Create a working lung model & teach kids to breathe easy!

The respiratory system has many different parts that work together to help you breathe.   Your mouth and nose pull air from outside your body into your respiratory system.  There are sinuses, which are hollow areas between the bones in your head that help regulate the temperature and humidity of the air that is inhaled.  The pharynx is a tube that delivers air from your mouth and nose to the trachea, a passage connecting your throat and lungs.  Bronchial tubes are at the bottom of the trachea that connect into each lung. The lungs remove oxygen from the air and pass it into your blood.  The bloodstream delivers oxygen to all your organs and other tissues

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​But that's not all!  Muscles and bones help move the air you inhale into and out of your lungs. Some of the bones and muscles in the respiratory system include the diaphragm, which helps your lungs pull in air and push it out.  The ribs surround and protect the lungs and heart.

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Other important components of the system are:

• Alveoli, tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place.
• Bronchioles, small branches of the bronchial tubes that lead to the alveoli.
• Capillaries, blood vessels in the alveoli walls that move oxygen and carbon dioxide.
• Cilia, tiny hairs that move in a wave-like motion to filter dust and other irritants out of your airways.
• Epiglottis, a tissue flap at the entrance to the trachea that closes when you swallow to keep food and liquids out of your airway.
• Larynx, a hollow organ that allows you to talk and make sounds when air moves in and out.

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​Using some common materials, we can build a lung model to help us learn how they function.  Our model can also help us remember some important structures that are a necessary part of our respiratory system.  ​

​CHECK OUT MY TIKTOK VIDEO DEMONSTRATION BELOW, AND THEN READ ON FOR MORE DETAILS!

@gkatzchronicle Make a model lung for your students to demonstrate lung function. #biology #teachertribe #teachersoftiktok #scienceproject #funscience #diyscience ♬ original sound - ✨Just vibe✨

​Materials

• Clear (stiff, not flexible) plastic drink bottle (Gatorade or Vitamin Water are good choices)
• Three balloons
• 2-3 straws
• Tape (masking tape or duct tape) 
• Scissors
• Utility Knife
• Rubber band

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Procedure

• Measure an inch or two from the bottom of the plastic bottle and cut the bottom off carefully. The bottle represents the thoracic cavity.
• Cut a hole in the top of the bottle top large enough for a plastic straw to fit through.  The straw represents the trachea.
• Using 1-2 additional straws and tape, build two bronchi coming off the trachea.  Tape them so that they are airtight. Tape two balloons on the ends of each bronchi to represent two lungs.
• Then place the trachea, bronchi, and lungs inside the bottle, using the bottle top with the hole cut out to hold them in place. 
• Cut the narrow section off the third balloon and position the larger section across the cut bottom of the bottle.  The part of the balloon that covers the open section of the bottle should be loose enough to be pulled down and pushed up.  (Depending on the size of the balloon and the bottle, it may be necessary to tie a knot at the end of the balloon and cut the opposite section off.)  In either case, this balloon represents the diaphragm.  
•  Secure it in place with a rubber band or tape, if necessary.  ​

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​Model Breathing

​Gently pull down on the diaphragm. This should cause air to flow into the lungs.  Allow the diaphragm to return/move upward and the air from the lungs will be expelled. 

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​Scientific Explanation

The diaphragm is a strong muscle that expands and contracts.  As it does so, it causes your lungs to fill with air and then empty out again. 
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The movement of the balloon-diaphragm matches your own breathing – when you breathe in, your lungs fill with air just like the balloons inside the bottle do. That’s because the diaphragm expanded making room for air inside the lungs. When you breathe out, your diaphragm contracts (or squeezes in) pushing all the air out of your lungs.
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In your model, as the diaphragm balloon is pulled it creates more space inside the bottle. Air then comes down the trachea straw and fills the lung balloons with some air to fill the space! When you let go of the diaphragm balloon, the space no longer exists, so the air from the lung balloons is expelled making them deflate.

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Imperfect lung model

​Although this lung model is fabulous, there are some characteristics it does not share with real lungs.  Human lungs aren’t the same size. To accommodate the heart, the right lung is larger than the left lung.  Also, lungs have lobes.  The right lung has three and there is two lobes in the left.  Thin sacs called pleura surround each lobe and separate them from the chest wall.  

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​Think About It

After student models have been completed, discuss respiratory function with students.  Have them place their hands on their chest breath in and out.  Ask them to explain what happens to their chest when they exhale and inhale and why it does so.  Other questions you could ask include:

• Why can some people inhale more air at one time than others? 
• What might happen if you punctured your chest cavity?  
• What are some things you can do to keep your lungs healthy?