Chapter 18 Second law of thermodynamics Chapter 18: Second Law of Thermodynamics(热力学第二定律) O The second law of thermodynamics ○ Reversible and irreversible process(可逆过程 与不可逆过程 o Carnot cycle(卡诺循环 Entropy(熵)
Chapter 18 Second Law of Thermodynamics The second law of thermodynamics Reversible and irreversible process (可逆过程 与不可逆过程): Carnot cycle(卡诺循环) Chapter 18: Second Law of Thermodynamics（热力学第二定律） Entropy(熵)
Chapter 18 Second law of thermodynamics ◆第二定律的提出 1功热转换的条件第一定律无法说明 2热传导的方向性、气体自由膨胀的不可 逆性问题第一定律无法说明 热力学第二定律的两种表述 1开尔文说法:不可能制造出这样一种循 环工作的热机,它只使单一热源冷却来做功,而 不放出热量给其他物体,或者说不使外界发生任 何变化
Chapter 18 Second Law of Thermodynamics 1 开尔文说法：不可能制造出这样一种循 环工作的热机，它只使单一热源冷却来做功，而 不放出热量给其他物体，或者说不使外界发生任 何变化 . 第二定律的提出 1 功热转换的条件第一定律无法说明. 2 热传导的方向性、气体自由膨胀的不可 逆性问题第一定律无法说明. 一 热力学第二定律的两种表述
Chapter 18 Second law of thermodynamics New words Engine Efficiency 热机效率 Reversible and irreversible process 可逆和不可逆过程p433 Entropy 熵p440
Chapter 18 Second Law of Thermodynamics New words Engine Efficiency 热机效率 Reversible and Irreversible Process 可逆和不可逆过程 p433 Entropy 熵 p440
Chapter 18 Second law of thermodynamics 818-1 The second Law of Thermodynamics P429-430 Some one-way processes P429-430 自然过程是不可逆的,是按一定的方向进行的。 1功热转换p429 通过摩擦而使功变热的过程是不可逆的 例如:飞轮转动、焦耳实验(重物下落)。 The initial potential energy of the rock changes to kinetic energy as the rock falls, but you will never see the reverse happen-a rock at rest on the ground suddenly rise up in the air because the internal energy is transformed into kinetic energy
Chapter 18 Second Law of Thermodynamics §18-1 The second Law of Thermodynamics P429-430 1 功热转换 p429 通过摩擦而使功变热的过程是不可逆的。 例如：飞轮转动、焦耳实验（重物下落）。 The initial potential energy of the rock changes to kinetic energy as the rock falls, but you will never see the reverse happen-a rock at rest on the ground suddenly rise up in the air because the internal energy is transformed into kinetic energy. Some one-way processes P429-430 自然过程是不可逆的，是按一定的方向进行的
Chapter 18 Second law of thermodynamics 2热传导现象P429 热量由高温物体自动地传向低温物体的过 程是不可逆的。 Heat flows naturally from a hot object to a cold object; heat will not flow spontaneously a cold object to a hot object Second Law of Thermodynamics: p430 Heat flows naturally from a hot object to a cold object; heat will not flow spontaneously form a cold object to a hot object
Chapter 18 Second Law of Thermodynamics Heat flows naturally from a hot object to a cold object; heat will not flow spontaneously a cold object to a hot object. 2 热传导现象 P429 热量由高温物体自动地传向低温物体的过 程是不可逆的。 Second Law of Thermodynamics: p430 Heat flows naturally from a hot object to a cold object; heat will not flow spontaneously form a cold object to a hot object