# Thermodynamics and YOU 12/10/18

By Richard E. Bleil, Ph.D.

For a time, I worked at a department store in the Men’s Sportswear department. I wish I could say that this was when I was in high school, but sometimes life takes you in unexpected directions. Although it was not necessarily suitable for a career as advanced as mine, I would not trade it for anything. I met wonderful people, felt like a part of the team (something that has been missing for a long time), and learned a lot.

One surprising lesson was the amount of work it takes to be a sales associate. Seriously, be nice to the sales associates. They don’t make the policies, they don’t have authority, but they work so hard and take so much abuse. For example, I had to unload shipments from trucks, unload the clothes, unfold them, hang them, and more.

Often I would start at seven in the morning, with a store that did not open until ten to unload and hang clothes. This was challenging, because I worked partly on commission, and had a sales goal to keep my job. Each day I unloaded, I lost three of my eight hour day to do truly difficult work. The goal was always to have the new shipment unloaded and on the floor before the day started, but, depending on the amount of good arriving, this couldn’t always happen, and periodically we would have to continue working as customers arrived.

One day, as I was still unfolding and hanging sweaters, a sales associate from the department next to mine (rather less busy than ours) came over to chat. We started talking about thermodynamics (I am, after all, trained in statistical thermodynamics) and how it affects everything.

This is the thing about the laws of thermodynamics. Everything that occurs, must occur according to the laws of thermodynamics. Everything. Not just in class, and not just in science, but everything. And the reality is that you know these laws. Oh, you may not know the names or the mathematics involved, but you know the laws.

For example, if you touch a hot surface, you know the heat will flow from the hot surface into you. This is the zeroth law (yes, the zeroth; it was decided that it was more fundamental than the first law, but the first law had already been established). Simply stated, heat flows from a region of high temperature to low. I know, you’re thinking “duh”, because you knew this already. You also know that energy tends to go from high to low. If you’re standing on the sidewalk in the center of a hill with a ball, you know the ball will roll down, not up. It rolls to lower energy, which is the first law. You also know that, if you don’t regularly clean your living area, it falls into chaos. This is the second law.

One of the least well understood laws is the second law. It is often misquoted as saying that entropy (which can be thought of as chaos) can never decrease. This is wrong. If this were true, life would be impossible, because if it were, once water evaporates, it could never condense again. We would have no liquid water on earth. What the second law actually says is that the entropy OF THE UINIVERSE can never decrease. This means that the entropy of a given system can decrease. It won’t naturally, but it will decrease if work is done on the system (and in doing that work, the entropy of the surroundings must increase at least as much as the entropy of the system so the entropy of the universe does increase).

This brings us back to the start of the blog; unpacking sweaters. How it swung to the laws of thermodynamics, I may never remember, but I explained that, as I was unpacking, the second law was kicking in. Unpacking, and unfolding, the entropy of the system was increasing. It was high to begin with, since the sweaters came in boxes, some folded, some already on hangers, with no order to the boxes or styles within, but unpacking and unfolding, their entropy was increasing. My goal was to decrease the entropy, put all of the sweaters on hangers, in a neat display, by color and style, and all increasing from small to large. To decrease the entropy of the system (defined here by the sweaters), I had to do work on the system. Of course, the entropy of the surroundings had to increase by at least as much, or more, because of the second law. The surrounding entropy was increasing by the garbage I generated in emptying the boxes and discarding the packing materials, plus the carbon dioxide I was creating by burning the energy my body needed to perform the work.

The laws of entropy surround us. Every time there is roadwork, house work, gardening work, anything that you do that takes work follows these laws. It’s a fun game (at least to me) to think about this when I do things. Even blogging. I think of the first law (from where is the energy coming, in this case, the energy to move my fingers and stay alive, plus the energy from the central energy plant to run my electronics) and the second law (organizing my thoughts and typing the letters and words in a manner that is low entropy, that is ordered, so you can understand them).

Here’s my challenge to you, and it won’t be a surprise. Think about this for a time. Whenever you find yourself doing something, think about the energy cost or accumulation, and if entropy of the system is increasing or decreasing.

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