This is the key to the Edible Aquifer Activity
I have, which recreates a simple aquifer structure.
The Edible Aquifer Activity uses ice cream, clear club soda, crushed ice, straws, (crushed) graham crackers, and food coloring to simulate an aquifers, groundwater, and pollution. The students build it layer-by-layer, and are able to visualize what an aquifer looks like. When they're finished building the aquifer and answering the questions in the worksheet, they are welcome to eat the aquifer, and answer what happens to the food coloring "pollution".