National Standards for Grades 5-8
 
Students develop and write their own dichotomous keys! Introduce the discretionary aspects of scientific organization while teaching a systematic approach to classification. Students actively observe and identify the chemical properties of six white powders that look alike by reacting them with iodine, vinegar, and water. They use the data to recognize similarites and differences that enable them to complete a classification chart from which they generate pairs of opposing statements to be used in creating dichotomous keys.