Early Humans Making Tools

Tool manufactures know that sometimes you have to heat-treat a material to make it harder or stronger. Ancient toolmakers had come across that trick long ago. Archaeological research from South Africa pushes back the date of the earliest use of heat-treatment at least 45,000 more years, to more than 70,000 years ago. Kyle S. Brown a doctoral student at the University of Cape Town, and his colleges report finding stone tools that show signs of being heated to about 600 degrees Fahrenheit. Heat-treating in this way made it so the stone was easier to knap, or shape into a tool by striking it with another stone.