This Teacher Tip comes to us from Dawn Miller in Kansas.
When teaching Human Anatomy I use a two liter pop bottle, a balloon and a quart plastic sandwich bag to illustrate a model of the lungs. Cut the pop bottle in half and tape the plastic bag to the cut end so it covers it with half the bag hanging off the bottle. Put the balloon in the mouth of the bottle so it hangs down in the bottle and stretch the opening of the balloon over the mouth of the bottle to form the lung. Now the students can pull down on the plastic bag and see the balloon inflate like the diaphragm does in our bodies.