what happens as you pull down the balloon

When you pull down the balloon at the bottom of the lung model (bottle with balloons), it makes the “lung” balloons inside expand, just like real lungs filling with air.

Quick Scoop

What this model represents

• The bottle = your chest cavity or rib cage.

• The balloon(s) inside the bottle = your lungs (and sometimes alveoli).!

• The balloon stretched across the bottom of the bottle = your diaphragm.

What happens as you pull down

When you pull the bottom balloon (diaphragm) down:

• The space inside the bottle gets bigger (volume increases).

• Air pressure inside drops below the outside air pressure.

• Air is pushed in through the straw/opening at the top, so the inner balloons inflate/expand.

In simple terms: pulling the bottom balloon down = diaphragm contracting → chest cavity gets larger → air is drawn into the lungs → lungs inflate.

What if you let go or push it up?

• Letting the bottom balloon go back up (or pushing it up) makes the space inside smaller, pressure rises, and air is forced out, so the inner balloons deflate.

• This mimics exhaling in your real respiratory system.

TL;DR: As you pull down the balloon at the bottom of the model, the balloons inside the bottle inflate because the volume inside increases, pressure drops, and air is drawn in—just like breathing in.

Information gathered from public forums or data available on the internet and portrayed here.