Simple images of common activities are arrayed for primary learners to evaluate. For each, they determine whether or not the activity will increase one's heart rate. They draw a circle around those that do, a box around those that don't, and a heart around each of their favorites. For fun, teach the class how to count their heartbeats while you time them for one minute. Repeat the count after a sedentary activity and after being in motion. Use this as part of a physical education lesson or one about the cardiovascular system.