This exhibit explores heartbeats and how hard the heart muscle works by asking the visitor to use voluntary muscles to do what the specialized, autonomic muscle cells of the heart do seemingly effortlessly. Three plastinated hearts—a human’s, a cow’s and a small dog’s—are dramatically displayed in vitrines. Each heart has a corresponding industrial-grade squeeze ball actuator on a stand in front of it. Below each vitrine are two LED lights. One light corresponds to the speed of the heartbeat of that animal (cow=50/minute, human=70, dog=100). When a visitor squeezes the actuator, the other LED light begins to pulse in time with the visitor’s rate of squeezing. The visitor would be challenged to squeeze the actuator at the same rate as the other, steadily flashing LED next to it.