The First Law of Thermodynamics

I need to take a tangent from my series on the second law of thermodynamics and discuss the first law of thermodynamics. 

Heat is not a conserved quantity.  Work is not a conserved quantity, but the sum of heat and work is a conserved quantity. The first law is related to the law of conservation of energy; in fact it is one case of that law.

Entropy as a Religious, Spiritual or Self-Help Metaphor

This post is part of a series, Nonsense and the Second Law of Thermodynamics. The previous post is entitled The Second Law and Creationism.

While browsing around the Internet for misuses of the term "entropy," I found some examples of the use of entropy as a metaphor. For example:

In human development and performance, entropy is somehow equated with limitations. It should be noted that if we go on to accept that people have limitations and a capacity for sin, then the natural pattern of human performance is not towards excellence but mediocrity. I say this because there are challenges, adversities, and even suffering, which are essential for healthy growth, although we don't normally seek or invite them. Overcoming these challenges, help us to see limitations as mere imaginations. Since entropy is very difficult to keep at bay, why must we continue to struggle against it in life? (Source)

I think that this paragraph has to be read as a somewhat confusing metaphor. It is not easy to characterize as a correct or incorrect understanding of entropy, but I suggest it is a bad metaphor. Entropy is not something that we can struggle against in the long term.

Converting Units of Temperature

In the course of writing articles for this blog, on occasion I write a post on the conversion of units.  Units can be confusing for some, and if I can add some clarity, I think it is worth doing.  This post addresses conversion between units of temperature. 

The most common temperature conversion that one wants to do is to convert degrees Celsius to degrees Fahrenheit or vice versa.  I hope to explain how to do this conversion in such a way that one need not memorize a formula, even to get the exact answer.

First, it is worthwhile to mention a quick and dirty approximation that almost anyone can do in his or her head.  It is not exact, but it is useful, if you are traveling to a country that uses a scale that is different than the one you use to think about ambient temperatures.

The Second Law and Creationism

This post is part of a series,Nonsense and the Second Law of Thermodynamics. The previous post is entitled Entropy and Information Theory.

Creationists and other people confused about the second law of thermodynamics  often bring up some variant of the idea that life is somehow a counter-example the second law of thermodynamics.  If entropy were disorder (which it is not), is it not obvious that life is highly ordered?

Therefore they seem to conclude that life is an example of decreasing entropy. The flaw in their thinking is not so much the confusion between disorder and entropy; the argument could be made with an accurate description of entropy. It would still be incorrect.

Entropy and Information Theory

This post is part of a series,Nonsense and the Second Law of Thermodynamics The previous post is entitled  Partition Functions.

The posts in this series are primarily about the second law of thermodynamics, the concept of entropy, and the use and abuse of these ideas.  I would be remiss, however, not to mention information theory and the role that entropy plays.  This post is not intended to be a comprehensive introduction to information theory.  Readers especially  interested in this topic will want to read other sources in addition to this post.

Temperature Anomalies and Graphing Data

Globally Averaged Temperature Anomaly

One statistic that is used to understand climate is the annual globally averaged temperature anomaly.  It is not the only measure of global warming; there are a great many others, but it is one that the media tend to focus on because it is a convenient way of explaining what is happening to surface temperatures as a function of time.

The data here are taken from Global Land-Ocean Temperature Index (C) (Anomaly with Base: 1951-1980), which includes data from 1882-2007.  There are updated numbers available for more recent years, but I am using these data to respond to an argument made by a friend.

Partition Functions

This post is part of a series,Nonsense and the Second Law of Thermodynamics. The previous post is entitled Fluctuations.

In previous posts it was shown that entropy is related to the the number of ways that a system can arrange itself subject to constraints such as constant energy.

The previous post on fluctuations showed that for very large numbers that fluctuation from the most probable distribution, are insignificant.  Most of the distribution is contained within the square root of N of the most probable result.