|Pople, Stephen Explaining Physics: GCSE Edition. NewYork: Oxford. Oxford University Press (1987): 89.||"The deepest ever successful breathheld dive was a staggering 86 m by a Frenchman, Jacques Mayol, in 1973"||86 m|
|Somers, Lee H. Research Diver's Manual. Michigan, University of Michigan. (1971): 21.||"The current record breathhold dive is to a depth in excess of 240 ft."||73.2 m|
|Dugan, James & Vahan, Richard. Men Under Water. Tompkins, New York: Cornell University (1975): 51.||"One Soviet diver, Soloviev, reached a depth of 165 feet without breathing apparatus in 1958."||50.3 m|
|Pirie, Robert G. Oceanography; Contemporary Readings in Ocean Sciences. Virginia, University of Virginia (1977): 4.||"…feet and diving to such a depth without any breathing apparatus is no mean feat… his deepest free dive was 190 feet…."||57.9 m|
|Free Diving. Talk Diving Guide. 2007-2008.||"The world record for no limits free dive is held by Herbert Nichst who descended to 214 meters in 1997 in Greece."||214 m|
SCUBA is an acronym for Self Contained Underwater Breathing Apparatus. Scuba diving is a form of underwater diving where the diver uses scuba diving set to breathe while they are swimming underwater. Early diving relied mostly on pumping air above the water, but this does not require that. It allows divers to carry their own supply of (usually) compressed air which allows them to stay under water without depending on rushing back up to the surface.
However, supplying air for the diver isn’t the only factor needed to ensure the safety of the diver. As the diver descends, on top of the normal atmospheric pressure, water exerts increasing pressure on the chest and lungs. The pressure exerted on the body is about one atmosphere for every 10 meters of depth. In result, the pressure of inhaled breath must counter the opposing pressure in order to inflate the lungs. Due to this, it generally becomes harder to breathe through a tube past three feet under water.
Divers such as Herbert Nichst and Jacques Mayol have dove into depths deeper than most people have ever gone. Not only that, they managed to do it without a breathing apparatus. This is what makes their accomplishment so amazing. Mayol set the world record in 1973 by free diving 86 meters deep into the water. That record, however, was broken by Nichst in 1997, where he broke the world record by descending 214 meters deep in Greece.
Roman Klichinsky -- 2009