When students sit up, their chest cavity will be more open and allow them to take in even more air. To demonstrate this, hold up an empty disposable 12oz plastic water bottle, which represents their lungs. Squeeze the water bottle with your hand to resemble our lungs when we are sitting with poor posture. With the bottle still squeezed, go to the water fountain and fill it up until water starts to overflow. Hold up the bottle to show the students that the bottle is full, then release your squeeze on the bottle and let it expand to full size. This illustrates how our lungs work when we are sitting up with the correct posture. The students will notice that the water level lowers, and we are then able to put more water in the bottle.
Justin Davidson, Riley County High School, Riley, KS
