======Bell Jar Breathing Model======


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====Summary====                   
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====Procedure====  
  - Place two balloons inside a bell jar and connect them to a Y-tube, which passes through a bung at the top of the jar.  
  - Stretch a rubber sheet over the open bottom of the bell jar to act as the diaphragm.  
  - Pull the rubber sheet downward to demonstrate inhalation: the increased volume lowers air pressure inside the jar, causing air to enter the balloons and inflate them.  
  - Push the rubber sheet upward to demonstrate exhalation: the decreased volume raises air pressure inside the jar, forcing air out of the balloons so they deflate.


====Links==== 
Bell Jar Lung Model Video - Dr Dan's Anatomosphere: 
{{youtube>5rbl6PwjyXk?}}\\
Bell jar model of the human breathing system - Sean Clifford: 
{{youtube>NYT0qlKwHuI?}}\\
📄 Modelling the Mechanism of Breathing - Beyond Science: [[https://europeanlung.org/wp-content/uploads/2023/12/Modelling-the-Mechanism-of-Breathing-Teacher-Demonstration-Guide.pdf]]\\


====Variations====
  * Add labels or color-coding for trachea, bronchi, lungs, diaphragm, and thoracic cavity to reinforce anatomical connections.  
  * Modify the model by adding a moveable “ribcage” structure to show the role of intercostal muscles in breathing.


====Safety Precautions====
  * Handle glass jars carefully to avoid breakage.  
  * If using sharp tools to cut or modify equipment, supervise closely.  
  * Ensure the rubber sheet is stretched securely to avoid snapping.  
  * Do not inhale directly from balloons or tubing used in the demonstration.



====Questions to Consider====
  * What causes air to move into the lungs during inhalation?  
  * How does the diaphragm contribute to changes in air pressure inside the chest?  
  * Why do the balloons deflate when the rubber sheet is pushed upward?  
  * What limitations does this model have in representing real breathing?  
  * How would this process change if the diaphragm or intercostal muscles could not function properly?