SCUBA Diving, Urban Legends and Mythbusters

[I Dive]

If you take a e-learning class, you will not learn anything.

This one doesn't count, too many people accept this as fact..

 

[Paladin]

Actually, you lose 60% of your body heat through your head!

 

[kjvander]

Does the air pressure on the INSIDE of a scuba tank increase as the diver ascends?

depends....does the pressure decrease as they descend.....minus the breathing....i could work out the formulas....but i am too lazy....

just remember PV=nRT

 

[iztok]

Actually, you lose 60% of your body heat through your head!

Well truth is actually less then 10%.

 

[Paladin]

The absolute pressure inside the tank does not change with depth. However, the effect of that pressure can change with a change in outside pressure.. If you have 150 PSI in a tank at the surface (sea level), then there is a pressure difference of about 135 PSI and the air in the tank is usable (down to sea level air pressure). But at a depth where the pressure outside the tank is also 150 PSI, then the tank is "empty." As the diver ascends, the external pressure drops, causing a pressure differential that allows some of the air to be used.

10%? Really? My drill sergeant told us it was 60%.

 

[MaxBottomtime]

If you make a surface swim in a lake you will be picked up by a water-dropping helicopter and dropped in the middle of a forest fire.

Nitrox make you feel less tired.

The pee will rinse out of your wetsuit.

All diving deaths are a direct result of solo diving.

You should continue classes and become an instructor by the time you have 100 dives.

 

[gbray]

Is a shart more dangerous in a wet suit or a dry suit?

 

[kjvander]

The absolute pressure inside the tank does not change with depth. However, the effect of that pressure can change with a change in outside pressure.. If you have 150 PSI in a tank at the surface (sea level), then there is a pressure difference of about 135 PSI and the air in the tank is usable (down to sea level air pressure). But at a depth where the pressure outside the tank is also 150 PSI, then the tank is "empty." As the diver ascends, the external pressure drops, causing a pressure differential that allows some of the air to be used.

10%? Really? My drill sergeant told us it was 60%.

technically if you take into account the temperature gradient as well there will be a slight depressurization and repressurization of an unused cylinder of air during a dive. Albiet small there will be a pressure fluctuation due to the surface temperature and the bottom temp....now where you are diving there will of course be a difference in these as with the Great Lakes can be 75 at the top and 40 at the bottom there will be some decrease in pressure....like i said though i am too lazy to work out what the % of pressure loss is due to a temperature gradient.

however you are right....the external pressure to the tank will not affect the internal pressure.....

 

[KBeck]

OK, I'm going to regret bringing this one back up, but the ever favorite female question--
If I dive during that time of the month, will sharks attack me?
or, the opposite:
Menstrual blood is "dead" blood and therefore does not attract sharks.

While not a particularly appealling myth to test on public television, it's reasonably testable without putting an -ahem- real test subject in the water---any diver, with testable collected fluids could theoretically work.

 

[ligersandtions]

You will die if you dive with a steel tank and a wetsuit.