To explore the respiratory system (a bit further, as we really were talking about it all along with the circulatory system), we first diagrammed the organs involved.  Then, the students did a little experiment to measure their vital lung capacity (how much air can be forcibly taken in and blown out) and the tidal lung capacity (how much is taken in and out during normal breathing).  The kids has SO much fun with this one!  They really were surprised at how much air they *couldn&#x27;t* blow.  I…