💨 Make a Lung
Build a working lung model from a plastic bottle and balloons — push and pull to see exactly how your diaphragm powers breathing!
🧰 What you need
Safety note: Ask an adult to cut the bottle — the cut edge is sharp.
🔬 Steps
- 1
Ask an adult to cut the bottom off the plastic bottle — about 5 cm from the base.
- 2
Tie one small balloon to the end of the drinking straw. Push the straw up through the bottle neck so the balloon hangs inside.
- 3
Seal the bottle neck around the straw with modelling clay — it must be airtight.
💡 Squeeze the clay firmly around the straw — any air leak will stop the model from working. - 4
Cut the neck off the second balloon and stretch it over the open bottom of the bottle like a drum skin. This is the diaphragm.
- 5
Pull the diaphragm balloon DOWN — watch the lung balloon inside INFLATE!
💡 This is exactly what your real diaphragm muscle does — it pulls down to create a vacuum that draws air into your lungs. - 6
Push the diaphragm UP — watch the lung balloon DEFLATE!
🧠 The Science
Your lungs cannot inflate themselves — they are pulled open by your diaphragm. When your diaphragm (the dome-shaped muscle below your lungs) contracts and flattens, it increases the volume of your chest cavity. More volume = lower air pressure inside. Higher pressure outside = air rushes in through your windpipe — that's inhaling! When the diaphragm relaxes and domes upward, the volume decreases, pressure increases, and air is pushed out — that's exhaling. The balloon model mimics this perfectly!
📚 Related Lessons
- 🏃 Staying Healthy — Eat well, drink water, exercise, and sleep — four golden habits for a healthy body!
- 💨 Air We Breathe — Air is all around us — we breathe in oxygen and breathe out carbon dioxide, and plants keep our air fresh!