This experiment uses slices of bread and food coloring to simulate how pollutants seep into the ground after rainfall. Students can observe how different amounts of precipitation affect the spread and depth of pollution in porous layers.

1. Place slices of white bread upright in a tray or container to simulate soil layers.
2. Drop one drop of dark food coloring onto the crust area of the bread to represent a pollution source.
3. Using a pipette or dropper, drip a measured amount of water (rainfall) onto the food coloring spot.
4. Repeat the experiment with different amounts of water to test how precipitation influences pollution spread.
5. Measure how far the food coloring spreads across the surface and into the depth of the bread.
6. Record observations for each trial and compare results.

📄 Cheap & Easy Environmental Science Lab: Using Bread and Food Colouring to Model Ground Pollution! - The Roaming Scientist: https://www.theroamingscientist.com/post/cheap-easy-environmental-science-lab-using-bread-and-food-colouring-to-model-ground-pollution

📄 Groundwater Pollution - Guardians of the Environment: https://floridadeprecycle.org/docs/HS/HS_Bio_L1_Engage_Lab_Investigation.pdf

• Use different bread types (white, whole grain, rye) to model soils with different porosity and permeability.
• Change the color of the pollutant to test visibility in different bread types.

• Food coloring may stain skin, clothing, and surfaces—wear gloves and protect the workspace.
• Do not consume the bread once food coloring and water have been applied.

• How does the amount of rainfall affect how far the pollutant spreads? (More rainfall carries the pollutant deeper and farther.)
• Which bread type best represents highly porous soil? (Whole grain bread, because it has more holes and absorbs faster.)
• What real-world situations could this model represent? (Chemical spills, fertilizer runoff, oil leaks, or pesticide contamination.)
• How does this experiment help explain why groundwater pollution is difficult to clean up? (Once pollutants seep into porous layers, they spread widely and are hard to remove.)