The respiratory system
The respiratory system helps you breathe. When you breathe in, you take oxygen from the air: every cell in your body needs it. When you breathe out, you get rid of carbon dioxide, a gas your body does not need.
The gas we need. It goes from the lungs into the blood.
The waste gas. It leaves through the nose and mouth.
The path of the air
- 1👃 Nose and mouth
The air comes in here.
- 2🌬️ Trachea
A tube in your neck that takes the air down to the lungs.
- 3🫁 Lungs
Two big organs in your chest. They fill with air like balloons.
- 4🩸 Into the blood
Oxygen passes from the lungs into the circulatory system, and the blood carries it all around the body.
The diaphragm
Under the lungs there is a big, flat muscle called the diaphragm. When it moves down, there is more space in your chest and air rushes in. When it moves up, it pushes the air out.
You need a plastic bottle with the bottom cut off, two straws, three balloons, elastic bands and modelling clay. The two balloons on the straws inside the bottle are the lungs; the balloon stretched over the bottom is the diaphragm. Pull the bottom balloon down: the lungs fill with air. Let it go: the air comes out. Air is a gas, so it moves into any space it finds. Ask an adult to help you with the scissors!
