Summary Use molecule models to show a simplified version of the nitrogen cycle. This activity needs a reworking. Science content Biology: Food Webs, Ecosystems, Biomes (3, 4) Chemistry: Atoms, Molecules (3-7) Lessons activity is in Chemistry of plants and soil Materials Molecule model kits - list will come when activity is tested Procedure Start with the N2 molecule. Then give students the atoms needed to move around the cycle. Give them clues each step to aid in model building: they might make two identical molecules, or that they should make a water molecule first, then use the remaining atoms to make the molecule with nitrogen in from the remaining atoms and bonds. At each step, explain how living things make and use the molecules: Plants need nitrogen but are not able to use the nitrogen in the air. They rely on bacteria to catch it. Bacteria in the soil, and some specialized bacteria that live in the roots of some plants can “fix” the N2 to make NH3 (and also NH4), which can be taken up by plants. In the soil extra ammonia is converted to another molecule, nitrate, by bacteria when there is oxygen around. Nitrate is converted to nitrogen gas again, by bacteria. More H is used. Notes Ammonification molecules last few pics - editing in process Grades taught Gr 6 Gr 7
