Effects of Increasing Entropy

The inequality (3.1) obviously interlinks an increase in entropy with the direction of time. If S h) S(ti), then t2 has to be valid, meaning that t2 indicates a later point in time, ti, however, an earlier one. It seems that the second law of thermodynamics determines what is future and what is past. 

If the entropy and thereby the atomic disorder inside a piece of matter is continuously increased, certain external effects soon become noticeable. 

Main Effect The main effect is that the matter becomes warmer (Fig. 3.12). To demonstrate this, entropy can be increased for example mechanically by strong hits with a hammer (Experiment 3.2). 

Another way of formulating this effect Of two otherwise identical objects, the one with more entropy is the warmer one. An object with no entropy is absolutely cold (Fig. 3.13). 

As mentioned, entropy always moves spontaneously from warmer locations to colder ones (Fig. 3.14). When fast moving atoms collide with ones moving more slowly, they are themselves slowed while their collision partners speed up. As a result, the agitation and, therewith, the total disorder at the warmer locations gradually decrease while they continuously increase at the colder locations. In a homogeneous body, the process continues until the level of agitation is the same everywhere and the body is equally warm everywhere. This state is called thermal equilibrium. 

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