First post on this forum so hoping it is in the right place. In class today we did an experiment where our teach took two paper cups, and placed X amount of pennies in one before stacking the other cup inside of it. We had 10 of these cup/penny contraptions each and a scale. The purpose of this experiment was to determine how much a penny weighted. What I did was first massed them all. I then though that if I subtract the smallest mass from all the larger ones I know the difference MUST be from an increase in amount of pennies. From this though I am not quite sure where to go, should I assume the smallest increase between two different masses is the mass of a penny? My teacher compared it Millikan's Oil Drop experiment not really sure what he did to calculate the charge on an electron and how it can be applied though.