The part of physics that studies heat: how heat moves, how it turns into other kinds of energy (like movement or electricity), and how other kinds of energy turn into heat. It is the science behind engines, fridges, air conditioners, and power plants — anything that uses heat to do work, or uses work to move heat.

The part of physics是物理學裡研究熱的那個分支 that studies heat：how heat moves熱怎麼移動，how it turns into other kinds of energy怎麼轉變成其他形式的能量 (like movement or electricity)（像是運動或電），and還有 how other kinds of energy turn into heat其他形式的能量又是怎麼轉變回熱。It它 is the science behind engines, fridges, air conditioners, and power plants是引擎、冰箱、冷氣和發電廠背後的科學——anything任何東西 that uses heat to do work用熱來做功，or uses work to move heat或用功來移動熱的都跟它有關。

People often meet it through its famous rules, called the laws of thermodynamics. One of them says energy never disappears; another says heat always moves from the hot thing to the cold thing by itself, never the other way round unless a machine pushes it.

People人們 often meet it常常是透過來認識它 through its famous rules它那些有名的規則，called the laws of thermodynamics這些規則叫做「熱力學定律」。One of them其中一條 says energy never disappears說能量永遠不會消失；another另一條 says heat always moves from the hot thing to the cold thing by itself說熱永遠會自己從熱的東西移動到冷的東西，never the other way round不會反過來，unless a machine pushes it除非有機器去推動它。

Note the -s at the end: it looks plural, but it is a subject name like 'physics' or 'economics', so we say 'thermodynamics is difficult', not 'are'.

Note注意 the -s at the end字尾的-s：it它 looks plural看起來像複數，but但 it它 is a subject name其實是學科名稱 like 'physics' or 'economics'像「physics」或「economics」那樣的，so所以 we say我們會說 'thermodynamics is difficult'「thermodynamics is difficult」，not 'are'而不是「are」。

It is a technical word from science and engineering; you will see it in textbooks and hear it in classrooms, not in daily chat. Outside the lab, people sometimes wave at it as a joke for 'a rule nobody can break' — 'you can't beat thermodynamics' means the situation simply cannot work.

It這 is a technical word from science and engineering是一個來自科學和工程的專業詞彙；you你 will see it in textbooks會在教科書上看到它 and hear it in classrooms在課堂上聽到它，not in daily chat但不會出現在日常閒聊裡。Outside the lab在實驗室之外，people人們 sometimes wave at it as a joke有時候會開玩笑地用它 for 'a rule nobody can break'來指「沒有人能打破的規則」——'you can't beat thermodynamics'「you can't beat thermodynamics」 means the situation simply cannot work的意思就是這個情況根本行不通。