light and this is done by the use of a UV-visible spectrometer. Therefore another objective is to learn how to use a UV-visible spectrometer, learn how visible and UV absorbance of a compound is solution is related to concentration (Beer-Lambert law). Beer-Lambert law states that the amount of light energy absorbed at a particular wavelength by a compound or solution is proportional to its concentration in that solution. Also, learn about oxidation of less active metals and complex ion formation. The hypothesis for this experiment is that the amount of copper in a penny is no more than 2.5% by mass if it was produced after 1982. This is because due to the increasing price of copper, Congress made a mandate limiting the amount of copper used. This was done 1982; prior to that the penny contained about 95% copper. The pennies used in this experiment we dated, 1995, 1997 and 2011 andtherefore were all subject to the mandate which means they should all consist 2.5% copper by mass and mostly zinc.