Why is a copper nickel alloy used in silver coins?

Tell Me Why Questions for preschoolers | Tell Me Why science questions | Tell Me Why science questions and answers | Tell Me Why answers to hundreds of question | Tell Me Why Questions and Answers | Tell Me Why Questions | Questions on Tell Me Why

Do You Know the answer of the above Question? Tell Me Why Questions.Blogspot.Com will give you the answer of the same Question. Read and Understand them and Improve your Knowledge... 
Silver has fascinated man for many thousands of years. Ancient civilizations found silver deposits plentiful on or near the Earth's surface, and so, coins in those times were made of silver. However, silver gradually became more and more expensive, as the demand for it increased. Finally, it was found that the amount of silver needed to make a coin cost more than the value of the coin itself! So coins began to be made of a copper-silver alloy. This alloy looks like silver but is much cheaper than pure silver.
Today, if a silver coin was actually made of pure silver the metal would cost more than 20 times the value of the coin. However coins of pure silver are still available, but they cost their true worth, and people buy them as an investment. You can also buy silver bars as an investment too.