The Importance of Combining Copper and Tin

When metals are made out of just one element like copper, for example, it's quite easy for those atoms to move past one another. When you add a different element into there like tin, what's happening at the atomic scale is that atoms of copper are being replaced by atoms of tin. And when you do that inside the atomic structure, it means that those atoms can't move as easily because these atoms have different sizes. So bronze was a material that was harder and stronger and stiffer than anything that come before. It made it much better for making weapons and you could make sharp knives that wouldn't blunt because it was an alloy, not an element.