Our project started out being based upon the principles of Henry’s Law. Henry’s law states that when so much pressure is put onto a gas, that gas will dissolve into a liquid. However, our project concentrated more on the bends.


When people go diving, they breathe off of a scuba tank. These tanks are more pressurized than the normal air. The deeper you go down, the more air you need so that the pressure of the water equals the pressure of the air you are breathing. When people breathe the air at a high pressure, they inhale more nitrogen and oxygen than normal. This nitrogen dissolves into the blood stream and remains there. Unless the diver comes up at a slow and controlled rate (in order to release the nitrogen from their blood stream) they will get the bends. The bends is an illness, which is caused by nitrogen bubbles forming in the blood stream and lodging themselves in between the joints. These bubbles are formed because the nitrogen molecules, which are in between the liquid molecules, join together. It gets its name as “The bends” because when the diver surfaces they will curl up because of the pain and “bend over.” These people must be taken to a hyperbaric chamber. The chamber will be pressurized to the original pressure where the nitrogen will dissolve back into blood. From then, the pressure will slowly be let out of the chamber so that the nitrogen will be released from their body low enough to avoid the bends.


Our experiment demonstrated getting rid of the bends by depressurizing a club-soda bottle at a constant rate. We pressurized the club-soda bottle with carbon dioxide pumper to 30 PSI or 206.7 KPA. This carbon dioxide dissolved into the water, and no bubbles were formed. We slowly let the carbon dioxide out, dropping 5 PSI per every 45, 55 seconds and then one minute in different trials. We used a pressure sensor in order to monitor how much pressure we lost at a time. We were trying to slowly let the carbon dioxide out so that when we opened the club-soda bottle at 103 KPA, no bubbles would form. Little by little we depressurized the bottle, by opening the two way valve slowly. We dropped five PSI each time and waited 30 seconds in between dropping five PSI, so that we would be able to see if any bubbles formed. We needed to find a constant rate where if we dropped five PSI at a time, no carbon dioxide bubbles forming by the end. If bubbles formed, we knew that we had let the pressure out too quickly. It took one minute to drop five PSI each time so that no bubbles formed.


Our experiment was an accurate portrayal of a way to avoid the bends. The club-soda bottle represented a diver that was underwater who surfaced too quickly. Underwater, a diver with nitrogen dissolved into the there blood will not notice anything. However, if they surface too quickly and do not make decompression stops, the pressure of the water goes away and the nitrogen forms bubbles. This is the same with a club-soda bottle. If you look at a club-soda bottle, you will not notice any bubbles. That is because the cap is keeping all the pressure inside. However, when the bottle is opened, bubbles will suddenly start rising.This is the same as an underwater diver. While underwater the diver does not know that there is nitrogen in his/her blood stream because the diver would not experience any pain underwater. Much like a soda bottle, while pressurized, the club soda bottle does not give off any bubbles, but if the pressure is released too fast bubbles are formed. During scuba diving if the nitrogen is released from the bloodstream too quickly as a result of the the diver surfacing too quickly the nitrogen will form into bubbles and get lodged in the joints therefore causing the bends. In the experiment, we tried to “save the bottle” from getting the bends. By letting the carbon dioxide out of the bottle in a slow and controlled way, the bubbles did not form. We were tried to find that rate if we let the carbon dioxide out of the bottle too fast, bubbles would form. If a diver comes up slowly and makes decompression stops, the nitrogen is able to escape out of the blood stream and bubbles will not form.

Our experiment’s goal was to find the accurate rate in which to drop five PSI without bubbles forming. In the two trials for 45 seconds we got bubbles both times while dropping to 15 PSI. In the two trials for 55 seconds we got bubbles at the same point, while dropping to 15 PSI. Then after two trials at 45 and 55 seconds, we tried three trials for one minute. For every trial for one minute, no bubbles formed and as a result, we decided that one minute was the accurate rate.

Back to DEEP main Animations Index Background Essay Links Results
Bibliography Diagrams Analytic Essay Lab Report Movies Photos
Back to Top