The purpose of this experiment is to demonstrate the concepts of groundwater, aquifer, infiltration, leaching, percolation, water table and soil profile. Add a layer of gravel to the bottom of the cup. This represents the water holding material which makes up the aquifer. Place a paper filter on top of the gravel. Water passes through but not the soil and sand above it.
Many soils act as semi-permeable membranes.
Add layers of sand and soil, compacting as you go. Spray water on top of soil - this simulates rain. This is a good way to demonstrate infiltration. See food coloring in withdrawn water. Add food coloring to top of soil and ask students how much water will need to be added to the system before all the coloring is gone.