熱力學 I 溫度與平衡 十八世紀前人類對熱現象的認知還帶有點神秘的色彩在其中，熱力學較科學化的發展可溯源自工業革命時代，人類對熱與機械功之間轉換關連的研究，影響熱力學源起發展的一個非常重要因素為溫度的觀念。

Presentation on theme: "熱力學 I 溫度與平衡 十八世紀前人類對熱現象的認知還帶有點神秘的色彩在其中，熱力學較科學化的發展可溯源自工業革命時代，人類對熱與機械功之間轉換關連的研究，影響熱力學源起發展的一個非常重要因素為溫度的觀念。"— Presentation transcript:

1 熱力學 I 溫度與平衡 十八世紀前人類對熱現象的認知還帶有點神秘的色彩在其中，熱力學較科學化的發展可溯源自工業革命時代，人類對熱與機械功之間轉換關連的研究，影響熱力學源起發展的一個非常重要因素為溫度的觀念。

2 繼焦爾等人之後對熱力學發展影響較大的當屬卡諾(Sadi Carnot)。卡諾提出可逆熱機的概念，並推導出最高熱機效率的原則，實際上即為熱力學的第二定律。卡諾的理論的提出事實上早於熱力學第一定律，但熱力學第二定律理論正式的提出是在第一定律成立之後才由克勞修斯(Clausius)自卡諾理論中發現，而熵(entropy)的名稱與概念於1865年由克勞修斯正式賦予。

3 十九世紀接近尾聲時，原子的概念逐漸被接受，於是科學家們嘗試各種方式經由集體原子或分子的平均行為來表達宏觀熱力學的參數如溫度、壓力等，此為動力理論(kinetic theory)的起始。動力理論逐漸的發展為一門更為完備的熱力學理論，也就是現在所熟知的統計熱力學(statistical mechanism)。

4 The worst common burns you can imagine are steam burns
The worst common burns you can imagine are steam burns. You have not only water heated to its boiling point but gaseous steam carrying the heat of vaporization. It’s a great deal of energy in a small space.

5 熱力學第零定律 若系統C與系統A、B同時達到熱平衡(如上圖左所示，此刻系統A、B間為絕熱接觸)，則當系統A與B改為可傳熱接觸時（如上圖右），其熱力學參數不會再變化，亦即系統A與B間也已達到熱平衡的狀態。(Suggested by Ralph Fowler,1931)

6 溫度 每組等狀態曲線相對於一平衡狀態 達到不同的熱平衡狀態相對於不同的等狀態曲線。 達到熱平衡者（或每條等狀態曲線）有其共同的特性
定義描述此特性的參數為溫度 溫度為決定是否為達到熱平衡的性質。

7 凱氏溫標（絕對溫標）

8 Measuring temperature
The measure of temperature is a way of expressing how much heat one object is holding relative to another. There are several examples shown at right. You can base a thermometer on thermal expansion of a gas, differential expansion of bimetal strips, even on something as wild as laser-doppler shift. H.W.: Find the principle three thermometer

9 Conversions are expected
Values on the temperatures scales (Fahrenheit, Centigrade/Celsius, and Kelvin) may be readily interconverted. Physics professors will want values to eventually be in Kelvins because that’s the form in SI units..

10 Thermal expansion—linear
A change in length will accompany a change in temperature. The size of the change will depend on the material.

11 17.4 Thermal Expansion

12 Coefficients of expansion

13 Thermal Expansion Water is interesting. There are no other liquids that expand to become less dense as a solid than they are as a liquid. This is fortunate, if lakes were to freeze and dense ice sink to the bottom, everything in the water would die as the liquid became solid from the bottom up. Thermal expansion joints allow roads to expand and contract without any stress to the material used to build. H.W.: Find the minimum gap size required when building a bridge

14 James Joule and the mechanical equivalent of heat
Joule knew a mass above the ground had potential energy. He dropped an object on a cord, turning a paddle in water monitored by a very accurate thermometer. His conclusion was to connect energy conservation (potential and kinetic) to heat as a third form observed.

15 Thermal Stress

16 If a steel is confined to a strictly fixed length, estimate the pressure increase per degree temperature increase 2.4×103 B. 2.4×104 C. 2.4×105 D. 2.4×106 E. 2.4×107 P a <PowerClick><Answer>4</Answer><Option>5</Option><Point>1</Point></PowerClick>

17 實驗上得知，不同溫度的系統間為導熱接觸時會有能量的互移(除了功之外)，且此轉移僅因有溫度差而存在，我們稱轉移之能為熱。
熱(Heat) 實驗上得知，不同溫度的系統間為導熱接觸時會有能量的互移(除了功之外)，且此轉移僅因有溫度差而存在，我們稱轉移之能為熱。

18 Specific heat values

19 heat current in conduction
Mechanisms of Heat Transfer heat current in conduction Thermal conductivity

20 一保麗龍保溫箱的厚度為2公分，總表面積約為0. 8平方公尺。若於箱內置1kg的冰，此時外面溫度為30度，問多久之後箱內的冰會完全溶化
一保麗龍保溫箱的厚度為2公分，總表面積約為0.8平方公尺。若於箱內置1kg的冰，此時外面溫度為30度，問多久之後箱內的冰會完全溶化? (冰的溶解熱為334kJ/kg) 2 B. 4 C. 6 D. 8 E Hr <PowerClick><Answer>4</Answer><Option>5</Option><Point>1</Point></PowerClick>

21 How about a metal frying pan with a wooden handle?
Why is it a good reason not to pick up a metal frying pan by its bare handle? How about a metal frying pan with a wooden handle? <PowerClick><Answer>2</Answer><Option>3</Option><Point>1</Point></PowerClick> Wood B. Copper C. same

22 熱的對流(Convection) 熱隨著物質的流動而流動。

23 Heat current in radiation
Stefan-Boltzmann constant The net rate of radiation from a body

24 The Rattlesnake