The mirror is made out of a metal called bronze which is a mixture of copper and tin. You melt the two metals in a pot and mix them together. The scientific name for a mixture of metals is 'alloy'. When you mix two metals together like this, the new metal will have different qualities from the metals that you started off with. Bronze is harder than pure tin or pure copper would be. The mirror was made by beating a lump of bronze until it was as thin as a sheet of cardboard. Then it was polished to make it shiny enough to reflect the light back from your face. Sometimes these mirrors had handles made out of bone or ivory.