Goddess-mother of the Earth

[pozorvlak]

I've finally finished reading The Turquoise Mountain, Brian Blessed's account of his first attempt on Everest, and of the filming of the documentary Galahad of Everest. It's taken me ages because in the early stages I skipped about a lot, and it's hard to get excited about reading a bit of the book that you've read before - the time I've taken to read it should not be treated as a poor review! He didn't reach the summit, but he did reach about 25,400 feet (7,750m), before having to turn back due to weather, bureaucratic interference and lack of supplies (the BBC expedition were being supported by the international Peace Climb, who started stripping their tents and gear off the mountain when the BBC were still climbing).

By the way, the name "Brian Blessed" will be immediately familiar to all the Brits, and probably completely unknown to everyone else. He's a much-loved Shakespearean actor, with a huge booming voice and the frame and beard to match, famous to my parents' generation for his role in Z-cars, and to mine for his roles in Flash Gordon, The Black Adder and so on. He's the guy who gets rather anachronistically lynched by the Ku Klux Klan at the beginning of Robin Hood, Prince of Thieves. In real life, he's obsessed with Everest, and particularly with the expedition of Mallory and Irvine.

Some things that struck me:

• One of the unexpected difficulties of climbing Everest is the heat: even at the North Col, at over 7,000m, they were experiencing temperatures of 40C during the day (at sunset, it apparently drops to -20C in around half an hour).
• Losing weight on an Everest trip is a given, and losing 20-30lb is not unusual. Brian Blessed, who usually weighs about 16st/220lb/100kg, and dropped to about 14 in the course of his training, was down to nearer 10st/140lb/65kg on his return!
• You have to be awesomely fit. Blessed claims to have been running "10-14 miles a day, with the odd marathon thrown in for good measure". Even allowing for a bit of dramatic exaggeration (he is an actor), that's pretty impressive.
• Getting ready to go in the morning at altitude takes ages - ice needs to be melted and boiled for tea, tricky high-altitude gear needs to be put on with fingers made clumsy by cold, and the altitude makes your brain slow and befuddled. On their final day of climbing, it took them nearly five hours to make a start. "Nice to know it's not just me", I thought. But I have a question for the physicist-mountaineers out there: why does water take longer to boil at altitude? Water boils at a lower temperature, so it should be quicker. Is it that it needs to be melted from ice first? Or is it that there's less oxygen around for combustion? If the latter, it should be possible to solve it - the problem of creating high temperatures using chemical reactions at high altitude and with minimal danger and weight penalty has received substantial attention, but I can't find anything about this by Googling. Am I missing something?
• Shortly before he has to turn back, Blessed sees a hallucination (or vision, if you will) of all the members of the twenties expeditions, sitting on the snow in their shorts, smiling and waving at him. I rather like the idea of the ghosts of all the early mountaineers living together on Everest, able to enjoy the beauty of the mountains but not to be touched by the conditions.

At the less glamorous end of the mountain-activities scale, I climbed my 67th Munro, Chno Dearg, on Saturday. You've seen Trainspotting? The bit where Tommy takes them all for a walk, and they hate it so much they decide to go back onto heroin? That's where we were. Corrour is literally a railway station and a pub (which is now, mirabile dictu, open during the day - the previous owners, having failed utterly to get this whole "capitalism" thing, used to open up only after the last train of the day had left. Unsurprisingly, it's now under new management). It's impossible to reach Corrour by road - even 4x4s have to be brought in by rail. On a good day, it's rather lovely, and I had a great day there last May climbing the two hills on the West side of Loch Treig. Saturday was not a good day. It was rainy, wet, cold and miserable all day. A series of navigation errors (hey, you try following a compass bearing for any significant distance through a sloping bog in the mist) meant we took much longer to reach the summit than expected and came down in the wrong valley, then had to force the pace (with all three of us suffering some form of leg trouble) to get back to the station before the last train came at 1830.

Fortunately, as we staggered onto the platform at 1825, we were met by a large group celebrating the fact that two of their number had bagged their final Munro, who took one look at us and thrust a bottle of whisky into our hands :-)

Comments

[neoanjou.livejournal.com]

I have no idea as to the actual answer, but in terms of basic physics, to raise 1kg of water by 1˚ C requires about 4.2 kJ (it varies dependent upon temperature, but not by much), whereas the 'Enthalpy of fusion' (which you may have learnt at school as the 'latent heat of fusion') for 1 kg is 333.5 kJ - i.e. roughly the same amount of energy is required to melt the ice as bring the water to boiling point (on a mountain).

Also add in the fact that heating/cooling rates are in general proportional to temperature difference, and one can imagine that water would take a significantly longer length of time to boil - at least twice as long, probably more that 3 times.

[pozorvlak.livejournal.com]

I'm having a bit of trouble finding a comprehensible method of calculating water boiling points at a given altitude (or a table that goes up to 7000m), but I'll accept your claim that melting and boiling the water takes roughly the same amount of energy :-)

The other factor, which I should have realised from my own limited camping experience, is that cooking takes significantly longer when your surroundings are cold - all the heat from the burner gets sucked away into the atmosphere. Even in Wales, we found it was essential to do as much cooking as possible before nightfall, and at -20C this effect's going to be immense.

Still, I think the idea of an HTPB (http://en.wikipedia.org/wiki/HTPB)/N20-powered camping stove has legs :-)

[michaelp-j (from livejournal.com)]

Having made tea from snow on a Primus stove at -20C at least a dozen times, I can vouch for the fact that it takes a *long* time. It also doesn't help that a huge snow block produces a depressingly small amount of water, so that you have to keep adding snow blocks as you go along in order to produce a full pan of boiling water. The recommended technique we used was to make extra water whilst the stove and pan and tent (we were cooking inside) are warm and then store it in Thermos flasks overnight. Even at -25, a Thermos of water won't freeze in the tent overnight, and is usually still tepid in the morning, which gives you a massive headstart on that first cup of tea of the morning.

On the physics, I'd agree that the latent heat issue is the main problem when making boiling water from snow. At altitude you've also got to consider that the lack of oxygen may reduce the combustion efficiency of your stove, too.

[neoanjou.livejournal.com]

The relationship between temperture of a phase change and pressure is a little complicated, but in this case it can be approximated for the transition between water and steam by T_boil = ( 0.0002044 ln(P) + (373.15)^(-1) )^(-1) ), where T_boil is in Kelvin, and P is in atmospheres.

Apparently the pressure at the top of Everest is about 1/3 atmospheric, taking this as √10 ( i.e. so ln(P) = 0.5 ), one will find that water will boil at circa 86˚ C.

[pozorvlak.livejournal.com]

Nifty, thanks!

[neoanjou.livejournal.com]

Okay - I suck.

There should be a minus sign in front of the 0.0002044, and thinking about it, we should be looking at 1/3 atm, not √10 as I was using (which would only be useful to use if we were using logs to base 10) ...

Anyway, the correct expression is:
T_boil = ( --0.0002044 ln (P) + (373.15)^(-1) )^(-1)

Therefore, for 1/3 atm one finds T_boil is 71 ˚C, which is in agreement with values I've seen quoted on the net. However I've also seen that 1/4 atm at the top quoted, which would lower the boiling point to 64 ˚C.

[antoniabaker.livejournal.com]

am currently living in high altitude, on the plus side tea is cool enough to drink a few seconds after you pour it, i don't know if that makes sense from a physics point view.

On the down side it is giving me nose bleeds, had a horrendous one at a hot tub party while wanderign around in a bikini drinking veuve cliquot (envy my job much?) and it did not add to my sex appeal.