Laws of Thermodynamics

Laws of Thermodynamics

The field of thermodynamics studies the behavior of energy flow in natural systems. From this study, a number of physical laws have been established. The laws of thermodynamics describe some of the fundamental truths of thermodynamics observed in our Universe. Understanding these laws is important to students of Physical Geography because many of the processes studied involve the flow of energy.

First Law of Thermodynamics:

The first law of thermodynamics is often called the Law of Conservation of Energy. This law suggests that energy can be transferred from one system to another in many forms. Also, it can not be created or destroyed. Thus, the total amount of energy available in the Universe is constant. Einstein's famous equation (written below) describes the relationship between energy and matter:

E = mc2

In the equation above, energy (E) is equal to matter (m) times the square of a constant (c). Einstein suggested that energy and matter are interchangeable. His equation also suggests that the quantity of energy and matter in the Universe is fixed.

Second Law of Thermodynamics

Heat cannot be transfer from a colder to a hotter body. As a result of this fact of thermodynamics, natural processes that involve energy transfer must have one direction, and all natural processes are irreversible. This law also predicts that the entropy of an isolated system always increases with time. Entropy is the measure of the disorder or randomness of energy and matter in a system. Because of the second law of thermodynamics both energy and matter in the Universe are becoming less useful as time goes on. Perfect order in the Universe occurred the instance after the Big Bang when energy and matter and all of the forces of the Universe were unified.

Third Law of Thermodynamics

The third law of thermodynamics states that if all the thermal motion of molecules (kinetic energy) could be removed, a state called absolute zero would occur. Absolute zero results in a temperature of 0 Kelvins or -273.15° Celsius.
Absolute Zero = 0 Kelvins = -273.15° Celsius
The Universe will attain absolute zero when all energy and matter is randomly distributed across space. The current temperature of empty space in the Universe is about 2.7 Kelvins.

Why are the three Laws of Thermodynamics so important?

Our concept of "Modern Science" is based on a series of major discoveries that define our understanding of the universe. Advancements in mathematics, biology, physics, chemistry, and other disciplines have usually been accompanied by defining, or discovering, fundamental principles. The Laws of Thermodynamics are important because they control interactions of everything in the universe - regardless of scale. These rules stretch across every form of science known to humankind.

Classical physics is, from a certain perspective, entirely based on Newton's Laws of motion. Most of the equations and principles taught in physics are based on these simply stated rules. In a similar way, thermodynamics is defined and based on the fundamental principles known as the Laws of Thermodynamics. All of the equations and guidelines used to design engines, analyze machines, and understand natural phenomena are subject to these laws.

The Laws of Thermodynamics take on a special importance because of their scope. It has been shown that Newton's laws of physics are only applicable in certain conditions. These conditions include pretty much every situation important to most engineers, chemists, and scientists. However, there are some known conditions where "Newtonian" physics are inaccurate. The Laws of Thermodynamics have no such exceptions. Energy is conserved, regardless of the amount or type of energy. Closed systems always tend towards greater entropy unless externally modified, whether those systems are atomic or galactic in size.

This means that the three Laws of Thermodynamics have influence over every scientific discipline, every biological or geological process, and every interstellar system. We can immediately test certain ideas against the Laws of Thermodynamics to see if they follow some of the universe's most basic rules. Ideas that don't follow those rules are either wrong or must be caused by some supernatural influence. For example, perpetual motion machines are provably impossible according to the Laws of Thermodynamics. The first law shows that energy (or matter) cannot be created from nothing, and the second law shows that a closed system will degrade its own energy over time. A machine that runs forever without any external energy source is either fictional or powered by some unnatural source.

Implications of the Laws of Thermodynamics, much more than other concepts, have sparked fierce debate about the very origins of the universe. The Laws of Thermodynamics leave some popular scientific theories in serious doubt. The fact that matter can neither be created or destroyed, according to the First Law of Thermodynamics, raises questions about where all of the matter in the universe came from.

Interestingly, there are those who shrug off disagreements between the Laws of Thermodynamics and certain popular scientific theories. While the fundamental laws of matter and energy, the Laws of Thermodynamics, are used to measure truth in every other discipline, some scientists ignore these laws as they pertain to their theories. Since the Laws of Thermodynamics define the rules of the natural universe, how do we explain things that those Laws say are not possible? If matter cannot be created, where did it come from? It is certainly here, and nothing natural can create it.

This makes a supernatural source more than just a possible conclusion - it makes it the only conclusion that fits the Laws of Thermodynamics. If something exists when natural laws say that it cannot be created, then something or someone operating outside of those laws must be responsible. The Laws of Thermodynamics lead us not only to greater knowledge of the natural universe, but they point us toward answers outside of that universe as well.