Sunday, March 27, 2011

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.

Friday, March 25, 2011

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.

Friday, March 4, 2011

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.