Soap
We seem to go through a lot of soap in the shower. It seems crazy that a bar of soap doesn't even last a week.
Recently I thought I would get the to bottom of this. While I didn't get to to the bottom, I did end up slightly below the surface; the rest of the family wasn't really on board.
The Idea: Determine how much soap I use in one shower.
The Plan: Weight the soap before and after. I thought that dry vs wet might be trouble, so I got the soap wet before the initial weighings.
The Results: I weighed my soap for 6 days. Folks started to get annoyed that the scale wasn't in its normal spot, so I ended up stopping my collection. Come on family, it's for science.
| day | Before(g) | After(g) | Used(g) |
|---|---|---|---|
| 1 | 107.2 | 105 | 2.2 |
| 2 | 59.6 | 55.4 | 4.2 |
| 3 | 33.6 | 29.9 | 3.7 |
| 4 | 14.8 | 11.6 | 3.2 |
| 5 | 10.7 | 8.9 | 1.8 |
| 6 | 55.1 | 52.7 | 2.3 |
A new bar is ~112g. The average use above is ~3g. That gives us ~37 uses per bar; if we assume we can use up the whole thing, and that everyone uses the same amount as me. (Squishing an old soap onto a new bar is a post for another day.) I think the first assumption is reasonable, the second, probably less so.
As noted above, the family wasn't completely committed to this undertaking. Prioritizing family harmony over robust data collection, the experimennt ended. I've since learned to live with our current rate of soap consumption.