where did the metals age really begin? and who discovered how to use metals?

Question

im doing a science assignment and need help!

Answer 1

The "metal age" started with the Bronze Age.
See more at:
http://www.bergen.org/technology/bronze.html

Answer 2

http://en.wikipedia.org/wiki/Bronze_Age
IRON AGE:

(1200 - 550 BCE)
The Iron Age is divided into two subsections, Iron I and Iron II. Iron I (1200-1000) illustrates both continuity and discontinuity with the previous Late Bronze Age. There is no definitive cultural break between the thirteenth and twelfth century throughout the entire region, although certain new features in the hill country, Transjordan and coastal region may suggest the appearance of the Aramaean and Sea People groups. There is evidence, however, that shows strong continuity with Bronze Age culture, although as one moves later into Iron I the culture begins to diverge more significantly from that of the late second millennium.

Answer 3

Copper Age, then Bronze and Iron. It follows the Stone Age. Timeline is regionally dependent. See ref.