Causal Loop Diagrams Exponential growth of a bank

Causal Loop Diagrams

Exponential growth of a bank account. The two positive connections between Bank balance and interest added for a positive feedback loop.

Causal Loop Diagrams

Earth’s Energy Balance. More absorbed sunlight increases Earth’s temperature. A warmer Earth sends off more heat radiation (a. k. a. longwave, infrared, or terrestrial) to space keeping our planet from getting too hot. Earth’s albedo is the fraction of sunlight reflected back into space without being absorbed.

Connections (+ or - ? ? ) Remember use nouns Absorbed Sunlight Earth’s Mean Temperature Planetary albedo Earth’s Mean Temperature Emitted Infrared Cloud Cover snow Cover Volcanic aerosol Earth’s Mean Temperature Planetary albedo Water Vapor Earth’s Mean Temperature CO 2 Earth’s Mean Temperature Knowing the “sense” of connections between two system components is essential to understanding overall system behavior. If when the first increases the second also increases the connection is positive. If when the first increases the second also decreases the connection is negative.

Connections (+ or - ? ? ) Answers Absorbed Sunlight Planetary albedo Emitted Infrared Cloud Cover snow Cover Volcanic aerosol Water Vapor CO 2 Remember use nouns + - Earth’s Mean Temperature + or - Earth’s Mean Temperature + Planetary albedo - Earth’s Mean Temperature + Earth’s Mean Temperature

Example • Draw a causal loop diagram to describe the following: • The sun becomes brighter causing Earth to warm. As the Earth warms it gives off more longwave radiation until it settles into a new equilibrium temperature.

Example • Draw a causal loop diagram to describe the following: • The sun becomes brighter causing Earth to warm to a new equilibrium temperature. sunlight + Earth’s mean Temperature - - Emitted infrared energy +

Air Resistance

Connections (+ or - ? ? ) Size (area) of car Air resistance force Air temperature Air resistance force Speed of car Air resistance force Remember use nouns

Air resistance Net downward Force weight

Connections (+ or - ? ? ) Size of parachuet Air resistance force Altitude Air resistance force Jumper’s speed Air resistance force Size of parachuet Net downward force Altitude Net downward force Jumper’s speed Remember use nouns Net downward force

Draw a causal loop diagram to describe the following: As the sky diver falls she travels faster and faster until reaching a terminal velocity. Include diver’s speed, air resistance and net downward force in your diagram.

Gas pedal depression MPH above speed limit car’s speed

Home Heating