Make a lung model science experiment : Fizzics Education


Make a lung model

Make a lung model

Follow FizzicsEd 150 Science Experiments:

You will need:

  • A clean dry plastic bottle (around 600mL works well but other sizes are OK too)
  • Two balloons
  • A straw
  • Scissors
  • Sticky tape, masking tape or electrical tape
  • A rubber band
  • Blu-tack, modelling clay, plasticine or firm playdough


Sticky tape, a black straw, scissors, plastic bottle, blu tak and two red balloons

Carefully cut the bottom off the plastic bottle and cut the top (the rounded part) off one of the balloons.

2 Wrapping sticky tape around the end of a plastic bottle that has a balloon diaphragm attached

Stretch the cut part of the balloon over the bottom of the bottle so it forms a thin skin like the surface of a drum, with the neck of the balloon hanging free. Secure with tape. This balloon represents the diaphragm.

3 A black straw inserted into a balloon and a rubber band securing it in place

Put the straw inside the other balloon and attach them using the rubber band. Be careful to make it tight enough that it won’t slip off but not too tight to crush the straw (you need air to flow through).

4 Straw and balloon placed inside the plastic bottle that has a balloon diaphragm attached at the bottom

Put the balloon inside the bottle. It should be hanging free and not touching the other balloon. This hanging balloon represents the lung.

5 Blu Tak being used to seal the opening of a plastic bottle with a straw poking out

Hold the straw in place using the blu-tack (or other modelling material) to create a lid. Ensure the entire neck of the bottle is covered to make an air-tight seal.

6 Finished lung model made with a plastic bottle, balloons and a straw

Your lung model is ready to use!


Carefully pull the balloon at the base of the bottle up and down and watch as the other balloon inflates. This represents the action of the diaphragm and the inflation of the lungs.

8 Human body torso build

Why Does This Happen?

When you breathe in, your diaphragm – the muscle at the base of your lungs, contracts. This expands your chest cavity, lowering the air pressure of the cavity below the air pressure outside, and inflating the lungs.

You can see this same principle at work in this ‘homemade lung’. When you pull on the diaphragm balloon, it lowers the air pressure in the bottle. This pulls in air from outside the bottle, allowing the balloon at the top – the lung – to inflate.

Video of this experiment during a Facebook Live presentation

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Learn more!

Teaching about the human body? From 5 senses to the skeletal system, the Human Body workshop has you covered!
Get in touch with FizzicsEd to find out how we can work with your class.


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