This interactive simulation of human homeostasis provides students the opportunity to explore how our body maintains a stable internal environment in spite of of the outside conditions, within certain limits. This simulation allows students to investigate a phenomenon that may in real life, be dangerous to humans. Students are asked to regulate the internal body temperature of an individual using clothing, exercise, and perspiration. A four- page exploration sheet guides students through the simulation, including a short prior knowledge piece providing information on how to use the simulation and introductory questions. Two separate activities are included: one that helps students understand the how each external factor affects initial body temperature and another that allows students to explore effects on body temperature after one hour. In the second portion of the interactive simulation students try to maintain a stable body temperature when the factors are changed. Students choose the factors of exercise level, sweat level, body position, clothing, and nutrients in terms of both water and food to maintain homeostasis. The simulation generates data tables and graphing during specific time intervals of outside temperature and body temperature. Students may also alter the outside temperature as part of the simulation. Students adjust the exercise level, amount of clothing, and sweating levels. Water level, sugar level, and fatigue level are influenced by the students’ choices and are illustrated by bar graphs and line graphs. This simulation can provide an introduction to a lesson or unit that explores how body systems interact. This simulation provides a good foundation for continued study of how the body systems interact and would be an excellent starting point for a lesson or unit on this concept. This interactive simulation provides students with a strong introduction to how body systems interact as the simulation illustrates how to maintain body temperature, sugar level and fatigue level and students are made aware of the consequences of not maintaining those levels. The importance of water and food are also emphasized. Students can rerun the simulation making different choices to determine the effects on homeostasis. Student exploration sheets provide guides for different runs with students setting their own parameters for the runs and drawing conclusions from the resulting changes. Teachers can view student assessment responses by assigning the simulation to a class created within the ExploreLearning site. Access to the teachers guide is provided with the free 30 day access and is helpful and complete. Vocabulary of dehydration, heat stroke, homeostasis, hypothermia, and involuntary, voluntary and thermoregulation are explained in detail in the accompanying teacher’s vocabulary guide.