how does the movement of the diaphragm cause air to go in and out
When the diaphragm moves, it changes the size of your chest cavity, which changes the air pressure and makes air flow in and out of your lungs.
Inhalation: air goes in
When you breathe in:
- The diaphragm contracts and moves downwards , becoming flatter.
- This makes the chest (thoracic) cavity bigger.
- Because the space is bigger, the pressure inside the lungs becomes lower than the outside air pressure (a slight vacuum).
- Air flows into the lungs from the outside, moving from higher pressure (outside) to lower pressure (inside).
A simple picture to imagine: your chest is like a syringe. Pull the plunger down (diaphragm moves down), the space inside increases and liquid (air) is sucked in.
Exhalation: air goes out
When you breathe out:
- The diaphragm relaxes and moves upwards into its dome shape.
- The chest cavity becomes smaller.
- The pressure inside the lungs becomes higher than the outside air pressure.
- Air is pushed out of the lungs as it moves from higher pressure (inside) to lower pressure (outside).
Quick step‑by‑step summary
- Diaphragm contracts → moves down → chest volume increases → lung pressure drops → air goes in.
- Diaphragm relaxes → moves up → chest volume decreases → lung pressure rises → air goes out.
In short, the diaphragm doesn’t push air in; it changes chest volume and pressure so air is sucked in on contraction and pushed out on relaxation.
Information gathered from public forums or data available on the internet and portrayed here.
