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Overview of the Respiratory System

Author(s): Nancy Moreno, PhD, Barbara Tharp, MS, and Judith Dresden, MS.
Showing Results for: lung model Return to Presentation

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In this activity, students build a breathing machine that models how the lungs, chest, and diaphragm interact during breathing. Students will make predictions, build a model, make observations, and draw conclusions during this investigation to discover how changes in volume affect air flow into or out of the lungs.  

Divide the class into groups of 2-4 students. (If desired, each student may perform the investigation individually.) Have the Materials Manager from each group collect the necessary materials.

Direct the students to slide a balloon into the top of the bottle and roll the open end (mouth) of the balloon over the top edge of the bottle. The balloon will represent a lung. Cut off the bottom of the second balloon and tie a knot in the stem (mouth) of the remaining piece (see illustration). While one student holds the bottle, another should slide the cut end of the balloon around the cut end of the bottle.

Ask students to predict what might happen when the bottom balloon is pulled downward. Have students try pulling the balloon gently, while making sure not to pull it off the bottle.  Ask, What happened to the inside of the balloon? Explain that what they just observed is similar to what happens when each of us breathes in.

Next, direct the students to squeeze the sides of the bottle gently and push the bottom balloon into the space in the bottle. Ask, What happened?