and why? (Heavier, larger grains like gravel settled first due to gravity and size.)
- Why do finer sediments like clay take longer to settle? (They are lighter and remain suspended in water longer.)
- How does this experiment model real-world sediment deposition? (It mimics how sediments settle in lakes, rivers, and oceans to form layers of sedimentary rock.)
- What does the quality of sorting tell us about the energy of the environment? (Well-sorted sediments form in low-energy environments like still water; poorly sorted sediments form in high-energy environments like floods or volcanic flows.)