Title: How Honest is Abe? 

Purpose: To find out the unknown metal and it’s density in pennies manufactured after 1982.

Procedure: For this lab, we conducted two experiments. The first was to conduct a density test on pennies and copper. To do this, we took a 100ml, graduated cylinder and filled it to 20 or 30ml with distilled water. Next, we placed a weighed amount of copper into the graduated cylinder and read the water level, making sure to read the meniscus correctly. Then, we took the reading of water and copper and subtracted it from the initial reading when the graduated cylinder was empty. This gave us the volume of the metal. To calculate the density of the copper, we took the amount of copper that was dumped in the water divided by the volume. Ex. 11.65g/1.5ml=7.84 g/cm³. We then calculated the percent error of the real density of copper and that of the density we came up with. The same experiment was conducted using pennies instead of copper. We found that the pennies had a much higher percent error than the copper did. The question "How Honest is Abe" now arises.

The second experiment that was conducted was to find out what is inside a penny other than copper. To do this, we held pennies over a Bunsen burner using a tongs. The pennies would melt and a drop of metal would form inside the copper lining of the penny. When that bubble would form, we would take the penny and shake it over a small square piece of particleboard. The unknown metal would then fall out from inside the penny. We would collect this metal and save it in a beaker for later use.

That was only half of the experiment. Then next phase was to figure out the density of this unknown metal. To do this, we used a burette instead of a graduated cylinder for you can read the meniscus to the nearest hundredth of a milliliter rather than the nearest tenth. There was one problem however. The pieces of unknown metal were far too large to stick in the burette. We had to somehow manipulate their shape to get the to fit in the small opening at the top of the burette. To accomplish this task, a pliers was used to bend the unknown metal in half once or twice to create a small, compact piece. We also melted some unknown metal in a test tube over a Bunsen burner. When the metal started to melt and boil, we tilted the test tube and allowed the unknown metal to slide down the inside of the test tube. It cools rather quickly, so we ended up with a long thin strip. The strip was perfect size to fit in the top of the burette. To figure out the unknown metal’s density, we weighed out a certain amounts of crushed, melted and reformed pieces on the electronic scale. Then we added the pieces to the burette, which was filled with distilled water to a certain point. Usually we used 30ml. The density was found by using the procedure listed above.

Now came the tough part in finding out which metal this really is. Thank God for the Internet. The United States Mint homepage provided a helpful hint as to what exactly what the penny is made of.

Data:

*These are only 4 of the 9 trials that we did. We took these numbers and manipulated the density to get a very very low percent error. It turns out we arrived at .7% error. We couldn’t get any closer without fudging out data to the point of cheating.

Observations: We found that pennies before 1982 contain close to 100% copper. We know this because when they are heated under a flame, the pennies would not melt and turn red hot. They make great tattoo burners. We also perfected the method on how to drip the unknown metal from the inside of the penny onto the particleboard. It takes practice and the right flick of the wrist, combined with the knowledge and understanding on when to remove the penny from the flame. Other observations were: that the unknown metal is very hot, but cools very quickly, splatters great distances when dropped from high altitudes or with great force, and burns the flame proof counter tops.

Conclusion: Since the main objective was to find out "How Honest is Abe", the answer has to be: because of budget cuts, high national debt rates, cheap bureaucratic senators and cheating presidents, Abe ain’t so honest anymore. However before all of the budget cuts, high national debt rates, cheap bureaucratic senators and cheating presidents, Abe was quite honest. We ascertain that the unknown metal inside the penny is zinc (at least that is what the United States Mint web page says). It has a density of 7.14 g/cm³. We arrived at a density of 7.19 g/cm³, which means we had .7% error. I hope that that is good enough. Even though we manipulated our answer, it is still pretty darn close to the actual thing. This lab is very easy to get a good grade on based on your lab results and trials; however, it’s the lab report that separates the overachievers from the slackers and whiners (Taylor). The main point is not how good a grade you earn, but how much you learn doing the lab and writing it, but we got an A+ no matter what.