Oxygen- The Life

Oxygen
Oxygen is the most abundant element. The Earth's crust is estimated to be 49.52% oxygen by weight. Approximately 20% of the atmosphere is oxygen, the rest is mostly nitrogen. Oxygen consititues about 85% of sea water, 47% of dry soil, 42% vegetation, 46% of igneous rocks, and 65% of the human body.
Although oxygen is the most abundant of all the elements and is a major component of most materials in our environment, it was not the first element discovered. Many rarer elements were known and prized by the ancients including gold, silver, lead, tin, and mercury. Carbon and sulfur were used in gunpowder in the sixteenth century. The ancients all used oxygen, but oxygen was not isolated nor understood until the latter part of the eighteenth century.
Two men are credited with the discovery of oxygen. In about 1773, a Swedish chemist, Karl William Scheele, and an Englishman, Joseph Priestley. Neither Priestly nor Scheele realized that they had discovered a new element. THey both co...