One student did an experiment with sand, gravel, food coloring and water. the steps of the experiment are shown below. fill about half of a plastic cup with layers of gravel and sand. pour water into the cup and observe it seep through the layers. add two drops of food coloring on one side of the gravel layer. observe the food coloring mix with the water. what does the student's experiment most likely demonstrate? movement of groundwater through sinkholes movement of pollutants through the groundwater chemical reaction between acid rain and groundwater chemical reaction between groundwater and layers of earth