Lung Model Materials List Each group needs: 2-liter empty plastic bottle 2 straight plastic drinking straws; available inexpensively at restaurant supply stores or donated by fast-food chains; do not use the flexible drinking straws 2 9-inch balloons 1 larger balloon; for example, for a punch ball 2 rubber bands Instructions 1. Peel off the labels, if any, on the 2-liter bottles. 2. Cut off the bottom of the bottle 3. Stick two drinking straws through the opening at the TOP and model clay around the straw so that it is air tight. 4. Place one 9-inch balloon on the end of each straw and secure them with rubber bands 5. Stick the balloon ends of the straws through the bottle opening and tightly screw on the lid. 6. Stretch out the larger balloon and place it over the open bottom of the bottle. Summary Questions 1. Pinch and pull the diaphragm (bottom balloon) down. Watch the balloon inside the bottle. What do you observe? Sketch a picture of your observation. Why do you think this happens? Do you think this demonstrates inhaling or exhaling? Explain. 2. Push the diaphragm (bottom balloon) up. Watch the balloon inside the bottle. What do you observe? Sketch a picture of your observation. Why do you think this happens? Do you think this demonstrates inhaling or exhaling? Explain. 3. Why do you think some people can inhale more air at one time than others can? 4. What might happen if you punctured your chest cavity? 5. Which parts of the model lung represent the lungs, chest cavity, rib cage, and diaphragm?