This activity involves making different kinds of soaps from lard and from commercially available fatty acids and then comparing their properties.
Students record observations from their tests of the four soaps.
Using evidence from their investigation, students should be asked to compare the four soaps and explain differences between the soaps. For example, students should discuss why oleic acid soap is a gel, potassium oleic soap is a liquid, and stearic acid soap is a solid. Grades 9-12 Students implement a proposed design, measuring and mixing ingredients to make a soap. Students should be asked to describe results from the product evaluation stage of the technological design process. Physical Science Standards Properties and Changes of Properties in Matter, Grades 5-8 A characteristic property of stearic acid soaps is they are less soluble in water than other soaps due to the structure of stearic acid.