Scuba Snopes

[dfx]

no, they get heavier

My double steel 100s are much lighter when full carrying them down the hill to the water than after the dive and carrying them back up

Ah, they must work by letting out air and replacing it with water throughout the dive...

 

[nimoh]

Ah, they must work by letting out air and replacing it with water throughout the dive...

I have always wondered why my reg breathes wet on my second dive

 

[boulderjohn]

Ah, they must work by letting out air and replacing it with water throughout the dive...

Ah! There's another myth!

Taking your tank below 200 PSI is likely to introduce water into the tank. We are going to have to do a visual inspection to make sure it didn't happen, and we are going to have to charge you for it.

 

[nimoh]

Ah! There's another myth!

Taking your tank below 200 PSI is likely to introduce water into the tank. We are going to have to do a visual inspection to make sure it didn't happen, and we are going to have to charge you for it.

at some places, the visual inspection IS the myth while the cost is real

 

[chrpai]

When you Join the Tribe™ by becoming a PADI Divemaster, you align yourself with the largest and most respected dive tribe in the world—that of PADI Professionals.

 

[knotical]

... a full cylinder is always heavier than when it is empty ...

Unless it's filled with helium, which would make it lighter. <myth!>

 

[dumpsterDiver]

Unless it's filled with helium, which would make it lighter. <myth!>

It is NOT a myth! the tank will be lighter. Helium weighs less than air! Don't you know that?

 

[knotical]

It is NOT a myth! the tank will be lighter. Helium weighs less than air! Don't you know that?

Ah, now I understand. Compressed helium weighs less than non-compressed air.

 

[dumpsterDiver]

Ah, now I understand. Compressed helium weighs less than non-compressed air.

I never said that... Can we assume STP.. standard pressure and temp?

 

[dfx]

I never said that... Can we assume STP.. standard pressure and temp?

Right... So a tank filled with helium at ambient pressure will be lighter than a tank filled with air at ambient pressure... Now since a tank filled with air at higher pressure will be heavier than the one at ambient pressure, that means that a tank filled with helium at higher pressure will be even lighter... right?