Pressures Under Water

After talking about fluids and pressure in class, I decided to see what pressures humans can withstand under water. I was able to think about the pressure I feel when I go to the bottom of my pool of my 8 foot pool, and I wanted to see how deep a person can go before it becomes unsafe. The average human can withstand 3 to 4 atmospheres of pressure, which equals about 3x10^5Pa. This would mean that a human would be able to dive about 20 meters (66ft) into water without any scuba gear. This can be figured out with the formula: 

P=pgh+Patmospheric

3x10^5Pa= (1000kg)(9.8m/s^2)(h)+(1.013x10^5Pa)

h=20m

After calculating this I decided to research what is the farthest a human has dove into water without wearing any scuba gear, and I found that the current world record is 214 meters (702 feet). In order to do this, the person needed to have a weight to take him down and a system that brought him back up from the water. Using the same formula, I found that this person experienced 2x10^7Pa of pressure, which is much higher than the average person is said to be able to withstand. By having a system that was able to bring the person down and back up meant that he did not have to experience the pressure for long, but either way it is a very dangerous experiment and physics shows that it should not be recommended.