4 ms·
A few calculations about the possible explosion: - Assuming the inside of the thermos is at room temperature (and that there was enough dry ice initially), the
by maho 11y ago
A few calculations about the possible explosion:
- Assuming the inside of the thermos is at room temperature (and that there was enough dry ice initially), the pressure should be around 60bar. This is the vapor pressure of carbon dioxide at room temperature [1].
- At 60 bar and with a volume of, say, 1 liter, the energy available for the explosion is roughly 60bar x 1liter = 6kJ [2]. This is a TNT-equivalent [3] of about 1.5g, or about 10-100 firecrackers. Enough to cause injuries, but not enough for structural damage to a balcony [citation needed].
In my personal opinion, the most dangerous thing was handling the thermos. I believe letting the thermos sit on the balcony for a few days and closing doors and curtains (to prevent glas shards flying in) would have been a much safer alternative.
[1] http://en.wikipedia.org/wiki/Carbon_dioxide_data#Vapor_pressure_of_solid_and_liquid http://en.wikipedia.org/wiki/Carbon_dioxide_data#Vapor_press...
[2] https://www.google.com/search?q=60+bar+*+1+liter&ie=utf-8&oe=utf-8 https://www.google.com/search?q=60+bar+*+1+liter&ie=utf-8&oe...
[3] http://en.wikipedia.org/wiki/TNT_equivalent http://en.wikipedia.org/wiki/TNT_equivalent
- TheLoneWolfling 11y agoYour energy estimation makes no sense whatsoever. The figure you gave is for isobaric expansion, which is an entirely different beastie. Also, he mentions ~100bar, not ~60 bar. When I did a first approximation assuming adiabatic expansion, I got ~22KJ. See https://news.ycombinator.com/item?id=9449086 https://news.ycombinator.com/item?id=9449086
- maho 11y agoYou are absolutely right, I should have used the formula for adiabatic expansion. However, I maintain that the pressure inside the thermos should only be 60atm, since this is the vapor pressure of CO2 at room temperature [1], where the liquid and the gas phase are in equilibrium. This is like the butane in a lighter: Butane evaporates at room temperature, but there is an equilibrium between liquid phase and gaseous phase when the pressure is higher. Using 60bar and the adiabatic formula, I get 12.5kJ of energy. [1]: http://en.wikipedia.org/wiki/Carbon_dioxide#Physical_properties http://en.wikipedia.org/wiki/Carbon_dioxide#Physical_propert...
- TheLoneWolfling 11y agoOk, that works. I was just going from the article's figure of 100atm. I probably should have double-checked that figure.