Breathing+Investigation+7

OBSERVE: Pull down slowly on the stretched balloon. What happens to the balloon inside the cup? The balloon expands when you pull the stretched balloon down because the there is now more space in the cup and to fill the space the small balloon inflates with air.

Push up on the stretched balloon. What happens inside the cup? Inside the cup the small balloon shrinks when you push up on the stretched because there is now less space in the cup so the small balloon deflates to match the cup's volume.

EVALUATE: Is there more or less space inside the cup when you pull down on the large balloon? There is more space inside the cup when you pull down on the large balloon.

IDENTIFY: When you pull the large balloon down, what fills the extra space in the cup? Air that fills the small balloon through the straw is what fills the extra space in the cup when you pull down on the large balloon.

COMPARE: How is the air pressure in the balloon similar to the air pressure in your lungs? Write down what you think happens when you breathe air into your lungs. When you breath in, your lungs fill with air like the small balloon when you pull down on the large balloon. Then when you exhale, your lungs deflate like the small balloon when you push up on the large balloon.

You clearly have an understanding of how and why lungs expand and collapse. Good work!