The Metal of Coins 2

The history of coin manufacture and use is interesting. The US Mint has a fabulous website with a great deal of information about coins at: https://www.usmint.gov/learn/history. One important aspect of making coins is the metal that is used.  Precious metals like silver and gold were commonly used decades ago, but now, governments need to use other metals so that the value of the metal in the coin is not greater that the value of the coin!

In this exploration we will construct a scale to learn more about how to measure small weights and then compare coins to see about their face value and their metal value.

Material Required

• A small jar, pill bottle or can

• A stiff piece of plastic from a juice or soda container

• A water or soda bottle cap

• A piece of graph paper

• Glue or glue gun

• Marker pen

• Coins

Procedure to make the scale

1. Using a small pill bottle or jar, fill it with pebbles, gravel or stones.

2. To the lid of the jar glue a strip of plastic as shown in the picture below. The strip of plastic used in this example was about 5 inches long.

3. Cut the end of the plastic strip to a point and color the tip with a marking pen so it stands out. Glue a bottle cap as show in the picture below.

4. Create a graph paper scale so that when the pointer moves up and down, it will point to a line on the graph.  Add a line and numbers on the graph so you can report where the tip of the plastic points. See the picture below. Support the graph paper by gluing it to a cardboard and block of wood or invent a way that the graph paper will stand up vertically by itself.

Now your scale is ready for use.  Let's see how we can use it.

Using the Spring Balance