|University Federico II
of Naples, Italy
There are processes so familiar in our every-day life that we do not wonder about how they occur. However, they are often processes of the utmost importance, whose mechanism has been clarified only after extensive studies. For instance:
- If your hands are greasy, you have realized that it is useless to wash them with water only. Grease is not washed away. On the contrary, if you use water and soap, your hands will become perfectly clean. What happened?
- Many of us have seen in TV, cinema or books the picture of the hunter at the Arctic Polar Circle who makes a hole
in the ice, and catches fishes. Did you wonder how is it possible that at such low temperatures (dozens of degrees below zero), under layers of ice, liquid water is still found, where fishes survive?
A inuit hunter
- Trying to dissolve sugar in a glass of water, you certainly noticed that a very great amount of it can be added, until the solution becomes syrupy. For other substances, instead, you have verified that a smaller amount dissolves in the same volume of water. Why is solubility different?
We could keep presenting many other examples. Perhaps you realized that the three processes described above have something in common, something to which we are so acquainted that we are not induced to think how precious it is: water!