Abstract
Abstract The purpose of this study was to develop a formaldehyde test practicum instructions using natural indicators for the first high school students. This research method refers to the development procedure developed by Borg and Galls. The trial of 104 leaf and flower crown samples which were estimated to have potential as a natural indicator for formalin testing was carried out. Only 3 natural indicators can be used for drops and filter paper, namely flower: ribosa ruellia, hibiscus rosa-sinensis L and balsamina Impatiens L purpel. Based on the results of the expert assessment and the teacher showed that the practicum instructions were suitable for use by junior high school students to test formalin.