Overview of the Respiratory System
Let’s Talk About It
This activity allows students to model how the lungs, chest, and diaphragm interact during breathing. The “Breathing Machine” shows students how changes in volume and pressure within the chest cavity affect air flow into or out of the lungs.
Using the diagram on page 8 of the Explorations mini-magazine, help students understand that the balloon inside the bottle represents our lungs, while the bottom balloon represents our diaphragm (a dome-shaped muscle below the lungs). Stimulate a more in-depth discussion by challenging students to think of ways their “Breathing Machines” are similar to and different from the human respiratory system. Some examples are listed below.
- Humans have two lungs.
- Our lungs fill the entire chest cavity, and are surrounded by a thin pleural membrane and thin liquid environment. There is no air space.
- Our lungs are not hollow; they have a spongy appearance inside.
- The chest cavity is divided into two spaces—one for each lung.
Have students stand up and take a deep breath. Ask, “What happens to your chest when you inhale, or breathe air in?” “What happens when you exhale, or breathe air out?” Students should notice that their chests expand when they inhale and contract when they exhale.
Keywords: breathing | breathing rate | diaphragm | lung capacity | lungs | respiration | elementary science investigation | lung model
- Moreno N., B. Tharp, and J. Dresden. (2011). The Science of Air Teacher’s Guide. Third edition. Baylor College of Medicine.
- Illustration © Williams & Wilkins. Licensed for use.
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