Sediment Sorting

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.

1. Provide each group with a lidded plastic jar, stopwatch, arrow stickers, and samples of clay, sand, silt, gravel, and plant material.
2. Have students pour all sediments into the jar until it is about half full.
3. Add water until the jar is about three-quarters full, leaving some air for mixing.
4. Secure the lid tightly.
5. Students take turns shaking the jar for at least 2 minutes.
6. Use arrow stickers to mark visible sediment layers on the jar.
7. Note observations about sediment size and order of settling.

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

• 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.

• 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.

• 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.)