This activity allows students to make lye soap from lard and test its properties against a commercial brand bar soap. Science and Technology Standards Abilities of Technological Design Students implement a proposed design, measuring and heating ingredients to make lard soap. Students evaluate completed technological products. They test and compare the behavior of lard soap and commercial soap in hard water.
Students describe results from the product evaluation stage of the technological design process.
They discuss results from their tests. Understandings About Science and Technology, Grades 5-8 Science helps drive technology, as it provides principles for better technique. Physical Science Standards Properties and Changes of Properties in Matter, Grades 5-8 Substances react chemically in characteristic ways with other substances to form new substances with different characteristic properties. When sodium hydroxide reacts with a fatty acid, it produces soaps, which are salts of fatty acids, and glycerol. Transfer of Energy, Grades 5-8 Heat moves in predictable ways, flowing from warmer objects to cooler ones.