A Liter a Lung
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)
T E A C H E R
8-14 metric rulers 8-14 scientific calculators 28 round balloons, 9 inch bathroom scale
lung model ®
Copyright © 2012 Laying the Foundation , Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org.
1
A Liter a Lung
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:
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.
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.
T E A C H E R
1.
2
A Liter a Lung
Modeling and Introduction:
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.
T E A C H E R
1.
Suggested Teaching Procedure:
1.
Instruct students to gather all recommended materials except the balloon.
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
A Liter a Lung
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.
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.
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.
T E A C H E R
7.
4
DATA AND OBSERVATIONS
Data Table 1: Lung Capacity Student
Name Health
Condition ExtraCurricular
Activity Average
Tidal
Volume
(cm3) Measured
Vital
Capacity
(cm3) Estimated
Vital
Capacity
(cm3) 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 Table 2: Measuring Tidal Volume Lung
Volume
(cm3)
1 Balloon
Diameter
(cm) 15 2 17 3 16 Average 16 Trial 2000 Data Table 3: Measuring Vital Capacity Trial Balloon
Diameter
(cm) 20.5 1 2 20.0 3 19.5 Average
20 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 (m2) Estimated Vital Capacity (cm3) 1.746 4365 Lung
Volume
(cm3)
4200 T E A C H E R
Data based on Zachary:
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.

2.
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.
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.
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.
Explain the importance of having a difference in your tidal volume and vital capacity.

Why might there be some variation in the measurements of different people?

5.
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.
List at list three factors that could impact a person’s vital capacity. What affect would
each factor have?





6.
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
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
T E A C H E R
4.
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.
7.
Explain the impact of your status on the cells in your body.



8.
“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.
How does your estimated vital capacity compare with those of other teammates?

9.
Answers will vary
Why is it important to know a person’s vital capacity?

When measuring your tidal volume, we took three measurements. Explain the
significance of taking three measurements rather than one.

11.
By taking three measurements, the accuracy of our data increases.
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.
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.
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.
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.
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.
T E A C H E R
10.
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.
A Liter a Lung
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
A Liter a Lung
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 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
A Liter a Lung
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
A Liter a Lung
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 cm3 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.
Figure 2
®
Copyright © 2012 Laying the Foundation , Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org.
8
A Liter a Lung
A Liter a Lung
Measuring Lung Capacity
DATA AND OBSERVATIONS
Data Table 1: Lung Capacity Student
Name Health
Condition ExtraCurricular
Activity Average
Tidal
Volume
(cm3) Measured
Vital
Capacity
(cm3) Estimated
Vital
Capacity
(cm3) Status Data Table 2: Measuring Tidal Volume Trial Balloon
Diameter
(cm) 1 2 3 Average Lung
Volume
(cm3)
Data Table 3: Measuring Vital Capacity Trial Balloon
Diameter
(cm)
1 2 3 Average
Lung
Volume
(cm3)
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 (m2) Estimated Vital Capacity (cm3) ®
Copyright © 2012 Laying the Foundation , Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org.
9
A Liter a Lung
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:
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
A Liter a Lung
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
A Liter a Lung
GRAPH 1
GRAPH 2
®
Copyright © 2012 Laying the Foundation , Inc., Dallas, TX. All rights reserved. Visit us online at www.ltftraining.org.
12
A Liter a Lung
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
A Liter a Lung
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