Physical Science Unit 8: Heat

Temperature Scales: Celcius, Fahrenhiet, Kelvin
Textbook 6.1-6.3

laws of Thermodynamics
Textbook 6.4-6.7

The 4 Laws of thermodynamics


There are 4 laws to thermodynamics, and they are some of the most important laws in all of physics. The laws are as follows

  • Zeroth law of thermodynamics – If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.  {By the power vested in me by the State of California and the Transitive Property of Geometry and Algebra, I hereby declare you in thermal equilibrium}


  • First law of thermodynamics – Energy can neither be created nor destroyed. It can only change forms. In any process, the total energy of the universe remains the same. For a thermodynamic cycle the net heat supplied to the system equals the net work done by the system. {You can’t win — you can only get out of a system as much work as has been put into it}


  • Second law of thermodynamics – The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium. {You alsways lose  – at least a little — every time you try}


  • Third law of thermodynamics – As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.  {You can’t get out of the game}