This simple model can be used to demonstrate the basic principles of
breathing. The model should be assembled as in the diagram. A swimming cap makes a suitable
diaphragm. The cap can be attached to the bottom of the bell jar, and the
balloons can be attached to the Y shaped tube, with
elastic bands[?] or plastic coated wire.
The cavity inside the bell jar is airtight. As the diaphragm is pulled down, the
volume of the cavity increases. This causes the
pressure to fall.
Air rushes in to equalise the pressure causing the balloons to inflate.
See Also
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