Lab Report - the Type of Metal a Coin Is Made

Rose Rogers

Period 6

9/12/15

Lab Report

Objectives and Introduction:

The objectives of this lab was to find out the type of metal a coin is made out of by calculating its density and comparing the precision of a triple-beam and a digital electronic balance. The independent variables were the type of coin (pre-1982 and post-1982). The dependent variables were the densities of the two coins. Lastly, the control variables were the amount of pennies and the type of balance scales.

Procedure:

First, we had to calibrate the triple beam balance and use it to weigh all ten of the pre-1982 pennies and all ten of the post-1982 pennies separately. Next, we weighed all ten of the pre-1982 pennies and ten of the post-1982 pennies on the digital scale and recorded the mass. Then, we filled a graduated cylinder with 50 ± 0.1 mL of water and recorded the volume. We repeated this step for both the pre-1982 and post-1982 pennies with the same amount of water. We then calculated the density by dividing the mass by the volume from both the triple beam balance and the digital balance for the pre-1982 pennies and post-1982 pennies. Lastly, we calculated the percentage error by using the formula: experimental value - expected value/expected value X 100.

Pre-1982 Percentage Error- 10.2-8.8/8.8*100 = 15.9%

Post 1982 Percentage Error- 6.3-7.2/7.2*100= -12.5%

Conclusion and Evaluation:

The density of the pre-1982 pennies were 10.2 g/mL. The density of the post-1982 pennies were 6.3g/mL. The pre-1982