🫁 Lung Model Experiment

How Do Your Lungs Help You Breathe?

Your lungs help you take in oxygen and release carbon dioxide every time you breathe. In this experiment, you will build a simple model that shows how your lungs expand and contract.

Materials

• 1 clear plastic bottle

• 2 balloons

• 1 straw

• Tape or rubber bands

• Scissors (adult help recommended)

Experiment Steps

1. Prepare the bottleCut the bottom off the plastic bottle with adult help.

2. Attach the balloon insideStretch one balloon over one end of the straw and secure it tightly with tape or a rubber band.

3. Place it in the bottlePut the straw with the balloon attached into the bottle so the balloon hangs inside.

4. Seal the topSeal the top opening around the straw so air cannot easily escape.

5. Create the diaphragmStretch the second balloon across the cut bottom of the bottle.

6. Test your lung modelPull the bottom balloon downward and watch the balloon inside the bottle inflate. Push it upward and the balloon inside will shrink.

🔬 The Science Behind the Experiment

In your body, the lungs sit inside your chest cavity. A large muscle called the diaphragm sits underneath them.

When you breathe in, the diaphragm moves downward. This increases the space inside your chest and lowers the air pressure, causing air to flow into your lungs and making them expand.

When you breathe out, the diaphragm moves upward, decreasing the space in the chest cavity. This pushes air out of the lungs.

In the model, the balloon inside the bottle represents the lung, while the balloon stretched across the bottom represents the diaphragm. When you pull the bottom balloon downward, the space inside the bottle increases, just like when the diaphragm moves down in your body, allowing the “lung” balloon to fill with air.