First law of thermodynamics and cannibalizing one's own body parts

Discussion in 'Physics' started by strantor, Nov 27, 2012.

1. strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
1,989
Consider this scenario:
You're hiking alone and enter a cave, the cave entrance collapses and seals you inside. You have reason to believe that rescue is coming, but not for at least 1 month. Assume death from starvation happens around 3 weeks. Inside the cave you have a tournicate, access to water and the ability to make fire.

If around the 3rd week you decided to cut off your own leg and eat it, would it prolong your life that one extra week until rescue? Or does this violate the 1st law of thermodynamics? Would it be an attempt at a human perpetual motion machine?

2. thatoneguy AAC Fanatic!

Feb 19, 2009
6,357
718
I'll have one of whatever Strantor is having, I can't seem to get my head around the problem right now.

strantor likes this.
3. THE_RB AAC Fanatic!

Feb 11, 2008
5,435
1,305
I think your perpetual motion analogy is sound. It's like a robot draining one of it's batteries to charge another battery, there is always less than 100% efficiency. The amount of stress etc from cutting off your leg and some attempt at healing would lead to increased calorie needs over normal, and eating the leg would not be a 100% efficient conversion of the nutrition to energy etc.

Remember the body canibalises itself quite well anyway when there is no food, both fat and muscle are broken down and used for survival energy.

However if Strantor was trapped in a cave by an accident, and the accident had ALREADY cut off his leg, then it would be much more beneficial to eat the leg over the few weeks then to not eat the leg. And it would give him something to do, and with a nice little fire would taste like chicken, mmmm.

strantor likes this.
4. tshuck Well-Known Member

Oct 18, 2012
3,531
675
Note to self: never accept an offer from strantor to go spelunking together...

#12, shortbus and strantor like this.
5. loosewire AAC Fanatic!

Apr 25, 2008
1,584
435
He was in the submarine too long,woke up from a bad dream.

@ Stantor,what was your duty on the submarine,was it a nuke

sub,with extra mayo.

Last edited: Nov 28, 2012
6. azzagbag New Member

Nov 28, 2012
1
0
Maybe the smoke from the fire would kill you before you got chance to eat your own leg, so you'd go to the trouble of sawing off your own leg and then not have the 'pleasure' of eating it. I vote for starvation.

7. MrChips Moderator

Oct 2, 2009
12,622
3,451
The energy loss from the trauma of consuming yourself externally will kill you faster.

thatoneguy likes this.
8. strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
1,989
I was a Fire Control Technician. My primary job was as an operator of target tracking system computers and missile/torpedo launching computers & systems. My secondary job was maintenance of the same. My tertiary job was a firefighter. 4th job was periscope operator, 5th-fathometer operator, 6th-well, this just keeps on going.
yes
always
Funny you should mention that. I just had one of those old submarine dreams a couple nights ago.
The atmosphere inside the sub is generated onboard. CO, CO2, farts, and other nasties are burned out of the air with "scrubbers" and the burnt stale "air" is reinfused with oxygen from the Oxygen generator - a byproduct of electrolysis. I estimate that the oxygen generator on a Los Angeles class submarine is designed to meet the needs of around 100 men. We had 150 onboard, and there just wasn't enough oxygen to go around. We were always burning "O2 candles" - a can of some chemical that got hot and gave off oxygen and a shitty smell when you drove a nail into it. But that still wasn't enough. Sometimes the oxygen was down to concerning levels. We could not come to the surface to get air because we were tracking some other submarine or we were where we were not supposed to be or whatever so we just had to deal with it. Living day to day with a sufficient amount of oxygen in the atmosphere is something that you take for granted until it's not there. Low atmospheric oxygen gives you bad headaches (or exacerbates you existing migraine issue in my case), makes you lethargic and sleepy, makes it hard to concentrate, and my favorite: gives you some trippy ass dreams. I call them submarine dreams. You wake up and remember all of it, and not really sure if it was a dream or not.
On the boat I used to have dreams inside of dreams. I would wake up and go to crews mess (dining room) and start getting food and people would be looking at me funny, then I look down and realize I'm naked and then I wake up and go to crews mess, eat me food, go on watch and relieve the offgoing guy, and then notice that my dad is the Officer of the Deck, so I wake up, skip breakfast, go on watch, relieve the other guy, track some contacts for a while, get up and go into the SONAR shack, and nobody is there - where are they? They can't be gone! this is just too weird, so I realize I'm dreaming and wake up again, back on watch, relieve the other guy, but am I awake this time? I don't know! Everything seems normal. Oh wait, there's the Officer of the Deck, and he's wearing an LSU jersey. I bet I'm still dreaming. See, I could take a **** right now, right in the middle of the control room, down the periscope well, and nobody would think that was strange, because I'm dreaming. "WTF Strantor, put your dick back in your pants!" - oops! guess I wasn't dreaming after all. true story.

thatoneguy and nerdegutta like this.
9. nsaspook AAC Fanatic!

Aug 27, 2009
3,006
2,348
Great story, but Stantor, 'what happens on subs stays on subs'.

10. nerdegutta Moderator

Dec 15, 2009
2,565
805
GREAT! (Oh man, too short. This should add some characters)

11. Sparky49 Well-Known Member

Jul 16, 2011
835
417
Pork.

Apparently human flesh tastes like pork...

Did you here about the Chinese dude who cut off his wang, cooked it and charged people £6'000 to eat some?

12. strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
1,989
Well, there was one guy who... and I'll leave it at that. this is a mixed audience after all. Telling submarine stories can go down hill real quick. Maybe one day I'll write a book about it and send you a copy .
Nope I missed that. If that's your kind of thing, search the net for "BME Pain Olympics"

13. tshuck Well-Known Member

Oct 18, 2012
3,531
675
I vote for an Off-Topic thread for submarine stories!

14. strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
1,989
If there were a "toxic" subforum of the "off topic" forum, there would already be such a thread in it. However, what I've already shared is probably pushing the bounds of acceptability, even in OT. I really have very little material that wouldn't be promptly deleted.

15. #12 Expert

Nov 30, 2010
16,655
7,293
You have renewed my gratitude for the life I have. It could have sucked ever so much more...it could have been like yours!

strantor likes this.
16. tshuck Well-Known Member

Oct 18, 2012
3,531
675
Hmmm... perhaps they are stories to be told whilst spelunking...

17. strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
1,989
Sure are. Care to join me?

18. strantor Thread Starter AAC Fanatic!

Oct 3, 2010
4,302
1,989
Lol. Well, it wasn't all bad, and that chapter is done. I'm thankful to have lived the life I have, and I cherish my experiences, even some of the bad ones.

19. thatoneguy AAC Fanatic!

Feb 19, 2009
6,357
718
Now that that is answered, potable water would be the biggest problem.

at least 2 qts/½ gallon per day. Preferably more. Water is heavy, so hope your cave has a natural river and you have filtering and purification systems along.

20. Syn7 New Member

Nov 13, 2012
11
1

That's hilarious and scary all at once. You couldn't pay me enough to go to war in a sub. I would be one of the guys that ends up in his rack rocking back and forth singing songs in some weird language nobody can identify. That being said, I would love to do short term dives in a mini sub or something.