Simple definition of relative dating
In the thinking of these philosophers all other substances were supposed to be combinations of the four elements, and the properties of substances were thought to reflect their elemental compositions.
Thus, Greek thought encompassed the idea that all matter could be understood in terms of elemental qualities; in this sense, the elements themselves were thought of as nonmaterial.
The modern concept of an element is unambiguous, depending as it does on the use of chemical and physical processes as a means of discriminating elements from compounds and mixtures.
The existence of fundamental substances from which all matter is made, however, has been the basis of much theoretical speculation since the dawn of history.
About 20 percent of them do not exist in nature (or are present only in trace amounts) and are known only because they have been synthetically prepared in the laboratory.
Most samples of naturally occurring matter are physical mixtures of compounds.
Elements can combine with one another to form a wide variety of more complex substances called compounds.
The number of possible compounds is almost infinite; perhaps a million are known, and more are being discovered every day.
He argued that the four Greek elements could not be the real chemical elements because they cannot combine to form other substances nor can they be extracted from other substances.
Boyle stressed the physical nature of elements and related them to the compounds they formed in the modern operational way.
This article considers the origin of the elements and their abundances throughout the universe.