1.2   SYSTEMS AND METHODS:   The grandest abstract of thermodynamics is the universe which is defined to be all that exists in a physical sense. Being infinitely vast, the universe extends way beyond the localized, vanishingly small, spaces of engineering systems and events. The impossibility of dealing with the entirety of the universe mandates a system approach.

NEWTON'S ANALYTIC METHOD:  Newton and his contemporaries believed motions of the planets in the solar system were regular and that by careful study, their behaviors (such as solar ecllipes, etc) could be understood, even predicted. Much interest then, was that motion of a body had two independent components - uniform motion and natural motion.

Newton studied the physical world exhaustively. He made many, very many insightful conclusions about specific issues. But more important and more lasting was the manner, the approach he took in each and all of his investigations. To this day, the basic method Newton used to contemplate, analyze, and study, forms the basis of the scientific method.

The essence of all methods of science and engineering study follows Newton's approach which was to isolate the system from the surroundings but then to admit influence of the surroundings on system change by means of three constructs: Force, Work and Heat. His technique works well for special investigations. Those understandings and information comprise what is called Newtonian, or Classical Mechanics.

With this talk about systems, boundaries and events, one might wonder why there is change, why do events occur? The answer has to do with energy.

ENERGY: Each of the infinity of relatively tiny pieces of the matter of the universe has energy and some masses have more energy than others. The natural collective tendency of energy among masses is that, in the course of by events, the trend is for all masses ultimately to have the same energy. In infinite time, the belief is that, the entire energy of the universe will be evenly distributed among all masses. Such interior to the system, "energy-leveling," events are called equilibration.

Presently some masses have significant energy and simply for that reason, have a propensity to change of their own accord such that their energy becomes less (yielded to the surrounding) to become closer to the energy of the surroundings. For a system of inert matter to change, energy must be supplied. Energy can be said to belong to either of two realms:



An extrinsic property is independent of the matter of the system. Extrinsic behavior is behavior that can be observed visually in space. It involves mechanical energy, i. e., kinetic energy and potential energy. The systems are bodies, particles, rigid bodies and such.

CLASSICAL MECHANICS:  might be called the beginning of the scientific method. An understanding of the power, focus and elegance of calculus and classical mechanics cannot be avoided by any student of thermodynamics. Newton's methods, insight, form the basis of thermodynamics, its methods, procedures... the very explanation of thermodynamics. The study of classical mechanics imparts Newton's method and instills mental discipline. Learn the basics.

BODY AND PARTICLE:  Methods and fundamental ideas of system selection, momentum, potential energy, kinetic energy and work are learned in regard to the very simplest system, the body (object) and particle. While body and particle can be interchange with no alteration of the physics or mathematics, generally particle is though of as smaller than a body. The table presents a summary of properties of mechanics.
NAME SYMBOL [dimensions]
mass: m ~ [m]
time: t ~ [t]
position:(#) P ~ [L]
velocity:(#) V ~ [L/t]
momentum:(#) mV ~ [m L/t]
angular momentum:(#) r x (mV) ~ [m L2/t]
center of mass:(#) rcm ~[L]
radius of gyration:(#) rcm~[L]
(#), requiring a vector origin and basis












EVENT:  Every physical analysis or design involves some event. Event is a change that occurs in time. Academically we study four possible types of events or occurrences of the system in accord with the different relationships the events have (or imagined to have) with time.

We will distinguish these events as:











ABOUT PROPERTIES IN GENERAL   Each property consists of i) a name and technical description and ii) at least one measurement process whereby measurements taken result in a number (or three, or nine numbers... depending upon the property). Thus a property is more than a number or numbers and the same set of numbers must be obtained (subject to measurement accuracy) by different measurement processes. For example, the distance between two parked automobiles might be measured by use of a tape measure by say, a sheriff. And that distance, measured by lasers from a satellite would be the same number.

With regard to numbers, physical properties are tensors. Each distinct physical property is ultimately described numerically by one number (the property being a scalar), or by 3 numbers (that property being a vector with the numbers determined relative to a space and time coordinate reference) or 9... numbers. .

Tensors are classed by rank as rank zero, rank one, two or some larger integer. There are (3)RANK , that is three raised to the "rank" numbers, and appropriated dinensions, vector basis and so, associated with a physical tensor or system properties. The "numbers" of physical properties must be established by some measurement process.

RANK NUMBERS NAME EXAMPLES
0 (3)0 scalar pressure, mass, density,
length...
1 (3)1 vector position, velocity, momentum,
area. {But not force. Force is a
vector but not a property}.
2 (3)2 tensor moment of inertial and material stress


























MEASUREMENT:  
Measurement, the driving force of science, is the process of making matter and events quantitative. Whatever characteristic of a system that can be measured has the possibility of being named a property. Whatever cannot be measured is not a property.

Measurement is property oriented, results in a number which has units. As a rule, numbers have units. Students at this level generally have adequate experience with ideas of measurement and property. The brief discussion below is focused on the needs of classical engineering thermodynamics, limited to simple, compressible substances with minor exceptions.

MEASURABLE AND NON-MEASURABLE PROPERTIES:  While the idea measurable properties (or primary, in some texts) might seems obvious, the fact that there are properties, physical characteristics of matter, which can be made quantitative but which cannot be measured. Non-measurable (or secondary) properties are made quantitative in relation to other properties that are measurable. There are subtle differences among types of properties but there are many steps of learning that can be accomplished with just a little of the sublty. Measurement itself has become a science. But limited to primary properties - that's all that can be measured. But before that, lets talk primary properties.

Qualifiers for properties of matter include the following distinctions and contrasts: