But unlike the balloon experiment your lungs cannot double in size as they are surrounded by a rib cage. You rib cage limits your lung expansion. This is actually called a pulmonary barotrauma. A pulmonary barotrauma can also lead to air bubbles being released into the arterial circulation, which is known as an arterial gas embolism. If you were to experience either a pulmonary barotrauma or a resulting arterial gas embolism, both are life threatening and should be avoided at all costs.
As explained above, your lungs are similar to balloons because they are flexible air spaces made of a soft expandable material. But even without the rib cage limitation and also like a balloon, your lungs have a capacity. After which they are likely to rupture. Your lungs are the same. Which means you must never hold your breath. This can happen either on an ascent from a dive or at high altitude if you fly too soon after scuba diving. Decompression sickness that occurs after a dive when you ascend too fast or if you miss decompression stops on a decompression stop dive.
The gas, which in this case is nitrogen, changes in volume by forming bubbles, as the pressure reduces. The bends can affect just about any part of the body. This includes:. Usual therapy for decompression sickness is recompression in a hyperbaric chamber.
The diver is taken back down to depth using air pressure in the recompression chamber. This is so the volume of the bubbles are decreased and dissolved back into the body.
The diver suffering from decompression sickness is then decompressed very slowly. This slow decrease in pressure is so that the nitrogen gas has a chance to release from the body slowly without forming of bubbles.
This is because you are breathing air in at the surface. As you descend to whatever depth you manage to reach as a snorkeler, the air and your lungs will compress with the pressure. For example, if you were able to free-dive down to 10 metres 33 feet , the size of your lungs would halve in size under the pressure. Then as you rise back up to the surface, your lungs will return to their normal size.
There are other air spaces in addition to your lungs that are affected by the pressure changes underwater. These includes your middle ear and your sinuses. Whilst the impact on these other air spaces is unlikely to be life threatening, nevertheless you need to be aware of them.
This is particularly true of your middle ear. The best way to avoid damaging your middle ear when scuba diving is to make sure you equalize the pressure.
This can be done by performing a Valsalva manoeuvre this is squeezing your nose and forcing air down your nostrils. However, your sinuses will be affected by having a cold. It is therefore not advisable to scuba dive when you have a cold or congestion. This is because the congestion can block the Eustachian tubes at the back of your throat. This will prevent you from equalising the pressure, or actually correcting the air volume inside your middle ear.
Consider the following examples:. Many of the safety rules and protocols in scuba diving were created to help a diver compensate for the compression and expansion of air due to changes in water pressure. For example, the compression and expansion of gas lead to the need to equalize your ears, adjust your BCD, and make safety stops. Those who have been scuba diving have experienced Boyle's Law first hand. For example:. Boyle's law explains some of the most important safety rules in scuba diving.
Here are two examples:. As mentioned above, Boyle's Law only applies to gases at a constant temperature. Heating a gas causes it to expand, and cooling a gas causes it to compress. A diver can witness this phenomenon when they submerge a warm scuba tank into colder water. The pressure gauge reading of a warm tank will drop when the tank is submerged in cool water as the gas inside the tank compresses.
Gasses that are undergoing a temperature change, as well as a depth change, will have to have the change in gas volume due to the temperature change accounted for, and Boyle's simple law must be modified to account for temperature.
Boyle's law enables divers to anticipate how air will behave during a dive. This law helps divers to understand the reasons behind many of scuba diving's safety guidelines. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile. There will be more molecules of each gas dissolved in the blood and tissues. Dissolved gases will diffuse out via the lungs on ascent as ambient pressure decreases, until a new equilibrium is established.
This will continue even after surfacing until all the dissolved gas is removed. A controlled ascent rate and the completion of decompression stops goes a long way to avoiding problems.
Diving gas laws A run down of the gas laws and how they apply in diving. Diving gas laws. At a constant volume, the pressure of gas varies directly with absolute temperature. Facebook Twitter Google Plus Email. Written by The Diver Clinic.
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