Gas exchange and breathing

The results come from a teaching model of typical results, not from your own breath. Real numbers differ from person to person, and from breath to breath.

The valves make every breath in pass through tube A and every breath out through tube B, so both tubes get about the same volume of air. How soon real limewater turns cloudy also depends on how much is used and how deeply you breathe.

The alveolus, the bell jar and the chain are models, not to scale. Time runs faster than real time: 3 minutes of step-ups and each 30-second record pass in a few seconds. Between steps the model waits while you read.

With reduced motion each step is drawn complete at once.