phy1004 thermal physics
phy1004 thermal physics
phy1004 thermal physics
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<strong>phy1004</strong>W<br />
Thermal Physics<br />
Apparent Paradox in Thermodynamics<br />
•All fundamental processes exhibit time reversal invariance,<br />
i.e. Both forward and backward movie of fundamental<br />
interactions look possible (have seen them before!!!)<br />
•Macroscopic change has a preferred direction, egs.<br />
►Bouncing balls come to rest … & never reverse their motion<br />
►Energy moves from hot to cold … & never the reverse direction<br />
•If the sub-microscopic world exhibits time reversal invariance,<br />
surely the macroscopic world (which is made up of the submicroscopic)<br />
should also be time reversal invariant !<br />
IG-10<br />
•Better to think of macroscopic change statistically<br />
►Bouncing ball increasing in height with each bounce is<br />
NOT impossible, just wildly (ridiculously!!) improbable<br />
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