School Project on Asthma?

How to make a model of the lungs

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To understand asthma, it's important to know how we breathe. This project involves creating either one-lung or two-lung model of the lungs to show what happens when we inhale and exhale.

One-lung model

Step 1 - Gather all the materials you will need:

• An empty two litre plastic pop bottle - you won't need the cap
• A balloon (red or pink is best to depict the lungs)
• A 15 cm x 15cm sheet of very thin rubber (red is best) - the thin rubber sheets sold in physiotherapy and exercise stores work well; alternatively, a 25 cm x 25 cm cut out from a plastic garbage bag will work
• Scissors
• Knife (with a sharp point)
• Rubber band (the kind used by postal workers works well)

Step 2 - Prepare the pop bottle:

• Cut the pop bottle about halfway up from the bottom, parallel to the bottom. It's easiest if you make an initial cut with the knife, then use scissors to cut the rest. Try to make the cut clean so there aren't any sharp points
• Keep the top part - the pouring end.

Step 3 - Attach the balloon:

• Push the bottom of the balloon part-way through the top of the bottle.
• Stretch the balloon opening over the top of the bottle.

Step 4 - The cover for the bottom of the bottle:

• Cover the bottom of the bottle with the rubber sheet then secure it around the bottle with the rubber band.
• Cut off the excess edges.

Finished! Now try it out. Pull the middle of the rubber sheet in and out. You will see the balloon inflating and deflating. This is a good model of how we breathe. If the balloon doesn't inflate, check for leaks.

You can also try labeling or marking what each part represents.

• The bottle represents our chest cage, surrounded by our ribs.
• The balloon represents our lungs.
• The bottom rubber piece represents our diaphragm, the main muscle for breathing.
• The opening of the bottle represents the opening of our nose or mouth.

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Two-lung model

Try making a two-lung model if you want a challenge. These are the steps for making a model with both lungs:

Step 1 - Gather all the materials you will need:

• An empty two litre plastic pop bottle - you will need the cap too
• Two balloons (red or pink is best to depict the lungs)
• A 15 cm x 15 cm sheet of very thin rubber (red is best) - the thin rubber sheets sold in physiotherapy and exercise stores work well; alternatively, a 25 cm x 25 cm cut out from a plastic garbage bag will work
• Scissors
• Knife (with a sharp point)
• A small "Y" or "T" joint - these joints allow air to come in one opening and exit out two openings. You can find these in the plumbing section in hardware stores
• A piece of plastic tubing (about 10 cm) that fits inside or around the joint
• Rubber band (the kind used by postal workers works well)
• An electric drill
• Wrench

Step 2 - Prepare the pop bottle: (see images above)

• Cut the pop bottle about halfway up from the bottom, parallel to the bottom - it's easiest if you make an initial cut with a knife, then use scissors to cut the rest. Try to make the cut clean so there aren't any sharp points.
• Keep the top part - the pouring end.

Step 3 - Prepare bottle cap:

• While holding the bottle cap with the wrench, drill a hole in the middle of the bottle cap just big enough for the plastic tubing to fit through. Ask your parents for help doing this.

Step 4 - Insert plastic tubing:

• Slide the plastic tubing a few centimeters into the cap opening.
• Screw the cap on the bottle.

Step 5 - Attach balloons:

• Attach the two balloons to the two top parts of the "Y" or "T" joint.

Step 6 - Attach joint to plastic tubing:

• Reach into the bottle and attach the joint to the plastic tubing.

Step 7 - The cover for the bottom of the bottle (see images above in Step 4 of the one-lung model)

• Cover the bottom of the bottle with the rubber sheet then secure it around the bottle with the rubber band.
• Cut off the excess edges.

Finished! Now try it out. Pull the middle of the rubber sheet in and out. You will see both balloons inflating and deflating. This is a good model of how we breathe. If the balloons don't inflate, check for leaks.

You can also try labeling or marking what each part represents.

• The bottle represents our chest cage, surrounded by our ribs.
• The plastic tubing represents our trachea (windpipe).
• The balloons represent our two lungs.
• The bottom rubber piece represents our diaphragm, the main muscle for breathing.

Background Information:

When the diaphragm (rubber sheet) drops, air enters our lungs because a negative pressure is created inside the chest cage (bottle). When the diaphragm relaxes, air exits our lungs because of the elastic recoil of the tissue in our lungs (the balloon).

You can also use an anatomy/physiology picture or a reference book to further illustrate how the lungs work and compare it to the model.

With asthma, the airways in the lungs narrow due to three possible reasons:

1. The lining of the airways becomes inflamed (swollen, red).
2. The amount of mucus in the airways increases.
3. Tiny bands of muscle that surround the airways can tighten up when exposed to one of your triggers.