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Google revives controversial cold-fusion experiments

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Re: Google revives controversial cold-fusion experiments

#161
post #154

Earlier quoted context omitted.

But even that is pretty vague, since a single Uranium atom fission event releases about 200 MeV of energy, whereas most of the Hydrogen/Deuterium/Tritium/Helium/etc. fusion pathways release around 10% of this per fusion event: D + T -> He fusion gives 17 MeV, 4 p -> He gives 27 MeV, D + D -> He is 12 MeV and so on. Now, the energy released per nucleon greater for fusion, but I'm not convinced that's a useful or intui…

How about energy per kilogram?

OK, so 235 kg of U_235 has the same number of fissile units (N atoms = 1000 x N_a) as 5 kg of D-T has of fusible units (2N atoms of combined weight 5 amu, or 1000 x N_a pairs) so (ignoring the N_a for now) one kg of U_235 gives 200 MeV / 235 = 0.85 MeV and the D-T fusion gives 17 MeV / 5 = 3.40 MeV

So, yeah, that's exactly four times the energy per kilogram. Now, why couldn't they just say THAT on the web page instead of the confusing and meaningless "this energy is 3-4 times more powerful than that energy" nonsense? But, thanks 'mikeash for clearing that up for me!

Re: Google revives controversial cold-fusion experiments

#162
What amazes me about cold fusion is that anyone, even the cranks, think it's plausible.

I mean, look at it from a conditional probability point of view. Initially, before any of the furor, the chance of it being real would have been very low. Then P&F have their fiasco. Their results were wrong. But somehow this was taken as meaning Cold Fusion was more likely than it had been previously. But how could that be? Their results, properly interpreted, were negative. Negative results can only reduce the probability something is correct, not increase it.

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