Lecture 12. Liquids and Their Properties. .. . .. 88
Molecular Pressure and Surface Tension . .. .. .. 88
Capillary Phenomena .. . . 91
Microscopic and Macroscopic Parameters .. .... . 93
Lecture 13. Ideal gas . .. ...... 94
The Equation of State 94
The Equation of the Gas State . .. .. . 95
Lecture 14. The Equations of State of Real Gases . . . 96
Kinetic Theory of Gasses . .. 97
Gas Pressure .. ... 98
Absolute Temperature . . .. 102
Lecture 15. Processes in the ideal gases . 102
Distribution of Gas Molecules by Velocities ........... 103
Transfer Phenomena 106
Diffusion .. .. . 106
Heat Conductivity .. 108
Internal Friction .. .. .. 109
Lecture 16. Internal Energy of a Gas ... 109
Work, performed by Gas . .. 110
Temperature and Heat . . 111
The first law of thermodynamics .. . 112
Thermodynamic Process . .... 113
Specific heat ....... 113
Application of the first law of thermodynamics to gas processes . 115
Lecture 17. Cycles .. . 119
The principle of operation of heat engine . ..120
Carnots Engine. Cycle of Carnot .. .. . 121
Work and efficiency of Carnots Cycle . . .. 121
Entropy .. . 125
Lecture 18. The second law of thermodynamics . .. . 127
Processes involving a change of gas state . . .. .129
Lecture 1. Introductory Lecture
The fields and uses of physics
The story of mans civilization is the story of his study of nature and the application of his knowledge in his life. The use of tools, first of stone and later of metals, the domestication of animals, the development of writing and counting, all progressed slowly since rapid advance was not possible until man began to gather data and check theories. Till that time most of mans knowledge was based on the speculation of the Greeks.
Non until a little over three centuries ago did man adopt the scientific method of studying his environment. After this the development of civilization has become increasingly more rapid. The advance of all the natural sciences has been almost simultaneous: in fact, many of the prominent scientists were working in more than one field of knowledge.
Probably more conditions under which man lives, physics deals not with man himself, but with the things he sees and feels and hears. This science deals with the laws of mechanics, heat, sound, electricity, light, in order to build our machinery age. Modern physics also deals with electronics, atomic phenomena, photo-electricity, X-rays, radioactivity, the transmutation of matter and energy and the phenomena associated with electron tubes and the electric waves of modern radio.
The practical application of the achievement of the physics continues to develop at an ever-increasing rate. Practical physics plays, therefore, no small role, for the laws of physics are applied in every movement we make, in every attempt of communication, in the warmth and light we receive from the sun, in every machine. Practical application of physics is not all made by physicists, for the majority of those who apply the principles of physics are called engineers.
In fact, most of the branches of engineering are closely related with one more sections of physics: civil engineering applies the principles of mechanics and heat; electrical engineering is based on fundamentals of electricity, etc. The relation between engineering and physics is so close that a thorough knowledge and understanding of physical principles is important for progress of engineering. One of the tools common to physics and engineering is mathematics. If we want to make effective the use of the principles and measurements of physical science, we must have a workable knowledge of mathematics. Physics and mathematics are thus the basic foundations of engineering.