Analytic Essay

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For our DEEP project, we conducted an experiment testing whether breathing from a nitrox scuba tank had an effect on the heart rate and oxygen saturation in our blood. To conduct this experiment, we had three different levels of physical activity that we tested ourselves on: standing stationary, walking, and running.  The way this translates into the pool is: sitting on the bottom, swimming lightly (frog-kicking and gliding), and swimming at an intense pace (with a flutter kick).  We used two different pools for this experiment, one that was eight and a half feet deep, and one that was fourteen feet deep.  Each of us did these three activities for five minutes, so we had a total of four results to average for each physical activities twice, two for each person.  On land, when the five minutes had elapsed, we immediately applied our pulse oximeter to our finger to see what our heart rate and oxygen saturation were.  When we were underwater, we surfaced, then used the pulse oximeter.


A pulse oximeter is an electronic medical tool that measures two things in the blood: oxygen saturation and heart rate.  We used both of these measures as ways to look for change over different trials.

        Unfortunately, due to our limited resources, we both had to share one nitrox tank, so we ran out of air before we could do a second trial for JP.  This also happened for the regular scuba tank trial, when we ran out of air, and were only able to do one of each trial apiece (we had two tanks with about 700 psi each).  Even so, we still collected a large amount of data.

Hypothesis For Reference:

- Breathing air from a nitrox scuba tank will result in the lowest heart rate and a highest oxygen saturation.

        The data that we came up with had some similarities when compared to our hypothesis.  However, most of the data we collected was not what we had assumed would happen. In our hypothesis, we guessed that while breathing off a nitrox tank, the heart rate would be lower and our oxygen saturation would be higher than on regular scuba.  We thought this would be most likely to happen because when breathing off of a nitrox tank, there is more oxygen available to breathe, so the heart would not have to work as hard.

-Here is the table of results:


    Unfortunately, there was a large amount of error in our experiment.  Some errors were uncontrollable, but most of the errors were things that we could have fixed. For instance, when we were experimenting with the Nitrox 32 scuba tank, the temperature of the water in the Pali pool was colder than the St. Matthew’s pool, so our data was slightly skewed by a higher heart rate, because our bodies were keeping us warm.  Also, since our hands were cold, it took a couple of minutes for the pulse oximeter to get a reading. By then, our heart rate and the oxygen had gone down slightly.  Another factor that affected our results was that we used two different people. This is important because everyone has a different metabolism, so their heart rate and oxygen saturation will be different. Another factor that affected our results was that during both the nitrox and regular scuba trials J.P. only had the opportunity to do one trial. This is because we ran out of air and pool space.


Another thing that skewed the data was the varying pool depths.  At the St. Matthew’s pool, the pool was eight and  a half feet deep, while the Palisades High School pool was fourteen feet deep.  This makes a slight difference while scuba diving because when you are breathing pressurized air from different depths has an effect on the amount of air you are breathing.  So, if the Pali High Pool was 75% deeper, that meant we were breathing approximately 18% more air.  Furthermore, there were some communication errors while doing the experiment.  This is because we were unclear on how deep we wanted to go, so when Michael went first, he was floating slightly up and down and not sitting at the bottom, so he was slightly changing depths.  Because of this, he was not fully relaxing, which increased his heart rate.  But, when J.P. went, he just stayed at the bottom and did not move.  

This difference made our heart rate and oxygen saturation slightly different. Our error section definitely showed that our results were not very accurate.  This is because the actual percentage of error was much higher than in any of the other trials, showing that our data was not entirely reliable. Overall, we think that our overall plan for our experiment was fine, but our execution and equipment had many flaws.


As we said before, when we looked at our results from our DEEP project, there was not much of a difference between the nitrox scuba trial and the regular air scuba trial.  Because of this we think think that the difference was not enough to conclude that nitrox affects one’s heart rate and oxygen saturation.  Furthermore, although we did do many trials for both our land trials and our scuba trials, we had some some problems getting good results.  This is because the way we had our experiment set up, we intended to have four results from each physical activity.  This means that collectively we did thirty six trials, a huge pool of results that should have given us a nice average.



However, as seen in our error section, we ended up only having twenty seven results.  What this meant for our experiment is that some trials only had one run through from each person, and thus we could not compare two different people.  So, after consulting with multiple professional scientists and doctors, we feel comfortable saying that we cannot conclude that are hypothesis is incorrect or correct; further research is needed on this topic.  However, if nitrox did lower heart rate and increase oxygen saturation, this would result in the heart is not working as hard.  This is because there is a higher oxygen concentration being carried by the hemoglobin, thus making it so that the heart does not need to pump as much blood to to the muscles to feed them oxygen.