1. Early human beings made their tools from stone and wood.
2. Later they used the bones of animals.
3. Then they discovered metals like copper and iron.
4. Tools made of copper and iron are much stronger than tools made of stone and wood.
5. Metals had the advantage of not just being harder but they can be heated in a fire and moulder or cast into different shapes. So it became possible to make a wider range of tools with such metals.
6. Hence the efforts of man to use the metals in making tools appreciated.
