M
Maddad
Guest
Beads of Doubt<br />http://news.bbc.co.uk/1/hi/sci/tech/2135779.stm<br /><br />We say that entropy of a closed system increases with time, but what we really mean is that the orderliness of the system decreases. If I have a nice china cabinet with Stangle dishes there are only a few ways that I can stack them. However, let my cats into the cabinet to play with them and the dishes will soon be scattered in a very disorderly manner. As I put the dishes back where they belong, I reflect that there are many more ways for the dishes to be arranged that look messy than there are for them to look orderly.<br /><br />Because objects in a system have very few orderly ways to be arranged, but many disorderly ways, it is more likely that a random rearrangement of the objects will result in an overall decrease in orderliness. As your system gets larger the number of possible disorderly combinations increases exponentially, but the number of orderly combinations increases much less. This means that it becomes more and more likely as the size of the system increases that any change will result in less order instead of more.<br /><br />By the time you get a large system, such as the 10<sup>28</sup>(10,000,000,000,000,000,000,000,000,000 or ten thousand trillion trillion) or so atoms in a human body, there is almost zero chance that any random change will result in more order. Those random changes will instead result in more disorder. For instance, there is very little chance that a stiff breeze will blow your hair into a neatly brushed appearance. It is much more likely that you will soon look like the Wild Man from Borneo.<br /><br />Recognizing that systems tend to become less orderly with time, scientists define time as the changes in a system that results in less order. This works just fine for large systems such as my hair, but on a very small scale there are reasonable combinations of random changes