The Metal of Coins
The story of the Pine Tree Shillings stimulates us to read more about the metals that coins were made of in that era. Silver was common because it was moldable and had value. Over the centuries many metals have been used for coins from precious gold and silver to less valuable metals like copper, bronze, nickel, iron, and even aluminum.
How do we know what metal is in our coin? In this exploration we will construct a simple scale to show the difference in weight between old pennies and new pennies. Even though this is a simple scale made of everyday materials, it can tell tiny differences between coins.
Materials Required
• A hand full of pennies with mixed dates,
• Two straws
• One round toothpick
• A cardboard piece
• Two scraps of packing foam or blocks of wood
• Two caps from plastic water or soda bottles
• A piece of aluminum foil
• A glue gun or glue
Procedure: Making the Balance
1. Mark the center of a straw and poke a toothpick through the center.
2. Glue two blocks of either foam, wood or some other spacer to a cardboard base so that it looks like the picture above. When complete, glue two segments of straws to the foam or wood block so the toothpick can rest on top.
3. Glue a bottle cap to each end of the long straw.
4. You now have a "balance," but it may still be too heavy on one side or another so you will need to add weight to the side that is higher than the other side. Add a piece of aluminum can or aluminum foil that you have folded to add weight to that arm. Slide the weight back and forth until your balance is "balanced." You will know it is balanced if you push it down on one side it stays and if you push the other side down it stays.
Your balance is now ready for operation!