Book 31, Question 1 · Video
Why do birds have air sacs as well as lungs?
A bird’s lungs are small and stiff, so air is pushed through them by balloon-like air sacs placed around the body. Air flows in one direction through the lungs, so fresh air passes by whether the bird is breathing in or out. That steady supply gives a flying bird plenty of oxygen, even high in thin air.
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What Crafty Clover says in this video
Intro
Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. Why do birds have air sacs as well as lungs?
The Big Idea
Birds breathe in a very special way! Their lungs get help from little balloons. Why do birds need air sacs too?
Small Stiff Lungs
Step one: Small Stiff Lungs. A bird's lungs are small and stiff, so they do not puff up and shrink the way yours do. Instead, something else has to push the air through them.
Balloon-Like Air Sacs
Step two: Balloon-Like Air Sacs. Balloon-like air sacs sit around the bird's body, in front of and behind the lungs. When they fill and squeeze, they push air through the lungs like a set of bellows.
One-Way Flow
Step three: One-Way Flow. Air moves in one direction through the lungs, so fresh air passes by whether the bird breathes in or out. That steady supply gives a flying bird plenty of oxygen, even high up where the air is thin.
A Closer Look
Let's take a closer look! Small and stiff. Push the air. Some sacs reach inside. Always fresh air.
Quick Facts
Quick facts! Many birds have nine air sacs. Some air sacs even reach into the bird's bones. Air flows one way through a bird's lungs. Birds get plenty of oxygen, even up high.
Think Like a Scientist
Now, think like a scientist! Put one hand on your belly and one on your chest. Take a slow, deep breath in. Feel your body rise as your lungs fill. Breathe out and feel it fall. Draw how your in-and-out breathing is different from a bird's one-way flow.
Outro
A bird's small, stiff lungs get help from balloon-like air sacs that push air through in one direction. Fresh air flows past whether the bird breathes in or out, so it always has oxygen for flying. Science is amazing! What will you discover next? Every question is a new adventure, so keep wondering and keep exploring with me! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!