This module, one of 25 on vocational education training for careers in environmental health occupations, contains self-instructional materials on obtaining heat stress measurements. Following guidelines for students and instructors and an introduction that explains what the student will learn are three lessons: (1) naming and describing the functions of the sections or parts of the dry bulb, wet bulb, and globe thermometers; and assembling and using the wet bulb and globe thermometers; (2) assembling a wet bulb globe temperature apparatus; and (3) determining the wet bulb globe temperature using a Botsball thermometer. Each lesson contains objectives, recommended methods and locations for practice, performance criteria, equipment and supplies to perform a task, detailed step-by-step instructions for learning a task, and performance exercises. Three performance tests cover using dry bulb, wet bulb, and globe thermometers; assembling and using the wet bulb globe temperature apparatus; and using a Botsball heat stress indicator. (CT)