## Wednesday, February 6, 2008

### Water (II): Resilience

I just checked out Mount Everest's height at Wikipedia, and it's at a staggering height of 8,840 m! You know what that means?

That means I, weighing 95 kg, would need approximately 8840(95)(9.81) = = 8238438 J of energy to scale that mountain fully! What a heck of a mountain!

Now just look at this: let's say I have 62.5 moles of water - that isn't very much, just about 1 litre of pure water. Assuming it is at room temperature, and assuming that I need very hot water at 373.15 K to make good hot chocolate for my family, the energy I need is given by a simple calculation:

I've done the above calculation assuming that the boiling process was done at constant volume inside a simple flask, and I used the latent heat of vapourization and specific heat capacity of water, as above. I mean, you probably won't boil away all the water right?

What in the world? I climb so high up, and all the energy I expended, can only be used to boil 3 litres of water? This is ridiculous!

Indeed. Heh. :p

Granted of course, I've neglected the inefficiency of the human body, the heat loss from the body due to the cold, the sapping of mental strength, the time loss due to sleep, as well as the energy loss because of additional weight (i.e. equipment). So the above calculation isn't really anything actually. :p