Oxygen is not an issue, because we use and metabolize it. The only effect that pure oxygen can have on a human body is the sickness called oxygen toxicity. When we breath a gas mixture with a high percentage of nitrogen, and a low percentage of oxygen, the nitrogen is forced into the blood, or in this case the water in the bottle. Nitrogen is absorbed into the body at severe depths, when it is under pressure, this is a result of both Henry and Dalton's Laws. However, if a diver ascends too quickly, this nitrogen in the blood forms tiny bubbles, blocking the flow to certain tissues. Although this diving sickness is unpredictable, Henry's Law describes the nature of how gases actually dissolve into our blood. Nitrogen dissolved in the blood stream is because of partial pressure, which is represented in Dalton's Law. Dalton's Law is the law, in which gases act according to their partial pressure.
Most divers breathe air when they dive, this mixture however, contains mostly nitrogen. At depth, the nitrogen is held in the blood by ambient pressure. if a diver were to suddenly ascend to the surface, this pressure would be greatly reduced. As a diver ascends, the ambient pressure begins to decrease. Nitrogen will move from the blood and tissues into the lungs, and will be vented from the person in an exhaled breath. This is why even recreational divers use this practice referred to as "safety decompression stops" of "safety stops". Because of these problems and concerns, the maximum depth for breathing is 200 ft. In order to avoid some of these problems, many divers breathe other gas mixtures. Nitrox is a mixture made up of nitrogen and little more than 20% oxygen. This is used at moderate depths, where oxygen toxicity is not a concern. The rules which apply to oxygen are different from those that apply to other gases. Oxygen dissolved into the blood is immediately taken by hemoglobin, this biomolecule transports oxygen throughout our bodies.
Other mixtures like trimix, reduce both the nitrogen and oxygen levels and introduce another constituent, helium. This new constituent, has a smaller molecule and is therefore less dense. It dissolves into blood much faster than nitrogen, this means lower ratios of dive and decompression time. In Heiox, oxygen and helium are mixed and decompression sickness is eliminated by the absence of nitrogen. Pure oxygen can be used at depths of twenty feet or shallower. Without nitrogen or helium, pure oxygen maximizes the rate of decompression and eliminates the risk of decompression sickness.
The experiment that we designed is and example of what happens when a person is breathing on air at different psi. Our experiment is meant to show which psi causes the most bubbles in the bottle. Although the bottle is not full representation of a human body, it shows which pressure causes more gas absorption into the water.