How to Make an Edible Model of the Respiratory System

To make an edible model of the Respiratory System, you will need:

• Laffy Taffy or similar malleable candy
• Lifesavers Gummies
• Licorice (red), such as Twizzlers or Red Vine
• Licorice Laces, (optional)
• a batch of Rice Krispy Treats (recipe below)
• red food dye (optional)
• parchment paper on a flat surface

First, make your trachea with the rings of cartilage with the licorice and about 8 Gummy Lifesavers. We used filled licorice, which is quite thick, so we only used one strand of it. If you use regular licorice, I would recommend putting two pieces of licorice together and threading them through the Gummy Lifesavers. This will make it a bit easier when you make the bronchi branch off to the two lungs. Leave space at both the top and bottom, so that you have a inch or two of the licorice sticking out at the top and several inches at the bottom.

Lay your trachea model on the parchment paper and take the top end of the trachea and mold a larynx out of Laffy Taffy and attach it to the licorice at the top of the model. It should cover the licorice that sticking out of the top of the model.
Using the trachea as a point of reference, sketch out the size of the lungs on the parchment paper. You can look at the diagram to get a rough lung shape. They will need to be about 8 inches tall and about 4 inches wide to match the scale of the rest of the model. You can mold the lungs freehand, without drawing it first on the parchment paper, but my students found it easier to sketch out the area in advance to give them an idea of the the relative size of the lungs to the trachea before adding the Rice Krispy Treats.

Next, make a batch of Rice Krispy Treats. I know you probably already know how to make these, but I have included the recipe, in case you need it.

Rice Krispy Treats

(source)

3 tablespoons butter or margarine
1 package (10 oz., about 40) Marshmallows OR 4 cups Miniature Marshmallows
6 cups Rice Krispies cereal or the like 

In large saucepan melt butter over low heat. Add marshmallows and stir until completely melted. Remove from heat. Add cereal. Stir until well coated. 

For this project, we used 8 oz. strawberry marshmallows and 2 oz. of plain marshmallows, which gave the lungs a nice pink-peach color. If you don't want to use the pink marshmallows, you can add a few drops of red food coloring or just leave it tan. (Note: If you use the dye, your hands may turn red as  you work with the treats.)

While your Rice Krispy Treats are still warm and malleable, put in in the areas you sketched for your lungs, molding it into the shape of the two lungs. With the leftover treats, mold little lumpy balls to represent the alveoli. 

Cut the bottom end of the licorice in half and arrange them on the lungs so that they look like they are branching off the bronchi. These represent the bronchioles. You can cut the Licorice into quarters to make even smaller bronchioles, or you can use Licorice Laces to make the bronchioles branch off. That was my original plan, but we couldn't find any Licorice Laces at the store.

You can now attach the alveoli balls you made earlier to the ends of the bronchioles, and your model is complete!

Air travels from the mouth or nose into the trachea, passes through the trachea and into the bronchus. These two primary tubes branch into smaller and smaller bronchial tubes. At the end of the smallest bronchial tubes, called bronchioles are sacs called alveoli. 

The alveoli are covered with capillaries. The deoxygenated blood has come into the lung through the arteries, flows through these capillaries, getting red of carbon dioxide and accepting oxygen from the air that has been brought into the alveoli by the bronchioles. The carbon dioxide travels back out of the alveoli, through the bronchioles, into the bronchial tube system, and out the trachea each time one exhales.

• Have your student tell you the parts of the respiratory system, using the model as a visual. 
• Have your student tell you the process the respiratory system goes through, using the appropriate terms.
• Have your student take a picture of the model or make a sketch of it and include it in his science journal. You can have him label the model with sticky notes before he takes the picture, or your student can label it after he includes it in his science journal.
• Since everything is edible, when you are finished with the study, you can enjoy a snack!

Resources:

• Exploring Creation with General Studies, Wile
• Exploring Creation with Human Anatomy and Physiology, Fulbright and Ryan