Topics: Mechanics - Air Pressure; Biology - Respiration
Equipment: Glass jar with balloons (lungs) and rubber sheet (diaphragm) affixed to the bottom.
Setup: Pull and push on the diaphragm, and watch the lungs inflate and deflate (inhale and exhale)
When the diaphragm is pushed upwards, the air inside the jar starts to compress, and the pressure is strong enough to squeeze the soft balloons, forcing out any air that is inside them. When the diaphragm is pulled back down, the air inside (still having nowhere else to go) fills the now expanding volume, pulling the balloons open. Similarly, as the balloons open, air is pulled into them (to fill the expanding volume inside the balloons). The key takeaway for this demo is understanding that the contractions of the diaphragm make breathing possible; the lungs do not expand and contract on their own.
Location: Shelf A-B7
Notes: There are spare balloons in B22.
Keywords: Lung, Air, Pressure, Respiration