物理学专业英语2PPT课件

1物理专业英语作业24 General Information普通信息普通信息34.1 Statistical Physics And Thermodynamics统计物理和热力学 Page 77-79&101Molecular physics is a branch of physics studying the structure and properties of a substance on the basis of the so-called molecular kinetic notions.分子物理学号称是在分子动力学概念的基础上，研究物质的结构和属性的物理学分支。4According to these notions,any body-solid,liquid or gaseous-consists of an enormous number of exceedingly small separate particles-molecules.(Atoms can be considered as monatomic molecules.)The molecules of a substance are in disordered,chaotic motion having no predominating direction.Its intensity depends on the temperature of the substance.根据这些概念，任何的物体固体、液体或气体，都由数量巨大且极其微小的单独微粒分子组成。（原子可以认为是单原子的分子。）物质的分子在做无序、无方向的不规则运动，运动的剧烈程度取决于物质的温度。5A direct proof of the existence of chaotic motion of molecules is Brownian motion.This phenomenon consists in that very small(visible only in a microscope)particles suspended in a fluid are always in a state of continuous chaotic motion that does not depend on external causes and is a manifestation of the internal motion of the substance.布朗运动直接证明了分子做不规则运动。这种微观现象（只有在显微镜下可见），悬浮在液体的微粒总是处于不依赖外界原因连续的不规则运动，是物质内部分子运动的表现形式。6The Brownian motion of particles is due to their chaotic collisions with molecules.粒子的布朗运动是它们分子间不规则碰撞的结果。The object of the molecular-kinetic theory is to interpret the properties of bodies that are directly observed in experiments(pressure,temperature,etc.)as the summary result of the action of molecules.物体的分子动力学理论是解释物体可以在实验中被直接观察（压强、温度等）作为分子活动概要结果的性质。7Its uses the statistical method and is interested not in the motion of separate molecules,but only in average quantities characterizing the motion of an enormous combination of particles.This explains its other name-statistical physics.它使用统计的方法，忽略分离的单个分子的运动，用平均数描述一个巨大的组合微粒的运动。这就解释了它另外的名称统计物理学。8Thermodynamics also studies various properties of bodies and changes in the state of a substance.Unlike the molecules-kinetic theory,however,thermodynamics studies macroscopic properties of bodies and natural phenomena without being interested in their microscopic picture.热力学也研究物体各种各样的属性和物态的变化。然而，和分子动力学理论不同，热力学研究物体的宏观性质和固有现象，并不专注于微观世界。9Thermodynamics permits us to arrive at a considerable number of conclusions on how processes go on without taking molecules and atoms into consideration and without treating the processes from a microscopic standpoint.热力学允许我们得出相当数量在没有考虑分子、原子和从微观角度未经任何处理的怎样继续工作的结论。10Thermodynamics is founded on several fundamental laws established as a result of generalizing a large amount of experimental facts.Consequently,the conclusions of thermodynamics have a very general nature.热力学几个基本定律是建立在大量实验事实归纳出的结果之上。因此，热力学有一个很一般（很普遍）的本质。11By considering the change in the state of a substance from different viewpoints,thermodynamics and the molecular-kinetic theory mutually supplements each other,forming in essence a single entirety.通过从不同的角度思考物质状态的改变，热力学和分子动力学理论彼此相互补充，在本质上形成一个独特的整体。12Turning to the history of the development of molecular-kinetic notions,we must point out first of all that ideas on the atomistic structure of a substances were already advanced by the ancient Greeks.These ideas,however,were nothing more than a brilliant conjecture.In the 17th century,atomistics again came to the forefront,but as a scientific hypothesis instead of a conjecture.说到分子动力学观念的发展历史，我们必须首先指出，古希腊人早已先行提出物质由原子构成的思想。然而，这些思想，只不过是一个英明的猜想。在17世纪，原子论再次来到科学前沿，但是以科学假说代替了猜想。13This hypothesis was developed especially greatly in the works of the outstanding Russian scientist Mikhail Lomonosov(17111765).He attempted to give a single picture of all the physical and chemical phenomena known at his time.He proceeded from the corpuscular(according to modern terminology-molecular)notion of the structure of matter.这个假设在杰出的俄罗斯科学家米哈伊尔罗蒙诺索夫（17111765）工作下得到了极大地发展。他一生致力于给已知的物理和化学现象绘制原子图像。他从物质由微粒（根据现代分子术语）构成的观点进行研究。14Revolting against the theory of thermogen(a hypothetic thermal liquid whose content in a body determines the extent of its heating)that prevailed at his time,Lomonosov saw the“cause of heat”in the rotation of the particles of a body.Thus,Lomonosov in essence formulated molecular-kinetic ideas.反抗热素论（一个假设物质热媒的含量决定了加热的程度）在他的时代占了上风（盛行），罗蒙诺索夫从物体粒子的旋转看到“热的成因”。因此，罗蒙诺索夫想本质的系统的阐述分子动能的观念。15In the second half of the 19th century and at the beginning of the 20th century,atomistics became a scientific theory owing to the works of a number of scientists.在19世纪下半叶到20世纪初，在大量科学家的努力工作下核子物理学成为了一门科学理论。16Summary of Key Terms关键术语摘要Temperature A measure of the average kinetic energy per molecule in a substance,measure in degrees Celsius or Fahrenheit or in kelvins温度：度量物质平均分子动能，可以用摄氏或华氏或开尔文来度量。17Absolute zero The lowest possible temperature that a substance may have-the temperature at which molecules of a substance have their minimum kinetic energy.绝对零度：物质的最低可能温度，这个温度下物质的分子动能最小。Heat The energy that flows from a substance of higher temperature to a substance of lower temperature,commonly measure in calories or joules.热：从高温物体流向低温物体的能量，通常用卡路里或焦耳来度量。18Internal energy The total of all molecular energies,kinetic plus potential energy,internal to a substance.内能：物质中所有的分子的分子能、动能和势能的总和。Specific heat capacity The quantity of heat per unit mass required to raise the temperature of a substance by 1 Celsius degree.比热容：单位质量的物质温度升高1摄氏度需要的热量。