DIY Model of Human Lungs

DIY Model of Human Lungs

Have you ever wondered how our lungs work? You can make a DIY model of your lungs at home and see for yourself!

Material Required:

A small plastic bottle, a drinking straw, 3 balloons, some air drying clay, cello tape


1. Take the bottle and cut its base. Make a small hole in the bottle cap.
2. Take the straw and cut it into three pieces, join the three pieces in the form of the capital letter ‘Y’. This should form a Y-shaped tube.
3. Take two balloons and secure them tightly at the arms of the Y-shaped tube. Use clay to secure them tightly to the tube.
4. Pass the base of the Y-shaped straw tube with the attached balloons, through the hole in the bottle cap. Ensure that the entire structure (tube + balloons) is inside the bottle.
5. Use clay at the top of the bottle cap, to secure the tube.
6. Take the third balloon and cut a small portion from the top, stretch this and use it to cover the base of the bottle.

How does it work?

This DIY model is based on the principle of volume and pressure. When the volume increases, the pressure decreases. When we pull the stretched balloon at the base of the bottle, the volume inside the bottle increases, and therefore pressure inside the bottle decreases. As a result, air from the outside moves into the balloons inside the bottle and inflates them. When we release the stretched balloon cover, the volume inside the bottle decreases, and hence the pressure increases. Since air moves from high pressure to low pressure, air moves out of the balloon inside the bottle and the balloon deflates.
The human lungs also work on the same principle. Lungs help in keeping us alive by breathing for us. The two balloons here are like your two lungs and the stretched balloon cover at the base is the diaphragm (a strong muscle in your body that expands and contracts to cause your lungs to fill with air and then empty again). The movement of the balloons matches your breathing; when you breathe in, your lungs fill with air just like the balloons did. That’s because the diaphragm expanded making room for air to get in through the straw (which represents your airway). When you breathe out, your diaphragm contracts (or squeezes in) pushing all the air out of your lungs.

By Aanavya Ranjan, Class IV, Army Public School, Akhnoor, Jammu & Kashmir