The Second Law of
Thermodynamics
Steven Bearden
Ariel Lewis
Rebecca White
Statements of the
Second Law
Cold
Heat
Hot
• No process is possible which consists solely in
the transfer of heat from one temperature
level to a higher one.
• Work is required
• No apparatus can operate in such a way that
its only effect in the system and surroundings
is to completely convert heat absorbed by a
system into work done by the system.
• You can’t have 100% conversion of heat into
work within a closed system.
Entropy
• Entropy is the driving force to
equilibrium.
• Intrinsic property that represents the
unavailability of a system’s thermal
energy for conversion into mechanical
work.
Carnot Engine
• Completely reversible
– No friction
– Infinitesimal
Temperature difference
– No unrestrained
expansion
– No change in
surroundings
Heat Engine
•
•
•
•
Realistic example
Heat reservoirs
Rejected heat
Irreversibility
Overview
• Flaws in first law
• Importance of second law