A Liter a Lung Measuring Lung Capacity OBJECTIVE In this investigation, students will compare the actual and expected vital capacities of their classmates. LEVEL Middle Grades Life Science CONNECTIONS TO AP AP Biology: III. Organisms and Populations B: Structure and Function of Plants and Animals. Structural, physiological and behavioral adaptation. TIME FRAME 60 minutes MATERIALS (For a class of 28 working in groups of 7) 8-14 metric rulers 8-14 scientific calculators 28 round balloons, 9 inch bathroom scale lung model T E A C H E R Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 1
TEACHER NOTES A Liter a Lung is an investigation for use during a lesson on the respiratory system. It introduces the students to the basic mechanism of respiration and the concept of lung capacity. The activity should be preceded by allowing students to explore or create a model of the lung and diaphragm. Instructions for creating a simple lung model are included below. Demonstration Materials: clear plastic bottle, 2 liter single hole stopper that will fit the mouth of the bottle 5 inches of small glass tubing that will fit in the hole in the stopper large balloon that is cut and can fit over the bottom of the 2 liter bottle one or two small balloons clear packing tape Y-shaped connector (optional) Assembly: 1. Carefully cut the bottom off of the plastic bottle. Try to cut the bottle smoothly so that there are not any jagged edges. Cover the cut edge with tape to minimize the sharpness. 2. Insert the glass tube into the rubber stopper so that the tube sticks out on both ends. Or, if you prefer, use an inverted Y-shaped connector to simulate the branching of the bronchi. 3. Attach the small balloon to the tube or Y-shaped connector using tape. Make sure it is completely sealed. To test it, try blowing up the balloon(s). Each balloon represents a lung. T E A C H E R 4. Tightly insert the stopper into the mouth of the 2 liter bottle such that the small balloons are on the interior of the cut bottle. 5. Tie a knot in the end of the large balloon and cut the balloon in half. 6. Using the half of the balloon with the knot, stretch the open end over the bottom of the 2 liter bottle. This balloon should fit tightly around the bottom of the bottle and will act as the diaphragm. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 2
Modeling and Introduction: 1. At this point, model for the students what happens when you push and pull on the knotted balloon. They should notice that the balloon(s) inside the 2-liter inflate with you pull on the knotted balloon and deflate when you push on the knotted balloon. 2. Explain to the students what each part in the model represents in the body. The plastic bottle represents the thoracic cavity. The balloon(s) on the inside of the bottle represent the lungs. The large balloon represents the diaphragm, the large muscle that separates the thoracic and abdominal cavities. The movement of this muscle causes our lungs to expand and contract. A Y-shaped connector would represent the trachea and bronchi and would allow for both lungs to be represented. Suggested Teaching Procedure: 1. Instruct students to gather all recommended materials except the balloon. T E A C H E R 2. Divide the students into teams of seven. 3. Prior to passing out the balloons, make sure you point out the recommended safety procedures. 4. Pass out one balloon to each student. It is advisable to allow the students at least one minute to make balloon noises with their balloons. This will allow the students an opportunity to get any tempting noises that they may want to make during the investigation out of their system before you begin. 5. Guide the students through the investigation. Students tend to have fewer questions about the procedure if they are completed together. 6. Students will measure their Tidal Volume. Tidal volume is the amount of air breathed in or out during normal respiration. Things to watch as you monitor the students: (1) that students are exhaling at a normal rate and (2) that they are turning the balloon on its side to measure the height. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 3
7. In the section titled Measuring Vital Capacity, students will have a chance to exhale as much as they can from a single breath into the balloon. Because many kids think this is a competition, watch them to be certain that they are in fact just inhaling and exhaling a SINGLE time. A Liter a Lung 8. Some students will struggle a bit with the graph in the section Converting the Diameter to Volume. Use a data projector or an overhead to model the use of this graph. Students could convert each measurement taken for Tidal Volume and Vital Capacity, but it is only necessary to convert the average. After completing this portion, Data Table 3 should be complete. 9. The Calculating Estimated Vital Capacity section requires the students to do several calculations. In addition, it is helpful if you set up stations for them to measure their height and weight. If you do not have a scale available, most students know about how tall they are and how much they weigh. They can use those values to complete this section. 10. Encourage students to use dimensional analysis when converting their height and weight from customary to metric units. 11. After each measurement or calculation, the students are instructed to share their results with their team. This is significant because you want the students to look for and discover trends in their data. Once the teams have completed the first six columns, guide them through the Status portion of Data Table 1. 12. When comparing the tidal volume and vital capacity, the vital capacity should be a much higher number. Ask students to brainstorm possible causes or problems that would cause a student s values to be very similar. 13. In an ideal situation, an organism s estimated vital capacity would be lower that its actual vital capacity. There are several factors like athleticism, altitude, or playing an instrument that could increase a person s lung capacity. T E A C H E R 14. Have the students answer the conclusion questions. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 4
DATA AND OBSERVATIONS Student Name Health Condition Data Table 1: Lung Capacity Extra- Curricular Activity Average Tidal Volume Measured Vital Capacity Estimated Vital Capacity Status Zachary None Water polo 2000 4200 4365 Low Abigail Cold Basketball 1200 2200 2100 High Keeley None Plays flute 2100 3000 3400 Low Chris None None 1900 4000 4000 Equal Terry None Basketball 2800 5100 5300 Low Connie None Runner 1900 2500 2300 High Twyla Asthma None 1500 1550 1550 Equal Eddie Mother smokes None 1900 4200 3800 High Data based on Zachary: Data Table 2: Measuring Tidal Volume Trial Balloon Diameter (cm) Lung Volume Data Table 3: Measuring Vital Capacity Trial Balloon Diameter (cm) 1 15 1 20.5 Lung Volume T E A C H E R 2 17 2 20.0 3 16 3 19.5 Average 16 2000 Average 20 4200 Data Table 4: Calculating Estimated Vital Capacity Weight in kilograms (1 lb = 0.454 kg) 63.56 Height in centimeters (1 in = 2.54 cm) 172.72 Body Surface Area (m 2 ) 1.746 Estimated Vital Capacity 4365
GRAPH 1 GRAPH 2 T E A C H E R
CONCLUSION QUESTIONS 1. Using Graph 1 and Data Table 1, compare the Tidal Volume and Measured Vital Capacity for your group as a whole. Is there a relationship between the two volumes? Explain. The tidal volume is less than the vital capacity. This is due to the fact that the amount of air being expelled in a normal breath will be a lot less than the lung can take in at its maximum. 2. Using Graph 2 and Data Table 1, compare the Estimated Vital Capacity and Measured Vital Capacity for your group as a whole. Is there a relationship between the two volumes? Explain. The Estimated Vital Capacity should be close to the Measured Vital Capacity. Ideally, the measured should be higher than the estimated simply because each person should be taking in more air than they actually can utilize. Very few students generally have a measured capacity that is higher than their estimated value. 3. Explain the importance of having a difference in your tidal volume and vital capacity. It is important that the vital capacity be higher than the tidal volume. This is due to the fact that an individual should have the ability to take in a greater amount of air than the tidal volume. 4. Why might there be some variation in the measurements of different people? Different people have different body structure, weights, and conditions that would impact their lung capacity. In addition, genetics and environment play a role in each person s lung capacity. T E A C H E R 5. List at list three factors that could impact a person s vital capacity. What affect would each factor have? Athleticism should increase a person s vital capacity Altitude People living in a higher altitude tend to have a higher lung capacity. Exposure to second hand smoke or pollution will decrease vital capacity Respiratory conditions, illnesses or diseases will decrease vital capacity Playing a wind instrument should increase a person s vital capacity 6. When comparing your estimated and measured vital capacity, what is your status? Do you feel this is an accurate status for you? Explain. Answers will vary
7. Explain the impact of your status on the cells in your body. High would mean that an individual is taking in enough air to meet the needs of the cells in their body. A vital capacity well above expected indicates a person who is in excellent physical condition. Equal means that the individual is taking in just enough air to meet the needs of their cells. Low would mean that an individual is not taking in enough air to meet their basic needs. An individual with a vital capacity well below expected is not breathing at optimal efficiency and should consider alternating their exercise regimen or other environmental exposures to improve their cardiovascular abilities. 8. How does your estimated vital capacity compare with those of other teammates? Answers will vary 9. Why is it important to know a person s vital capacity? Knowing your vital capacity is a gauge of your level of fitness or condition of your respiratory system. Low vital capacity could indicate a possible illness or respiratory condition such as asthma. 10. When measuring your tidal volume, we took three measurements. Explain the significance of taking three measurements rather than one. By taking three measurements, the accuracy of our data increases. 11. When exhaling air from your lungs, a small amount of air always remains. Predict what would happen if all of the air were to be exhaled from your lungs. T E A C H E R A small amount of air must remain in the lungs in order to prevent the tissues in the lung from coming in contact with each other. In the event that this takes place, the lung will have a difficult time inflating again. 12. List three sources of error or ways to improve the accuracy of the measurements that were taken. How would each possible error or improvement affect your calculated capacity? Answers will vary Students may not truly exhale the same amount of air each trial, the capacities calculated would be either larger or smaller than actual. The balloons may not all stretch at the same rate. The capacities would not be comparable between students. The use of a spirometer, a tool that is used to measure the lung capacity, would be a much more accurate way to measure lung capacity. 13. Did you observe a difference in Status between the boys and girls in your team or in the class? Answers may vary from class to class.
A Liter a Lung Measuring Lung Capacity Did you know that the average lung of a human being holds about 6 liters of air? That amount would be like holding a three liter bottle of soda in each lung. Is it important to know how much air your lungs can hold? Why is it important for the lungs to be able to hold that much air? The answer to both questions has to do with the process of breathing and its importance. The actual job of breathing and taking in air is done by the diaphragm. The diaphragm is a muscle located between the abdominal and thoracic cavity. The contraction of the diaphragm increases the amount of space (volume) in the chest cavity thereby lowering the internal pressure because of that cavity. The difference between the internal pressure in the chest cavity and the external pressure of the air outside, air is drawn into the lungs during what we call an inhale. As air enters the body, it travels through a complex network of tubes. From the mouth, the air passes through the pharynx and then the larynx. After passing the trachea, the pathway of air diverges when entering the bronchi. Smaller tubes called the bronchioles direct air to the smallest air sacs of the lung, the alveoli. It is estimated that each human has 300 million of these tiny air sacs in the lung. The alveoli are the site of gas exchange in the body. The oxygen needed by your cells for cellular respiration diffuses across into the capillaries. Carbon dioxide, the waste product of cellular respiration, will be released. At the same time that oxygen is diffusing across the alveoli, carbon dioxide is diffusing back into the lungs. In order for the waste product to be exhaled, the diaphragm muscles must relax. This causes the chest cavity to become smaller, increasing the internal pressure and forcing air out in an exhale. In order for an organism to sustain the life of every cell in the body, it is important for the lungs to take in enough air to provide every cell with the much needed oxygen. In the event that an organism does not take in enough air, cells begin to die. When cells die, tissues, and then organs, begin to fail and ultimately the organism will not survive. To determine if an organism is taking in enough air to ensure its survival, we can measure its lung capacity. Of course, many factors can affect lung capacity such as gender, height, smoking, physical condition, and altitude. This investigation will allow you to measure your lung capacity and determine if any of these factors play a role in determining your own lung capacity. Glossary: Expiration the act of exhaling air from the lungs. Inspiration the act of drawing in air into the lungs Tidal volume The amount of air breathed in or out during normal respiration. Total lung capacity The volume of air contained in the lungs at the end of maximum inspiration. Vital capacity The amount of air that can be exhaled out of the lungs after a maximum inspiration. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 5
PURPOSE In this activity you will compare the estimated vital lung capacity of each individual in your group to their actual, or measured, lung capacity. MATERIALS metric ruler scientific calculator 9 inch round balloon bathroom scale A Liter a Lung SAFETY ALERT Do not participate in this investigation if you have a latex allergy or breathing difficulties. Do not point the mouth of the balloon in the direction of a classmate when expelling the air from the balloon. PROCEDURE 1. In Data Table 1 of your student answer pages, record the names of each member of your group. 2. Record any extra-curricular activities that the students participate in at school or at home. 3. In the column labeled Health Conditions, record if the student has any respiratory related conditions like asthma, a chest cold, or exposure to second hand smoke. 4. Once your teacher hands you the balloon, stretch your balloon several times. 5. Inflate the balloon with air from your lungs to loosen its elasticity. Be careful not to blow it up more than two-thirds of the way full. Do not release the balloon while you are releasing the air. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 6
PART I: MEASURING TIDAL VOLUME 1. Tidal volume is the amount of air breathed in or out during normal respiration. In a normal rate of respiration, inhale and exhale a single breath into the balloon. (Do not try to exhale all of your air into the balloon at this point.) 2. Pinch off the end of the balloon. Do not tie it off. Figure 1 3. Place the balloon on a flat surface as pictured in Figure 1. 4. Using the metric ruler, measure the diameter of the balloon in centimeters. 5. Record the diameter of the balloon in Data Table 2 in your student answer pages. 6. Deflate the balloon and repeat steps 1-5 two more times. PART II: MEASURING VITAL CAPACITY 1. In this part of the investigation, you will measure your vital capacity. Vital capacity is the amount of air that can be forced out of the lungs after a maximum inspiration. Inhale as much air into your lungs as possible. 2. Exhale as much air into the balloon as possible. 3. Pinch off the end of the balloon. Do not tie it off. 4. Place the balloon on a flat surface as before. 5. Using the metric ruler, measure the diameter of the balloon in centimeters. 6. Record the diameter of the balloon in Data Table 3 in your student answer pages. 7. Deflate the balloon and repeat steps 1-6 two more times. 8. Calculate your Average Vital Capacity and record it in Data Table 3. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 7
PART III: CONVERTING THE DIAMETER TO VOLUME 1. Use Figure 2 to determine the volume of air that was in your balloon during your Tidal Volume and your Vital Capacity measurements. 2. On the x-axis, locate the average diameter of your tidal volume. Using a highlighter and a ruler, draw a vertical line from that point on the axis to the curved line. 3. Turn your ruler perpendicular to the line that you created for the diameter. Highlight horizontally across to the left and intersect the y-axis. Approximate the volume of air in cubic centimeters at that point on the y-axis. 4. This is your Average Tidal Volume. Record the volume in cm 3 on Data Table 2. 5. Repeat the process to determine your Average Vital Capacity. Record the volume in Data Table 3. 6. Once you have calculated your average vital capacity, realize that this number is your Measured Vital Capacity. This is what you have measured to be the amount of air that your lungs can hold. 7. Share with the group your Average Tidal Volume and Measured Vital Capacity. Record the results for each group member in Data Table 1. 8. Complete the Analysis and Conclusion sections of your student answer pages. A Liter a Lung Figure 2 Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 8
DATA AND OBSERVATIONS A Liter a Lung Measuring Lung Capacity Data Table 1: Lung Capacity Student Name Health Condition Extra- Curricular Activity Average Tidal Volume Measured Vital Capacity Estimated Vital Capacity Status Data Table 2: Measuring Tidal Volume Trial Balloon Diameter (cm) Lung Volume Data Table 3: Measuring Vital Capacity Trial 1 1 2 2 3 3 Average Average Balloon Diameter (cm) Lung Volume Data Table 4: Calculating Estimated Vital Capacity Weight in kilograms (1 lb = 0.454 kg) Height in centimeters (1 in = 2.54 cm) Body Surface Area (m 2 ) Estimated Vital Capacity Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 9
ANALYSIS CALCULATING ESTIMATED VITAL CAPACITY 1. In order to calculate your estimated vital capacity, we must first calculate your body surface area. 2. Using the bathroom scale, measure your weight in pounds. Convert your weight to kilograms. (Remember: 1 pound = 0.454 kilograms) 3. Record your mass in Data Table 4 in your student answer pages. 4. Your teacher has placed a yard stick or a metric ruler along the wall in your classroom. Measure your current height. 5. If you measured your height in inches, convert it to centimeters. (Remember: 1 inch = 2.54 centimeters) 6. Record your height in Data Table 4. 7. Using your weight in kilograms and your height in centimeters, you must calculate the surface area of your body. In other words, this calculation will show you how much area of your body is covered in cells that need the oxygen that you are breathing in when you respire. The Mosteller formula for calculating your surface area is below: A Liter a Lung 8. Record your Body Surface Area in Data Table 4. 9. The final step in calculating your estimated vital capacity is to multiply your body surface area by the ratio of vital capacity to surface area. 10. FEMALES: 2000 ml/m2 MALES: 2500 ml/m2 11. Record your Vital Capacity in Data Table 4. 12. Share with your group your Estimated Vital Capacity. Record the result for each group member in Data Table 1. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 10
STATUS ARE YOU SURVIVING? 1. Take a look at the data that you have collected from your team. 2. Create Graph 1 for Tidal Volume vs. Measured Vital Capacity for your team. 3. Create Graph 2 for Estimated Vital Capacity vs. Measured Vital Capacity for your team. 4. When comparing the two values, the two numbers should be at least at an equal value. Ideally, the measured vital capacity should be higher than the estimated vital capacity. 5. Complete the Status column of Data Table 1 for each member of your team: If the estimated and measured vital capacities are equal, draw an equal sign. If the measured is LOWER than estimated, draw a sad face. If the measured is HIGHER than the estimated, draw a happy face. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 11
GRAPH 1 GRAPH 2 Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 12
CONCLUSION QUESTIONS 1. Using Graph 1 and Data Table 1, compare the Tidal Volume and Measured Vital Capacity for your group as a whole. Is there a relationship between the two volumes? Explain. 2. Using Graph 2 and Data Table 1, compare the Estimated Vital Capacity and Measured Vital Capacity for your group as a whole. Is there a relationship between the two volumes? Explain. 3. Explain the importance of having a difference in your tidal volume and vital capacity. 4. Why might there be some variation in the measurements of different people? 5. List at list three factors that could impact a person s vital capacity. What affect would each factor have? 6. When comparing your estimated and measured vital capacity, what is your status? Do you feel this is an accurate status for you? Explain. Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 13
7. Explain the impact of your status on the cells in your body. 8. How does your estimated vital capacity compare with those of other teammates? 9. Why is it important to know a person s vital capacity? 10. When measuring your tidal volume, we took three measurements. Explain the significance of taking three measurements rather than one. 11. When exhaling air from your lungs, a small amount of air always remains. Predict what would happen if all of the air were to be exhaled from your lungs. 12. List three sources of error or ways to improve the accuracy of the measurements that were taken. How would each possible error or improvement affect your calculated capacity? 13. Did you observe a difference in Status between the boys and girls in your team or in the class? Copyright 2012 Laying the Foundation, Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org. 14