Ask them how recycling helps the cycle and the ecosystem. When the experiment is finished, they can compare the results from their hypothesis and draw conclusions about which substances are biodegradable and under what conditions. End the activity with questions. Inform the students that tomorrow the class is going to the local landfill. They will need to wear close-toed shoes and bring a lunch.
Bus ride to the landfill.
Enforce the rules. The students cannot touch anything and be away from the group. They need to be asking questions and writing down what they see. Someone will guide the class at the landfill. Find a quiet place to bring everyone together for a wrap-up session.