Please explain me alchemy in easy words with its small history.

Alchemy is the very old study and philosophy of how to change basic substances (such as metals) into other substances. It also studied how substances (and how they are changed into other substances) were related to magic and astrology. People who studied alchemy were called alchemists.
Alchemy?was born in ancient Egypt, where the word Khem was used in reference to the fertility of the flood plains around the Nile. Egyptian beliefs in life after death, and the mummification procedures they developed, probably gave rise to rudimentary chemical knowledge and a goal of immortality.
Alchemy?was based on the belief that there are four basic elements in nature: air, fire, water and earth.?Alchemy?is an ancient practice shrouded in mystery and secrecy. Its practitioners mainly sought to turn lead into gold.