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Analytic Essay

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For our experiment, we wanted to find out how breathing rate changes underwater, depending on the depth of the diver.

IS IT TRUE THAT YOUR BREATHING RATE CHANGES DEPENDING ON DEPTH?


WE WANTED TO FIND OUT.

The reason that we might see a difference in the breathing rate is because the air in the scuba tank is being delivered to the diver at a higher density the deeper they go.  You can compare it to inhaling in the shower when it is really steamy.

We had to come up with a way that we could time how many breaths the subject takes at a certain depth.  However, if they knew that we were timing how many breaths per minute they were taking, the rate might have changed. This is because they would have known what we were testing and would have had the power to alter the results by breathing faster or slower.

We decided that the best way to make sure the breathing rate was controlled was to occupy the subjects underwater.  We eventually came up with an idea: Give each subject a  different reading and a quiz to take at every depth.  This kept the subject thinking about the quiz.  We even told them we were testing reading comprehension.

We gave each subject a reading and a quiz on the reading to do underwater.  We timed them for a minute and counted how many breaths they took in that time.  We wrote the result on a transparency on a clipboard with an oil pastel.

Our hypothesis was that breathing rate would not change depending on the depth of the diver.  Even though the air in the scuba tank is being delivered to the diver at a higher density the deeper they go, it is just  so that they can breathe without having their lungs collapse.


Our hypothesis table looked like this

We found out that 12 to 15 BPM is the average breathing rate so we took the lower end just because our subjects were not completely full grown.

In our results we were correct in our hypothesis, figuring that the breathing rate of the person would not change depending on their depth.  However, the average breathing rates of certain people are different in our results.  This can be because of the size of their lungs, their excitement or anxiety while taking the quiz, if they were cold, hot, tired, and many other factors.


Here is what our Results Table looked like:


If the experiment would have been perfect, all averages would have been the same.  Some variables could not possibly have been controlled between the three subjects which resulted in our error:  lung size, physical condition, fatigue, body temperature, diving prowess, and possible frustration during the quiz.

The breathing rate of the people tested had very little difference, depending on their depth.  Looking at the results of Alex and Lawrence, we see that their depth really made no significant difference on their breathing rate.  Charlie had an overall wider difference between  his rate at different depths.  This could be because of other contributing factors. He told us he had found out that we were testing breathing rate before his (last dive) 8 foot dive so that may have affected that result.

After we finished the experiment portion of the project, we called Mr. Jim Spelich, who is a certified diver medic at the College of Oceaneering in Wilmington, California.  He told us that breathing rate won't really change depending on the depth that the diver is at, unless you go really deep (like 150 feet).  He also said that even then, there really is not a significant difference.

We also spoke to Mr. Harlan, who told us that the air in the scuba tank had the same chemical composition as the air we breathe on the surface.  Therefore, the breathing rate should remain the same underwater as on the surface.  The only thing that is adjusted is the density at which the air is delivered to the diver.

In doing this experiment, our results and the information we got from Mr. Spelich and Mr. Harlan allows us to conclude that:


THE BREATHING RATE OF A PERSON ON SCUBA, UNDERWATER DOES NOT CHANGE DEPENDING ON THE DIVER’S DEPTH.

Depth in Feet

A

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e

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a

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e


B

P

M