Two weeks ago, Soundings XVI performed Lab Experiment Number Two. Lab Experiment Number Two was similar to the previous, Lab Experiment Number One. The prompt was to compare the results of pennies dropped in water, versus the result of pennies being dropped into milk, both at 100 mL. The main purpose of this lab was to further discuss more scientific parts of this lab, such as the surface tension when the cylinder was close to overflowing for both the milk and water. Before performing this lab, my group and I created a hypothesis to reflect upon and to state what we believed would dictate the results.
The hypothesis stated that if we filled the dropped pennies into the graduated cylinder at 100 mL of milk, then the amount would be greater than that of the water. This hypothesis was proven wrong. Instead, this outcome was the opposite; water was able to hold more pennies than the milk by approximately ten pennies. Although, in some trials, such as trial one and two, the milk did hold more pennies instead of water, the overall average disproved my hypothesis. The calculated average for water was 145 pennies and the average for the milk was rounded to 143 pennies. This statement was also disproved by the teachers which also experienced similar results in the past. During the experiment, my group and I had performed three trials for both liquids. The results, for the water trails, were 145, 140, and 150 pennies. The results for the milk was 146, 144, and 140 (both shown in the table above). During the second lab debrief, my group and I had noticed our outcomes for the water was inconsistent compared to another group which had 146, 146, 145, and 145 as their results. Additionally, Mr Mercurio had stated that if there was a range difference of five pennies or more in the lab results, then there was an interference, which my group had, seeing that there was a ten penny difference in our results for the water. Conversely, the results for the milk were more consistent than that of the water. We all came to a conclusion that the interference with the water did not occur when dropping the pennies into milk. Most mistakes from the previous lab were fixed in this lab, proven by the results, compared to the last experiment. Although those problems were fixed, other problems were apparent during this experiment. One of the problems included measuring the meniscus. My group and I measured the 100 mL mark exactly where the meniscus was, however, we were supposed to measure directly under the meniscus to get the right measurement. Another problem was that the pennies did not drop in a similar patterns throughout the trials. Although this problem was unable to be fixed because one could not have possibly stuck their hand in the graduated cylinder to properly place the pennies, my group and I carefully dropped the pennies in the graduated cylinder to try to make them land in similar positions. This problem was uncontrollable and greatly affected the results. For the pennies that consistently dropped in a uniform …show more content…
For this lab there were two debriefs, in these debriefs we, as a class, discussed the topic of surface tension, meniscus, and how they affected our experiment. The meniscus, also stated before, gave the students a measuring problem in the beginning, when filling up the graduated cylinder to 100 mL. In Lab Debrief Part One, we discussed this situation and later found out that the meniscus was a curve of the liquid and could be either convex or concave. An observation in the experiment was when the pennies were displacing both water and milk, which created convex meniscus; this was the effect of surface tension. Surface tension was a large aspect of our experiment because this was what made more pennies fit into the water rather than the milk. Surface tension is defined as the cohesive force between particles which ties them together, and creates an elastic bubble on top of the graduated cylinder. In the end, the water had a stronger amount surface tension, therefore, it was able to hold five to ten more pennies then the