Overview: Students will gain an understanding of threshold (or "tipping point") behavior by examining the cumulative influence of the ghosts on Scrooge and the resulting changes in his behavior.
Lesson Objectives	Curriculum Context	Systems Thinking Concepts
Students will identify key characters and variables within Charles Dickens' A Christmas Carol. Students will create behavior-over-time graphs (BOTGs) of the following, or similar, variables: Cumulative Influence of Ghosts and Scrooge's Generosity Students will create a stock/flow (S/F) Map depicting the relationships among the following, or similar, variables:  Cumulative Influence of Ghosts, Scrooge's Generosity, and Scrooge's Threshold/Tipping Point. Students will demonstrate understanding of thresholds /tipping points through experimentation with a system dynamics model similar to their S/F map and through written explanations of thresholds found in various systems in life.	This lesson was developed for 7th grade Language Arts, but it may be adapted to other classes.  It incorporates the following elements of the Georgia Quality Core Curriculum.	Change over time   Delays Thresholds Tipping point Leverage Patterns and trends Accumulations Structure generates behavior Click here to go to definition search.  You may search for concepts or tools.
Materials	Length	Systems Thinking/ Dynamic Modeling Tools
Materials needed include: Whiteboard or overhead      projector Computer with modeling      software, including the      Scrooge II model Data projector	95 minutes	Behavior-over-time graphs Stock/flow diagrams Computer model

Click the appropriate platform below to download
the lesson plan and related computer models

Macintosh® Platform
PC Platform