The stupid questions thread.

[PINT of Stella. mate!]

*Not really my question. It's one of Frankie Boyle's.

Seeing as murderers (with good reason) tend not to leave any witnesses, is the entire Batman story just the revenge fantasy of a little boy dying in an alley?

 

[Ivan]

*Not really my question. It's one of Frankie Boyle's.

Seeing as murderers (with good reason) tend not to leave any witnesses, is the entire Batman story just the revenge fantasy of a little boy dying in an alley?

If that were the case, there would be more boning. :kiss:

 

[Spike-X]

*Not really my question. It's one of Frankie Boyle's.

Seeing as murderers (with good reason) tend not to leave any witnesses, is the entire Batman story just the revenge fantasy of a little boy dying in an alley?

Mind = blown.

 

[0psi]

Why the hell are people calling videos 'edits'?

Anyway, I should go do some job.

 

[k3n!f]

Do whales get decompression sickness after deep diving?

 

[0psi]

Do whales get decompression sickness after deep diving?

No because the air they breathe is at surface pressure.

You can however still get nitrogen narcosis but I'd assume being an aquatic animal with millions of years of evolution behind them they'd be all over that.

 

[Matt H]

Why the hell are people calling videos 'edits'?

Anyway, I should go do some job.

I think it's a BMX or skate thing. I have a park rat mate who has been calling it "edits" for years.

 

[k3n!f]

No because the air they breathe is at surface pressure.

This is where I get confused. If the whale takes a breath at atmospheric pressure at the surface (760mmHg), then deep dives and increases their dissolved nitrogen in the tissues and blood, if they rapidly resurface the increased dissolved nitrogen should come out of solution as bubbles and cause decompression sickness.

Am I missing something?

 

[Ivan]

This is where I get confused. If the whale takes a breath at atmospheric pressure at the surface (760mmHg), then deep dives and increases their dissolved nitrogen in the tissues and blood, if they rapidly resurface the increased dissolved nitrogen should come out of solution as bubbles and cause decompression sickness.

Am I missing something?

http://news.sciencemag.org/plants-animals/2007/12/why-do-whales-get-bends

 

[0psi]

http://news.sciencemag.org/plants-animals/2007/12/why-do-whales-get-bends

Well there you go.

Interesting that the cause was a similar scenario to the few cases of the bends with free divers. Polynesian pearl divers have been known to get an illness similar to the bends which is thought to be caused by lots of deep dives with small surface intervals.

As for the bends in general it's due to the expansion of gas which is breathed at pressure. If you breathe at the surface and dive down the gases get compressed but when you return to the surface they will be at the same volume etc. that you began with so no issues.
If you breathe gas at pressure then when you return to the surface the gases will be significantly bigger. For every 10m you go down pressure doubles. So 1 litre of air will be compressed down to 500ml at 10 metres and the reverse for on the way back up. If you breathe gas compressed to 2atm, the pressure at 10m, it would expand to roughly double when you got to the surface, ditto for all the dissolved gases in your body.

This isn't the same as narcosis which is toxicity of gas at pressure, pretty quickly fixed by reducing depth.

 

[0psi]

POSM would probably have a bit to add to this.

 

[geoff_tewierik]

Where can I buy 12" bicycle rims online so I can build my own wheels for my daughters balance bike project?

Have checked Araya (down to 16"), Velocity (down to 16"), Sun Ringle (down to 20"), Brompton (down to 16"), Alexrims (down to 18").

Stans, Mavic, DT Swiss, Shimano and SRAM don't go smaller than 26" either.

 

[g-fish]

Call/email velocity, they do custom work. Not sure whether they'd make custom 12" rims but it's worth a try.

Otherwise buy a 12" bike from k mart? They'll be steel though.

Sent from my Nexus S using Tapatalk 2

 

[0psi]

Chinese carbon special? Surely they'd be able to whip something up?

 

[k3n!f]

http://news.sciencemag.org/plants-animals/2007/12/why-do-whales-get-bends

My life has been changed forever.

Now if someone can explain to me the mechanism suxamethonium maintains a phase 1 block instead of persistent tetany my life will be complete. Dunno if that question belongs in the stupid questions thread though.

 

[PINT of Stella. mate!]

POSM would probably have a bit to add to this.

Not really, you've got most of it covered. Air breathed at the surface compresses with depth so as long as you don't take in any extra air when you're down there, there's should be no risk of barotrauma, the bends, gas embolisms or any of the other nasty shit.

Narcosis isn't as much of an issue for free-diving, nor is Oxygen toxicity as again there's only the amount of air in the lungs that will be affected the increased pressure. It is still possible but nowhere near as likely as when breathing pressured air.

As for whales, I wouldn't think that they get narked but then again the stupid fat f***ers often can't tell the difference between the sea and the beach so who knows...

 

[k3n!f]

Air breathed at the surface compresses with depth so as long as you don't take in any extra air when you're down there, there's should be no risk of barotrauma, the bends, gas embolisms or any of the other nasty shit.

I think I've got it now. I understood the gas compression/expansion due Boyle's Law, but was trying to figure out if precipitation of dissolved gas due to Henry's Law would pose a problem with rapid decompression.

Filled up my whole evening!

 

[0psi]

Narcosis isn't as much of an issue for free-diving...

You're not trying hard enough! Most people will experience some narcosis around 60m with it becoming severe at 80m. Me? I'm supersoft so I start narc'ing about 45-50m.

 

[Joel O]

Well there you go.

Interesting that the cause was a similar scenario to the few cases of the bends with free divers. Polynesian pearl divers have been known to get an illness similar to the bends which is thought to be caused by lots of deep dives with small surface intervals.

Decompression sickness is more common than you might think in freedivers. Divers competing in the no limits discipline always have a planned/controlled ascent which usually includes a decompression stop. It's also a real risk among the best spearfishers, especially in comps where surface intervals are often reduced. One of the Aussie divers ended up needing a decompression chamber after the world champs a few years ago. I saw a study a while back suggesting that the early stages of decompression sickness are worryingly common in spearfishing, even at a more recreational level, but can't find it at present.

As for the bends in general it's due to the expansion of gas which is breathed at pressure. If you breathe at the surface and dive down the gases get compressed but when you return to the surface they will be at the same volume etc. that you began with so no issues.
If you breathe gas at pressure then when you return to the surface the gases will be significantly bigger. For every 10m you go down pressure doubles. So 1 litre of air will be compressed down to 500ml at 10 metres and the reverse for on the way back up. If you breathe gas compressed to 2atm, the pressure at 10m, it would expand to roughly double when you got to the surface, ditto for all the dissolved gases in your body.

It is common for competitive freedivers to seal their tongue against the roof of their mouth and use it like a piston to force "excess" air into their lungs, repeating the process several times to significantly increase the amount of air in their lungs. how much are they increasing their risk of barotrauma? I wonder if any marine mammals do the same thing?

 

[Registered Nutcase]

What is with this those weird cartoons with people doing things in FB all of sudden?