1. Thermodynamics
Adapted By: Mr. Kling 

2. Laws of Thermodynamics
The study of thermodynamics is about energy flow in natural systems
The Laws of Thermodynamics describe what is known about energy transformations in our universe

3. First Law of Thermodynamics
Law of conservation of energy
“Energy is neither created nor destroyed but can be transformed from one form to another”
Energy of the universe is constant

4. Transfer vs. transformation
Transfer involves a change in location
e.g. water falling as rain, running off the land into a river then to the sea
Transformation involves a change in state
e.g. evaporation of water from a lake into the atmosphere
Energy examples

5. Second Law of Thermodynamics
Entropy Law
Entropy = disorder, randomness or chaos
“In an isolated system, entropy tends to increase spontaneously”
Every energy transformation or transfer results in an increase in the disorder of the universe

6. Second Law continued
Most conversions are less than 100% efficient and therefore some energy is lost or wasted
Usually this energy is lost in the form of HEAT (= random energy of molecular movement)
e.g. only 25% of chemical energy stored in gasoline is transformed in to motion of the car
75% is lost as heat!!
Without adding energy to a system, the system will break down
e.g. a house

7. Energy vs. materials
Within a system energy cannot be re-used BUT materials can be recycled over and over with little to no loss of utility
Energy flows through systems while materials circulate around systems
e.g. photosynthesis - E and carbon

8. Stock (or storage) Stock = stored energy or material Examples Water
Carbon
Energy

9. Equilibrium A state of balance among the components of a system
Steady state equilibrium - despite fluctuations, average condition of the system remains unchanged over time

10. Equilibrium in natural systems
In nature, most open systems are in steady state equilibrium
Steady state equilibrium compared to static equilibrium…

11. Equilibrium
Static equilibrium - no change in the system

12. Stability of an Equilibrium
Stable equilibrium - system returns to the same equilibrium after disturbance

13. Stability of an Equilibrium
Unstable equilibrium - system reaches a new equilibrium after disturbance

14. Feedback
The return of part of the output of a system as input so as to affect subsequent outputs
Responsible for maintenance of equilibria
e.g. thermostat

15. Negative feedback
Feedback that tends to neutralize or counteract any deviation from an equilibrium
Self-regulation leading to steady state equilibrium
Promotes stability
e.g. sea otter and sea urchin populations

16. Positive feedback
Feedback that amplifies or increases change and leads to a deviation from equilibrium
‘vicious cycle’
e.g. global warming and melting ice caps

18. Complexity and stability
Most natural systems are very complex with energy and material flow and feedback loops
The more complex a system, the more stable it is
e.g. old growth forest versus replanted monoculture