In the early 1800s, the world saw a great change which has made a huge impact in our daily lives. This later became known as the Industrial Revolution. Many machinery were built through the process of combustion reaction, a chemical reaction that occurs between a fuel and an oxidizing agent that produces energy. However, many of these combustion reactions did not produce the total theoretical amount of energy. This made many scientists wonder why the total amount of energy was not being used and where the unused energy went to. After several attempts to try and explain this phenomenon, it later became known as entropy. The most common definition of entropy is the measurement from order to disorder. This definition can be confusing and it does not help with the understanding of what entropy really is. Entropy is the measurement of how spread out energy is and once that energy is spread out it can not be used. To better understand what entropy is, we must better explain this phenomenon.

   The second law of thermodynamics states that the whole amount of energy is not converted into useful work. The remaining part of energy which is not converted into useful work is known as unavailable work. This basically means that the entropy of the system either remains the same or increases. However, it does not necessarily mean that the entropy of a system can not decrease. Entropy can decrease somewhere, provided it increases somewhere else by at least as much.  The entropy of a system decreases only when it interacts with some other system whose entropy increases in the process. For example, a very common item that has a decreasing entropy is a refrigerator. The system’s temperature is being lowered, therefore the energy of the molecules, a group of atoms bonded together, is lowered. In order to achieve this the entropy of the surrounding is increased by the exportation of heat and the conversion of useful work into heat. In simpler words, the refrigerator does generate heat but that work is used to release heat to the surrounding. This maintains both heat and cold separate from each other rather than both temperatures being evenly distributed to one another.

If we know that energy is produced with a difference of temperature, then what happens when there is no temperature difference? Let’s say we have two slabs of metal, both of which have a difference in temperature. If we lay the cold slab on top of the hot slab, we expect the heat from the hot slab to flow to the cold slab until the heat has been evenly distributed. Once the heat has been evenly distributed, nothing else happens. The two metal slabs have reached the highest measurement of entropy. Therefore, energy cannot be produced. On the other hand, if we had two metal slabs with the same temperature, we can not expect the metal slab to transfer heat to the other slab. However we can decrease the entropy of the two slabs by adding an external system with an increasing entropy. An example of this could be your hands. Whenever we clasp our hands together there is no temperature difference. Once we start to rub our hands against one another heat starts to build up but this did not occur on its own. An outside system in this case our muscle put in the work and exerted the heat from our muscle into the sliding hands.

Entropy is always becoming more spread out and less clumped together. This can let us know that in the future all the energy in the universe will be spread out and none of our engines will work. Our bodies is a prime example of increasing entropy. As we start to age our body tends to lose energy. We become less strong than we once were at a young age. However, this is not all bad news for us. On earth we have massive amount of clumped up energy that we haven’t used things like; coal, oil, and gasoline. When we burn those fuels we’re running our engines and we are spreading the energy out increasing the entropy. Nevertheless these are nonrenewable resources and once they are burned up we can not used them again. Fortunately, there is still one giant source of clumped energy that we can use and that is the sun. This lead to the creation of solar panels and grow a crop of biofuels. It may seem that we may have found a replacement for fossil fuel. Then again the definition of entropy does state that the energy of the sun will spread out as will all the energy in the universe. Once all the energy in the universe is evenly spread out nothing interesting can ever happen again. This is called the “Heat Death of the Universe” and it’s scientists best guess of how the universe will end. Why does entropy always increase? It is actually a statistical phenomenon. Let’s say we have a cardboard box and we have a layer of ping pong balls half of which are red the other half is blue. We arrange the ping pong balls so that all the red balls are at one side while the blue balls are at the other side. We vigorously shake the cardboard box and let the ping pong balls settle again. We will notice that the red and blue ping pong balls are all randomly distributed throughout the cardboard box. We can conclude that there is only one way to have all the red ping pong on one side and the blue ping pong balls on the other. Nonetheless, there are many different amounts of other possible arrangements. We can conclude that there is only one out of trillions that is that clumped up state which is the well-organized ping pong balls.

   Entropy can be explained in a numerous of ways. However, it may be difficult to grasp around the concept of what entropy really measures. If you think of entropy as being the measurement of energy being spread out we can come to many conclusions like the heath death of the universe.