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Henry’s Law states that the amount of gas dissolved in a liquid is proportional to the amount of pressure put on a liquid. Bottles at a deeper depth had fewer bubbles and bottles at a shallower depth have more bubbles. Our experiment proves that the deeper a diver is, the greater the amount of nitrogen is dissolved into his/her bloodstream, or when a diver is under a great amount of pressure, the greater the amount of nitrogen is dissolved into his/her bloodstream.

For our experiment, we wanted to answer the question, “How does water pressure affect the amount of gas (or bubbles) in club soda?” Our answer is that the deeper a club soda bottle is underwater, the smaller the number of bubbles.

Originally, we were going to run three trials for each depth. But, when we were done with the three trials, we had three leftover bottles which we used to do one more trial for each depth. The more trails you do, the more accurate your results will be.

If you look at our results page, you will see that the time for the bubbles at 5 feet is 3.2 seconds, 10 feet is 2.7 and at 15 feet it is 2.2 seconds. Because the times decrease at each deeper depth, more gasses were absorbed at each deeper depth. The gas is represented by the bubbles coming out of the bottle, and when the bottle is deeper underwater, the greater the amount of bubbles are dissolved. There are LESS bubbles at DEEPER depths.

Although the percentage of error is fairly small at 10 and 15 feet, at 5 feet it exceeds 10%, which is not very good, and it requires some assessment to see what the sources of error may be. Our first trials were all done at 5 feet, so no matter how much Rex and Lizzie prepared, they still had to get used to doing the experiment underwater. It was difficult for Lizzie to see and anticipate when Rex would open the bottle because it was very dark underwater by the wall and it was nearly impossible to communicate underwater. This source of error partially contributed to the error at the other depths.

There were ways that we could have corrected the error in our experiment. Instead of doing all of our trial runs above water, we should have run them underwater as well to get used to conducting our experiment underwater. This would have decreased most of the error in our first four trials for the depth of 5 feet. It may have also decreased the error at the other depths.

We figured out our conclusion and where our error came from, so now we must relate our experiment to the bends. The club soda bottle and all of the soda inside it represented the diver. The bubbles in the bottle represented nitrogen. If there were less bubbles, it meant that more bubbles were dissolved into the “diver.” Dissolved nitrogen in the bloodstream is what causes the bends. Since we discovered that there were fewer bubbles at deeper depths we came to the conclusion that the deeper a diver goes, there is a greater likelihood that the diver will get the bends.

Of course, there are other factors that contribute to causing the bends. If a diver is down at a fairly shallow depth of say, 30 feet, they may still get the bends if they are down there for too long. Also, if they come up too quickly or do not take a safety stop at 15 feet they are likely to get the bends.


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