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Purpose:
Using a respiration rate belt in combination
with the Relative Pressure Sensor, students will measure their breathing
rate before and after mild exercise, and analyze the differences
they observe.
Background Information:
 The
process of respiration begins with breathing, starting the circulation
of gases (oxygen and carbon dioxide) throughout the body. Respiration
also includes the metabolic reaction of oxygen in body cells, releasing
energy and producing carbon dioxide and water as waste products.
A person's breathing rate and their overall respiratory rate depend
on a variety of factors, including overall health, lung capacity,
level of activity, atmospheric conditions, and altitude, to name
a few. In general, a higher level of activity or exertion tends
to increase respiration rate, which returns to normal after a recovery
period following exercise.
In this activity the Pressure Sensor will be used with the Respiration
Belt to measure the change in pressure that occurs as the chest
cavity contracts (expands) and relaxes during breathing. The belt,
which is wrapped around the lower part of the ribcage (sternum),
has a rubber bladder inside that can be inflated using the attached
squeeze bulb. The air in the bladder can be released using the squeeze
bulb’s thumb screw valve. A second tube attached to the rubber
bladder can be connected to the quick-release connector of the Pressure
Sensor.
Hypothesize: How will your respiration
rate change after mild exercise? How long will it take to return
to normal?
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Equipment:
For each lab group:
Experimental Procedure:
Software
& Equipment Setup:
-
Click on one of the links below to download
a pre-configured DataStudio file for this force experiment,
and then open the file.
PASPORT users: Windows
(.zip file) or Macintosh
(.sit file)
ScienceWorkshop 500 users: Windows
(.zip file) or Macintosh
(.sit file)
When the file is opened, you should see two graph displays,
one showing Relative Pressure vs. Time and the other showing
Breaths per Minute vs. Time.
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Connect the Pressure Sensor to an Xplorer or
USB link (PASPORT users), or plug the sensor into the 500 Interface
(ScienceWorkshop 500 users).
If you are using the ScienceWorkshop 500 Interface, be sure
the sensor is associated correctly in the Experiment Setup window
when you open the DataStudio file.
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Place the belt of the Respiration Rate Sensor
around the sternum of the person whose breathing rate is going
to be measured. Arrange the belt so that the rubber bladder
is in front. Use the "hook" and "pile" materials on the ends
of the belt to fasten it snugly in place. (See diagram below.)
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Connect the end of the tube that comes from
the rubber bladder to the quick-release connector on the pressure
port of the Low Pressure Sensor.
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Close the thumbscrew valve (turn it clockwise)
on the squeeze bulb of the Respiration Rate Sensor. Use the
squeeze bulb to inflate the rubber bladder (between twenty and
thirty 'squeezes'). The belt should be tight but not uncomfortable.
Data
Recording:
Note: There are 3
parts to data recording: (run #1) measuring resting respiration
rate, (run #2) measuring respiration rate during exercise, and
(run #3) measuring respiration rate after exercise during the
recovery period.
-
Remind the test subject to breathe normally,
and click the Start button ( 
) to begin collecting data for resting respiration rate.
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After 60 seconds, click the Stop button ( 
) to end data collection.
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For respiration rate during exercise, instruct
the test subject to begin jogging in place or "stepping
in time", and repeat steps 1 and 2 above. Remind the test
subject to keep exercising even after you click "Stop",
until you are ready for the next step.
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For respiration rate after exercise, click the
Start button (
) AS SOON AS you instruct the test subject to stop exercising.
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Have the test subject sit down or stand very
still and continue to breathe as normally as possible. Encourage
the test subject not to try to hold his/her breath or breathe
more rapidly than is comfortable.
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Once again, click the Stop button (
) after 60 seconds.
You should now have recorded 3 data runs, reflecting the 3 conditions
for respiration rate.
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Data Analysis:
- Examine the graph display to view your data, using the Scale
to Fit button (
) in the Graph toolbar to resize the axes.
- Use DataStudio’s built-in analysis tools to determine the
minimum, maximum, and mean respiration rate for each data run.
Hint: Click the graph of Breaths
per Minute vs. Time to make it the active display. In the Graph
toolbar, click the down-arrow side of the Statistics button (
 ) to
select 'Mean'. ('Minimum' and 'Maximum'; are already selected
by default.) The minimum, maximum, and mean values will appear
in the legend box.
- Compare the results for each of the data runs. You may wish
to have your students record the data in a table like the one
below.
|
Data Run/Breath Rate
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Minimum
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Maximum
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Mean
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| Run #1: resting |
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| Run #2: exercise |
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| Run #3: recovery |
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Conclusions and Extensions:
- How did the respiration rate during exercise compare to the
resting respiration rate? How did the respiration rate during
recovery compare to the other two measurements of respiration
rate?
- How did the respiration rate during recovery change over time?
If the test subject had continued exercising for a longer period
before testing respiration rate during recovery, how might data
run #3 have been different?
- If this same experiment with the same test subject were repeated
on a different day, what additional factors might alter the results?
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