History of Metals .Copper,gold and silver are believed to be the first metals known to man because they exist in nature in the metallic state. Copper pieces dating back to 4000-3000 B.C.have been discovered. Early metal objects were made by hammering or beating the naturally occurring metal to the desired shape PDF文件使用"pdfFactory Pro”试用版本创建ww,fineprint..com,cnHistory of Metals •Copper, gold and silver are believed to be the first metals known to man because they exist in nature in the metallic state. •Copper pieces dating back to 4000-3000 B.C. have been discovered. • Early metal objects were made by hammering or beating the naturally occurring metal to the desired shape PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn