To get an idea of how a chemical pesticide or fertilizer ends up in your food, fill a container with water and add a few drops of food coloring. Place a stalk of celery in the water. When plants are growing, they drink water from the soil they a growing in. To speed up the process for our experiment, we’ve left the soil out and are letting our plant simply drink all the water it wants. A conventional farm uses strong chemicals called pesticides to help keep weeds and bugs away from the plants, but where does the pesticide go after it’s been sprayed? It lands on the plant and the soil and eventually ends up in the water the plant drinking. The food coloring represents the pesticides. Wait twenty-four hours. What happened? Ask your students what would happen if they ate this celery.