On August 26 we started the major investigation of the unit. To answer the question of what happens to our garbage, students made six model landfill bottles. Students had collaboratively decided the components to include in the bottles the day before this activity. They included banana, apple, aluminum foil, and a plastic spoon in their bottles, along with soil and water. The spoons were identified as compostable spoons, which were the ones that come with the school lunches. Students will observe the bottles for a few weeks to look for changes in the properties of the materials over time.
I asked the students to predict what will happen to the materials in the bottles. Students said the materials would break down and turn into compost. I asked if they thought that would happen if the bottle were closed or open. Many students thought that the materials in the closed bottle would not break down. This gave a reason to compare open and closed systems. We left 3 bottles open to the air, but we did put a screen over the top of the bottle to prevent geckos from getting in the bottles. We closed the other three bottles. Now we have an open system and a closed system to compare. Systems and system models is a focal crosscutting concept for this lesson.
We have to wait to see what will happen. Next class we will create our group models for these systems.