For
instance, Egyptian metalworkers knew how to make imitation gold by
mixing copper with other metals. The mixture wasn't gold, of course,
but it had the color of gold. However, a Greeks theory said that gold
and copper were really made of the same matter. They differed only in
the “form”. So it followed that one could make gold from copper
or even from lead.
Naturally,
metalworkers began to try to make real gold. This was probably the
beginning of a study called chemia. Exactly where this word comes
from no one knows, but it is the root of our word “chemistry”.
For
many centuries the students of chemia tried to make gold out of other
metals. But since this was impossible by the methods they used, they
always failed.
As
time passed, the Arabs became great conquerors. They won control of
Mesopotamia and Egypt and much more. And they took up the study of
chemia, which they called al chemia (al is Arabic for “the”).
This expression has come down to us as “alchemy”.
The
most important Arabian alchemist was Jabir ibn Hayyan. He lived about
A.D. 750 and is also known by the Latin form of his name, Geber. He
seems to have made a number of discoveries about ways to prepare
chemical. And it it was he who started the search for certain dry
powder that came to be called the philosopher's stone. Alchemists
believed that it would turn other metals into gold. And they searched
for it during hundreds of years.
Arabian
alchemists did discover some important new chemical substance. Among
these were ammonium chloride and certain strong alkalies. Most of
their time, however, was spent searching for the philosopher stone.
And after the year 1000, Arabian alchemy came to an end.
However,
by the 1100's Arabian books were reaching Europe. Books an alchemy
(and many more) were translated into Latin. Europeans the began to
search for the philosopher's stone.
Fortunatelly
by the 1500's a new spirit was on the sea. There was a swiss doctor
who called himself Paracelsus. He was an alchemist but not an
ordinary one. He didn't think it was at all important to find
methods for making gold. He thought alchemists should search for
medicine to cure sickness. He was not a great scientist and some of
his idea were entirely wrong. But he wanted to put an end to ancient
belief's and start over. There he was right. He was also right in
waiting to test ideas by experiments.
Beginning
in the 1580's an Italian scientist named Galileo showed that it was
very important to make accurate measurements. More could be learned
in this way than in any other. He work in physics and astronomy
helped to establish modern science.
Lavoisier,
a French chemist, explained that a candle didn't really disappear if
it burned. The carbon and hydrogen in it combined with the oxygen of
the air. They formed carbon dioxide gas and water vapour. If the
candle burned in a closed vessel, the weight of the candle and vessel
did not change.
Chemists
tried to arrange the elements in the order of their atomic weights.
The most successful arranger was a Russian chemist, Dmitri I.
Mendeleev. In 1869 he arranged the elements in rows and columns. He
published the first periodic table, which become the basis of
theoritical chemistry. The periodic table provides an easy way to
show the division of the elements into two acid and base.
As
chemistry had been developing so had the science of physics. Physics
deals with various forms of energy, such as heat, light, electricity
and magnetism. From about 1850 on, chemists began to apply the
findings physics to chemistry. In this way physical chemistry was
developed.
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