To gain a better understanding of the roles and functions of components of the human respiratory system and our need for clean air, students construct model lungs that include a diaphragm and chest cavity. They see how air moving in and out of the lungs coincides with diaphragm movement. Then student teams design and build a prototype face mask pollution filter. They use their model lungs to evaluate their prototypes to design requirements.
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- Colorado: Math
- a. Read, write, compare, convert and order positive rational numbers in a variety of forms including proper and improper fractions, mixed numbers, decimals, and percents (Grade 6)  ...show
- Colorado: Science
- International Technology and Engineering Educators Association: Technology
- Next Generation Science Standards: Science
- Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions. (Grades 6 - 8)  ...show
- Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success. (Grades 6 - 8)  ...show
- Explain how the air in the lungs and chest cavity changes according to air intake and diaphragm movement, and how this is impacted by polluted air.
- Develop a prototype air filter to be worn over the nose and mouth.
- Describe engineers' roles in the function and/or maintenance of the respiratory system and the air that it takes in.
- two-liter plastic bottle with cap, with the bottom cut off and holes drilled into the cap
- 2 plastic drinking straws or 6 inches (15 cm) of tubing (clear flexible tubing works well, 0.5-1.0 cm in diameter; available at hardware or pet supply stores)\
- 3 balloons (1 large enough to stretch over bottom of two-liter bottle; 2 smaller ones, representing lungs)
- 2 rubber bands
- 2-inch (5-cm) cube of soft modeling clay
- Respiratory System Worksheet, one per person
- Face Mask Filter Design Worksheet
- scissors, to cut plastic bottle
- drill, to make two holes in bottle cap to receive straws or tubing
- 1 model lung from first part of activity
- A variety of materials from which students may select to make a face mask filter, such as white paper, cotton balls, coffee filters, cloth, felt, gauze, foam, cotton batting, string, rubber bands, tape, etc.
- spray bottle of water
- timing device
- Dust in the Respiratory System Visual Aid, overhead transparency or handout
|bioengineering:||The use of artificial tissues, organs or organ components to replace damaged or absent parts of the body, such as artificial limbs and heart pacemakers. Source: The Oxford Pocket Dictionary of Current English, http://encyclopedia.com/doc/1O999-bioengineering.html|
|biomedical engineer:||A person who blends traditional engineering techniques with the biological sciences and medicine to improve the quality of human health and life. Biomedical engineers design artificial body parts, medical devices, diagnostic tools, and medical treatment methods.|
|constraint:||A limitation or restriction. For engineers, constraints are the limitations and requirements that must be considered when designing a workable solution to a problem.|
|diaphragm:||A strong wall of muscle that, when moved downward, creates suction in the chest that draws in air and expands the lungs. The diaphragm separates the chest cavity from the abdominal cavity.|
|engineer:||A person who applies his/her understanding of science and math to creating things for the benefit of humanity and our world.|
|model:||(noun) A representation of something for imitation, comparison or analysis, sometimes on a different scale. (verb) To simulate, make or construct something to help visualize or learn about something else (as a product, process or system) that is difficult to directly observed or experimented upon.|
|prototype:||A first attempt or early design of a new product or creation. May be revised many times.|
|system:||An assembly of parts and processes forming a whole:|
Before the Activity
- Gather materials and make copies of the Respiratory System Worksheet (one per person) and the Face Mask Filter Design Worksheet (one per group).
- Make available the Dust in the Respiratory System Visual as an overhead transparency or handout.
- Cut the bottom off each team's two-liter bottle.
- Drill two holes in each bottle lid, big enough for straws (or tubing).
With the Students: Part 1 – Creating a Model Lung
- Review the primary respiratory system components. Do this by having students label parts and describe their functions on the Respiratory System Worksheet, as described in the Assessment section.
- Divide the class into groups of two students each. Provide each team with the materials, cut-off bottle, screw lid with holes, straws (or tubing), balloons, rubber bands and clay.
- Direct teams to use the materials to make basic, functioning models of the human respiratory system, with tubes to carry air into lungs and a diaphragm that when pushed or pulled illustrates what happens to the lung cavity. Note: This portion of the activity is not open-ended, as each team should come up with the same design [see Figure 1], but do not give instructions on how to do it; let the students figure it out!
- Guide students who are having trouble by asking questions, such as: Which material might be used to move air through? Which materials might be able to be filled up with air? Of what might the bottom of the chest cavity be made?
- (For teacher only) How to construct the lung/diaphragm model: Step 1) Stick two straws [or tubing] through the two holes in the bottle cap. The straws represent the bronchi. Step 2) Place a balloon on the end of each straw [or tube] and secure with a rubber band. The balloons represent the lungs. Step 3) Feed the balloon ends of the straws through the top of the bottle and screw the lid on tightly. As necessary, use the clay to secure the straws in place. Step 4) Stretch out the larger balloon and place it over the open [cut-off] bottom of the bottle. The larger balloon represents the diaphragm.
- Once teams have constructed their model lungs, have them use their models to demonstrate what happens when the cavity fills up with air. Ask the students: What happens when the diaphragm is pulled? (Pulling the diaphragm down, away from the lungs, inflates the lungs by making the chest cavity larger and decreasing the pressure.) What happens when the diaphragm is pushed? (Pushing the diaphragm in, towards the lungs, deflates the lungs by making the chest cavity smaller and increasing the pressure.) (Make sure students see how air moving in and out of the lungs coincides with diaphragm movement.)
- Have one student in each group blow into the straws to inflate the lungs. Time the class together for one minute, having them count how many breaths they can take through the straws in one minute. Record this number to use when testing the face mask filters later.
With the Student: Part 2 – Creating a Face Mask Pollution Filter
- Now that we all have functioning lung/diaphragm respiratory system models, let's look at the entire system. What are the inputs to the system? (Answer: Air.) What are the outputs to the system? (Answer: Cleaned oxygen and carbon dioxide.) What might happen if the air intake is not clean? What types of things pollute the air? What happens to our lungs and respiratory system when these things pollute the air we breathe?
- Show students the attached Dust in the Respiratory System Visual Aid (also see Figure 2) and review what happens at each step of the respiratory system with the inhalation of dust.
- Today, our goal is to design a face mask filter that removes some pollutants from the air as a person breathes through it. The filter is for a person to wear over his/her nose and mouth when breathing in polluted air. We will test the filter to see how easy it is to breathe or move air through our model lungs.
- Hand out a design worksheet to each team. Have students fill out their names and define the problem on their worksheets
- Show students the available materials. Using the worksheet, have student teams brainstorm what materials they would use in their design of a filter that could be worn over the mouth to prevent polluted air from entering the respiratory system. Have them draw their designs on their worksheets.
- Have students construct their designs. Allow 15-20 minutes for them to create their face mask filter prototypes (see Figure 3).
- Next, have students fold their filter masks over the two straws in their lung models (see Figure 4). Have them blow into the straws, through the filter, to inflate the lungs. Ask the students: Was it harder to inflate the lungs than before? Is it easy to breathe through the filter? Time the class together for one minute, having them count how many breaths they can take through their filters into their model lungs in one minute. Record and compare this number on the worksheets.
- Lead a class discussion about the effectiveness of their filters. Discuss with students the need for filtering devices that can be placed over the nose and mouth when breathing in situations that involve pollution, dust or diseases. Engineers test a variety of materials to find the best combination of materials and design for this type of filter. Ask the students: Did your prototypes perform as you hoped? Did your prototypes meet your desired design requirements? Explain what worked and what did not work. If you could, what changes would you make to create an improved version of your face filter design?
- Respiratory System Worksheet (pdf)
- Respiratory System Worksheet (doc)
- Dust in the Respiratory System Visual Aid (pdf) (suitable for an overhead transparency or handout)
- Dust in the Respiratory System Visual Aid (doc) (suitable for an overhead transparency or handout)
- Face Mask Filter Design Worksheet (pdf)
- Face Mask Filter Design Worksheet (doc)
- If students are having trouble breathing through the filter it might be too thick or not porous enough. Suggest they remove the filter mask and re-design it for better air flow.
Activity Embedded Assessment
- What happens when the diaphragm is pulled? Why? (Answer: The lungs expand, increasing volume in the chest cavity, or inhalation.)
- What happens when the diaphragm is pushed? Why? (Answer: The lungs contract, reducing volume in the chest cavity, or exhalation.)
- What happens when you blow air into the straws? Why? (Answer: The lungs expand; air is pushed into the lungs.)
- Why can some people inhale more air than others? (Answer: Just like some people are taller than others, some people have a large chest cavity than others.)
- What happens when air pollutants get into the lungs? What happens when a lot of pollutants get into the lungs? What might restrict air flow? What happens to the chest cavity? (Some effects include reduced air intake, rapid breathing, mucus build-up, etc.)
- For younger students, create the model lungs following detailed instructions in TeachEngineering's grades 3-5 Just Breathe activity. Then, with a more limited amount of supplies, give students 10 minutes to create their face mask design prototype and 10 minutes to improve their design after testing.
- For older students, see if they can figure out what they might need in order to extend the model to the circulatory system, If they can figure what they need, have them construct it.
Every Breath You Take. 7th Grade Lesson Plan. Posted July 13, 2007. Download Clean Air Lesson Plans, Clean Air Campaign, Georgia Learning Connections. Accessed December 16, 2008. (Source of activity before modifications and additions) http://www.cleanaircampaign.com/for_schools/clean_air_lesson_plans/download_clean_air_lesson_plans
Malinda Schaefer Zarske, Jay Shah, Denise W. Carlson
© 2008 by Regents of the University of Colorado.
Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder
Last modified: July 3, 2015