AI-generated header illustration.
A muddy stream after rain is carrying a clue: water can move pieces of the ground. You can investigate that movement with a small hill in a tray. Your question is: does a covering of leaves change how much soil washes downhill?
Three words for changing ground
Weathering breaks down rock where it is. Erosion removes and carries material away. When carried material settles somewhere else, that is deposition. Sand, silt and other loose particles are called sediment. These processes help explain changing landscapes, as the National Park Service explains.
Set up your miniature hillside
Ask an adult to help. Use a washable surface, keep the tray stable and wipe up spills. Do not taste the soil or water. Wash your hands afterward.
- A deep, unbreakable tray
- Two equal portions of slightly damp soil, checked by an adult for sharp objects, animal waste and added chemicals
- A cup for gently pouring water
- A small amount of fallen leaves
- A towel, paper and pencil
This comparison is adapted from a USGS school erosion activity. Our version uses a slow pour, so it models flowing water rather than individual raindrops.
- Shape one soil portion into a low hill at one end of the level tray. Leave space at the other end for runoff.
- Draw the hill before adding water. Predict where loose soil will go.
- Slowly pour one cup of water onto the hill from just above its surface. Watch for channels and sediment collecting below.
- Ask your adult to empty and reset the tray with the second soil portion. Make a hill of similar size and shape, then cover it lightly with leaves.
- Repeat with the same amount of water, pouring from the same position at roughly the same speed.
Record what happened, even if it surprised you
Make two notebook headings: “bare hill” and “covered hill.” Under each, sketch any channels and the area where sediment collected. Did the water spread out or follow one route? Did leaves stay in place?
In the USGS comparison, plant litter reduced erosion. Your setup may differ. A single messy trial is not proof that a covering always works: uneven hills or a faster pour could change the result. Repeat before deciding.
What the tray cannot tell you
You began with loose soil, not solid mountain rock. The activity shows transport and settling; it does not recreate every way a real landscape changes. You also cannot convert one minute in your tray into a particular number of years outdoors.
Quick check: Soil leaves the hill, travels in water, then settles below. Which part is deposition? Answer: the settling. The movement away from the hill is erosion.
