Afrikan Rooted Thermodynamics (Energy)

There are 4 laws to thermodynamics, and they are some of the most important laws in all of physics. The laws are as follows

Zeroth law of thermodynamics – If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.First law of thermodynamics – Energy can neither be created nor destroyed. It can only change forms. In any process, the total energy of the universe remains the same. For a thermodynamic cycle the net heat supplied to the system equals the net work done by the system.Second law of thermodynamics – The entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.Third law of thermodynamics – As temperature approaches absolute zero, the entropy of a system approaches a constant minimum.

Before I go over these laws in more detail, it will be easier if I first introduce Entropy.

Entropy and Phase Space

Entropy is a very important thing in the realm of thermodynamics. It’s the core idea behind the second and third laws and shows up all over the place. Essentially entropy is the measure of disorder and randomness in a system. Here are 2 examples

Let’s say you have a container of gas molecules. If all the molecules are in one corner then this would be a low entropy state (highly organised). As the particle move out and fill up the rest of the container then the entropy (disorder) increases.If you have a ball flying through the air then it will start off with its energy organised i.e. the kinetic energy of motion. As it moves through the air however, some of the kinetic energy is distributed to the air particles so the total entropy of system has increased (the total energy is conserved however, due to the first law)

To get a more detailed picture of entropy we need to look at the concept of Phase Space. Some of the concepts for this may be a bit confusing but bear with me, once you’ve got your head round it it’s not that bad.

A phase space is just like a graph, but a point on this graph represents the whole state of a system. Let’s use an example. Imagine I have a box with 4 gas particles inside. Each point in the phase space for this system tells you where all 4 balls are located in the box.