Summary of Delta Mass Experiments:

In each of the experiments we did involving a question that began with the words: "Does mass change when. . .?", we found that mass did not change. In each experiment (ice & water, dissolving salt, and copper & sulfur) some type of a change took place. We made sure that the change took place within a closed container. This was important because we were trying to find out if the change in matter caused the difference in mass--we wanted to make sure that evaporation and spillage were not the reason for any measured change in mass.

Because we are not perfect, and our balances are not perfect, and mistakes are inevitable, we tried to collect as much data as possible so that we could minimize the effects of those imperfections on our results. Even though some groups' measurements would indicate that mass either increased or decreased, there were many more groups that found that there was no change in mass. We used histograms to help find the pattern in the data--and in every experiment the vast majority of data "stacked up" around the zero on the x-axis, indicating that the mass did not change.

In all of this, remember that our EABs are only reliable to (approximately) +/- 0.05 grams. Any time our measurements changed within that range we still considered that test to show "no change in mass".

Experiments like these 3 helped scientists establish a very important law of nature--the "Law of Conservation of Mass". This law states: In all changes, mass is exactly conserved. Please know this law for the next quiz and be able to offer some experimental evidence that supports it.

If you have any questions about this summary, please ask before the next quiz (which will be late next week).