Density of soap laboratory

Only after 19 years of laboratory one density of soap have I realized that the soap carving works best with fresh soap. I had already discovered that soap hardens with age, but I hadn't connected the dots that this leads to errors as old soap crumbles and shatters during the cutting process. Soap will have to be purchased each and every term with the amount appropriate to enrollment.

This term the students worked primarily with newly acquired soaps. Ivory no longer floats, that last floating Ivory was produced in 2023. Errors in volume measurements almost always lead to densities of more than one. Even for floating soap. With essentially all soaps being sinking soaps, students rarely encounter contradictory results. The students predict the soap will sink, and the soap sinks.

With only a single laboratory section, I could continue with the soap from yesterday.


A longer six data point table was generated during the demonstration phase.
The data was recorded to the white board and then on the Smartboard.

The Lux aqua sparkle was challenge to carve into a rectangular slab - Lux is a small and curvy bar. All surfaces are either convex or concave.

Despite carving challenges, the density was a reasonable value that correctly predicted the Lux would sink. Which the Lux did when placed in water. 


Soaps in use. Student pairs chose their soap. Not seen: the strange Kojie San gel soap which had the consistency of a soft clay.

Mor-Jacinta records data while McGievens cuts and measures the soap.

Measuring the soap



Jaysleen and DeAnne working on measuring the volume of their soap. 

Kyke awaiting results of a calculation

Tikikos records data while Emensio measures

Unica records while Darla makes measurements 

The only future recommendation is to work with fresh soap each term. The sequence of an initial measurement on Wednesday was a good foreshadowing of this laboratory.

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