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# 4.1: Where We Are Headed

We continue our pursuit of an energy conservation approach, which looks at the state of a system before an interaction and then looks at the state of the system after the interaction, trying to avoid the messy details that occur in between. With our understanding of heat, work, thermal energy and heat capacities in terms or our particle model of matter, we are in a position to make explicit connections to the traditional field of thermodynamics. Thermodynamics is a very practical discipline. Scientists from all fields (chemistry, physics, biology, earth sciences, environmental sciences) find thermodynamics to be a very useful approach to determining values of physical variables. Our goal is to demystify thermodynamics as much as we can. In particular, we make direct connection to our particulate models of matter and our Energy-Interaction Model. The connection of entropy and energy to particulate models of matter helps to make thermodynamics much less mysterious to most of us. We can more readily see why so many things in nature “are they way they are” in terms of our models.

We will actually spend very little time, relatively, on thermodynamics. We can’t expect to become experts in such a short time. But what we do hope is that you will develop some understanding of how traditional thermodynamics relates to what we have been doing. Perhaps, when you run across thermodynamics later in your studies or work, it won’t seem so mysterious. The idea of entropy and its connection to statistical arguments should make the second law of thermodynamics much more understandable. The ideas expressed in the second law are very general. They apply to all systems composed of many particles. That takes in just about everything, since essentially everything is made up of little particles.