Abstract
This experiment is conducted in order to determine the value of the density of copper. This is achieved by using one of the three pieces of equipment. The three equipment available, from which one is to be selected, are the pipette, the beaker, and the graduated cylinder. The equipment is selected on the basis of accuracy and precision of results from three trials with these apparatuses. The pipette was found to be accurate and precise enough to be used in this experiment. The results are tabulated in the results section according to the apparatus and the second table is for the density of copper. The density of copper was found to be 8.66 g/cc which is within 0.25 g/cc or 2.8% of the already known value. This value was found to be pretty much within the expected range. The difference may have been induced due to one of the errors discussed in the discussion section.
Discussion
The beaker, cylinder and the pipette were the three pieces of equipment used in this experiment. Among them, the pipette was the one with the highest accuracy as it shown closest values to the actual ones. Whereas, the apparatus with the highest precision was the cylinder because of the consistency observed in its values, and the difference was minute. The beaker was the one with the least precision and accuracy because of the fact that it showed irregularity in its values when compared with the cylinder and the pipette. With these observations in mind, the pipette was selected to proceed with the second part of the experiment.
The density of copper was found to be 8.66 g/cc ± ________ /ml based on the average of the three trials. Although it may be observed that 8.66 g/cc of copper is within 0.25 g/cc or 2.8% of the known value, and the known value is well within the range of uncertainty, and is almost equivalent to the known value of copper of 8.91g/cc, the average estimate is just a little bit lower than the known value.
The difference in the value of the density in this experiment might have resulted from the inaccurate dipping of the pipette in the container which contained the metal. For instance, the pipette may be touching the bottom of the container, thereby reducing the suction and hence reducing the volume of the sample.
Rounding the numbers, i.e. approximately rounding off the values, may have been one of the important sources of error, because it alters the value entirely and the error is carried forward into all calculations, thereby decreasing the level of accuracy. Furthermore, the variation in temperature also poses the risk of lowering the density of the metal. Yet another issue might have been the wetness of the apparatus, posing the risk of a minor error. But, it nevertheless poses the risk of inaccuracy and lack of precision.
There is a potential for improvements in the results by increasing the number of trials, and taking mean and repeating the experiment another time to ensure an increased effectiveness of results.
