Lesson Description: This series of activities helps the students to understand a closed loop system by using an interactive model. They will complete a lab exercise and explain the cycle of CO2 in the willow biomass energy production cycle. The students will be asked to synthesize the information from this activity with their knowledge of global warming. They will also compare and contrast data between willow biomass and other fossil fuel sources and make conclusions based on the data. Mathematically students will be using concepts of percentages and ratios to help asses the data.

Learning Outcomes:
Students will be able to:
- Explain the CO2 closure loop cycle in the willow biomass system
- Use a basic ratio to help understand the CO2 cycle in the willow biomass system
- Explain the benefits of using willow biomass as a source of energy
- Explain how using willow biomass as an energy source benefits the atmosphere
- Explain how the use of willow biomass affects the global warming concerns
- Compare and contrast using a venn diagram, the use of willow biomass vs. fossil fuels

Materials Needed:
CO2 closed loop cycle student worksheets (1 per student)
CO2 close loop cycle sheet (1 per student)
Graph paper (1 per student)

One-dollar bill or a representation of a dollar bill (1 per lab team) and 10 pennies
17 chips or markers (per lab team)
Calculator (1 per lab team)

Method: Set up lab teams (2-4 students per team) and ask them to work through the lab activity. Provide support as needed. If the students are not familiar with ratios then work through the activity as a guided instructor exercise instead of a lab activity.

Time Requirements: 90 minutes
Non-blocked classrooms: Recommend two class periods, pages 1-4 in the first lesson and pages 5-6 for the second lesson

Blocked or double period: Use one full block lesson or the double period to complete the full exercise.

MST standards: See overview chart for the MST standard correlation