In this unit, students investigate the question, “How does garbage impact our environment?”

In Cluster 1, to launch the unit, students observe and categorize garbage to learn about the properties of different materials. They develop a model of the garbage disposal system in their school, homes, and community, identifying components and interactions in the system. To learn about the impact of garbage on the environment, they explore photographs from around the world and read about garbage patches in the ocean. Throughout the cluster, students generate questions for investigation, which they compile and organize at the end of the cluster.

In Cluster 2, to investigate the question, “What happens to materials in a landfill?”, students set up landfill bottles filled with soil and different types of garbage materials. They collect preliminary observational and weight data, which they will use later as evidence for how and why different garbage materials changed. Half of the groups seal their landfill bottles and half leave them open. In addition, students are introduced to the idea that matter is made up of particles too small to see.

In Cluster 3, students revisit their landfill bottles to observe and record changes in the properties of the different garbage materials. They weigh their bottles and compare the weights of the closed and open bottles to their initial weights. By now, the rotting garbage has started to smell, which leads to the question of whether smell is something and whether gases, such as the smell and air, have weight. The class conducts investigations to learn that gas is a form of matter, has weight, and is made of particles that are too small to see and that move freely. They also read an article about the conservation of matter. Students apply what they’ve learned to create models of what is happening to the garbage materials in their landfill bottles.

in Cluster 4, Students investigate the question, “What happens to materials when they mix?” by mixing baking soda, calcium chloride, and water. They observe the chemical reaction, which produces gas, and learn that new substances can be created when materials mix, but that the total amount of matter is conserved. This concept helps them understand why their closed landfill bottles still weigh the same, but the open bottles now weigh less. To understand the changes in their garbage materials, students learn about decomposition by reading and swabbing materials on agar plates. They pull together evidence from investigations and readings for a science talk about why the food materials in their landfill bottles have changed. They also revise their models to capture new understandings of conservation and decomposition.

In Cluster 5, the unit culminates by addressing the question, “How can we reduce the amount of garbage we make?” Students read about how other communities have worked to mitigate the environmental impacts of garbage, and each triad develops their own solution to reduce the amount of garbage produced at their school. Students share their proposals with site decision makers or stakeholders.

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