Density of soap

On Monday I did a course introduction and then passed out a mathematics and graphing skills pre-assessment exercise. Wednesday I went over the pre-assessment in the first half of the class. In the second half I opted to do an introduction to density as was first done summer 2012. This has worked better than tackling the metric system, direct and calculated measurements, and the other material in chapter one. The text still needs to be edited to handle this option.

The Wednesday lecture demonstration starts with cubes of lead, aluminum, and wood. The density of water is also calculated and the connection between density and floating is presented. I wrapped up with the three identical vials of green fluid, two float, one sinks. This well prepares the students for the laboratory on Thursday and puts density at the center of the focus for the week.

Thursday the students explored the density of soap.


Roselino and Maria-Asunsion mass Lux soap


Bireen carves Safeguard.


Carving a bar of Safeguard soap.


Jesse Mihkel carves a bar of Lux Wake Me Up Soap. This soap defied my best attempts to calculate an accurate density. The soap sank, but I could not obtain a calculation where the mass exceeded the volume.



Entry of data was foiled by the disappearance of Excel.


The joys of Microsoft: these are new Win 7 machines that shipped with Office. The red bar is an activation notification. I am constantly reminded of why I favor Libreoffice.org and Gnumeric.


Board shot from Thursday laboratory.
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