Investigate+what+makes+you+breathe+21

OBSERVE: Pull down slowly on the stretched balloon. What happens to the balloon inside the cup? It starts to move in from the air pressure. Rethink your answer. Try the exploration again.

Push up on the stretched balloon. What happens inside the cup? it starts to move out and in. Just observe what happens only when you're pushing up.

EVALUATE: Is there more or less space inside the cup when you pull down on the large balloon? theres less space in the cup. Try it again and rethink your answer.

IDENTIFY: When you pull the large balloon down, what fills the extra space in the cup? Where's your answer?

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. Where is your answer?