一日無意中同朋友聊起本科時學過的課程，講到熱力學幾大定律時，忽然發覺雖然意思大約是知道的，卻已經無法准確而清楚地描述出來了。心下慚愧，趕忙上網搜了搜，重溫一遍。Wikipedia上摘錄下來的：The laws of thermodynamics, in principle, describe the specifics for the transport of heat and work in thermodynamic processes.

(記得以前總講熱力學三定律，其實一共有四個。)

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.

First law of thermodynamics：

Energy can neither be created nor destroyed. It can only change forms.

In any process in an isolated system, the total energy remains the same.

For a thermodynamic cycle the net heat supplied to the system equals the net work done by the system.

Second law of thermodynamics：

The entropy of an isolated system consisting of two regions of space, isolated from one another, each in thermodynamic equilibrium in itself, but not in equilibrium with each other, will, when the isolation that separates the two regions is broken, so that the two regions become able to exchange matter or energy, tend to increase over time, approaching a maximum value when the jointly communicating system reaches thermodynamic equilibrium.

Third law of thermodynamics：

As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.

大學時代曾說物化是天書，即使現在讀來，也還是有點拗。倒是還聽說了另外一個比較搞笑的版本，不知是哪個才子想出來的，基本符合科學描述的同時又頗有意味。一並奉上。

第一定律: Life sucks.

因爲能量守恒, 所以不可能無中生有, 不勞而獲.

第二定律: It's getting worse.

宇宙的亂度不斷增加, 功不斷地被轉換成亂度.

第三定律: You are gonna die.

由於絕對溫度大於零, 宇間間的總亂度不斷增加, 終究有一天會朝向死亡.

順便介紹一下熱力學之父，天才的法國物理學家，工程師Nicolas Léonard Sadi Carnot 。他27歲時發表了這一生唯一一部著作，在一定程度上，卻成爲了熱力學的奠基人

Nicolas Léonard Sadi Carnot (1 June 1796 – 24 August 1832) was a French physicist and military engineer who, in his 1824 《Reflections on the Motive Power of Fire》(in french《Réflexions sur la puissance motrice du feu et sur les machines propres à développer cette puissance》), gave the first successful theoretical account of heat engines, now known as the Carnot cycle, thereby laying the foundations of the second law of thermodynamics. He is often described as the "Father of thermodynamics", being responsible for such concepts as Carnot efficiency, Carnot theorem, Carnot heat engine, and others. (source: Wikipedia)