A diagram of how respiration works. A balloon is attached to the end of a small oil lamp chimney. The container is sealed tight with a sealing wax. As the chimney fills with air, the balloon expands, showing a representation of what a lung looks like while it is expanded. As expected, air leaves the balloon when the chimney is not covered, forcing air to leave the "lung". The piece on the right helps to control the air pressure within the container.