Exhibit: Beat your Heart
Squeeze the ‘heart’ in time with the flashing light. The muscles in your hand will start to get tired after a while, but your heart muscle pumps throughout your lifetime without ever getting tired.
When you squeeze the bulb, you pump ‘blood’ just like your heart does when it contracts. The bulb has valves, just like your heart, to make sure the blood is pumped the right way around your body. The heartbeat sound is made by the valves of your heart as they open and close at the start and finish of each squeeze. Your heart is made of cardiac muscle which never tires. The muscles in your hand are different and they tire very quickly – you wouldn’t be able to pump all your blood around your body with your hand for very long!