Just to Clarify
Bill Bryson, in A Short History of Everything, includes a section on most major fields of scientific inquiry, and makes them accessible to us amateurs. In a section on the laws of thermodynamics, here's how Bryson clarifies each law for us (except the zeroth, which states, "If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other."
First law:
"for a thermodynamic cycle the sum of net heat supplied to the system and the net work done by the system is equal to zero"
Bryson translation:
"you can't create energy"
Second law:
"The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium"
Bryson translation:
"a little energy is always wasted"
Third law:
"As temperature approaches absolute zero, the entropy of a system approaches a constant"
Bryson translation:
"you can't reduce temperatures to absolute zero - there will always be some residual warmth"
To be certain we understand how these laws came about, Bryson quotes the following from P. W. Atkins:
"There are four Laws. The third of them, the Second Law, was recognized first; the first, the Zeroth Law, was formulated last; the First Law was second; the Third Law might not even be a law in the same sense as the others."
If only they'd have made it this clear when I was in school.
First law:
"for a thermodynamic cycle the sum of net heat supplied to the system and the net work done by the system is equal to zero"
Bryson translation:
"you can't create energy"
Second law:
"The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium"
Bryson translation:
"a little energy is always wasted"
Third law:
"As temperature approaches absolute zero, the entropy of a system approaches a constant"
Bryson translation:
"you can't reduce temperatures to absolute zero - there will always be some residual warmth"
To be certain we understand how these laws came about, Bryson quotes the following from P. W. Atkins:
"There are four Laws. The third of them, the Second Law, was recognized first; the first, the Zeroth Law, was formulated last; the First Law was second; the Third Law might not even be a law in the same sense as the others."
If only they'd have made it this clear when I was in school.
Comments
"As Denis Overbye notes, the three principal laws are sometimes expressed jocularly as (1) you can't win, (2) you can't break even, and (3) you can't get out of the game."