Lessons Five through Seven focus on the second piece of the project wherein students devise the means by which to measure the energy used up doing activities, and in so doing learn additional target science content about levels of biological organization, the body's organ systems and their integrated function, and cellular respiration. Lesson Five asks the question: Where in our bodies are energy stores used up? Lesson Six asks the question: How do the ingredients for energy get to and into every working cell? And Lesson Seven asks the question: What can we measure, and how would we do so, to measure the energy used up by all working cells? This second piece of the project culminates with students being guided to devise indirect calorimetry. This technique uses a one-way valve to collect a student's expired air while doing a given activity. Using oxygen and volume sensors, the amount of oxygen consumed is calculated (Consolazio, Johnson, & Pecora, 1963), and this measurement indirectly determines the calories used up by all the body's working cells. Lesson Eight completes the project. Students redesign their school lunch and activity choices to balance the measurement of the calories consumed in school lunch choices with the calories used up doing chosen activities, thus promoting better health.