This is a working model of the human respiratory system.
The plastic bottle represents the chest cavity.
The two balloons inside are our lungs, and the straws act as the trachea and bronchi.
The balloon at the bottom represents the diaphragm, which plays a key role in breathing.
When we pull the bottom balloon (diaphragm) downward using the syringe or hand, the lungs expand — this shows inhalation.
When we push it back, the lungs deflate — this is exhalation.
Materials Required:
- 1 large plastic bottle (1 or 2-liter)
- 2 balloons (lungs)
- 1 small balloon (diaphragm)
- 2 plastic straws or pen refills (bronchi/trachea)
- 2 syringes (to demonstrate air pressure)
- Rubber band or tape
- Scissors or cutter
- Cardboard box (as base for fixing model)
- Thread or glue
- Color paper (for decoration and labels)
Model Making Video Steps:
Step 1: Make the Lung Cavity
- Take a plastic bottle and cut off its bottom (keep the top intact for inserting straws).
- Insert two straws through the mouth of the bottle and seal it with clay or glue so air doesn’t escape.
Step 2: Attach Balloons as Lungs
- Tie one balloon to the end of each straw inside the bottle — these represent the lungs.
- Pull the balloons inside the bottle so they hang loosely.
Step 3: Make the Diaphragm
- Take a small balloon, cut its neck, and stretch the balloon’s body over the open bottom of the bottle.
- This balloon will act as the diaphragm.
Step 4: Syringe Connection (Optional Motion Mechanism)
- Attach a syringe to the diaphragm part (using tape/thread) to pull/push the diaphragm and simulate breathing.
Step 5: Fix the model on a cardboard box
- Make a cut in the top surface of the box and fix the plastic bottle vertically inside.
- Decorate the box with labels: Trachea, Lungs, Diaphragm, etc.