Bathtub Water Level Model Water Supply Water Level Sewer Faucet Drain Water pressure “Cloggage” Cloud – input/output that doesn’t affect model Converter – constant used within the model Flow – causes conditions to change Stock – tells what conditions are Link – connects two parts of a model Key to Symbols

Compound Interest Model Bank Balance Earning Interest R The R means that this is a self-reinforcing or “positive” feedback loop which makes the result exponential Interest Rate Cloud – input/output that doesn’t affect model Converter – constant used within the model Flow – causes conditions to change Stock – tells what conditions are Link – connects two parts of a model Key to Symbols

Compound Interest Model Can be represented by a relatively simple equation Can also be shown graphically Where: A – Final amount P – Principle amount r – Interest Rate t – Time (years)

Increased Resolution Requires Increased Computing Resources Rule of thumb: 10X more CPU for a doubling of resolution

Sources Slide 1 and 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 “An Introduction to Systems Thinking”, High Performance Systems, Inc. Slide 3 http://www.crackerjackgreenback.com/the-basics/compound-interest-a-lesson-from-benjamin-franklin/ Slide 4 http://co2now.org/Know-the-Changing-Climate/Climate-System/ipcc-faq-climate-change-weather.html Slide 5 http://www.atmosp.physics.utoronto.ca/people/guido/research.html Slide 6 http://serc.carleton.edu/eslabs/weather/5c.html Slide 7 http://serc.carleton.edu/eet/envisioningclimatechange/teaching_notes.html