 we will now look at the place of thermodynamics in mechanical engineering and in engineering. First, let us consider what is engineering all about. It is a bit difficult to provide a simple definition of engineering, but let me make an attempt. Let us say that on one side we have nature, on the other side we have us humans. Nature provides us resources, water, air, solar energy, stored energy in the form of fuels of various kinds, many minerals. What we want is a good life. So what we do to use the resources of nature to provide us a good life can generally be called engineering and the people who do this are engineers. This turns out to be a rather wide definition of engineering, but I think most of us will agree that it is a reasonably nice way to define engineering. It is a wide thing, mechanical engineers. In fact, many people like tailors, cooks, cobblers, which we generally do not consider as engineers, can also be considered engineers from this definition of engineering and I do not think there is anything wrong with this definition. Now this course, although it is of thermodynamics, will have a mechanical engineering flavor. In fact, significant flavor of mechanical engineering because the background of all the three teachers who are involved in this is that of mechanical engineering. So let us see what mechanical engineering is all about. The scheme is similar. We are now trying to define what mechanical engineering is all about. Again we begin on one side with nature and here the resources that we are going to look at is energy resources quite often known as fuels plus materials which are available in nature. On the other side is of course good and comfortable life for us. Now mechanical engineering essentially does use the resources of nature to provide us good life, but it does it through what we generally call machines. The machines we look at are of various kinds. One set of machines will use the natural resources, energy and materials to provide energy. At a certain rate we call it power and of course we will use energy for good life for say transportation and to drive machines. We will also have machines that produce machines and we have machines that produce gadgets and machines of all kinds that directly or indirectly provide us with good life. So this I suppose is a general scheme of mechanical engineering. Now where does thermodynamics come in? We will notice that one of the schemes in mechanical engineering was machines that use natural resources and produce energy which we can use for driving our cars, running our refrigerators, washing machines and anything that we see. The natural resources are usually in the form of fuel. I will put fuel in quotes because even solar energy may be considered as a fuel of some sort. This provides energy in the form of heat. We stand in the sun, we feel warm, we burn some fuel, heat is liberated. Whereas this energy which machine produce is in the form of work. The science which looks at such machines which convert heat to work and maybe even vice versa wherever it is needed is known as thermodynamics. So thermodynamics is essentially going to look at stuff which interacts doing or absorbing work and which interacts doing and absorbing heat. And these could be machines, these could be gadgets, these could be anything. In thermodynamic we just call this thermodynamic systems. This word we will define again later. Although thermodynamics was initially developed by engineers looking at engines, pumps, compressors, fans. As the science developed it turns out that thermodynamics is a proper branch of physics. If you take up any good book on higher level of physics you will find a chapter, at least a chapter on thermodynamics along with mechanics, fluid mechanics, electricity, magnetism and others. The contributors to thermodynamics come from all fields. Engineers have contributed to it. Physicists have contributed to it. Chemists have contributed to it. Even mathematicians have helped in formalizing the science of physics. And of course this list is not complete. The users of thermodynamics are all types of scientists and all kinds of engineers. Among engineers perhaps mechanical engineers use it the most followed by chemical and metallurgical engineers. Even aerospace engineers, electrical engineers, you name it they will be using thermodynamics. Thank you.