Page 142 - The Creation Of The Universe

140 THE CREATION OF THE UNIVERSE

body temperature by 6°C as a result of the evaporation of just a liter's worth
of water. The more energy he expends, the more his body temperature will
increase but, at the same time, the more he will sweat and thus cool off.
Among the factors that make this magnificent thermostat system of the
body possible, foremost are the thermal properties of water. No other liq-
uid would provide for sweating as efficiently as water does. If alcohol were
present instead of water for example, the reduction in heat would be only
2.2°C; even in the case of ammonia, it would be only 3.6°C.
There is another important aspect of this matter. If the heat released
within the body were not conveyed to the surface, that is to the skin, nei-
ther the two properties of water nor the process of sweating would be of
any use. Thus the structure of the body must also be highly conductive of
heat. It is at this point that another vital property of water comes into play:
unlike all other known liquids, water has a very high capacity for thermal
conductivity, that is, the ability to conduct heat. For this reason, the body
conveys the heat generated inside it to the skin. (The blood vessels near
the skin expand to achieve this and this is why we become flushed when
we're overheated.) If water's thermal conductivity were less by a factor of
two or three, the rate of conveyance of heat to the skin would be much
slower and this would make it impossible for complex life forms like mam-
mals to live.
What all this shows is that three very different thermal properties of wa-
ter work together to serve a common purpose: cooling off the bodies of
complex life forms such as human beings. Water is a liquid specially cre-
ated for this task.

A Temperate World
The five different thermal properties of water mentioned in Henderson's
book The Fitness of Environment also play a key role in bringing about the
mild and balanced climate that Earth has.
Water's greater latent heat and thermal capacity as compared with oth-
er liquids are the reasons that bodies of water heat up and cool off more