# Essay on Formal Laboratory Report

Submitted By bennerb
Words: 497
Pages: 2

This lab was to discover the densities of pennies from before and after 1982. Before 1982, pennies were made out of one hundred percent copper. After 1982, they were only coated in copper. Finding the densities of the pennies and comparing them to each other helps us to identify the metal used in the core of the pennies that were minted after 1983. My personal hypothesis was that the core of the pennies is zinc. To complete this experiment, the materials needed included twenty-five pre-82 pennies, twenty-five post-1982 pennies, a one hundred milliliter graduated cylinder, a balance, paper towel, and graph paper. The control variable is using the same scale to measure the mass of the pennies so that they aren’t measured differently. The independent variable would be the different pennies from different years. The dependent variable would be the different densities depending on each penny.
The first step in this procedure was to pick one set of pennies; either pre-1982 or post-1982 pennies, then record the mass of five pennies at a time from the balance. My partner, Luke and I were to keep adding five pennies at a time and measure them until all twenty-five were used. For the next step, we filled a one hundred milliliter graduated cylinder to the twenty milliliter mark with water. Using the same set of pennies, Luke and I dropped five pennies in the cylinder at a time and recorded what the level of water rose to each time after we dropped the pennies in. Then, we subtracted the original amount of water that was in the cylinder (twenty milliliters) from the level that the water rose to and recorded the answer as the volume in the tables that Miss Stilson gave us. We repeated this step until all twenty five pennies were in the cylinder. Next, we emptied the cylinder and dried off all of the pennies and put them back in