Penny Lab report

            
            
             The nature of this experiment was to see what year the U. Mint changed the composition of the pennies. In this lab we may use anything to determine when it happened. We are not allowed to damage the pennies in anyway. For our hypothesis we didn't have one because we had no prior education on the composition of pennies. .
             II. Materials and Methods.
             Materials:.
             1) One set of 10 pennies ranging from the year 1970's to the late 1980's.
             2) An Graduated cylinder.
             3) An electronic balance .
             4) Assorted beakers and Erlenmeyer flasks.
             5) Assorted test tubes.
             6) Pipettes.
             Methods:.
             We gathered our materials and began our experiment. We carefully dumped the 10 pennies out onto the lab table and put them in chronological order. First we used the electronic balance to find the mass of the pennies. Secondly we used a graduated cylinder, which we filled with 50 milliliters of water. We then proceeded to drop one penny at a time into the graduated cylinder to see the volume of each individual penny. We would then have to pour the water out into a small beaker and dump the penny out refill the graduated cylinder and add any lost amount of water back into it. This continued until all 10 of the pennies had been analyzed for their volume. .
             III. Results.
             See graphs!!.
             IV. Discussion.
             The year that the pennies changed was in 1983, according to our experiment. After our experiment I got on the Internet and did some researching, and I found out that the actual penny changed in 1982. It was made gradually over that year so I think that our 1982-penny was made before the change. The year before the penny changed the average mass was 3.1 grams. During 1982 the penny fluctuated between 3.0 to 2.5 grams. It stayed steady at 3.1 until 1983 where all the pennies began being made to the average mass 2.5. The average density of a penny before the change was 10.3, it fluctuated in 1982 between 10.3 grams/milliliters and 25 grams/milliliters.