Soil Erosion Demonstration
Gather 4 or 5 one- or two-liter plastic pop bottles. Fill the bottles with hot water and peel off the labels.
Cut about one-third of the side of one bottle. This will hold the soil. Cut a hole through a second bottle and insert the first bottle through this hole.
Using a pair of pliers, carefully heat a needle. Pierce a bottle cap with the needle. This will be used as a cap for the top drip bottle whose bottom has been cut off to form a funnel.
Stack the bottles with the drip funnel at the top. A spacer bottle without a top or bottom is in the middle.
Place water in the top funnel and observe the clarity of the water as it flows from the soil bottle to an overflow cup.
Experiment by applying different mulches to the surface or by using soils with different percentages of organic matter (garden versus forested soils).
Soil high in organic matter and soils covered with mulch will yield clearer runoff.
Bare soils or soils low in organic matter will yield much dirtier runoff.