The CPI takes a constant basket of goods and sees how the price changes from year to year. If the price of the basket of goods increases, then there is price inflation. If the price of the basket of goods decreases, then there is deflation.
Copper and tin mainly make up bronze but other elements include phosphorus, manganese, silicon and aluminium.
Bronze is a dark metal made from an alloy of copper and tin. Bronze was one of the earliest and most useful metals discovered by mankind. It was harder than copper, stone or wood and could be made into weapons, containers and tools. Bronze is still widely used today to make statues, door handles and jewelry.