The seventh grade is studying energy flow in an ecosystem. They have learned that producers (plants) form the basis of all food webs using energy from the sun. They have also studied the idea that plants need things in cycles like Carbon and Nitrogen. To test whether or not these elements have to come from soil they set up solar polar pumps to supply liquid nutrients to tomato seedlings. They opened the hydroponic kits and had to assemble them with very little direction from their teacher.