Stearic acid, one of the fatty acids produced by Henkel Corporation, Emery Division, is an important component of dripless candles. In this activity, students make candles with and without stearic acid and observe differences in the way they burn. Science as Inquiry Standards Abilities Necessary to Do Scientific Inquiry Students are challenged to determine the reason stearic acid sometimes is added to paraffin to make candles. Students conduct an investigation. Abilities of Technological Design Students identify appropriate problems for technological design.
Students implement a proposed design and make two types of candles.
Students evaluate completed technological products when they compare two types of candles for physical characteristics, amount of smoke, and amount of dripping. A characteristic property of paraffin is a softening point which is below its melting point, resulting in its tendency to drip when burned. A characteristic property of stearic acid-containing candles is that they soften at a higher temperature than candles without stearic acid. Substances react chemically in characteristic ways to form new substances with different characteristic properties. Paraffin and oxygen react to produce light energy in addition to the chemical products of combustion.