I investigated the differences in substances left behind on the white keys versus the black keys of a piano! Piano keys collect dirt over time, making it desirable to clean them regularly. It is clearer to see when the white keys get dirty than when the black keys get dirty. Thus, if the foldscope images showed the black keys dirtier than the white keys, this would help to inform piano players that they must clean the black keys more thoroughly than expected! I hypothesize that black keys will be dirtier than white keys, as white keys are used more often in beginner piano pieces, and the regular use may clean off the dust that naturally lands on the keys over time.
I took 3 samples from black keys and 3 samples from white keys, and have displayed them next to each other for comparison. From a visual comparison, it seems like there are no clear differences in the quantity of dirt present on the white keys and the black keys. This result contradicts my hypothesis, and suggests that piano players can clean the different keys with similar rigor and achieve good results!
There are several limitations in this investigation. First, there are many more black keys and white keys than the number sampled in this study. Further, I sampled small segments around the middle of each key, but each sampled segment may not be representative of the full keys. Thus, the results are not conclusive regarding the level of dirtiness of white keys and black keys, and can be further studied to support piano players!