WATER AND THE METALS
Some Considerations Touching Water and the Metals
WATER
THE SUN’S HEAT causes the water of the ocean to rise as vapour, while in winter the water freezes, becomes solid and more like the earth in its nature. Whatever state we may find it in, whether as vapour in the heavens or earthbound as ice, it must always return to its liquid state. So we find the rain falling and giving rise to springs. Furthermore the sea never freezes right through to the bottom. This is due to the fact that ice floats on water. The water in the depths too, is warmer than near the surface, for it is heaviest at 4 degrees Celsius. The water in the sea thus never becomes entirely solid, and so too, glaciers can slide down into the valleys because they have water under them. The water vapour in the air moreover must fall back to earth again as rain. As Goethe says ” It comes from Heaven, to Heaven it rises, for ever changing.” One might ask why the water in the depths of the seas never freezes ? It is because water must always seek to be liquid. It is only on the surface and not in its depths that water solidifies. The water does indeed become solid ice but in doing so it becomes lighter and is pushed upward while other substances as they cool become heavier and sink to the bottom. Glaciers show us that even as ice, water still flows and indeed it never becomes truly solid but is more like a kind of fluid stone. Under pressure ice will melt and so a skater is not really skating on ice at all, but on a film of water produced by the weight of his body pressing on the ice. All this is summarised in the following dictation:—
“Water ever strives to remain liquid. Its home is therefore the ocean which is the bloodstream of the earth. It must always seek its way back to its liquid state, its home. Water also unites with air and with solid matter. Fish could not live in the sea if it did not have air dissolved in its waters. Sea water too, has much salt dissolved in it. When sea water is evaporated this solid salt is left. Water always contains something of earthy origin, i.e. its saltness, and something of the air. Thus water unites earth and air and acts as an intermediary between them.”
And has water any other mediating attributes ? From what they have already learnt, the children will adduce many examples. Water is a link between the different parts of the earth and a means of communication between peoples. Nations are united by ocean routes, trade flows on them. East and West are united by the sea. And is there not in man too a fluid that unites everything ? The blood flows to every part of the body and wherever it flows it is the unifying principle. As the cities of the earth are linked by waterways so are the different parts of the body by the arteries. Through water all things are united.
Having thus indicated to the children something of the true nature of water, its chemical aspects may now be more closely examined. The children will remember how carbonic acid gas had no effect on litmus paper until the latter was moistened, when it turned red and similarly how quick-lime did not turn the litmus blue until a drop of water had been added to it. Acid and alkali do not appear until water is present. When the tongue is perfectly dry we cannot distinguish acid from alkali. Taste is only made possible by the presence of water. A little experiment will drive this point home. Take some crystals of citric acid, the substance which gives lemons their sour taste. Moisten a little with water and the solution will turn litmus red and must therefore be an acid. In contrast take some ordinary baking soda. When moistened this will turn litmus blue, and must therefore be an alkali. Mix the two dry powders together. Nothing happens. But if water is poured over the mixture, it will foam up violently. The reaction is just like the one we had when caustic soda and hydrochloric acid were mixed together. What we have made is the well-known effervescing powder. In this way we learn that acid and alkali only react on one another when water is present. Water alone makes the combination possible.
Next day the children should be asked to enumerate all the instances in which water plays a unifying role; as for example in the slaking of lime, the combination of acid and alkali to form salts, its power of dissolving salts and air as also its function in binding nations together etc. We can then add the information that it is only in water that colours appear. The children are familiar with the rainbow. When does it appear? When light and darkness meet; the sun with the dark curtain of rain. But between the two there must be water, in the form of raindrops. Once again water is the unifier, in this case of darkness and light. The Greeks and Romans called the rainbow the ” Rainbow of Hermes ” (or Mercury), for Mercury was the messenger who bore down everything from Heaven to Earth and also from Earth up to Heaven again.
Goethe’s poem ” Gesang der Geister iiber den Wassern ” (Song of the spirits on the waters) forms a fitting and lovely conclusion for the dictation in which all this is summarised. Every word of the poem can be prepared in class and so there is no need to comment upon it. It expresses and summarises everything, simply and conclusively. From what was at first mere knowledge —mere information, there spontaneously arises within the child, a something it can cherish in its heart. This will remain with it to form the basis for further studies. It would be superfluous at this stage to speak to the children of Hydrogen and Oxygen. It is better for them to regard water as a unit. Later they will understand more easily that even in water, opposites interact, that in it too contradictions are united. Once it is appreciated that water in itself unites the greatest paradoxes, its ability to unite all things will appear even more wonderful.
THE METALS Having considered water in this simple way, the children can now turn to the metals. A selection of metals should be displayed and the children should have plenty of opportunity of seeing them and of familiarising themselves with the peculiarities of each. It is best only to take the more easily obtainable and more important metals. Sodium and calcium being in fact only pseudo- metals are best left out of account. The following are recommended: gold, silver, lead, tin, iron, copper and mercury. In what follows we shall see why just these seven are taken as best suited to our purpose. It will help the children to learn the characteristics of the metals, if objects made of them are brought to their notice.