The following activity demonstrates how water infiltration can carry pollution underground. The exercise requires:
Student No. 1 - holds a slice of bread vertically.
Student No. 2 - adds a drop of food coloring (pollutant) to the top crust edge of the bread
Student No. 3 - sprays water (rain) on the food coloring Allow drainage to seep through the crust into the bread.
As the polluted water seeps down it spreads out, making it difficult to locate where the pollution originated. The water and food coloring will remain together as the water moves. This illustrates visually how pollutants are carried by water; that pollutants are not filtered out by the ground; and that human activities can affect groundwater quality.
Courtesy Joe Pitts, Missouri Department of Natural Resources Groundwater Protection Curriculum Guide 1994