1. Broadcasting and Development in Zambia
The objective is to convert a regular penny into a gold penny using alchemy.
Alchemy is the medieval forerunner of chemistry, based on the supposed transformation of matter. For example, alchemists convinced people that they could turn cheap metals into gold by doing certain chemical reactions. However, the people would soon realize that these methods did not work. This lab will show how mixing certain metals to create an alloy, will make a penny appear gold.
Materials.
- Penny.
- Burner.
- Tongs.
- Evaporating dish.
- Pipette.
- Zinc.
- NaOH.
- Water.
- Beaker.
Procedure.
Before the lab, all pennies were cleaned by the teacher. Enough zinc was put in an evaporating dish to cover the bottom. Three pipettes of NaOH were added to the dish and stirred with a popsicle stick. The burner was lighted with a match and the evaporating dish with the NaOH and the zinc was placed on the stand over the burner. A penny was submerged into the NaOH and covered in zinc.
The penny was left in the mixture for ten minutes so that it would appear silver. However, because the dish was not close enough to the burner it took about five minutes longer to plate. Once plated with zinc, the penny was removed using tongs and placed in a beaker of water to clean. The penny was removed and dried with a paper towel. Using the tongs, each side of the penny was placed in the flame of the burner for several seconds and then the penny was put back in the water.
The above procedure was repeated with a second penny. However, the stand was moved closer to the burner so that the plating process occurred in ten minutes.
Results.
The surface of the penny that was in contact with the zinc filings changed from light brown in color to silver in color. This "silver " penny turned from silver colored to gold colored while it was in the burner flame.
Conclusion.
The purpose of this lab experiment was to explore the use of physical and chemical changes to imitate alchemists and turn a penny from copper to "silver " to "gold ".