Science 4th grade | UNIT 1: Humans and animals 1.4 Skeletons and movement
We use our lungs for breathing. We need to breathe to stay alive. We breathe in and breathe out.
The lungs are found in the chest. They are protected by the ribs. The lungs are like stretchy sponges that fill up with air.
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Activity 1.4 (Investigating breathing)
You will need: a balloon
Put your hands on your ribcage.
Breathe in. What do you feel?
Now breathe out. What do you feel?
Breathe in again. Hold the balloon to your mouth and breathe out. What happens to the balloon?
What does this show you?
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Questions
1) When you breathe in, does your chest get bigger or smaller?
Why do you think this is so?
2) When you breathe out, does your chest get bigger or smaller?
Why do you think this is so?
3) Explain how we are able to blow up a balloon.
4) Why do you think we breathe faster when we exercise?
Breathing
*** (Air enters the body through the nose or mouth.
The air goes down the windpipe and into the lungs.
Air leaves the body through the nose or mouth.
Air is squeezed from the lungs and travels up the windpipe.)
When we breathe in, oxygen from the air moves into the blood vessels in the lungs. Blood carries the oxygen to the heart and then to the other parts of the body. We need oxygen to live.
As your body uses up oxygen, it makes carbon dioxide. Carbon dioxide is a waste gas that the body must get rid of. The blood carries the carbon dioxide back to the lungs. We get rid of carbon dioxide in the air we breathe out.